Arid oasis irrigation area corn close planting yield increasing method and system based on drip irrigation under plastic film

Abstract

The invention belongs to the technical field of plant cultivation, and particularly relates to a corn close planting chemical control yield increasing method based on drip irrigation under mulch, four density levels and three planting specifications are set, influences of the density levels and the planting specifications on corn population source library characteristics, physiological growth, yield and quality are researched, and the optimal density and planting specification for improving the yield and quality are screened out. Three chemical control agents of ethephon, mepiquat chloride and chlormequat chloride are selected, three application gradients are set, the influence of the chemical control agents on the growth and yield of the corn is observed, and the appropriate type and dosage of the chemical control agents are determined. A split region design is adopted, a quantitative relation between water and nitrogen management and corn growth is researched, a water and nitrogen coupling effect is defined, a chemical regulation and control scheme for densification and lodging resistance under a close planting condition is provided, and the corn productivity is improved.

Description

Technical Field

[0001] The present invention belongs to, but is not limited to, the technical field of plant cultivation, and particularly relates to a method and system for increasing the yield of close - planted maize with chemical regulation in arid irrigation areas based on drip irrigation under plastic film. Background Art

[0002] The unique geographical environment in the northwest region provides rich light and heat resources for the growth of crops. In recent years, the high - yield records of maize and spring wheat in China have been continuously obtained in the high - yield creation fields in this region, indicating that there is great potential for large - scale yield increase in the northwest region. Analyzing the relationship between crop yield and its component characteristics such as grain weight and grain number, the results show that high yield mainly comes from the increase in the total number of grains. Many studies believe that increasing density and other methods are relatively feasible and reliable ways to obtain high yield. When the density of maize in the northwest region is increased by 25% on the existing basis and with supporting chemical regulation and lodging - resistance measures, the yield has the potential to increase by 1500 kg / hm 2 . This trend also affirms the role of compact maize in increasing yield through close planting. Focusing on the yield - increasing mechanism and population photosynthesis research of compact maize, it is clear that the yield increase of compact maize combines two factors: heterosis and population light energy utilization, which has promoted the large - scale popularization and application of compact maize varieties.

[0003] After a series of water - saving technologies such as drip irrigation under plastic film are widely applied in the northwest region, the water - saving effect is obvious. On the basis of stable production, the irrigation water volume of wheat and maize is reduced to less than 50% of the traditional mode, greatly improving the irrigation water utilization rate. The application of drip irrigation under plastic film on crops such as wheat and maize is found to enable the roots to better regulate the photosynthesis, carbon metabolism process and the nitrogen absorption and utilization ability of leaves by transporting various substances through bleeding sap, increasing the dry matter accumulation. Under the condition of reducing water supply, the yield is increased by 4.7% - 5.0% compared with that without drip irrigation under plastic film, and the water use efficiency is increased by 26.51%. Summary of the Invention

[0004] Aiming at the problems existing in the prior art, the present invention provides a method for increasing the yield of close - planted maize with chemical regulation in arid irrigation areas based on drip irrigation under plastic film.

[0005] The present invention is realized as follows. A method for increasing the yield of close - planted maize with chemical regulation in arid irrigation areas based on drip irrigation under plastic film includes:

[0006] S1: Under the conditions of drip irrigation under plastic film, water - nitrogen regulation, and chemical regulation, 4 density levels are set, and 3 different planting specifications are set to study the effects of different maize densities and planting specifications on the source - sink characteristics, physiology, growth, yield, and quality of the maize population, and to screen the density and planting specifications that can improve yield and quality;

[0007] S2: Select three different types of chemical control agents, namely ethephon, mepiquat chloride, and chlormequat chloride, and set three application gradients. Observe the changes in traits such as the physiological growth of maize and the characteristics of yield components, clarify the relationship between the type of chemical control agent and the application dosage and crop growth, and determine the application plan of chemical control agents for maize in the Hexi Corridor;

[0008] S3: Adopt a split-plot design, with the main treatment being three lower limits of irrigation water and the sub-treatment being four nitrogen application rates; Monitor the process of maize growth changes, clarify the quantitative relationship between indicators such as yield and water use efficiency and the amount of irrigation water and nitrogen application rate, and explore the appropriate water and nitrogen management plan under the condition of a planting density of 120,000 plants / hm 2 ².

[0009] Furthermore, the density levels are 90,000 plants / hm 2 , 105,000 plants / hm 2 , 120,000 plants / hm 2 , 135,000 plants / hm 2 ; The planting specifications are 1 plant per hole, an interval of 1 plant and 2 plants, and 2 plants per hole.

[0010] Furthermore, the three lower limits of irrigation water are I50, I65, and I80 respectively; The four nitrogen application rates are: 0, 200 kg / hm 2 (N200), 400 kg / hm 2 (N400), 600 kg / hm 2 (N600).

[0011] Another object of the present invention is to provide a maize close planting chemical control and yield increase system based on the maize close planting chemical control and yield increase method based on drip irrigation under plastic film. This system specifically includes:

[0012] Density regulation module: Under the conditions of drip irrigation under plastic film, high water and fertilizer, chemical regulation, and increasing the application of organic fertilizer, four density levels are set, and three different planting specifications are set; Study the effects of different maize densities and planting specifications on the characteristics of the maize population source-sink, maize physiology, growth, yield, and quality, and screen the density and planting specifications that can improve yield and quality;

[0013] Chemical control regulation module: Connected to the sowing module, select three different types of chemical control agents, namely ethephon, mepiquat chloride, and chlormequat chloride, and set three application gradients. Observe the changes in traits such as the physiological growth of maize and the characteristics of yield components, clarify the relationship between the type of chemical control agent and the application dosage and crop growth, and determine the application plan of chemical control agents for maize in the Hexi Corridor;

[0014] The water-nitrogen regulation module, connected to the chemical regulation module, adopts a split-plot design. The main treatment has 3 lower irrigation limits, and the sub-treatment has 4 nitrogen application rates; it monitors the growth change process of maize, clarifies the quantitative relationships between indicators such as yield and water use efficiency and irrigation amount and nitrogen application rate, and explores the appropriate water-nitrogen management plan under the condition of a planting density of 120,000 plants / hm 2 2.

[0015] Combined with the above technical solutions and the technical problems solved, the advantages and positive effects of the technical solutions to be protected by the present invention are as follows:

[0016] First, the present invention conducts technological innovation in view of the extremely scarce water resources in the inland river irrigation area of the Hexi Corridor oasis and the huge pressure to improve the productivity of the main crops.

