Drip irrigation cultivation method for improving quality of tobacco leaves in dry soil

Abstract

The invention relates to the technical field of tobacco planting, in particular to a drip irrigation cultivation method for improving the quality of dry soil tobacco. The invention discloses a drip irrigation cultivation method for improving the quality of tobacco leaves in dry soil. The method comprises the following steps: (1) sowing, seedling raising and transplanting; (2) under-mulch drip irrigation is adopted for irrigation, drip irrigation belts shaped like a Chinese character'feng 'are adopted for under-mulch drip irrigation, the hole spacing is 30 cm, and the rated flow is 3.0-4.0 L / h; (3) controlling the water consumption modulus of the dry land flue-cured tobacco at 25.97%, 39.63% and 34.40% in the root extension period, the vigorous growth period and the mature period respectively; (4) fertilizing: N: P: K = 1: 0.8: 3, additionally applying a cake fertilizer to a base fertilizer, and spraying a microelement fertilizer to leaf surfaces; carrying out topdressing for five times; the drip irrigation technology has good economic benefits, social benefits and environmental benefits when applied to flue-cured tobacco production in the dry land tobacco area, the yield and average price are higher than those of CK by 6.41 kg / mu, 1.10 yuan / kg, 2.13% and 395.60 yuan / mu respectively, and the first-class and medium-class tobacco proportion output values are higher than those of CK by 6.41 kg / mu, 1.10 yuan / kg, 2.13% and 395.60 yuan / mu respectively.

Description

Technical Field

[0001] The present invention relates to the technical field of tobacco leaf cultivation, and particularly relates to a drip irrigation cultivation method for improving the quality of dryland tobacco leaves. Background Art

[0002] Flue-cured tobacco is a crop with relatively high water requirements, and the water requirement during the entire growth period is 400 - 600 mm. Moreover, the water requirements vary in different growth stages, and the water supply directly affects the yield and quality of tobacco leaves, which also results in the basic distribution of tobacco leaves in paddy field areas in production areas. The terrain of Jianghua Yao Autonomous County belongs to the typical southern hilly area, and the area of paddy fields within the jurisdiction is limited. The bottleneck in the development of tobacco leaves has emerged. Especially in recent years, with the tightening of the policy of non-grain use of farmland, in order to promote the sustainable development of local tobacco leaves and at the same time resolve the contradiction between tobacco and rice for land use to a limited extent, encouraged by the government's policies, more and more tobacco farmers have begun to try growing tobacco leaves on dry land. In the traditional production process of dryland tobacco leaves, irrigation is mainly adopted, which has problems such as large water consumption, large labor consumption, damage to soil structure, fertilizer loss, etc., and is not conducive to the diffusion and migration of nutrients. Therefore, it is very necessary to apply drip irrigation technology in dryland tobacco leaf production. This technology can not only effectively alleviate the negative impacts of drought, less rain, poor water conservancy and irrigation conditions on dryland plots on tobacco leaf production, reduce labor intensity, improve efficiency, relieve the tension in labor employment and solve the problem of insufficient labor force, but also improve the water and fertilizer utilization rate of tobacco plants, avoid the accumulation and loss of a large amount of nutrients in the soil, keep the soil structure undamaged, and improve the yield and quality of flue-cured tobacco.

[0003] Domestic and foreign scholars have reported a large amount of research on drip irrigation for flue-cured tobacco, but mainly focused on the effects on the growth and yield of flue-cured tobacco, while the research on the characteristics of water and fertilizer requirements and physiological indexes of flue-cured tobacco is very little. There are also controversies in the application models of drip irrigation technology for flue-cured tobacco, and there is no supporting cultivation technology for dryland flue-cured tobacco production under drip irrigation mode yet. Due to the diverse ecological types of tobacco fields and different planting environments of flue-cured tobacco in Yongzhou tobacco-growing area, it is necessary to conduct in-depth research on aspects such as the water requirement, water consumption, water consumption intensity, prediction and forecasting of soil moisture content, and water-saving irrigation quota of flue-cured tobacco. Among them, the determination of irrigation quota and its distribution during the growth period of tobacco plants are the core of the irrigation system for flue-cured tobacco. In addition, the research on flue-cured tobacco fertilization technology mainly focuses on the influence of the integrated water and fertilizer fertilization technology on the quality of flue-cured tobacco, while there is no report on the optimization of the pipeline network layout mode of the drip irrigation system for dryland flue-cured tobacco planting, and there are also few reports on the research of the integrated water and fertilizer fertilization time, fertilization method and water and fertilizer coupling effect under drip irrigation mode. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0005] A drip irrigation cultivation method for improving the quality of dryland tobacco leaves, the method comprising the following steps:

[0006] (1) Seeding, raising seedlings and transplanting;

[0007] (2) Irrigation is carried out by drip irrigation under plastic film, and the drip irrigation under plastic film adopts a "rich" - shaped drip tape layout;

[0008] (3) Control the water consumption modulus of dry - land flue - cured tobacco at the root - stretching stage, vigorous - growth stage, and maturity stage to be 25.97%, 39.63%, and 34.40% respectively;

[0009] (5) Fertilization: N:P:K = 1:0.8:3, increase the application of cake fertilizer as base fertilizer, spray micronutrients on the leaf surface; and carry out 5 top - dressings.

[0010] Preferably, in step (1), the planting density is 1.2m × 0.5m.

[0011] Preferably, in step (2), the drip tape adopts a drip tape with a hole spacing of 30cm and is arranged in cooperation with a ridge height of 40cm.

[0012] Preferably, the drip tape is made of PE material.

