A shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland

Abstract

The invention discloses a shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland, and relates to the field of agricultural irrigation. The cultivation method of the present application aims at the problems of easy compaction of salinized farmland soil, low soil fertility, and low crop biomass in the Hetao irrigation area, and combines two irrigation technologies, shallow buried drip irrigation and aerated drip irrigation, to achieve high yield and high quality of silage corn in saline-alkali land. Shallow buried drip irrigation promotes water exchange between the surface layer and the middle and deep layers of the soil, ensuring water supply during the growth period, and aerated drip irrigation achieves effective oxygenation of irrigation water, improves soil alkaline phosphatase, urease, and catalase activities to promote soil urea decomposition, oxidation-reduction, and aeration improvement, which can significantly improve the biomass and quality of silage corn, improve farmers' planting intentions, enhance environmental friendliness, and greatly improve the mechanization level of silage corn production, easy operation, and reduce manual labor.

Description

Technical Field

[0001] The invention relates to the field of agricultural irrigation, and in particular to a shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized cultivated land. Background Art

[0002] Salinization is a global problem. The global salinized land area is increasing every year. By 2050, more than 50% of cultivated land will face the risk of salinization. The salinized cultivated land area in my country accounts for 7% of the total cultivated land area. Among them, the Hetao Irrigation District, as an important grain base in my country, is also facing the challenge of land salinization. The Hetao Irrigation District currently has 560,000 hm2 of cultivated land. 2 The saline-alkali land is about 323,000 hm2 2 Soil water, fertilizer, air and heat are essential factors in the growth and development of crops. Ensuring their good supply is crucial to maintaining and increasing crop biomass. However, salinized farmland has the characteristics of high total salt content, high pH value (alkaline soil), soil compaction, poor aeration, low fertility level, and poor water and fertilizer retention capacity, which is not conducive to crop emergence and normal growth.

[0003] Silage corn is known as the "king of feed". It generally accounts for about 80% of the roughage in the daily diet of dairy cows in the United States and other countries. In recent years, the planting area of ​​silage corn has shown a rapid upward trend. The Hetao Plain is an important silage corn planting area in my country. Dairy cow breeding started early and has a good development foundation, and the demand for feed is large. In the face of saline-alkali land and salinization hazards in the Hetao Plain, it is necessary to improve the resistance of silage corn planted on saline-alkali land.

[0004] At present, there are few integrated cultivation methods for field silage corn, especially cultivation methods based on saline-alkali farmland. Due to the large area of ​​saline-alkali farmland and important forage ecological niche occupied by the Hetao Irrigation District, there is an urgent need to study the saline-alkali land cultivation technology for silage corn in order to improve the quality and biomass of silage corn cultivated in saline-alkali land. Summary of the invention

[0005] The present invention provides a shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland. Aiming at the current problems of easy compaction of salinized farmland soil, low soil fertility, low crop biomass and other problems affecting the yield and quality of silage corn in the Hetao irrigation area, a new integrated water, fertilizer and air irrigation cultivation method suitable for planting silage corn in slightly salinized farmland in the Hetao irrigation area is provided. The method can effectively improve the survival rate, biomass, quality and water and fertilizer utilization efficiency of silage corn in the seedling stage, improve the soil moisture and salt conditions, and promote the sustainable development of agriculture.

[0006] In order to solve the above technical problems, the present invention provides a shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland, comprising the following steps:

[0007] S1. Select saline-alkali farmland with flat terrain, irrigation conditions, and convenient layout and operation of the water, fertilizer and gas integrated drip irrigation device pipe network, and carry out deep loosening and shallow turning before sowing;

[0008] S2. The water source should be groundwater and / or canal water, with the mineralization controlled to be ≤3g / L and the sodium adsorption ratio not exceeding 18;

[0009] S3. Use an integrated water, fertilizer and gas drip irrigation system for irrigation. The integrated water, fertilizer and gas drip irrigation system includes a drip irrigation belt. The buried depth of the drip irrigation belt is 5-8cm, and the spacing between the drip irrigation belts and the planting row spacing is 50-100cm;

[0010] S4. Select silage corn varieties for sowing and carry out field management. Use an integrated water-fertilizer-gas drip irrigation system for irrigation during the entire growth period. Apply organic fertilizer, nitrogen fertilizer, and phosphorus fertilizer as base fertilizer before sowing. Use an integrated water-fertilizer-gas drip irrigation system to apply nitrogen fertilizer as topdressing at the flaring stage and milky stage of silage corn. Apply 150-250kg / mu of organic fertilizer, 15-25kg / mu of nitrogen fertilizer, and 5-10kg / mu of phosphorus fertilizer during the entire growth period. During this period, pest control and weeding management are carried out;