[0017] There are long-term technical problems in maize production that inhibit the improvement of productivity, such as low population effects and mismatched water and fertilizer management. The present invention increases the population effect by increasing the planting density, adopts an exogenous growth regulator control plan to control problems such as lodging and empty stalks that are prone to occur after close planting, and implements an accurate water and fertilizer management mode to match the water and nutrient requirements of high-density populations. Through the comprehensive application of a number of key technologies, the synchronous improvement of the population effect, productivity and water use efficiency of maize under high-density planting is achieved. The precision cultivation technology of maize under drip irrigation under plastic film with close planting and water and fertilizer control in the Hexi irrigation area is integrated, the maize planting specifications in the Hexi region are clarified, the chemical regulation plan for increasing density and resisting lodging is determined, and the water-nitrogen coupling effect and its quantitative standard under close planting conditions are clarified, providing a technical solution for the improvement of maize productivity in the Hexi irrigation area.

[0018] At important growth stages of maize such as the large bell-mouth stage and silking stage, leaf area, plant height, and dry matter perform better at a density of 135,000 plants / hm 2 and a density of 120,000 plants / hm 2 However, since at a density of 135,000 plants / hm 2 the maize plants have a higher plant height and ear height, lower stem diameter and ear length, and more serious baldness length and lodging, the yield level at 135,000 plants / hm 2 is affected to a certain extent. It is preliminarily clarified that the best suitable density for high-yield and high-quality maize in the Hexi region is a density of 120,000 plants / hm 2 with 1 plant per hole and 1 hole every 2 plants planted alternately.

[0019] Applying chemical control agents can regulate morphological indexes such as maize plant height and ear height, and promote yield. Compared with the control of spraying clear water, the dwarfing effect of applying chemical control agents is obvious. The plant height decreases by 0.17% - 4.22%, the ear height coefficient is between 38.71% - 42.30%, the yield increases by 0.46% - 5.36%, and the water use efficiency increases by 0.43% - 5.32%. Applying the compound preparation of 2.5% paclobutrazol and 7.5% mepiquat chloride at 375 / hm 2 has an obvious dwarfing effect on maize plants, with the ear height coefficient being 40.54% - 41.92% and a relatively high yield. It is the optimal chemical control plan under the conditions of close planting of maize in the Hexi Corridor.

[0020] Through calculation, it can be known that the appropriate irrigation quota for maize in the Hexi Corridor is 5700.00m 3 / hm 2 , and the nitrogen application rate is 440kg / hm 2 . The maize is irrigated 11 times during the whole growth period, and the irrigation time and amount are determined according to the soil conditions. Immediately after sowing, irrigate 450m 3 / hm 2 to ensure the emergence rate and uniform emergence. Irrigate 450m 3 / hm 2 at the 6-leaf stage and 8-leaf stage respectively, irrigate 900m 3 / hm 2 at the big trumpet mouth stage, irrigate 2250m 3 / hm 2 after entering the filling stage, irrigate 900m 3 / hm 2 after entering the milk ripening stage, and can irrigate 300m 3 / hm 2 and stop irrigating after reaching the dough stage. The nitrogen fertilizer is applied in 8 times. The base fertilizer before sowing accounts for about 13%. After that, it is applied 2 times in combination with irrigation from the 6-leaf stage to the big trumpet mouth stage, about 6% each time. It is applied 3 - 4 times from silking to milk ripening stage, about 8% - 9% each time, and can be applied 2 more times until the dough stage, accounting for 6% - 8%.

[0021] Second, establish a thousand-acre demonstration area in Zhangye, Wuwei and other places in Gansu to carry out the demonstration of the high-efficiency cultivation technology model of drip irrigation under plastic film with close planting and chemical control. The yield of the demonstration area reaches 18518kg / hm 2 , with a 16.74% increase in yield compared with the conventional planting mode, a 30.94% increase in irrigation water utilization rate, and a 10.84% water saving. Calculated according to the demonstration and promotion of 1.2 million mu in the Hexi Corridor in the next 3 years, the cumulative increase in maize yield is 144.13 million kg, and the increased efficiency is 115 million yuan. At the same time, a cumulative water saving of 64 million cubic meters can be achieved, which is close to the annual ecological water consumption in this area, and can provide effective support for regional ecological construction.

[0022] The arid regions in the northwest have long faced the dilemmas of water shortage and low crop yields. At the same time, the northwest regions are rich in light and heat resources and have excellent soil conditions, which are the prerequisites for high crop yields. The method of increasing maize yield through close planting and chemical control under drip irrigation under plastic film realizes a 33% increase in population effect by adjusting the maize planting specifications, uses compound growth regulators to enhance the lodging resistance of plants, and optimizes the drip irrigation water and nitrogen supply plan. Combining the drip irrigation under plastic film close planting cultivation technology, chemical control and lodging resistance technology, and water and fertilizer precise management plan forms the high-efficiency cultivation technology mode of drip irrigation under plastic film close planting and chemical control for maize in the Hexi Corridor. The suitable planting density is 120,000 plants / hm 2 , with one or two plants planted at intervals, and mepiquat chloride is applied at 150 - 300 ml / hm at the 6 - 8 leaf stage 2 , and the irrigation quota is 5700 m 3 / hm 2 , and the nitrogen application rate is 440 kg / hm 2 . The drip irrigation under plastic film technology is a water-saving cultivation technology suitable for wide application in the arid regions of the northwest, which can solve the problem of lack of irrigation water. After adjusting the maize planting specifications, the regional cultivation density can reach 120,000 plants / hm 2 . At the same time, by adopting chemical control measures, the lodging risk caused by excessive density is curbed, providing a guarantee for enhancing the maize population effect. The technology of the present invention can completely replace the existing technology in terms of yield, water-saving effect, etc., and can realize the overall improvement of maize production capacity in the Hexi Corridor, which is a comprehensive mode that can fill the regional technology gap.

[0023] Water shortage in the arid regions of the northwest inland has always been a key factor restricting agricultural development. Through the screening and selection of drought-resistant, salt-tolerant and high-water-use-efficient crop varieties, according to the needs of the region and crops to resist water and salt stress, research the methods of regulating soil water and salt in the root zone under drip irrigation under plastic film, shallow buried drip irrigation and other modes, clarify the suitable cultivation modes, planting specifications and optimized water and fertilizer management measures on the basis of high yield and quality, develop target exogenous regulators that can effectively reduce the ineffective evapotranspiration of the population, and form an integrated mode of highly integrated multiple technologies in the whole process of regional crops, aiming to play a key role in improving water use efficiency, saving resources and ensuring regional food security.