[0013] Preferably, the time of the 5 top - dressings is as follows: apply the first seedling - promoting fertilizer at the time of transplanting, apply the second seedling - promoting top - dressing about 7 days after transplanting; carry out small soil - banking, break the plastic film and dig out the seedlings about 14 days after transplanting, and apply the third seedling - promoting top - dressing; apply the fourth special top - dressing by watering 20 - 25 days after transplanting; apply the remaining fifth special top - dressing + part of potassium sulfate by watering during the vigorous - growth stage; apply the remaining potassium sulfate by watering 45 - 50 days after transplanting.

[0014] Preferably, the vigorous - growth stage is 35 - 40 days after transplanting.

[0015] Preferably, in step (5), the mass ratio of N - P₂O₅ - K₂O in the base fertilizer is 8 - 10 - 11; the mass ratio of N - P₂O₅ - K₂O in the seedling - promoting fertilizer is 20 - 9 - 0; the mass ratio of N - P₂O₅ - K₂O in the special top - dressing is 10 - 0 - 32.

[0016] The beneficial effects of the present invention:

[0017] The application of the drip irrigation under plastic film technology involved in the present invention in the production of flue - cured tobacco in dry - land tobacco areas has good economic, social, and environmental benefits. The yield, average price, proportion of upper - medium - grade tobacco, and output value are 6.41 kg / mu, 1.10 yuan / kg, 2.13%, and 395.60 yuan / mu higher than those of CK respectively. Brief description of the drawings

[0018] Figure 1 Enzyme content of each treatment;

[0019] Figure 2 Each period of drip - irrigated flue - cured tobacco;

[0020] Figure 3 Changes in soil organic matter of tobacco-growing soil in each treatment (g / kg);

[0021] Figure 4 Changes in available nitrogen in tobacco-growing soil in each treatment (mg / kg);

[0022] Figure 5 Changes in available phosphorus in tobacco-growing soil in each treatment (mg / kg);

[0023] Figure 6 Changes in available potassium in tobacco-growing soil in each treatment (mg / kg). Detailed implementation manners

[0024] To make the objectives, technical solutions and advantages of the present invention clearer, the following will, in conjunction with the embodiments of the present invention, clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are some but not all of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the scope of protection of the present invention.

[0025] Experimental Example 1 Cost-benefit of drip irrigation technology in dryland flue-cured tobacco production and its influence on tobacco leaf quality

[0026] 1 Materials and methods

[0027] 1.1 Test site: Dryland tobacco leaf production base in Baimangying, Jianghua County, Yongzhou City.

[0028] 1.2 Test materials: Yunyan 87, source: Tobacco Leaf Technology Center of Yongzhou City.

[0029] 1.3 Test methods

[0030] 1.3.1 Test design

[0031] A randomized block test was adopted, including drip irrigation on film (T1), drip irrigation under film (T2), and traditional irrigation technology (CK). There were a total of 3 treatments, 3 replicates, a total of 9 plots, and each plot was 1 mu.

[0032] 1.3.2 Test operation

[0033] Seeding and raising seedlings: Float seeding on December 20, 2023; Transplanting date: March 17, 2024. The drip irrigation system is laid with a "Feng"-shaped PE main pipe and PVC50 hoses. The lower and upper limits of field irrigation management are set at 55% - 85% of the field water holding capacity. For the fertilization plan, the 101 fertilization plan is adopted, with 11.3 kg of pure nitrogen applied per mu, and the ratio of nitrogen, phosphorus, and potassium is 1:0.8:2.7. According to the actual situation of the research area, a sub-surface patch drip irrigation tape with a nominal diameter of 16 mm, a wall thickness of 0.2 mm, a water outlet hole diameter of φ3 mm, a rated working pressure of the drip head ha = 0.1 MPa, a rated flow rate Q = 3.0 - 4.0 L / h, and a drip head spacing of 0.3 m is selected. According to the requirement of a 1.2 m ridge spacing for flue-cured tobacco planting, a drip irrigation tape outlet spacing of 1.2 m is selected, and a branch pipe is set every 50 m. The lower and upper limits of field irrigation management are set at 55% - 85% of the field water holding capacity.

[0034] 1.4 Investigation and statistics

[0035] (1) Record the irrigation volume, evaporation volume, energy consumption, laying cost, operation management and maintenance cost, etc.; (2) Record and compare the agronomic traits of tobacco plants, the quality of tobacco leaves, the yield and output value, and the promotion and application benefits (economic benefits, ecological benefits, social benefits), etc.: ① Growth period investigation: Select 20 representative tobacco plants in the middle row of each treatment as fixed-point plants, and observe and record the following periods: transplanting period, rosette stage, budding stage, topping stage, maturity stages of lower, middle, and upper tobacco leaves, and the whole growth period in the field. ② Agronomic trait investigation: Select 10 representative tobacco plants in the middle row of each plot as fixed-point plants, and investigate and record the following agronomic traits at the root elongation stage (14 days after transplanting), rosette stage (starting when a certain treatment plot enters the rosette stage, about 35 days after transplanting), vigorous growth stage (55 days after transplanting), and maturity stage (75 days after transplanting) of flue-cured tobacco: plant height, number of leaves, stem girth, field uniformity, maximum leaf area of the lower part, maximum leaf area of the middle part, maximum leaf area of the upper part (leaf area = length * width * 0.6345), and the yellowing situation of tobacco leaves in layers. ③ Economic trait analysis: Randomly select 300 plants in each plot for marking, strictly grade the cured tobacco leaves, and calculate the ratio of upper and middle-grade tobacco, the yield and output value of tobacco leaves.