[0011] Among them, the irrigation system according to the growth period is as follows:

[0012] Seedling stage: drip irrigation 1-3 times, irrigation quota 5-10m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0013] Jointing stage: drip irrigation 1-3 times, irrigation quota 5-10m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0014] Large bell mouth stage: drip irrigation 1-3 times, irrigation quota 10-15m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0015] Male stalk extraction period: drip irrigation 1-3 times, irrigation quota 10-15m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0016] Milky stage: drip irrigation 1-3 times, irrigation quota 20-25m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0017] S5. Harvest silage corn during the milky stage.

[0018] As a preferred embodiment, in S4, the organic fertilizer is decomposed sheep manure and / or cow manure, the nitrogen fertilizer is urea, the N content in the urea is ≥46%, and the phosphate fertilizer is diammonium phosphate fertilizer and liquid phosphoric acid in a mass ratio of 6:4, the N content in the diammonium phosphate fertilizer is ≥12%, P2O5 is ≥48%, and the P2O5 content in the liquid phosphoric acid is ≥85%.

[0019] The mode of integrated cultivation of silage corn with water, fertilizer and air and the field management measures provided in the present application solve the practical problems of pests and diseases, waste of water and fertilizer resources and environmental pollution in the process of corn cultivation, achieve high yield and high efficiency of silage corn, select the main silage corn varieties for local use, adopt organic and inorganic fertilizers, improve the biomass and quality of silage corn, reduce the breeding cost of livestock, and have the characteristic of "saving fertilizer"; it combines two irrigation technologies, shallow buried drip irrigation and aerated drip irrigation. Shallow buried drip irrigation significantly reduces the salinity of the surface soil, promotes the water exchange between the surface and middle and deep layers of the soil, and ensures the water supply in the late growth period. Aerated drip irrigation increases the oxygen content of the soil, realizes the effective oxygenation of irrigation water, increases the activity of soil alkaline phosphatase, urease and catalase to promote the decomposition of soil urea, redox and aeration improvement, improves the activity of soil enzymes, promotes the growth of silage corn roots, and significantly increases the root density. Finally, the silage corn achieves a higher biomass and quality, improves farmers' planting intention, and enhances environmental friendliness.

[0020] As a preferred solution, in S4, the ratio of the application amount of the nitrogen base fertilizer and the two nitrogen topdressings is 4:3:3.

[0021] As a preferred solution, in S1, a large amount of water is flooded before plowing. The depth of flooding should be >30cm to allow natural infiltration. When the soil moisture does not hinder plowing, deep loosening and shallow plowing can be carried out. The depth of deep loosening is 30-35cm, and the depth of plowing is 15-25cm.

[0022] As a preferred solution, in S3, the integrated water, fertilizer and gas drip irrigation system also includes a PE pipe, the drip irrigation belt is laid parallel to the corn planting direction, the drip irrigation belt is laid in 1 pipe 2 rows or 2 pipes 4 rows, and the PE branch pipe is laid perpendicular to the drip irrigation belt.

[0023] As a preferred solution, in S3, the drip irrigation tape has a dripper spacing of 0.2-0.5 m and a single hole flow rate of 0.5-2 L / h.

[0024] As a preferred solution, in S4, wide and narrow rows are used for sowing, with wide spacing of 60-80 cm, narrow spacing of 30-50 cm, and planting density of 3500-5500 plants per mu.

[0025] As a preferred solution, in S4, sowing is carried out when the ground temperature at 5 cm reaches a stable level of 10° C. or above, and the sowing time is from April to May.

[0026] As a preferred solution, the integrated water, fertilizer and gas drip irrigation system includes a system main pipeline, a water storage tank, a liquid fertilizer storage device, a Venturi-type fertilizer applicator, a micro-nano bubble generating device, a water making valve, a pressure reducing valve, a pressurizing valve and a drip irrigation network. The drip irrigation network includes a drip irrigation belt and a PE pipe. One end of the water outlet of the water storage tank is connected in parallel with the micro-bubble generating device, and the other end is connected in series with the system main pipeline. The Venturi-type fertilizer applicator is connected in parallel to the system main pipeline through the water making valve. The liquid fertilizer storage device is arranged at the feed end of the Venturi-type fertilizer applicator. The pressurizing valve and the pressure reducing valve are arranged in the system main pipeline, and the system main pipeline is connected to the drip irrigation network.