[0024] In view of the unique climate and soil environment of the region, under the continuous upward pressure of the industry, the space for improving production capacity and quality by breaking through a single factor such as optimized varieties or water-saving and salt-resistant cultivation technologies is getting smaller and smaller. To continuously improve the production capacity of grain and cotton crops on a large scale and in the long term, it is necessary to support the whole-process optimized management on the basis of drought-resistant, salt-tolerant and high-water-use-efficient varieties, establish a comprehensive technology integrating multiple technologies, and promote the coordinated development of the entire ecosystem of soil - crop - environment, which is the key to the unified improvement of the production capacity, quality and water use efficiency of grain and cotton crops in the northwest inland irrigation areas.

[0025] The demonstration application of the technical solution of the present invention has increased the yield by more than 15% compared with the current situation, and solved the technical problem of increasing the yield under the water shortage condition in this region. Description of the Drawings

[0026] Figure 1 is the flow chart of the method for increasing the yield of close - planted and chemically - controlled maize based on drip irrigation under plastic film provided by the embodiments of the present invention;

[0027] Figure 2 is the influence of planting density on the leaf area index of maize (2023) provided by the embodiments of the present invention;

[0028] Figure 3 is the influence of planting density on the leaf area index of maize (2024) provided by the embodiments of the present invention, where: Figure a shows the leaf area index of maize under different cultivation modes and planting densities (M6, M7, M8, M9 are the maize sowing densities of 6000 plants / mu, 7000 plants / mu, 8000 plants / mu, and 9000 plants / mu respectively; X1, X1.5, X2 are sowing 1 plant per hole, sowing 1 plant per hole and then sowing 2 plants per hole at intervals, and sowing 2 plants per hole), and Figure b shows the leaf area index of maize under different planting densities;

[0029] Figure 4 is the influence of planting density on the plant height of maize (2023) provided by the embodiments of the present invention;

[0030] Figure 5 is the influence of planting density on the plant height of maize (2024) provided by the embodiments of the present invention, where: Figure a shows the plant height of maize under different cultivation modes and planting densities, Figure b shows the plant height of maize under different planting densities, and Figure c shows the plant height of maize under different planting specifications;

[0031] Figure 6 is the influence of planting density on the SPAD value of maize (2024), where Figure a shows the SPAD value of maize leaves under different cultivation modes and planting densities, Figure b shows the SPAD value of maize leaves under different planting densities, and Figure c shows the SPAD value of maize leaves under different planting specifications;

[0032] Figure 7 is the influence of planting density on the dry matter weight of maize (2023) provided by the embodiments of the present invention;

[0033] Figure 8 is the influence of planting density on the dry matter weight of maize (2024), where Figure a shows the dry matter weight of maize under different cultivation modes and planting densities, Figure b shows the dry matter weight of maize under different planting densities, and Figure c shows the dry matter weight of maize under different planting specifications;

[0034] Figure 9 is the influence of planting density on the yield of maize (2023), where Figure a shows the yield of maize under different cultivation modes and planting densities, and Figure b shows the coupling effect of the yield of maize under cultivation modes and planting densities;

[0035] Figure 10 Effect of chemical regulation on maize plant height provided by the embodiments of the present invention;

[0036] Figure 11 Effect of chemical regulation on morphological characteristics of maize plants provided by the embodiments of the present invention;

[0037] Figure 12 Effect of water-nitrogen regulation on the change of leaf area during the growth period of maize (2023, 2024) provided by the embodiments of the present invention;

[0038] Figure 13 Effect of water-nitrogen regulation on the change of above-ground biomass during the growth period of maize provided by the embodiments of the present invention;

[0039] Figure 14 Effect of water-nitrogen regulation on the change of plant height during the growth period of maize provided by the embodiments of the present invention. Detailed implementation manners

[0040] In order to make the objectives, technical solutions and advantages of the present invention clearer and more understandable, the present invention will be further described in detail below in conjunction with embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0041] As Figure 1 shown, the embodiments of the present invention provide a method for increasing the yield of maize by close planting and chemical control based on drip irrigation under plastic film. The method includes:

[0042] S1: Under the conditions of drip irrigation under plastic film, high water and fertilizer, chemical regulation, and increased application of organic fertilizer, 4 density levels are set, and 3 different planting specifications are set to study the effects of different maize densities and planting specifications on the source-sink characteristics, physiology, growth, yield and quality of maize populations, and to screen the densities and planting specifications that can improve yield and quality;

[0043] S2: Select 3 different types of chemical control agents, namely ethephon, mepiquat chloride and chlormequat chloride, and set 3 application gradients to observe the changes in traits such as the physiological growth and yield components of maize, clarify the relationship between the type of chemical control agent and the application dose and crop growth, and determine the application scheme of chemical control agents for maize in the Hexi Corridor;

[0044] S3: Adopt a split-plot design, with the main treatment being 3 lower limits of irrigation water and the sub-treatment being 4 nitrogen application rates; monitor the process of maize growth changes, clarify the quantitative relationship between indicators such as yield and water use efficiency and the irrigation water volume and nitrogen application rate, and explore the appropriate water-nitrogen management scheme under the condition of a planting density of 120,000 plants / hm 2 condition.

[0045] This method first sets multiple planting density levels (90,000 - 135,000 plants / hm2 ) and different planting specifications (1 plant per hole, 1 plant with a 2-plant interval, 2 plants per hole) to optimize the spatial configuration of individual and population of maize. Under the condition of high-density planting, the canopy structure of the population can make more full use of light energy and improve photosynthetic efficiency. At the same time, different planting specifications can optimize the individual competition relationship, reduce the light shading effect caused by over-dense planting, and increase the yield per unit area.

[0046] The drip irrigation under film technology can achieve precise irrigation and integrated management of water and fertilizer, reduce water evaporation, improve the soil water retention capacity, and ensure that maize can still obtain sufficient water supply under high-density planting conditions. At the same time, the setting of different lower irrigation limits (50%, 65%, 80% of field water holding capacity) enables the systematic evaluation of the growth performance of crops under different water management conditions, and finally determines the best irrigation strategy to adapt to different soil and climate conditions and improve water use efficiency.

[0047] Under high-density planting conditions, the competition among maize individuals intensifies, which easily leads to over-tall plants and slender stems, thus increasing the risk of lodging. This method uses chemical regulators such as ethephon, mepiquat chloride, and chlormequat chloride, and sets low, medium, and high dose gradients. By regulating the growth hormone level of plants, it inhibits internode elongation, promotes stem thickening, and improves lodging resistance. At the same time, the chemical regulator can also promote root development, improve nutrient absorption capacity, and make the plants more adaptable to the high-density environment.