[0036] Appearance quality evaluation index: total score ≥ 90, among which the first-level index oil content ≥ 16, softness ≥ 16, elasticity ≥ 7; the second-level index maturity ≥ 14, color ≥ 14, gloss intensity ≥ 7, thickness 7 - 8. ④ Chemical composition: The internal chemical composition of flue-cured tobacco leaves: After the tobacco leaves are taken out of the curing barn, C3F is selected as the representative of middle tobacco leaves from each treatment sample pole, and the conventional chemical composition of the tobacco leaves is measured. Nicotine 2.0 - 3.0%, total sugar 20 - 35%, reducing sugar 18 - 30%, sugar-alkali ratio 7 - 15, potassium content > 2%, chlorine content < 0.8%, potassium-chlorine ratio > 4, starch < 4.5%. Conventional chemical composition analysis. The total sugar, total nitrogen, nicotine, chlorine, and starch in the chemical composition of tobacco leaves are determined by an ALLANCE continuous flow analyzer. The potassium content is determined by flame photometry. Total sugar-alkali ratio = total sugar / total alkaloid, total nitrogen-alkali ratio = total nitrogen / total alkaloid, potassium-chlorine ratio = total potassium / total chlorine. ⑤ Detection of various enzymes: Select B2F, C3F, and X2F as the representatives of upper, middle, and lower tobacco leaves, and peroxidase (POD), superoxide dismutase (SOD), and polyphenol oxidase (PPO) are tested using kits from Nanjing Jiancheng.

[0037] 2 Results

[0038] 2.1 Comparison of cost-benefit among treatments

[0039] Compared with the traditional irrigation area (CK), the water consumption in the drip irrigation area on film (T1) can reduce labor by 130 yuan per mu, save water by 5 m³ per mu, save 45.45% of irrigation water, and save electricity cost by 45 yuan per mu. Compared with the traditional irrigation area (CK), the water consumption in the drip irrigation area under film (T2) can reduce labor by 134 yuan per mu, save water by 7 m³ per mu, save 54.54% of irrigation water, and save electricity cost by 63 yuan per mu. Compared with the drip irrigation area on film (T1), the water consumption in the drip irrigation area under film (T2) can reduce labor by 4 yuan per mu, save water by 2 m³ per mu, save 33.33% of irrigation water, and save electricity cost by 18 yuan per mu. The differences in labor reduction, water saving, and cost reduction among different treatments are significant. See Table 1 and Table 2.

[0040] Table 1 Labor reduction in drip irrigation

[0041]

[0042] Table 2 Water saving in irrigation

[0043]

[0044]

[0045] Note: The field irrigation takes 55% - 85% of the field water holding capacity as the lower and upper limit indicators for field irrigation management. The electricity price is the stepped electricity price of 0.6 yuan per degree.

[0046] 2.2 Comparison of growth periods among treatments

[0047] The growth period of tobacco plants in the T treatment was shortened by about 5 - 6 days compared with the CK. See Table 3.

[0048] Table 3 Comparison of growth periods among treatments

[0049]

[0050] 2.3 Comparison of agronomic traits among treatments

[0051] The plant height, stem diameter, maximum leaf length, and maximum leaf width in the T2 treatment were significantly higher than those in the CK. The stem diameter and maximum leaf length in the T2 treatment were significantly higher than those in the T1 treatment. See Table 4.

[0052] Table 4 Comparison of agronomic traits of tobacco plants in each treatment (75 days after transplanting)

[0053]

[0054] 2.4 Comparison of economic traits among treatments

[0055] The yield per mu, average price, proportion of upper and middle - grade tobacco, and output value in the T2 treatment were 6.41 kg / mu, 1.10 yuan / kg, 2.13%, and 395.60 yuan / mu higher than those in the CK respectively; the yield, proportion of upper and middle - grade tobacco, and output value in the T1 treatment were 4.56 kg / mu, 0.93%, and 167.13 yuan / mu higher than those in the CK respectively (Table 5).

[0056] Table 5 Comparison of tobacco leaf income in each treatment

[0057]

[0058]

[0059] 2.5 Comparison of internal chemical components of tobacco leaves among treatments

[0060] The reducing sugar in each treatment was 21.5 - 23.2%, nicotine was 2.11 - 2.19%, total nitrogen was 2.34 - 2.58%, chlorine was 0.32 - 0.38, potassium was 2.88 - 3.15, and the sugar - nicotine ratio was 9.23 - 10.27%. Among them, the content of reducing sugar, nicotine, total nitrogen, potassium and the sugar - nicotine ratio in the T2 treatment were higher than those in other treatments. See Table 6.

[0061] Table 6 Comparison of internal chemical components of tobacco leaves among treatments

[0062]

[0063] 2.6 Enzyme content in each treatment

[0064] Select B2F, C3F, and X2F as representatives of upper, middle, and lower tobacco leaves. The SOD value of the lower leaves ranges from 202.2 to 213.1, the SOD value of the middle leaves ranges from 214.1 to 225.4, and the SOD value of the upper leaves ranges from 202.3 to 211.7; the POD value of the lower leaves ranges from 47.7 to 48.4, the middle leaves range from 40.5 to 43.2, and the upper leaves range from 39.2 to 41.5; the PPO value of the lower leaves ranges from 17.4 to 19.3, the middle leaves range from 13.2 to 14.8, and the upper leaves range from 12.5 to 13.7. Among them, the contents of SOD, POD, and PPO enzymes in the lower leaves of the T2 treatment are significantly higher than those of other treatments.