[0027] As a preferred solution, the water storage tank is internally provided with a water level sensor, the micro-nano bubble generating device is provided with a dissolved oxygen electrode, and water meters are provided on the water pipes leading from the water storage tank to the system main pipeline and from the system main pipeline to the drip irrigation network.

[0028] When the integrated water, fertilizer and gas drip irrigation system of the present application is used for water, fertilizer and gas irrigation, the filtered water flows into the water storage tank, and the micro-bubble generating device circulates to generate micro-nano bubbles to make the dissolved oxygen content in the water storage tank reach a predetermined value. After stabilization, it can enter the main pipeline of the system, and the liquid fertilizer is mixed with the dissolved oxygen water in the main pipeline of the system by using the venturi tube fertilizer applicator according to the fertilizer input amount. The uniformly mixed water, fertilizer and gas solution maintains a constant water pressure through the pressure boosting valve and the pressure reducing valve provided in the main pipeline of the system, and irrigates the crops through the drip irrigation belt to achieve effective soil oxygenation.

[0029] Compared with the prior art, the present invention has the following beneficial effects:

[0030] 1. The cultivation method of the present application has greatly improved the mechanization level of silage corn production, combined the two irrigation technologies of shallow buried drip irrigation and aerated drip irrigation, promoted the water exchange between the soil surface and the middle and deep layers, ensured the water supply during the growth period, achieved effective oxygenation of irrigation water, and increased the activity of soil alkaline phosphatase, urease, and catalase to promote soil urea decomposition, redox and aeration improvement, which can significantly improve the biomass and quality of silage corn. According to preliminary experimental studies, silage corn using this cultivation method has achieved higher biomass (increased yield by 14%-18%), and is easy to operate, reducing the amount of manual labor.

[0031] 2. The cultivation method of the present application promotes the root growth of silage corn, significantly increases the root density, increases the proportion of medium and coarse roots, improves the crop's resistance to lodging, and promotes the roots to penetrate deeper into the soil, improves the root water absorption efficiency and ability, and plays a role in drought resistance and lodging resistance.

[0032] 3. The cultivation method of the present application increases the dissolved oxygen content of irrigation water based on water-gas mixing technology, fills the technical gap of using aerated water for silage corn cultivation, promotes the growth of silage corn yield and the virtuous cycle of crops and soil, and stimulates farmers' enthusiasm for planting. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 : The dynamic distribution characteristics of water content in the whole growth period of corn in the T5 shallow buried drip irrigation aeration treatment group and the CK non-shallow buried non-aerated drip irrigation treatment group in Example 1 of the present invention;

[0034] Figure 2 : Dynamic distribution characteristics of salt content in corn during the whole growth period in the T5 shallow buried drip irrigation aeration treatment group and the CK non-shallow buried non-aerated drip irrigation treatment group in Example 1 of the present invention. DETAILED DESCRIPTION

[0035] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0036] The embodiment of the present invention adopts an integrated water, fertilizer and gas drip irrigation system, specifically a water, fertilizer and gas integrated drip irrigation device produced by Henan Fengrun Environmental Protection Technology Co., Ltd. The water, fertilizer and gas integrated drip irrigation device includes a water source, a water pump, a filter, a water storage tank, a fertilizer storage device, a fertilizer dissolving device, a liquid fertilizer storage device, a Venturi-type fertilizer applicator, a micro-nano bubble generating device, a water valve, a pressure reducing valve, a pressure boosting valve, a flow meter, a dissolved oxygen electrode, and a drip irrigation network. The fertilizer storage device, the fertilizer dissolving device, and the liquid fertilizer storage device can be manually operated and connected to the system through a hose. The Venturi-type fertilizer applicator is connected in parallel to the main pipeline of the system through a water valve, and can be opened and closed according to actual needs. The fertilizer inlet end of the Venturi-type fertilizer applicator is equipped with a filter for filtering solid impurities. The main pipeline of the system is connected to the drip irrigation network, and the drip irrigation network is specifically a shallowly buried underground drip irrigation network. The drip irrigation network includes a water pump water pipe, a PVC trunk pipe, a PE branch pipe, and a drip irrigation belt.