[0048] This method sets nitrogen application rate gradients of 0, 200 kg / hm 2 , 400 kg / hm 2 and 600 kg / hm 2 to optimize nitrogen supply in combination with high-density planting and chemical control strategies. Under high-density planting conditions, the nitrogen demand of plants increases. Reasonable nitrogen application management can promote photosynthesis, increase dry matter accumulation, and at the same time avoid the risks of overgrowth and lodging caused by excessive nitrogen application. Through gradient experiments, the best nitrogen application strategies under different densities and water management are screened out to improve nitrogen fertilizer utilization rate and reduce environmental pollution.

[0049] During the whole growth period, sensors and remote sensing technologies are used to monitor key parameters such as plant growth, water status, leaf nitrogen content, and photosynthetic efficiency. Through data analysis, the effects of different combinations of planting density, planting specification, chemical regulator application gradient, lower irrigation limit, and nitrogen application rate on maize growth are evaluated. Based on the monitoring data, dynamic adjustment is carried out to achieve precise irrigation, precise fertilization, and precise chemical control, ensuring that the crop growth is in the best state and improving yield and quality.

[0050] Through the comprehensive optimization of multiple factors such as close planting, drip irrigation, chemical control, nitrogen application, and water management, this method constructs an efficient, high-yield, and resource-saving spring maize planting mode. Compared with the traditional planting method, this method can increase the yield per unit area while reducing the waste of water and fertilizer, reducing environmental pollution, and realizing the sustainable development of agriculture. Finally, this method can provide scientific management strategies for maize planting in different regions, improve planting efficiency, and contribute to the refined production of modern agriculture.

[0051] The density levels are 90,000 plants / hm 2 , 105,000 plants / hm 2 , 120,000 plants / hm 2 , 135,000 plants / hm 2 ; The planting specifications are 1 plant per hole, 1 plant with a 2-plant interval, and 2 plants per hole.

[0052] The three lower limits of irrigation are I50, I65, and I80 respectively; the four nitrogen application rates are: 0, 200 kg / hm 2 (N200), 400 kg / hm 2 (N400), 600 kg / hm 2 (N600).

[0053] The embodiment of the present invention provides a maize close-planting chemical control and yield-increasing system based on the maize close-planting chemical control and yield-increasing method based on drip irrigation under plastic film. This system specifically includes:

[0054] Density regulation module. Under the conditions of drip irrigation under plastic film, high water and fertilizer, chemical regulation, and increasing organic fertilizer application, 4 density levels are set, and 3 different planting specifications are set; study the effects of different maize densities and planting specifications on the population source-sink characteristics, maize physiology, growth, yield, and quality of maize, and screen the density and planting specifications that can improve yield and quality;

[0055] Chemical control regulation module, connected to the sowing module, selects 3 different types of chemical control agents, namely ethephon, mepiquat chloride, and chlormequat chloride, and sets 3 application gradients, observes the changes in traits such as maize physiological growth and yield component characteristics, clarifies the relationship between the type of chemical control agent and the application dose and crop growth, and determines the application plan of chemical control agents for maize in the Hexi Corridor;

[0056] Water and nitrogen regulation module, connected to the chemical control regulation module, adopts a split-plot design, with the main treatment being 3 lower limits of irrigation and the sub-treatment being 4 nitrogen application rates; monitors the maize growth change process, clarifies the quantitative relationship between indicators such as yield and water use efficiency and the irrigation amount and nitrogen application rate, and explores the appropriate water and nitrogen management plan under the condition of a planting density of 120,000 plants / hm 2 .

[0057] Under the conditions of drip irrigation under plastic film and high water and fertilizer, an optimization experiment on the density level and planting specifications of spring maize was carried out. Four density levels were specifically set, namely 90,000 plants / hm 2 , 105,000 plants / hm 2 , 120,000 plants / hm 2 and 135,000 plants / hm 2 . At the same time, three planting specifications were set, namely 1 plant per hole, 1 plant with a 2-plant interval, and 2 plants per hole. By studying the effects of different densities and planting specifications on the source-sink characteristics, physiological growth, yield and quality of maize, the optimal cultivation density and planting specifications were screened out, laying a foundation for improving yield and quality.

[0058] Three chemical regulators, ethephon, mepiquat chloride and chlormequat chloride, were selected for the experiment, and three application gradients were set respectively to explore the effects of chemical regulators on the physiological growth and yield components of maize. The change rules of chemical regulators on plant height, ear length, grain number per ear and grain quality of maize were observed, and the effects of chemical regulator types and their application doses on crops were clarified. Through comprehensive analysis, an application plan of chemical regulators suitable for spring maize in the Hexi Corridor area was formulated to optimize the chemical regulation technology.

[0059] Under the condition of a density of 120,000 plants / hm 2 , a split-plot design was used for the experiment. The main treatments were 3 lower irrigation limits, namely I50 (50% of the field water holding capacity), I65 (65% of the field water holding capacity) and I80 (80% of the field water holding capacity); the sub-treatments were 4 nitrogen application rates, namely 0, 200 kg / hm 2 , 400 kg / hm 2 and 600 kg / hm 2 . The growth dynamics of maize from the seedling stage to the maturity stage were monitored, the effects of irrigation amount and nitrogen application rate on yield and water use efficiency were analyzed, and the optimal water-nitrogen management model was explored.

[0060] The experiment adopted a randomized block split-plot design, and each treatment was repeated three times to ensure the reliability of the results. Data such as plant height, biomass, leaf area index, and grain number per ear of the crop were recorded during the irrigation and fertilization management processes, and the experimental data were analyzed using key indicators such as yield, water use efficiency, and nitrogen use efficiency to reveal the quantitative effects of different irrigation and nitrogen application combinations on maize growth and yield.

[0061] Through multi-factor experiments such as density, chemical regulator type and application gradient, and water-nitrogen management scheme, the mechanism of their effects on maize growth and yield components was comprehensively analyzed. Combining the experimental data, the grain number per ear, ear weight, grain yield and quality characteristics of maize were evaluated, and the key technical parameters for high-yield and high-quality spring maize cultivation were clarified, providing a scientific basis for agricultural production.

[0062] Based on the experimental results, a technical plan for increasing the yield of spring maize through close planting and chemical control under drip irrigation under plastic film was formulated. This plan combines the optimal density level (120,000 plants / hm 2 ), planting specifications (1 plant per hole), chemical control agent application plan (ethephon + appropriate amount of chlormequat chloride), and water and nitrogen management plan (lower irrigation limit I65, nitrogen application rate 400 kg / hm 2 ), achieving a significant increase in maize yield and a substantial improvement in water and fertilizer use efficiency, providing highly feasible and practical technical support for spring maize planting in the Hexi Corridor region.