[0065] Table 7 Comparison of enzyme contents in each treatment

[0066]

[0067] 3 Conclusions

[0068] Drip irrigation under mulch (T2) saves 54.54% (7 m 3 / mu) of water compared with traditional irrigation (CK), reduces labor by 134 yuan / mu, and reduces the electricity cost by 63 yuan / mu (P < 0.05). Drip irrigation under mulch (T2) shortens the growth period of tobacco plants by 6 days, increases the stem girth by 11.42% (up to 2.83 cm), and increases the maximum leaf area by 35.01% (2387 cm 2 ). The nicotine content of the tobacco leaves under drip irrigation under mulch (T2) is 2.26%, the potassium content is 3.15%, and the sugar-alkali ratio is 10.27, which is significantly better than that of traditional irrigation. The SOD activity of the lower leaves is 213.1 U / g, and the POD activity is 48.3 U / g, enhancing the antioxidant capacity. The proportion of first-class tobacco under drip irrigation under mulch (T2) is 62.14%, which is 2.34% higher than that of traditional irrigation, and the yield reaches 134.45 kg / mu, with an increase of 5.01%. It can be seen that drip irrigation under mulch realizes the synergistic effect of water saving, quality improvement, and efficiency increase, providing a technical paradigm for the sustainable development of dryland flue-cured tobacco in the whole country.

[0069] Experimental Example 2 Study on water consumption characteristics and nutrient demand laws of dryland flue-cured tobacco at different growth stages

[0070] 1 Materials and Methods

[0071] 1.1 Test site: The dryland tobacco leaf production base in Baimangying, Jianghua County, Yongzhou City.

[0072] 1.2 Test materials: Yunyan 87, source: Yongzhou Tobacco Technology Center.

[0073] 1.3 Test design

[0074] 1.3.1 Design of water requirement characteristics test: A randomized block experiment was adopted, with drip-irrigated flue-cured tobacco fields (T) and drip-irrigated fields without seedlings (CK). The specifications of the high ridges are the same, with a bottom width of 45 cm, a top width of 25 cm, a length of 50 m, and a height of 40 cm. Each treatment had 3 replicates, for a total of 6 plots, and each plot had an area of 1 mu.

[0075] 1.3.2 Design of nutrient requirement test: A total of 4 treatments (T) were set on the basis of equal nitrogen application. T1: Single application of chemical fertilizer; T2: Chemical fertilizer + cake fertilizer; T3: Single application of cake fertilizer; T4: No fertilizer. For the fertilization plan, the 101 fertilization plan was adopted, with 11.3 kg of pure nitrogen applied per mu, a nitrogen-phosphorus-potassium ratio of 1:0.8:3.0, and 15 kg of cake fertilizer per mu. Each treatment had 3 replicates, for a total of 6 plots, and each plot had an area of 80 plants.

[0076] 1.3.2 Test operation

[0077] Sowing and seedling raising: Floating seedling raising on December 20, 2023; Transplanting date: March 17, 2024, transplanting under the film, with the whole process covered with film. According to the actual situation of the research area, a patch-type drip irrigation tape under the film was selected, with a nominal diameter of 16 mm, a wall thickness of 0.2 mm, and an outlet hole diameter The rated working pressure of the drip head ha = 0.1 MPa, the rated flow rate Q = 3.0 - 4.0 L / h, and the drip head spacing is 0.3 m. According to the requirement of the ridge spacing of 1.2 m for flue-cured tobacco planting, the outlet spacing of the drip irrigation tape was selected to be 1.2 m, and a branch pipe was set every 50 m.

[0078] The drip irrigation method adopted a combined near and far grouped rotation irrigation method. The branch pipes for simultaneous irrigation were distributed on no more than 2 sub-main pipes to maintain the stable operation of the pump power performance and ensure the balanced water use of the field. The basic physical property indexes of the soil before transplanting: bulk density, porosity, field water holding capacity, saturated water content, etc. The lower and upper limits of field irrigation management were set as 55% - 85% of the field water holding capacity. For the fertilization plan, the 101 fertilization plan was adopted, with 11 kg of pure nitrogen applied per mu, a nitrogen-phosphorus-potassium ratio of 1:0.8:3.0. In accordance with the "Yongzhou City Tobacco Production Technical Plan", water-soluble nitrogen-phosphorus-potassium topdressing was used for topdressing, and integrated drip irrigation fertilization of water and fertilizer was implemented.

[0079] 1.4 Recording and investigation objectives

[0080] (1) Agricultural records and meteorological records. (2) Growth period. Including sowing, emergence, seedling establishment, transplanting, rosette stage, budding, maturity of lower leaves, maturity of top leaves, number of days in seedling stage, number of days in field stage. (3) Agronomic traits. Plant type, leaf shape, plant height, stem girth, internode distance, number of effective leaves, angle between stem and leaves, length and width of middle leaves, calculate the single leaf area, single leaf area = 0.6345×(leaf length×leaf width), where: 0.6345 is the constant for calculating leaf area of flue-cured tobacco.) (4) Botanical traits. Plant type, leaf shape, leaf color in seedling stage, leaf color in field stage, angle between stem and leaves, thickness of main vein, field uniformity, maturity characteristics, growth potential in seedling stage, growth potential in field stage. (5) Resistance. Observe the incidence of main diseases in seedling stage - damping-off, Rhizoctonia solani. Investigate the incidence of main diseases in field stage - mosaic disease, black shank, bacterial wilt, brown spot, etc. (6) After transplanting, measure the soil water content at 0 - 10 cm, 10 - 20 cm, 20 - 30 cm every 3 days during root extension stage and rapid growth stage, and every 2 days during maturity stage, 15 cm away from the seedlings, calculate the daily transpiration water loss; at the same time, measure the soil water content at the same time and the same depth of CK as the evaporation of bare soil; the difference between the two is the daily water consumption of flue-cured tobacco. Multiply by the number of plants per hectare to obtain the water demand characteristics of Jianghua dryland flue-cured tobacco. The water consumption of flue-cured tobacco at different growth stages can be calculated according to the water balance principle by the formula:

[0081] ET 1-2 =10∑ n i＝1 γ i H i (W i1 -W a )+P+Ⅰ+K-R-D

[0082] Where: ET 1-2 is the water consumption of the stage crop, mm; n is the total number of soil layers;

[0083] i is the soil layer number; γi is the dry bulk density of the i-th layer of soil, g / cm 3 ;