[0037] One end of the water outlet of the water storage tank is connected in parallel with the micro-bubble generating device, and the other end is connected in series with the main pipeline of the system. The water storage tank is equipped with a water level sensor inside. Water meters are installed on the water pipes leading from the water storage tank to the main pipeline of the system and from the main pipeline of the system to the drip irrigation network. The micro-nano bubble generating device is equipped with a dissolved oxygen electrode to indicate the dissolved oxygen content of the irrigation water. The water storage capacity of the water storage tank, the water output of the system, and the dissolved oxygen content are all displayed on a digital display screen, and the water output can be adjusted according to the target dissolved oxygen content and irrigation volume.

[0038] The specific operation process of the integrated water, fertilizer and gas drip irrigation system is as follows:

[0039] a. Use a water pump to draw water from the water source into the filter, filter the solid impurities in the water and then flow it into the water storage tank to keep the water in the water storage tank at a constant pressure. The microbubble generator circulates to generate micro-nano bubbles. The inhaled air is controlled by a gas flow meter, and the outflowing water is microbubble water. The dissolved oxygen content in the irrigation water is measured by a dissolved oxygen electrode, and the water volume is monitored by a water meter. Microbubbles are circulated until the dissolved oxygen content in the water storage tank reaches a predetermined value and the operation is stable.

[0040] b. Fertilizer is sucked in by a Venturi fertilizer applicator. It should be ensured that the fertilizer is stirred before being sucked in so that there are no obvious particles and it is uniform. The fertilizer is stored in a liquid fertilizer storage device in advance. The amount of fertilizer input is determined according to the irrigation volume. When taking it, the weighing method is used to connect it to the Venturi fertilizer applicator. The Venturi fertilizer applicator is connected in parallel with the system main pipeline so that the input fertilizer can directly enter the system main pipeline.

[0041] c. The water pressure of the evenly mixed water-fertilizer-gas solution is kept constant through the pressure-boosting valve and pressure-reducing valve installed in the main pipeline of the system, and matched with the design pressure of the drip irrigation network, so as to carry out drip irrigation for crops. When the Venturi fertilizer applicator finishes sucking in the fertilizer, the water valve of the parallel Venturi fertilizer applicator is closed.

[0042] d. A flow meter is added at the outflow point after pressure reduction, aeration and fertilizer mixing to monitor the irrigation water volume. During operation, various instrument indexes are monitored and displayed on the digital display screen to ensure sufficient mixing of water, fertilizer and gas so that drip irrigation can be carried out continuously.

[0043] The present application provides a shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland, comprising the following steps:

[0044] S1. Plot selection and processing:

[0045] Select saline-alkali farmland with flat terrain, irrigation conditions, and convenient layout and operation of the water-fertilizer-gas integrated drip irrigation device pipe network; carry out a large amount of flooding before plowing, the flooding depth should be >30cm, and natural infiltration, and plowing can be carried out when the soil moisture does not hinder plowing. Before sowing (mid-to-late April), use a rotary tiller for deep loosening and shallow plowing, with a deep loosening depth of about 30-35cm and a plowing depth of about 20cm.

[0046] S2. Water source selection:

[0047] The water source can be groundwater or canal water, and the sediment content of the irrigation water source can be reduced by static sedimentation or filtration separation. Because groundwater in saline-alkali areas is prone to salinization, the groundwater quality must be analyzed first to control the mineralization degree to ≤3g / L and the sodium adsorption ratio not exceeding 18. If the groundwater mineralization conditions do not meet the needs of drip irrigation, a mixture of groundwater and canal water can be used as the water source to achieve qualified water source mineralization conditions.

[0048] S3. Drip irrigation network layout:

[0049] An integrated water, fertilizer and gas drip irrigation system is used for water, fertilizer and gas application. PE branch pipes and drip tapes are laid according to the crop planting direction. The drip tapes are laid parallel to the corn planting direction. It is advisable to adopt 1 pipe 2 rows or 2 pipes 4 rows laying method with a burial depth of 5-8cm. The PE branch pipe should be laid vertically with the drip tape. The spacing between drip tapes should be adapted to the planting row spacing, preferably 50-100cm. The dripper selection and dripper spacing control are carried out according to the crop planting density. Generally, the dripper spacing is 0.3m and the single hole flow rate is 0.5-2L / h.

[0050] S4. Sowing method:

[0051] a. Variety selection: According to the actual light and heat conditions and cultivation conditions, and in line with the characteristics of high and stable yield, density resistance and lodging resistance, disease and insect resistance, strong resistance to saline-alkali and suitable for mechanized operation, choose medium and late maturing silage corn varieties according to local conditions, avoid planting varieties with a long growth period, ensure the safe maturity of grains and high yield and high quality, and properly dry the seeds before sowing to improve germination and survival rate.