[0063] Evidence related to the technical effects obtained in the embodiments of the present invention.

[0064] 1. Influence of density regulation on leaf area

[0065] Leaf area index at the large bell-mouth stage in 2023, density 135,000 plants / hm 2 Treatment with 1 plant and 2 plants in intervals, 120,000 plants / hm 2 Treatment with 2 plants per hole was higher than 90,000 plants / hm 2 Treatment with 2 plants per hole, 90,000 plants / hm 2 Treatment with 2 plants per hole, 80,000 plants / hm 2 Treatment with 2 plants per hole, the leaf area indices reached 8.24 and 8.20 respectively. There was no significant difference in multiple comparisons among the main treatment densities of the leaf area index, and no significant difference in multiple comparisons among the sub-treatment planting specifications.

[0066] As Figure 3 shown, leaf area index at the silking stage in 2023, density 135,000 plants / hm 2 Treatment with 1 plant per hole, 135,000 plants / hm 2 Treatment with 1.5 plants per plant, 135,000 plants / hm 2 Treatment with 2 plants per hole was higher than 90,000 plants / hm 2 Treatment with 1 plant per hole, 90,000 plants / hm 2 Treatment with 1.5 plants per hole, 90,000 plants / hm 2 Treatment with 2 plants per hole, 105,000 plants / hm 2 Treatment with 2 plants per hole, reached 16.59, 16.53, and 16.21 respectively. In multiple comparisons among the main treatments of the leaf area index, 135,000 plants / hm 2 > 120,000 plants / hm 2 , 105,000 plants / hm 2 > 90,000 plants / hm 2 , and showed significant differences. There was no significant difference in multiple comparisons among the sub-treatment planting specifications.

[0067] As Figure 4 shown, leaf area index at the large bell-mouth stage in 2024, density 135,000 plants / hm2 At this time, the leaf area index was significantly higher than that of other density treatments. The higher the sowing density, the higher the leaf area index. There was no significant difference among the planting specifications of 1 plant per hole, 1.5 plants per hole, and 2 plants per hole.

[0068] 2. Effects of density regulation on SPAD value

[0069] As Figure 5 shown, in the large flare stage in 2024, the SPAD value decreased with the increase of density, and there were significant differences among them. The SPAD value of 1.5 plants per hole was significantly higher than that of 1 plant per hole and 2 plants per hole treatments.

[0070] 3. Effects of density regulation on dry matter

[0071] As Figure 6 shown, for the dry matter of corn in the large flare stage, the treatments of 1.5 plants per hole at a density of 105,000 plants / hm², 1.5 plants per hole at a density of 135,000 plants / hm², and 2 plants per hole at a density of 135,000 plants / hm² were higher than other treatments, which were 511.60, 529.21, and 520.28 kg / mu respectively. Through multiple comparisons among the main treatment densities, the main treatment densities of 135,000 plants / hm² and 105,000 plants / hm² were significantly higher than other main treatments. There was no significant difference in multiple comparisons among the sub-treatment planting specifications. 2 1.5 plants per hole treatment, 135,000 plants / hm² 2 1.5 plants per hole treatment, 135,000 plants / hm² 2 2 plants per hole treatment were higher than other treatments, and were 511.60, 529.21, and 520.28 kg / mu respectively. Through multiple comparisons among the main treatment densities, the main treatment density of 135,000 plants / hm² 2 , 105,000 plants / hm² 2 were significantly higher than other main treatments. There was no significant difference in multiple comparisons among the sub-treatment planting specifications.

[0072] For the dry matter of corn at the silking stage, the treatments of 1 plant per hole at a density of 135,000 plants / hm², 1.5 plants per hole at a density of 120,000 plants / hm², and 2 plants per hole at a density of 135,000 plants / hm² were higher than other treatments, which were 751.03, 738.30, and 734.65 kg / mu respectively. Through multiple comparisons among the main treatment densities, 135,000 plants / hm² 2 1 plant per hole treatment, 120,000 plants / hm² 2 1.5 plants per hole treatment, 135,000 plants / hm² 2 2 plants per hole treatment were higher than other treatments, and were 751.03, 738.30, and 734.65 kg / mu respectively. Through multiple comparisons among the main treatment densities, 135,000 plants / hm² 2 was significantly higher than 105,000 plants / hm² 2 , 90,000 plants / hm² 2 . There was no significant difference in multiple comparisons among the sub-treatment planting specifications.

[0073] As Figure 7 shown, for the dry matter amount in the large flare stage in 2024, with the increase of density, there was a tendency to increase, but there was no significant difference among them. There was no significant difference in multiple comparisons among the treatments of 1.5 plants per hole, 1 plant per hole, and 2 plants per hole.

[0074] 4. Effects of density regulation on plant traits

[0075] The plant height at the corn harvest stage was 120,000 plants / hm² 2Treatment with 1.5 plants per hole, 135,000 plants / hm 2 Treatment with 2 plants per hole, 120,000 plants / hm 2 Treatment with 2 plants per hole, 135,000 plants / hm 2 The treatment with 1.5 plants per hole was higher than other treatments, reaching up to 319.6 cm. The ear height was 120,000 plants / hm 2 Treatment with 2 plants per hole, 120,000 plants / hm 2 Treatment with 1.5 plants per hole, 135,000 plants / hm 2 The treatment with 1 plant per hole was higher than other treatments, reaching up to 133.1 cm.

[0076] Table 4-1-1 Effects of planting density on maize plant traits at harvest stage (2023)

[0077]

[0078] The stem diameter generally decreased with the increase in density. Higher plant height and ear height, and smaller stem diameter will lead to the occurrence of maize lodging, which is consistent with the lodging rate data. The highest lodging rate occurred at a density of 135,000 plants / hm 2 When it occurs, it will have a certain impact on the yield. The longer the maize ear length and the larger the bald length, the shorter the ear length and the larger the bald length at higher densities. The internode lengths of the 1st to 3rd nodes of maize were generally smaller at a density of 120,000 plants / hm 2 which is beneficial to reducing the occurrence of lodging.

[0079] 5. Effects of density regulation on maize yield

[0080] As Figure 8 shown, the density level of 120,000 plants / hm 2 had a 19.8% higher yield than the treatment of 90,000 plants / hm 2 (local cultivation density), and the yield could reach 17,314.43 kg / hm 2 . The yield difference among planting specifications was significantly higher in the treatment with 1.5 plants per hole than in the treatments with 1 plant per hole and 2 plants per hole.