[0084] Hi is the soil layer thickness, cm;

[0085] Wi1 and Wi2 are the soil moisture of the i-th layer of soil under control and experimental treatments respectively, %;

[0086] P, I, K, R, and D are the effective rainfall, irrigation water volume, groundwater recharge, runoff, and deep percolation volume in different periods, in mm. When the rainfall is less than 5 mm, σ = 0, which is ineffective rainfall; when the rainfall is between 5 and 50 mm, σ = 1, which is effective rainfall; when the rainfall is greater than 50 mm, σ = 0.8, which is effective rainfall. The water consumption modulus is calculated by the formula: water consumption modulus (%) = water consumption in each growth stage / total water consumption × 100%. (7) Nutrient determination: During the root elongation stage, vigorous growth stage, and maturity stage, 3 - 5 plants are sampled every 7 days to measure the nitrogen, phosphorus, and potassium contents of the roots, stems, and leaves, and then multiplied by the number of plants per mu to obtain the nitrogen, phosphorus, and potassium nutrient demand characteristics of dryland flue-cured tobacco.

[0087] 2 Results

[0088] 2.1 Growth period of tobacco plants and rainfall

[0089] The field growth period of flue-cured tobacco plants under drip irrigation under plastic film in dryland of Jianghua is 113 days, and the rainfall during the whole growth period is 373.45 mm.

[0090] Table 8 Growth period of tobacco plants

[0091]

[0092]

[0093] Note: Source of rainfall data: National Meteorological Information Center - China Meteorological Data Network. The influence of groundwater level is not included in this experiment.

[0094] 2.2 Water consumption, water consumption intensity, and water consumption modulus of flue-cured tobacco in each growth period

[0095] The water consumption for dryland flue-cured tobacco production in Baimangying, Jianghua is 510.28 mm, among which the water consumption in the root elongation stage, vigorous growth stage, and maturity stage is 132.5 mm, 202.22 mm, and 175.56 mm respectively. The water consumption moduli are 25.97%, 39.63%, and 34.40% respectively. Among them, the water demand in the vigorous growth stage is the highest, followed by the maturity stage (the results are as Figure 2 shown).

[0096] Table 9 Water consumption, water consumption intensity, and water consumption modulus of flue-cured tobacco in each growth period

[0097]

[0098] 2.3 N, P, and K contents in roots, stems, and leaves at different growth stages

[0099] The nutrient distribution and absorption in roots, stems and leaves (see Table 10) all follow certain rules. Taking the treatment of cake fertilizer + chemical fertilizer as an example (the trends of other treatments are the same as this one), when flue-cured tobacco is transplanted for about 30 days and enters the root-extending stage, the nutrient distribution of N and K in roots reaches a peak and then gradually decreases with the progress of the growth period. The P nutrient content in roots is relatively stable during the whole growth stage of flue-cured tobacco, with a small variation range. However, in other treatments, the P nutrient distribution in roots increases before the vigorous growth stage.

[0100] Table 10 N, P, K contents (%) in roots, stems and leaves at different growth stages

[0101]

[0102] 3 Conclusions

[0103] The water consumption for the production of dryland flue-cured tobacco in Baimangying, Jianghua is 510.28 mm, among which the water consumption in the root-extending stage, vigorous growth stage and maturity stage is 132.5 mm, 202.22 mm and 175.56 mm respectively. The water consumption modulus is 25.97%, 39.63% and 34.40% respectively. The water demand is the highest in the vigorous growth stage, followed by the maturity stage.

[0104] When flue-cured tobacco is transplanted for about 30 days, the nutrient distribution of N and K in roots reaches a peak and then gradually decreases with the progress of the growth period. The P nutrient content in roots is relatively stable during the whole growth stage of flue-cured tobacco, with a small variation range. However, in other treatments, the P nutrient distribution in roots increases before the vigorous growth stage.

[0105] Experimental Example 3 Effects of the Interaction between Subsurface Drip Irrigation and Ridge Height on Soil Moisture and Flue-Cured Tobacco Growth

[0106] 1 Materials and Methods

[0107] 1.1 Test variety: Yunyan 87

[0108] 1.2 Test site: Tobacco production base in Baimangying, Jianghua

[0109] 1.3 Test design

[0110] 1.3.1 The operation steps of the interaction test between subsurface drip irrigation and ridge height are ridging - fertilizing - laying a water supply belt on the ridge - covering with film - transplanting tobacco seedlings. The test sets two factors: the distance between subsurface drip irrigation holes (W) and ridge height (H). For W: there are 3 levels, namely spacing 20 cm (W1), spacing 30 cm (W2), and spacing 50 cm (W3); for H: the high ridge specifications are bottom width 45 cm, top width 25 cm, length 50 m, height 40 cm (H1), and the low ridge specifications are bottom width 45 cm, top width 35 cm, length 50 m, height 30 cm (H2). There are a total of 6 treatments, 3 replicates, 18 plots, each plot is 1 mu, and the fertilization schemes for each treatment are the same.

[0111] Seeding and raising seedlings: Floating seedling raising on December 20, 2023; Transplanting date: March 17, 2024, transplanting under the film. According to the actual situation of the research area, select the patch-type drip irrigation tape under the film, with a nominal diameter of 16 mm, a wall thickness of 0.2 mm, and a water outlet hole diameter The rated working pressure of the drip head ha = 0.1 MPa, and the rated flow rates Q = 4.0 L / h, 3.0 L / h, and 2.0 L / h for hole spacings of 20, 30, and 50 cm respectively. According to the requirement of the ridge spacing of 1.2 m for flue-cured tobacco planting, select a drip irrigation tape outlet spacing of 1.2 m, and set the lateral pipe every 50 m.

[0112] Pour the root-fixing water for 15 min; For field irrigation, use 55% - 85% of the field water holding capacity as the lower and upper limit indicators for field irrigation management.