[0052] b. Sowing time: Sowing can be carried out when the ground temperature at 5cm reaches above 10℃ stably, usually from late April to early May.

[0053] c. Sowing: Use shallow buried drip seeder to complete sowing, fertilization, soil covering, compaction and laying of drip irrigation pipes at one time, ensure that the drip irrigation pipes are shallowly buried and not damaged, and sow in wide and narrow rows (wide row spacing 70cm, narrow row spacing 40cm); reasonably control the planting density, generally 3500-4000 seedlings per mu, for saline-alkali plots with high land preparation quality, good overall production conditions and the use of density-resistant and lodging-resistant corn varieties, the seedling density can be set to 4500-5500 plants per mu.

[0054] S5. Field management:

[0055] a. Management during the seedling stage: Chemical or manual weeding should be carried out after sowing according to local conditions. For plots with good soil moisture, closed weeding after sowing and before seedlings should be the main method; for plots with poor soil moisture, stem and leaf weeding after seedlings should be the main method; for plots where chemical weeding was not carried out before seedlings or closed weeding was not effective, timely post-seedling weeding can be carried out during the corn jointing stage and the 2-4 leaf stage of weeds based on weather conditions.

[0056] b. The irrigation time and amount should be determined according to the actual soil moisture, weather conditions, corn growth period and water source conditions. The recommended irrigation system according to the growth period is as follows:

[0057] Seedling stage: drip irrigation 1-3 times, irrigation quota 5-10m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0058] Jointing stage: drip irrigation 1-3 times, irrigation quota 5-10m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0059] Large bell mouth stage: drip irrigation 1-3 times, irrigation quota 10-15m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0060] Male stalk extraction period: drip irrigation 1-3 times, irrigation quota 10-15m 3 / mu, dissolved oxygen content is 8-20mg / L;

[0061] Milky stage: drip irrigation 1-3 times, irrigation quota 20-25m 3 / mu, dissolved oxygen content is 8-20mg / L.

[0062] The total irrigation volume during the whole growth period is 50-75m 3 / mu. If the growth condition is poor, supplementary irrigation should be carried out in time. A single irrigation should be 10-15m 3 / mu.

[0063] c. Adopt the integrated fertilization method of water and fertilizer, adjust the fertilizer dosage according to the climatic conditions and biomass intention, and the recommended fertilization system is as follows:

[0064] Applying organic fertilizers such as decomposed sheep manure and cow manure before sowing together with nitrogen fertilizer and phosphorus fertilizer as base fertilizer can effectively alleviate the problems of low effective nutrients, poor soil, and easy compaction in mild and moderate saline-alkali land. It is recommended to apply 150-250kg / mu. Nitrogen fertilizer is 15-25kg / mu and phosphorus fertilizer is 5-10kg / mu during the whole growth period; urea (N≥46%) is used for nitrogen fertilizer, and diammonium phosphate fertilizer (N≥12%, P2O5≥48%) and liquid phosphoric acid (P2O5≥85%) with a mass ratio of 6:4 is used for phosphorus fertilizer. The ratio of nitrogen fertilizer base fertilizer and two nitrogen fertilizer topdressing is 4:3:3. The time for nitrogen fertilizer topdressing is preferably during the silage corn flaring period and milk maturity period. All phosphorus fertilizer is applied as base fertilizer, and nitrogen fertilizer topdressing is applied with water and gas using an integrated water-fertilizer-gas drip irrigation system.

[0065] d. Pest and disease control: According to the peak period of diseases, prevent diseases such as corn leaf blight, stem rot, ear rot and smut in advance; according to the occurrence and forecast of insect pests, timely control cutworms, corn borers, aphids and armyworms by spraying foliar pesticides.

[0066] S6. Harvest: Harvest corn during the milky stage, leaving a stubble height of no less than 10 cm to prevent soil and drip irrigation pipes from being brought in. Use a harvester to harvest the entire corn plant and chop it into pieces, with a length of 3 cm.

[0067] Embodiment 1

[0068] The embodiment of the present application is located in the saline-alkali farmland in the Hetao Irrigation District, specifically Qianjin Farm in Pingluo County, Shizuishan City, Ningxia. The salt content of the 0-20 cm soil plough layer is 1.52 g / kg, and the above-mentioned shallow buried aerated drip irrigation silage corn cultivation method for slightly salinized farmland is adopted, and the cultivated crop is mid-late maturing silage corn.