[0081] 6. Effects of chemical regulation on maize plant height

[0082] As Figure 9 shown, compared with the control of spraying clear water, the plants were generally dwarfed after spraying the chemical regulator. By the filling stage, the plant height no longer increased significantly, and the plant height of the treatment with the regulator decreased by 0.17% - 4.22% compared with the control.

[0083] Applying different doses of chemical regulators also has an impact on plant height. Except for ethylene, the greater the application dose, the more obvious the plant height dwarfing. In particular, the treatment with 1.5 times the dose is significantly lower than the treatments with 0.5 times and 1 times the dose. Among them, the plant height of the treatment with 1.5 times the dose of mepiquat chloride decreased by 5.18% and 5.05% respectively compared with the treatments with 0.5 times and 1 times the dose, and the treatment with 1.5 times the dose of chlormequat chloride decreased by 5.50% and 2.20%.

[0084] 7. Effects of Chemical Control Regulation on the Ear Position Coefficient of Maize

[0085] The height of the ear leaf is the main index to measure the effect of chemical control regulation. In this experiment, the average ear position coefficients of applying ethylene, mepiquat chloride, chlormequat chloride and the control were 41.09%, 41.01%, 40.30% and 42.96% respectively. The ear position coefficients of the treatments with chemical control agents were generally between 38.71% and 42.30%, lower than the control level. According to the understanding of the ear position coefficient, under the optimal density conditions, the ear position coefficient and ear position height at high-yield levels are significantly lower than those at medium-yield and low-yield levels.

[0086] Table 4-2-1 Effects of Chemical Regulation on the Morphological Indexes of Maize

[0087]

[0088] As can be seen from Table 4-2-1, the angles above the ear, at the ear position and below the ear at high-yield levels are also smaller than those at medium- and low-yield levels. In this study, the average values of the angles above the ear of the three regulator treatments were 34.67°, 34.61° and 35.23°, the angles at the ear position were 29.48°, 27.77° and 31.58° respectively, and the angles below the ear were 34.51°, 32.81° and 32.86° respectively. Overall, they are also smaller than the control levels of 35.33°, 30.44° and 35.00°.

[0089] 8. Effects of Chemical Regulation on Maize Yield

[0090] Adopting chemical control measures generally improved the maize yield, with the improvement range between 0.46% and 5.36%. Overall, applying mepiquat chloride increased the yield by 5.36%, and applying chlormequat chloride increased the yield by 3.80%. Among them, the maize yields of the treatments with 0.5 times and 1 times the dose of mepiquat chloride reached 16988 kg / hm 2 and 16427 kg / hm 2 .

[0091] Chemical control measures also improved the water use efficiency and irrigation water use efficiency. Except that the treatment with 1.5 times the dose of ethylene remained the same, the improvement ranges of the other treatments reached 0.25% - 9.11% and 0.32% - 9.27% respectively. The water use efficiency and irrigation water use efficiency of the treatments with 0.5 times and 1 times the dose of mepiquat chloride reached 4.43 kg / m 3, 4.29 kg / m 3 and 3.42 kg / m 3 , 3.31 kg / m 3 , much higher than other treatments, indicating that applying mepiquat chloride at 150 - 300 ml / hm 2 can effectively promote the improvement of maize water use efficiency.

[0092] Table 4 - 2 - 2 Effects of Chemical Regulation on Maize Yield

[0093]

[0094] 9. Effects of Water - Nitrogen Regulation on Maize Growth

[0095] (1) Effects of Water - Nitrogen Regulation on Maize Leaf Area Change

[0096] As Figure 10 shown, during the whole growth period of maize, the leaf area shows a trend of first rapid growth and then slow growth; after entering the mature stage, the leaves begin to senesce and fall off, and the change range of leaf area in each treatment is relatively small. Nitrogen is an important factor affecting leaf growth. After applying nitrogen, the increase in leaf area is obvious. The higher the nitrogen application rate, the greater the increase in leaf area, especially when the water supply is relatively abundant, the increase is obvious. Under the I65 treatment, when the nitrogen application rate increases from 0 to 200 kg / hm 2 , the leaf area increases by 10.11%. When it increases from 200 kg / hm 2 to 400 kg / hm 2 , the leaf area increases by 8.51%. When the nitrogen application rate increases from 400 kg / hm 2 to 600 kg / hm 2 , the overall leaf area only increases by 0.36%, indicating that after the nitrogen application rate reaches a certain level, the plant's absorption of nitrogen approaches saturation.

[0097] Water supply is also a guarantee condition for the increase in leaf area. Under the condition of no nitrogen application, increasing the irrigation amount will also increase the leaf area. The leaf area of the I65 treatment increases by 10.55%, while that of the I80 treatment increases by 15.38%. At the N200 level, the I80 and I65 treatments increase by 14.72% and 16.12% respectively compared with the I50 treatment. At the N400 level, the I80 and I65 treatments increase by 8.45% and 11.24% respectively compared with the I50 treatment. At the N600 level, the I80 and I65 treatments increase by 8.22% and 10.62% respectively compared with the I50 treatment. After the water supply increases step by step, the increase in leaf area gradually decreases with the increase in nitrogen application rate. It shows that water supply has a certain promoting effect on the increase in maize leaf area, but after exceeding a certain amount, the response of leaf area increase to water decreases.

[0098] (2) Influence of water and nitrogen regulation on the change of maize biomass

[0099] As Figure 11 shown, maize, as a nitrogen indicator crop, is significantly affected by nitrogen fertilizer in its growth and development. It can be seen from Table 4-3-2 that the maize biomass under the three irrigation treatments increases with the increase of nitrogen application rate at each growth stage, and the increase of maize biomass during the growth period shows a trend of fast-slow-fast. Under different irrigation treatments, the biomass of maize at the milk ripening stage without nitrogen application is significantly lower than that with nitrogen application. Under the I80 treatment, the biomass of maize at the milk ripening stage under the N200, N400, and N600 treatments is 1512.9 kg / hm 2 , 3975.9 kg / hm 2 and 5788 kg / hm 2 higher than that without nitrogen application respectively, and the biomass increases by 6.76%, 17.76%, and 21.95% respectively. Similar to the leaf area, in the early growth stage of maize, the biomass of maize under the I65 and I80 treatments is higher than that under the I50 treatment. At the jointing stage, the dry weight of maize biomass under the I65 and I80 treatments is 301.2 kg / hm 2 and 720.9 kg / hm 2 higher respectively. With the increase of rainfall in the middle and late growth stages, the maize biomass shows a negative growth with the increase of the lower limit of irrigation. Under certain irrigation conditions, increasing the nitrogen application rate is beneficial to the growth and development of maize and increases the maize biomass, but too much soil moisture content may have the opposite effect and inhibit the growth and development of maize.