[0113] Table 11 Specific situations of each treatment 1.4 Investigation and statistics

[0114] (1) Soil volumetric water content: Before each watering and 1 day after watering, measure the water content of the 0 - 20 cm soil layer. Select one row in each plot and measure the water content at 3 points and then take the average. Statistically analyze the soil moisture content during the root elongation period, vigorous growth period, and maturity period.

[0115] (2) Record and compare the growth period, agronomic traits of tobacco plants, leaf quality, yield and output value (300 plants), and promotion and application benefits (economic benefits, ecological benefits, social benefits), etc. with chemical components.

[0116] 2 Results

[0117] 2.1 Changes in soil water content of each treatment

[0118] The ridge height has no significant effect on the soil water content, while the drip irrigation hole spacing has a significant effect on the soil water content. With the increase of the hole spacing, the soil moisture content before watering and 1 day after watering shows a gradually decreasing trend. The soil moisture content before watering and 1 day after watering in each period of the 20 cm and 30 cm hole spacing treatments are significantly higher than those of the 50 cm hole diameter treatment. See Table 13. This may be because the smaller the hole spacing, the more the number of holes, the larger the wetting range, and the corresponding increase in soil water content.

[0119] Table 12 Changes in soil water content of 0 - 20 cm for each treatment (%)

[0120]

[0121] 2.2 Agronomic traits of flue-cured tobacco in each treatment

[0122] According to the results in Table 13, under the same ridge height, the plant height, maximum leaf length, and maximum leaf width are optimal under the treatment with a drip irrigation tape hole spacing of 30 cm. Moreover, the plant height, stem diameter, number of leaves, maximum leaf length, and maximum leaf width under the high-ridge treatment are all higher than those under the low-ridge treatment. This may be because the soil layer of the high ridge is thicker and looser, which is conducive to the deep extension of the tobacco plant roots and promotes the growth of tobacco plants.

[0123] Table 13 Agronomic Traits of Flue-cured Tobacco under Each Treatment

[0124]

[0125] 2.3 Comparison of Economic Traits under Each Treatment

[0126] The percentages of first-class and upper-middle-class flue-cured tobacco under the high-ridge treatment are higher than those under the low-ridge high treatment. The percentages of first-class and upper-middle-class flue-cured tobacco under the drip irrigation under plastic film treatment with a hole spacing of 30 cm are higher than those under the treatments with hole spacings of 20 cm and 50 cm. There are significant interaction effects between the hole spacing of the drip irrigation tape and the ridge height on the percentages of first-class and upper-middle-class flue-cured tobacco.

[0127] Table 14 Comparison of Economic Traits under Each Treatment

[0128]

[0129] 2.4 Comparison of the Internal Chemical Components of Tobacco Leaves under Each Treatment

[0130] The internal chemical components of tobacco leaves under the treatment with a hole spacing of 30 cm are relatively moderate. The reducing sugar, total nitrogen, chlorine, and sugar-alkali ratio are significantly higher than those under the 20-layer and 50-cm treatments; the nicotine, potassium, total nitrogen, sugar-alkali ratio, and nitrogen-alkali ratio of the high-ridge treatment are moderate and increase compared with the low-ridge height. This may be because too small a hole spacing may cause the roots to concentrate near the drippers, affecting the natural expansion of crop roots and soil structure; while the larger the hole spacing, the larger the wetting range, which will lead to a decrease in irrigation uniformity and affect the uniform growth of crops.

[0131] Table 15 Comparison of the Internal Chemical Components of Tobacco Leaves under Each Treatment

[0132]

[0133] 3 Conclusions

[0134] The soil moisture content before and after watering at each period in the treatments with hole spacing of 20 cm and 30 cm was significantly higher than that in the treatment with hole diameter of 50 cm. Under the same ridge height, the plant height, maximum leaf length and maximum leaf width were the best in the treatment with hole spacing of 30 cm for drip irrigation tape, while the plant height, stem diameter, number of leaves, maximum leaf length and maximum leaf width in the high ridge treatment were higher than those in the low ridge treatment. The rate of superior and superior middle tobacco in the high ridge treatment was higher than that in the low ridge treatment. The rate of superior and superior middle tobacco in the drip irrigation treatment under film with hole spacing of 30 cm was higher than that in the treatments with hole spacing of 20 cm and 50 cm. There was a significant interactive effect between the hole spacing of drip irrigation tape and the ridge height on the rate of superior and superior middle tobacco. The internal chemical composition of tobacco leaves in the treatment with hole spacing of 30 cm was relatively moderate, and the reducing sugar, total nitrogen, chlorine and sugar-alkali ratio were significantly higher than those in the treatments with hole spacing of 20 cm and 50 cm. The nicotine, potassium, total nitrogen, sugar-alkali ratio and nitrogen-alkali ratio were moderate in the high ridge treatment, and increased compared with the low ridge height. It can be seen that W2H1 is the best drip irrigation tape hole spacing and ridge height treatment method.

[0135] Experimental Example 4 Effects of drip irrigation fertilization method and fertilization frequency under film on nutrient utilization rate and flue-cured tobacco yield and quality

[0136] 1 Materials and methods

[0137] 1.1 Test variety: Yunyan 87

[0138] 1.2 Experimental location: Jianghua Baimangying tobacco production base.

[0139] 1.3 Experimental design See Table 16. There are 9 treatments and 27 plots in total.

[0140] Table 16 Experimental design of fertilization method and fertilization frequency of drip irrigation under film

[0141]

[0142] There were 6 treatments, 3 replications, 18 plots, each plot was 1 mu, and the fertilization schemes for each treatment were the same.

[0143] One-time fertilization without film removal (C1): Apply 101% base fertilizer + topdressing fertilizer once before film laying.