[0069] In this example, two factors, water volume (W) and dissolved oxygen in water (O), are set to test the effects of different irrigation methods, where the irrigation is sufficient (W1: 112 mm) and insufficient (W 0.8 :90mm), the dissolved oxygen content of irrigation water is high dissolved oxygen (O1, 19mg / L), insoluble oxygen (O 0.8 , 10 mg / L) and no aeration (O0), with a total of 5 treatment groups: T1:W1O0, T2:W1O 0.8 、T3:W1O1、T4:W 0.8 O 0.8 、T5:W 0.8 O1, T1-T5 are all designed for shallow buried drip irrigation, the depth of the drip irrigation belt is 6-7cm, and the spacing between the drip irrigation belts and the planting row spacing is 80cm. In addition, the design of non-shallow buried drip irrigation treatment group T6: W 0.8 O1 and control group CK:W 0.8 O0, shallow buried drip irrigation adopts the method of laying drip tape directly on the soil surface. The depth of the drip tape is 2-3cm. The drip irrigation system structure and irrigation method of shallow buried drip irrigation are the same as those of shallow buried drip irrigation. The spacing between drip tapes and the average spacing between planting rows is about 80cm, the spacing between drippers is 0.3m, and the single hole flow rate is 1L / h.

[0070] The main experimental area adopts a large area design without repetition. In order to avoid marginal effects and mutual penetration of water between treatments, a 1m wide protection row is set on the outermost side of the irrigation area group. The sowing date is selected as May 13, 2023. Wide and narrow rows are planted, with a wide row of 70cm and a narrow row of 40cm. Drip irrigation tape is laid in the middle of the narrow row, with 5,500 plants per mu and a plant spacing of 22cm.

[0071] Irrigate 5 times during the whole growth period: once during the seedling stage to jointing stage (May 13th - June 13th); once during the tasseling stage (June 14th - July 3rd); once during the tasseling stage (July 4th - July 26th); and twice during the milky stage (July 27th - September 2nd) to meet the water demand of silage corn during the key growth period. The specific irrigation time should be determined according to the growth conditions of corn and soil moisture conditions.

[0072] Among them, the irrigation system of the W1 treatment group is as follows:

[0073] Seedling stage: irrigation quota 10m 3 / mu;

[0074] Jointing stage: irrigation quota 10m3 / mu;

[0075] Big flare period: irrigation quota 15m 3 / mu;

[0076] Male tsunami period: irrigation quota 15m 3 / mu;

[0077] Milky stage: total irrigation quota 25m 3 / mu;

[0078] Where W 0.8 The irrigation regime for the treatment groups was as follows:

[0079] Seedling stage: irrigation quota 5m 3 / mu;

[0080] Jointing stage: irrigation quota 10m 3 / mu;

[0081] Big flare period: irrigation quota 10m 3 / mu;

[0082] Male tsunami period: irrigation quota 15m 3 / mu;

[0083] Milky stage: total irrigation quota 20m 3 / mu.

[0084] Organic fertilizer is applied as base fertilizer in combination with land preparation in S1 at one time, with an application rate of 200 kg / mu, 20 kg / mu of nitrogen fertilizer and 8 kg / mu of phosphate fertilizer during the whole growth period; urea (N≥46%) is used as nitrogen fertilizer, and diammonium phosphate fertilizer (N≥12%, P2O5≥48%) and liquid phosphoric acid (P2O5≥85%) with a mass ratio of 6:4 are used as phosphate fertilizer, of which the ratio of base nitrogen fertilizer and two topdressing nitrogen fertilizers is 4:3:3. The time for topdressing nitrogen fertilizer should be during the flaring stage and milky stage of silage corn. Nitrogen fertilizer is applied along with water and gas using an integrated water-fertilizer-gas drip irrigation system; all phosphate fertilizers are applied as base fertilizer.

[0085] The harvest date of silage corn is selected as October 11, 2023. The biomass, root growth, soil moisture throughout the growth period, salt distribution, crop evapotranspiration, and soil enzyme activity of the treatment groups using different irrigation methods are investigated and statistically calculated.

[0086] 1. Crop evapotranspiration is an important part of the farmland water conversion process. The test results are shown in Table 1. The water balance relationship in the root layer is shown in the following formula (1):

[0087]

[0088] Where: ET during the calculation period cis crop evapotranspiration (mm); P is precipitation (mm); I is irrigation (mm); W t+Δt , W t are the soil moisture content at time t+Δt and t (mm) respectively; F is the water exchange amount at the lower boundary of the soil, which is positive for upward recharge and negative for downward water leakage.