[0100] (3) Influence of water and nitrogen regulation on the change of maize plant height

[0101] It can be seen from Table 4-3-3 that in the first half of the maize growth period, the plant height of maize increases rapidly, and by the silking stage of maize, the plant height of maize no longer increases. Nitrogen fertilizer can promote cell division and elongation, making maize grow in the vertical direction. Increasing the nitrogen application rate can significantly increase the plant height of maize. At the silking stage of maize under the I65 treatment, when the nitrogen application rate increases from 0 to 200 kg / hm 2 , the average plant height increases by 6.5 cm. When the nitrogen application rate increases from 200 kg / hm 2 to 400 kg / hm 2 , the average plant height increases by 17.1 cm. When the nitrogen application rate increases from 400 kg / hm 2 to 600 kg / hm 2 , the average plant height only increases by 0.9 cm. Under the I50 and I80 treatments, when the nitrogen application rate increases from 400 kg / hm 2 to 600 kg / hm 2 , the average plant height decreases by 15.8 cm and 6.3 cm respectively. As Figure 12 shown.

[0102] 10. Effects of Water and Nitrogen Regulation on Maize Yield

[0103] (1) Effects of Water and Nitrogen Regulation on Maize Harvest Indexes

[0104] As can be seen from Table 4-3-1, the ear length, ear diameter, number of rows per ear, and number of grains per row of maize all showed an increasing trend with the increase of nitrogen application rate under the three irrigation treatments. When the nitrogen application rate increased from 400 kg / hm 2 to 600 kg / hm 2 , the ear length and number of grains per row of maize decreased. The highest yield was obtained under the I80N600 treatment, reaching 19392 kg / hm 2 , which was significantly higher than that of the I80N0 and I80N200 treatments by 6051 kg / hm 2 and 4191 kg / hm 2 . The yield increased by 46.34% and 27.73% compared with the two treatments respectively. The overall yield was not significantly correlated with irrigation. The yields at the I50 and I65 levels increased by 212 kg / hm 2 and 633 kg / hm 2 respectively compared with I80.

[0105] (2) Effects of Water and Nitrogen Regulation on Maize Yield and Water Use Efficiency

[0106] As can be seen from Table 4-3-2, the maize yield increased with the increase of irrigation and nitrogen application rate, and only decreased when the nitrogen application rate increased from 400 kg / hm 2 to 600 kg / hm 2 under the I65 treatment. The highest yield was obtained under the I65N400 treatment, reaching 19430 kg / hm 2 , and there was no significant difference from I65N200, I80N600, and I80N200; overall, there was a positive correlation between yield and irrigation. The yields at the I80 and I65 levels increased by 19.72% and 23.49% respectively compared with I50, and the yield decreased slightly when the irrigation amount was the highest. Among the treatments with higher yields, the treatment with the highest water use efficiency was I65N400, indicating that under this irrigation and nitrogen application condition, high yield can be achieved while the effective utilization of water reaches the optimal level.

[0107] Table 4-3-2 Effects of Water and Nitrogen Regulation on Yield and Water Use Efficiency of Spring Maize

[0108]

[0109] Example 1: Optimization Experiment of Chemical Control Agents under High-Density Conditions

[0110] 1) Experimental Conditions

[0111] Planting density: 120,000 plants / hm 2

[0112] Planting specification: 1 plant per hole

[0113] Lower limit of irrigation: I65 (65% of field water holding capacity)

[0114] Nitrogen application rate: 400 kg / hm 2 (N400)

[0115] Chemical control agents: Three chemical control agents, ethephon, mepiquat chloride and chlormequat chloride, were selected and low-dose, medium-dose and high-dose application gradients were set respectively.

[0116] 2) Experimental procedures

[0117] Density and planting specification: The planting density was set at 120,000 plants / hm 2 , and the planting specification of 1 plant per hole was adopted for standard sowing.

[0118] Irrigation and nitrogen application: Based on 65% of the field water holding capacity as the lower limit of irrigation, 400 kg / hm 2 of nitrogen fertilizer was applied and evenly applied through the drip irrigation system.

[0119] Application of chemical control agents: Different gradients of ethephon, mepiquat chloride and chlormequat chloride were sprayed respectively during the critical growth stages of maize (jointing stage and heading stage), and parameters such as plant height, ear height, leaf area index, and number of kernels per ear were recorded.

[0120] 3) Experimental results

[0121] Data showed that the combination of high density and medium-dose ethephon treatment could significantly inhibit the excessive growth of maize, increase the number of kernels per ear and ear weight. The low-dose mepiquat chloride treatment improved the lodging resistance of maize plants. Through comprehensive analysis, the medium dose of ethephon was determined as the optimal chemical control plan.

[0122] Example 2: Water and nitrogen optimization experiment under low irrigation conditions

[0123] 1) Experimental conditions

[0124] Planting density: 105,000 plants / hm 2

[0125] Planting specification: 1 plant with a 2-plant interval

[0126] Lower limit of irrigation: I50 (50% of field water holding capacity)

[0127] Nitrogen application rate: 200 kg / hm 2 (N200)

[0128] 2) Experimental procedures

[0129] Density and planting specification: The planting density was set at 105,000 plants / hm 2, Adopt the planting specification of planting one plant every two plants to ensure ventilation and light transmission.

[0130] Irrigation and nitrogen application: Set the lower limit of irrigation to 50% of the field water holding capacity, and apply 200 kg / hm 2 of nitrogen fertilizer, and evenly distribute the drip irrigation water volume.

[0131] Growth process monitoring: Regularly record growth parameters such as plant height, biomass, number of leaves, chlorophyll content, dry matter accumulation, etc., and measure the final ear weight and grain yield.

[0132] 3) Experimental results

[0133] Data analysis shows that the combination of low irrigation condition (I50) and low nitrogen application rate (N200) can significantly improve water use efficiency (WUE). Under the planting specification of planting one plant every two plants, the ventilation and photosynthesis efficiency of corn plants are significantly improved, the final yield reaches a satisfactory level, and at the same time, irrigation water and nitrogen fertilizer input are saved.

[0134] These two examples respectively verify the optimization effects on corn growth and yield under different planting densities, application of chemical control agents, and water and nitrogen management conditions, providing specific support for the further popularization of high-efficiency corn planting techniques.

[0135] The system provided by the present invention sets different planting density levels of 90,000 - 135,000 plants / hm 2 in the planting area to adapt to different ecological conditions and target yield requirements. The increase in planting density increases the number of plants per unit area and improves the utilization rate of light energy and space. In a high-density planting environment, the growth competition among plants intensifies. Therefore, this system combines other regulation means to ensure the coordinated growth of crop individuals and populations.