[0144] Remove the film and apply fertilizer in batches (C2): 101 base fertilizer + 5 topdressings; transplanting base fertilizer (N-P2N5-K2O 8-10-11) + seedling fertilizer (N-P2N5-K2O 20-9-0) + cake fertilizer, (about 7 days after transplanting) seedling fertilizer (2); (about 14 days after transplanting) small soiling, breaking the film and digging out the seedlings, and applying the third seedling fertilizer; (about 20 days after transplanting) pouring the fourth special topdressing (N-P2N5-K2O 10-0-32); (in the vigorous growth period, 35-40 days after transplanting) pouring the remaining fifth special topdressing (N-P2N5-K2O 10-0-32) + part of potassium sulfate + large soiling + knocking off 2-3 bottom leaves; (about 45-50 days after transplanting) pouring the remaining potassium sulfate. Topdressing is done by pouring.

[0145] Integrated water and fertilizer application in stages (C3): The fertilization plan is the same as C2, and the application method is to apply fertilizer along with water.

[0146] Seeding and seedling raising: floating seedling raising on December 20, 2023; transplanting date: March 17, 2024, transplanting under film. According to the actual situation of the study area, a patch drip irrigation tape under film was selected, with a nominal diameter of 16mm, a wall thickness of 0.2mm, and a water outlet diameter of The rated working pressure of the dripper is ha = 0.1 MPa, and the rated flow rate of 30 cm hole spacing is Q = 3.0 ~ 4.0 L / h. According to the requirement of 1.2 m spacing between flue-cured tobacco planting ridges, the outlet spacing of the drip irrigation belt is selected to be 1.2 m, and the branch pipe is set at 50 m.

[0147] Water the roots for 15 minutes; the lower and upper limits of field irrigation management are 55% to 85% of the field water holding capacity. Fertilizer application is carried out according to the experimental design. All topdressing fertilizers are water-soluble fertilizers.

[0148] (1) Record the soil nutrients of each treatment: 1) Soil testing. Before tillage and 40d, 55d, and 75d after transplanting flue-cured tobacco, collect soil from the 0-20cm ridge layer, and select 5 points in each plot to prepare mixed soil samples. Soil pH was determined by the potentiometric method; soil organic matter was determined by the potassium dichromate volumetric method; soil alkaline nitrogen, available phosphorus, and available potassium were determined by the alkaline diffusion method, sodium bicarbonate extraction molybdenum antimony colorimetric method, and acetic acid extraction flame photometry, respectively; soil bulk density and porosity were determined by the ring knife method. 2) Nitrogen, phosphorus, and potassium nutrient utilization efficiency. 75d after transplanting flue-cured tobacco, select 5 tobacco plants with uniform growth in each plot, dig out the sample plants, and rinse them with clean water. The roots, stems, and leaves of the sample plants were collected separately, sterilized in a constant temperature box at 105℃ for 30min, and dried at 80℃ to constant weight. The Hz SOQ-Hz 0: method was used to boil the dry sample, and the N, P, and K contents of the plants were determined by the Kjeldahl method, the molybdenum antimony colorimetric method, and the flame photometry method. Calculation formula:

[0149] Accumulation amount of N(P,K) per unit area (kg / hm2) = N(P,K) content in tobacco plant (organ) (%) x dry matter weight of tobacco plant (organ) (g) x

[0150] Planting density / 1000;

[0151] N(P,K) nutrient absorption efficiency (FAE, %) = Accumulation amount of N(P,K) in tobacco plants per unit area / Application amount of N(P,K) per unit area x 100;

[0152] N(P,K) nutrient utilization efficiency (FUE, kg / kg) = Dry matter weight of tobacco leaves per unit area / Application amount of N(P,K) per unit area;

[0153] N(P,K) tobacco leaf production efficiency (LPE, leg / leg) = Dry matter weight of tobacco leaves per unit area / Total accumulation amount of N(P,K) elements in tobacco plants per unit area;

[0154] N(P,K) harvest index (HI, %) = Accumulation amount of N(P,K) in tobacco leaves per unit area / Accumulation amount of N(P,K) in tobacco plants per unit area x 1000

[0155] (2) Record and compare the growth period, agronomic traits, tobacco leaf quality, yield and output value, as well as the promotion and application benefits (economic benefits, ecological benefits, social benefits) and chemical components of tobacco plants.

[0156] 2 Results

[0157] 2.1 Changes in soil nutrients for tobacco cultivation and nutrient utilization rate of flue-cured tobacco

[0158] 2.1.1 Organic matter

[0159] The content of soil organic matter is an important indicator of the basic fertility of cultivated land soil, and is closely related to soil structure, adsorption, permeability, and penetrability. With the progress of the growth of flue-cured tobacco, the content of soil organic matter in tobacco-growing soil first increases and then decreases; the content of organic matter in the F2C3 treatment is the highest at each stage ( Figure 3 ). It can be seen that increasing the use of cake fertilizer and applying topdressing in several times by the integrated water and fertilizer management method can increase the content of soil organic matter in tobacco-growing soil.

[0160] 2.1.2 Alkaline hydrolyzable nitrogen

[0161] The level of soil nitrogen content and the nitrogen supply capacity determine the growth and development of crops and the production potential of cultivated land. With the progress of the growth of flue-cured tobacco, the content of alkaline hydrolyzable nitrogen in tobacco-growing soil gradually decreases; the content of alkaline hydrolyzable nitrogen in the F2C3 treatment is the highest at each stage ( Figure 4 )

[0162] 2.1.3 Available phosphorus

[0163] Phosphorus is an essential macronutrient for crop growth, development, high quality, and stable yields. The phosphorus obtained by crops mainly comes from the soil phosphorus pool. As the growth process of flue-cured tobacco progresses, the available phosphorus content in the tobacco-growing soil first increases and then decreases, and the available phosphorus content in the F2C3 treatment is the highest in each period ( Figure 5 ).