[0089] The boundary flux is obtained by the positioning flux method, in which the unsaturated hydraulic conductivity is solved by the saturated hydraulic conductivity, and the water content and matrix potential are converted by the VG model. The specific calculation process is shown in the following equations (2)-(5):

[0090]

[0091] H=hm+hg(3)

[0092]

[0093] Where: K is the unsaturated hydraulic conductivity (cm / d); H is the soil water potential (the sum of matrix potential hm and gravity potential hg, cm); Ks is the saturated hydraulic conductivity (cm / d); is the soil water content (cm 3 / cm 3 );θ r is the residual moisture content (cm 3 / cm 3 );θ s is the saturated water content (cm 3 / cm 3 ), α and n are shape parameters.

[0094] Table 1 - Water sources and dissipation composition of silage corn under different irrigation methods

[0095]

[0096]

[0097] 2. Soil enzyme activity refers to the ability of soil enzymes to catalyze the transformation of substances. It participates in the synthesis and decomposition of humus in the soil and various redox reactions, and is closely related to soil fertility. Urease, catalase and alkaline phosphatase related to urea conversion, soil organic matter conversion and soil organic phosphorus were selected as soil quality evaluation indicators. In addition, the growth of corn roots is the most intuitive biological organ that reflects its ability to absorb water and nutrients. The root growth of silage corn at 40 and 60 cm was obtained through root scanning. The results are shown in Table 2 below.

[0098] Table 2 - Biomass, quality, enzyme activity and root characteristics of silage corn under different irrigation methods

[0099]

[0100]

[0101] Note: The same letters in the same column indicate no significant difference (P>0.05), and different letters indicate significant difference (P<0.05).

[0102] As shown in Table 1-2 above, through preliminary experimental research, in the T1-T3 treatment groups, with the increase of aeration dissolved oxygen, the evaporation of farmland water decreased, and the soil moisture content increased. When the irrigation amount was reduced, aeration achieved a biomass similar to that of the high irrigation treatment (T3: 3211.96 and T5: 3171.65 kg / mu). At the same time, by comparing the T2 and T4-T5 treatment groups, it can be seen that sufficient water irrigation and dissolved oxygen can help promote the growth of crops. Therefore, the biomass of silage corn increased with the increase of dissolved oxygen and irrigation amount, and the soil enzyme activity was improved.

[0103] By comparing the T5, T6 and CK treatment groups, it can be seen that the silage corn saline-alkali land cultivation method combined with shallow buried drip irrigation and aerated drip irrigation in this application has the characteristics of water saving, increasing yield, promoting root growth and improving soil microenvironment. The shallow buried drip irrigation of the T5 treatment group achieved significantly higher biomass than the conventional drip irrigation of the T6 group. Figure 1-2 As shown in the data, shallow buried drip irrigation promotes salt leaching and significantly reduces the salinity of the surface soil. Compared with surface drip irrigation, it forms a larger low-salt area, promotes water exchange between the surface and middle and deep layers of the soil, changes the dynamic characteristics of soil moisture throughout the growth period, and forms a deeper moisture belt, which is most obvious in the middle of the growth period, ensuring water supply in the late growth period. Shallow buried aerated drip irrigation significantly promotes upward water replenishment, meeting the water needs of silage corn during the growth period (54.39-60.63%).

[0104] At the same time, shallow buried drip irrigation significantly increased the activities of soil alkaline phosphatase, urease, and catalase, promoted soil urea decomposition, soil redox, and improved ventilation conditions. Shallow buried drip irrigation promoted the growth of corn roots. The root density increased significantly in the 20-60cm depth range, and the proportion of medium and coarse roots increased, which improved the crop's resistance to lodging, promoted the roots to penetrate deeper into the soil, and improved the root water absorption efficiency and ability.