[0136] The drip irrigation system of this system consists of underground drip irrigation pipes, pressure regulating devices, and water source connection devices, which can directly supply water to the crop roots below the soil surface.

[0137] Underground drip irrigation pipes can reduce water evaporation and improve water use efficiency;

[0138] Pressure regulating devices (flow control valves and variable pressure regulators) ensure uniform water flow and prevent uneven irrigation caused by uneven water pressure;

[0139] The water source connection device connects to an external water source and can adjust the irrigation cycle and irrigation water volume according to needs to adapt to the water demand in different growth stages.

[0140] The fertilization device is linked with the drip irrigation system and can achieve different nitrogen application rates (0, 200 kg / hm 2 , 400 kg / hm 2 and 600 kg / hm2 ) supply enables more precise fertilization.

[0141] The fertilization channels are proportioned according to the preset nitrogen supply amount to achieve precise fertilization at different growth stages;

[0142] The fertilization device is combined with the drip irrigation pipeline and adopts the integrated water and fertilizer technology, enabling the fertilizer to infiltrate into the soil with water, improving the nutrient absorption efficiency, and reducing nitrogen loss and environmental pollution;

[0143] The nitrogen application schemes at different density levels can be dynamically adjusted to match the nutrient requirements of the crops and ensure balanced population growth.

[0144] The chemical regulator application device of this system includes a storage unit and an application spraying unit, which evenly applies the regulator through multiple spraying nozzles and matches the spraying spacing according to the planting density.

[0145] The regulator can be used to adjust the plant height, promote root growth, and improve the lodging resistance, and is especially suitable for crop growth regulation in a close planting environment;

[0146] By adjusting the application amount, precise intervention can be carried out for different growth stages to avoid overgrowth or nutrient competition imbalance under close planting conditions;

[0147] The spraying device can be adapted to the drip irrigation system and is applied synchronously in combination with the water and fertilizer supply to improve the absorption rate and action efficiency of the chemical control agent.

[0148] The monitoring system includes a soil moisture sensor, a crop growth monitoring device, and a data processing unit, which are used for precise monitoring and dynamic adjustment of the planting strategy.

[0149] The soil moisture sensor is set near the underground drip irrigation pipeline to monitor the soil moisture condition in real time and transmit information to the data processing unit to determine whether irrigation is required;

[0150] The crop growth monitoring device collects growth parameters such as plant height, leaf area index, and biomass through means such as photography, laser ranging, or near-infrared sensing, providing data support for planting management;

[0151] The data processing unit analyzes the monitoring data and can be linked with the irrigation, fertilization, and chemical control systems to achieve intelligent planting management and improve crop yield and resource utilization efficiency.

[0152] This system integrates the drip irrigation, fertilization, chemical control, and monitoring systems under the same management system and optimizes the management strategy through data analysis.

[0153] The monitoring data is used to dynamically adjust the irrigation and fertilization schemes to ensure that the crops are in the best growth state;

[0154] Synchronously adjust nitrogen application and water management to avoid waste or environmental pollution caused by excessive fertilization;

[0155] Through high-density planting combined with precise regulation, increase the yield per unit area and achieve efficient and sustainable agricultural production.

[0156] In summary, this system can precisely manage water and fertilizer supply, optimize the dense planting growth of crops, improve resource utilization rate, and combine intelligent monitoring technology for dynamic regulation to achieve a high-yield, efficient, and sustainable corn dense planting mode.

[0157] The above are only specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any modification, equivalent replacement, and improvement made within the spirit and principle of the present invention by those skilled in the art within the technical scope disclosed by the present invention shall be covered by the protection scope of the present invention.

Claims

1. A corn dense planting method based on drip irrigation under film, including planting density setting, drip irrigation management, fertilization management, chemical regulator application and growth monitoring, characterized in that: Set multiple planting density levels; Water supply is provided through sub-membrane drip irrigation system; Apply fertilizers according to the pre-set fertilizer plan; Apply chemical regulators according to a preset application schedule; Monitor corn growth parameters and adjust planting management measures based on monitoring data.

2. The method for densely planting corn based on drip irrigation under film according to claim 1, characterized in that: The multiple planting density levels include 90,000 plants / hm2 2 , 105,000 plants / hm 2 , 120,000 plants / hm 2 and 135,000 plants / hm 2 .

3. The method for densely planting corn based on drip irrigation under film according to claim 1, characterized in that: The drip irrigation management includes setting different irrigation lower limits, which include 50%, 65% and 80% of field capacity.

4. The method for densely planting corn based on drip irrigation under film according to claim 1, characterized in that: The fertilization management includes setting different nitrogen application rates, including 0, 200 kg / hm 2 , 400kg / hm 2 and 600kg / hm 2 .

5. A corn dense planting system based on sub-film drip irrigation, comprising a planting area, a drip irrigation system, a fertilization device, a chemical regulator application device and a monitoring system, characterized in that: A plurality of planting density levels are arranged within the planting area; The drip irrigation system includes an underground drip irrigation pipeline, a pressure regulating device and a water source connecting device; The fertilization device is connected to the drip irrigation system and includes a plurality of fertilization channels; The chemical regulating agent application device comprises a chemical regulating agent storage unit and an application spraying unit; The monitoring system comprises a soil moisture sensor, a crop growth monitoring device and a data processing unit, and is connected with the drip irrigation system, the fertilization device and the chemical regulator application device.

6. The corn dense planting system based on sub-film drip irrigation according to claim 5 is characterized in that: The multiple planting density levels include 90,000 plants / hm2 2 , 105,000 plants / hm 2 , 120,000 plants / hm 2 and 135,000 plants / hm 2 .

7. The corn dense planting system based on sub-film drip irrigation according to claim 5 is characterized in that: The pressure regulating device of the drip irrigation system comprises a flow control valve and a variable pressure regulator.

8. The corn dense planting system based on sub-film drip irrigation according to claim 5, characterized in that: The application spraying unit of the chemical regulator application device includes a plurality of spray nozzles, and the spacing between the spray nozzles matches the planting density.

9. The corn dense planting system based on sub-film drip irrigation according to claim 5, characterized in that: The soil moisture sensor of the monitoring system is arranged near the underground drip irrigation pipe to monitor the soil moisture content.

10. The corn dense planting system based on sub-film drip irrigation according to claim 5, characterized in that: The multiple fertilization channels of the fertilization device correspond to different nitrogen application rates, including 0, 200 kg / hm 2 , 400kg / hm 2 and 600kg / hm 2 .

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