[0164] 2.1.4 Available potassium

[0165] Flue-cured tobacco is a potassium-loving crop, and a large amount of potassium fertilizer needs to be applied when planting flue-cured tobacco. The potassium remaining in the plough layer soil is much higher than that in the bottom layer soil. As the growth process of flue-cured tobacco progresses, the available potassium content in the tobacco-growing soil first increases and then decreases, and the available potassium content in the F2C3 treatment is the highest in each period ( Figure 6 )

[0166] 2.1.5 Nutrient use efficiency of N, P, and K in each treatment

[0167] According to the results in Table 17, the nutrient use efficiency of N, P, and K in the F2C3 treatment is the highest.

[0168] Table 17 Nutrient use efficiency of N, P, and K in each treatment

[0169]

[0170] 2.2 Agronomic traits of flue-cured tobacco in each treatment

[0171] According to the results in Table 18, the plant height, stem diameter, number of leaves, maximum leaf length, and maximum leaf width of flue-cured tobacco under the F2C3 treatment are the best. This may be because the absorption rate of fertilizers by crops is improved due to the direct application of fertilizers near the crop roots. The integrated water and fertilizer technology can achieve small and frequent fertilization, meet the nutrient requirements of crops during the critical growth period, and thus improve the growth rate and yield of crops.

[0172] Table 18 Agronomic traits of flue-cured tobacco in each treatment

[0173]

[0174] 2.3 Comparison of economic traits in each treatment

[0175] According to the results in Table 19, for the dryland flue-cured tobacco planting in the medium-nitrogen, high-phosphorus, and low-potassium tobacco area of Baimangying, Jianghua County, adopting the F2C3 treatment, that is, 1:0.8:3 + 15 kg of cake fertilizer + micro-fertilizer spraying and the integrated water and fertilizer fractional fertilization scheme, the mu yield, mu output value, and superior tobacco rate of flue-cured tobacco are significantly higher than those of other treatments, which is the best fertilization scheme.

[0176] Table 19 Comparison of economic traits in each treatment

[0177]

[0178] 2.4 Comparison of internal chemical components of tobacco leaves in each treatment

[0179] Under the same N-P2O5-K2O ratio, the contents of reducing sugar, nicotine, total nitrogen, chlorine, potassium and the sugar-alkali ratio of the integrated water and fertilizer application with split fertilization are higher than those of split fertilization by watering and single fertilization, and the proportion of each component content is still relatively moderate.

[0180] Table 20 Comparison of the internal chemical components of tobacco leaves under each treatment

[0181]

[0182] 3 Conclusions

[0183] The contents of soil organic matter, available nitrogen, available phosphorus and available potassium are the highest under the F2C3 treatment; the nutrient use efficiency of N, P and K in tobacco plants is the highest; the plant height, stem diameter, number of leaves, maximum leaf length and maximum leaf width of flue-cured tobacco are the best under the F2C3 treatment. The use of the F2C3 treatment, that is, 1:0.8:3 + 15 kg of cake fertilizer + micro-fertilizer spraying and the integrated water and fertilizer application with split fertilization, the mu yield, mu output value and superior tobacco rate of flue-cured tobacco are significantly higher than those of other treatments, which is the best fertilization plan. Under the same N-P2O5-K2O ratio, the contents of reducing sugar, nicotine, total nitrogen, chlorine, potassium and the sugar-alkali ratio of the integrated water and fertilizer application with split fertilization are higher than those of split fertilization by watering and single fertilization, and the proportion of each component content is still relatively moderate.

Claims

1. A drip irrigation cultivation method for improving the quality of dryland tobacco leaves, characterized in that, The method comprises the following steps: (1) Sowing, raising seedlings and transplanting; (2) For irrigation, drip irrigation under plastic film is adopted, and the drip irrigation under plastic film adopts a "rich" - shaped drip irrigation tape layout; (3) Control the water consumption modulus of dry - land flue - cured tobacco during the root - extending period, vigorous - growth period and maturity period to be 25.97%, 39.63% and 34.40% respectively; (5) Fertilization: N:P:K = 1:0.8:

3. Increase the application of cake fertilizer as base fertilizer and spray micronutrients on the leaf surface; and then carry out 5 top - dressings.

2. The method according to claim 1, characterized in that In step (1), the planting density is 1.2m×0.5m.

3. The method according to claim 1, wherein In step (2), the drip irrigation tape used has a hole spacing of 30cm, a flow rate of 3.0 - 4.0L / h, and is arranged in cooperation with a ridge height of 40cm.

4. The method according to claim 3, wherein The drip irrigation tape is made of PE material.

5. The method according to claim 1, characterized in that The time for the 5 top - dressings is as follows: Apply the first seedling - promoting fertilizer at the time of transplanting, apply the second seedling - promoting top - dressing about 7 days after transplanting; carry out small soil - banking about 14 days after transplanting, break the plastic film and dig out the seedlings, and apply the third seedling - promoting top - dressing; apply the fourth special top - dressing by watering 20 - 25 days after transplanting; apply the remaining fifth special top - dressing + part of potassium sulfate by watering during the vigorous - growth period; apply the remaining potassium sulfate by watering 45 - 50 days after transplanting.

6. The method according to claim 5, wherein The vigorous - growth period is 35 - 40 days after transplanting.

7. The method according to claim 5, wherein In step (5), the mass ratio of N - P2O5 - K2O in the base fertilizer is 8 - 10 - 11; the mass ratio of N - P2O5 - K2O in the seedling - promoting fertilizer is 20 - 9 - 0; the mass ratio of N - P2O5 - K2O in the special top - dressing is 10 - 0 - 32.

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