[0105] The specific embodiments described above further illustrate the purpose, technical solutions and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. It is particularly pointed out that for those skilled in the art, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland, characterized in that: The following steps are involved: S1. Select saline-alkali farmland with flat terrain, irrigation conditions, and convenient for the layout and operation of the integrated water, fertilizer and air drip irrigation system, and carry out deep loosening and shallow turning before sowing; S2. The water source should be groundwater and / or canal water, with the mineralization controlled to be ≤3 g / L and the sodium adsorption ratio not exceeding 18; S3. Use an integrated water, fertilizer and gas drip irrigation system for irrigation. The integrated water, fertilizer and gas drip irrigation system includes a drip irrigation belt. The depth of the drip irrigation belt is 5-8 cm, and the spacing between the drip irrigation belts is 50-100 cm. S4. Select silage corn varieties for sowing and carry out field management. Use an integrated water-fertilizer-gas drip irrigation system for irrigation during the entire growth period. Apply organic fertilizer, nitrogen fertilizer, and phosphorus fertilizer as base fertilizer before sowing. Apply 150-250 kg / mu of organic fertilizer. Use an integrated water-fertilizer-gas drip irrigation system to apply nitrogen fertilizer topdressing at the flaring stage and milky stage of silage corn. Apply 15-25 kg / mu of nitrogen fertilizer and 5-10 kg / mu of phosphorus fertilizer during the entire growth period. During this period, pest control and weeding management are carried out; Among them, the irrigation system according to the growth period is as follows: Seedling stage: drip irrigation once, irrigation quota 5m 3 / mu, dissolved oxygen content is 8-20mg / L; Jointing stage: drip irrigation once, irrigation quota 10m 3 / mu, dissolved oxygen content is 8-20mg / L; Large bell mouth stage: drip irrigation once, irrigation quota 10m 3 / mu, dissolved oxygen content is 8-20mg / L; Male stalk emergence period: drip irrigation once, irrigation quota 15 m 3 / mu, dissolved oxygen content is 8-20mg / L; Milky stage: drip irrigation once, irrigation quota 20m 3 / mu, dissolved oxygen content is 8-20mg / L; S5. Harvesting silage corn at the milky stage; The integrated water-fertilizer-gas drip irrigation system includes a system main pipeline, a water storage tank, a liquid fertilizer storage device, a venturi-type fertilizer applicator, a micro-nano bubble generator, a water valve, a pressure reducing valve, a pressure increasing valve and a drip irrigation network. The drip irrigation network includes a drip irrigation belt and a PE pipe. One end of the water outlet of the water storage tank is connected in parallel with the micro-nano bubble generator, and the other end is connected in series with the system main pipeline. The venturi-type fertilizer applicator is connected in parallel with the system main pipeline through the water valve. The liquid fertilizer storage device is arranged at the feed end of the venturi-type fertilizer applicator. The pressure increasing valve and the pressure reducing valve are arranged in the system main pipeline. The system main pipeline is connected with the drip irrigation network. The water storage tank is internally provided with a water level sensor, the micro-nano bubble generating device is provided with a dissolved oxygen electrode, and water meters are provided on the water pipes leading from the water storage tank to the system main pipeline and from the system main pipeline to the drip irrigation network.

2. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S4, the organic fertilizer is decomposed sheep manure and / or cow manure, the nitrogen fertilizer is urea with N ≥ 46%, and the phosphate fertilizer is diammonium phosphate fertilizer and liquid phosphoric acid in a mass ratio of 6:4, with N ≥ 12% and P2O5 ≥ 48% in the diammonium phosphate fertilizer, and P2O5 ≥ 85% in the liquid phosphoric acid.

3. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S4, the ratio of nitrogen base fertilizer and two nitrogen topdressing applications was 4:3:

3.

4. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S1, a large amount of water is flooded before plowing, with a depth of >30 cm, and natural infiltration. When soil moisture does not hinder plowing, deep loosening and shallow plowing can be carried out. The depth of deep loosening is 30-35 cm, and the depth of shallow plowing is 15-25 cm.

5. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S3, the integrated water, fertilizer and gas drip irrigation system also includes a PE pipe. The drip irrigation belt is laid parallel to the corn planting direction. The drip irrigation belt is laid in a 1 pipe 2 rows or 2 pipes 4 rows manner, and the PE pipe is laid perpendicular to the drip irrigation belt.

6. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S3, the drip irrigation tape has a drip head spacing of 0.2-0.5m and a single hole flow rate of 0.5-2L / h.

7. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S4, wide and narrow rows are used for sowing, with wide spacing of 60-80 cm and narrow spacing of 30-50 cm, and the planting density is 3500-5500 plants per mu.

8. The shallow buried aerated drip irrigation cultivation method for silage corn in slightly salinized farmland according to claim 1, characterized in that: In S4, sowing was carried out when the ground temperature at 5 cm reached a stable level of 10°C or above, and the sowing time was from April to May.

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