Method for promoting yield of dominant strips of winter wheat in saline-alkali soil through nitrogen fertilizer distribution

Abstract

The invention discloses a method for promoting the yield of dominant strips of winter wheat in saline-alkali soil through nitrogen fertilizer distribution, and belongs to the technical field of quality improvement and efficiency improvement of winter wheat in saline-alkali soil. According to the method, tillage difference treatment is carried out before wheat is sown in a saline-alkali farmland in a season, by means of different characteristics of a tillage strip and a pure rotary tillage strip, transverse movement of water is artificially produced, salt is driven to leave a pure rotary tillage area, a dominant strip is formed in the pure rotary tillage area, the yield of winter wheat is increased, and nitrogen fertilizer is applied on the basis, so that the yield of the winter wheat is increased. By utilizing the characteristic that water moves and drives nitrogen to leave a pure rotary tillage strip, the yield increasing potential of a superior strip is excavated, and the nitrogen fertilizer utilization rate is further optimized. According to the method, the farmland yield is increased by about 25% compared with the conventional saline-alkali soil farmland yield, the farmland yield is increased by about 9% compared with the farmland only subjected to straw centralized turning and burying and pure rotary tillage alternating treatment, the yield increasing advantage is obvious, and the method has the popularization prospect.

Description

Technical Field

[0001] The invention relates to the technical field of improving the quality and efficiency of winter wheat in saline-alkali land, and in particular to a method for promoting the yield of dominant strips of winter wheat in saline-alkali land by distributing nitrogen fertilizer. Background Art

[0002] The area of ​​saline-alkali land in my country is 99.13 million hectares. If saline-alkali land can be fully utilized, production can be increased. However, studies have shown that when the soil salt content is higher than 0.3%, the growth and development of wheat will be affected by saline-alkali stress, which is not conducive to the formation of wheat yield and the improvement of arable land utilization efficiency.

[0003] Improvement and optimization of saline-alkali land is a complex process. Generally speaking, flood irrigation is the main technical measure for reducing salt in saline-alkali land, but coastal saline-alkali land has the characteristics of shallow groundwater level and high evaporation, and the problem of salt back is very serious. In addition, it is difficult to ensure a stable source of freshwater irrigation in winter and spring. Saltwater irrigation after winter wheat sowing seriously affects seed germination and the growth and development of wheat seedlings. The paper "Effects of Straw Returning Method and Strip Tillage Width Ratio on Soil Physical and Chemical Properties and Winter Wheat Yield in Coastal Saline-alkali Land" shows that reasonable tillage methods and fertilizer application rates can improve soil structure, increase the content of organic matter in the soil, and improve soil fertility and water and fertilizer retention capacity. However, although the paper proposes to improve the soil by combining tillage and rotary tillage, the strips with concentrated straw tillage have a lower soil bulk density and increased soil evaporation. The water absorption of straw in the tillage layer causes the water in the rotary tillage strips on both sides to move to the tillage strips. Among the main nutrients of plants, nitrogen, phosphorus and potassium, potassium has a higher mobility in the soil. Under the coordinated migration of water and salt, saline ions will concentrate in the tillage strips, and nitrogen will also concentrate in the strips due to the coordinated migration of water and nitrogen. This has an adverse effect on both the pure rotary tillage strips and the tillage strips: for the pure rotary tillage strips, the nitrogen in this part is reduced, and the soil nitrogen supply capacity is reduced. Although the soil salinity concentration is reduced, the potential for increasing production is limited due to the lack of nitrogen; for the tillage strips, a large amount of nitrogen accumulates in the strips, which will cause nitrogen waste and deterioration of soil physical properties. Therefore, the key to the next step of research is to improve production conditions, further overcome the above disadvantages on the basis of maintaining the advantages of zoned tillage, and increase wheat yields. Summary of the invention

[0004] In view of the above-mentioned prior art, the object of the present invention is to provide a method for promoting the yield of dominant strips of winter wheat in saline-alkali land by distributing nitrogen fertilizer.

[0005] To achieve the above object, the present invention adopts the following technical solution:

[0006] In a first aspect of the present invention, a method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution is provided, comprising the following steps:

[0007] (1) The farmland was divided into different strips: a 1.8 m wide tillage strip and a 5.4 m wide pure rotary tillage strip, with the two strips arranged continuously and alternately;

[0008] (2) Centralized straw burial: The straw on the pure rotary tillage strip is concentrated in the adjacent tillage strip for centralized straw burial;

[0009] (3) Fertilizing the farmland: Apply different amounts of nitrogen fertilizer to the tilled strips and pure rotary tillage strips;

[0010] (4) The farmland is tilled and then sown.

[0011] Furthermore, in step (1), the width of the farmland plot is a positive integer multiple of 7.2 m.

[0012] Furthermore, in step (2), after the previous crop corn is harvested, the corn stalks in the pure rotary tillage strip are crushed and concentrated in the plowing strip, so that the corn stalks are mixed into the 30-40 cm soil layer of the plowing strip.

[0013] Furthermore, in step (3), when applying basal fertilizer and topdressing fertilizer at the sowing period and jointing period, the nitrogen fertilizer application ratio per unit area of ​​the tillage strip and the pure rotary tillage strip is (30-90) kg hm -2 :(70-280)kg hm -2 ;

[0014] Phosphate and potash fertilizers were applied evenly in two strips during the sowing period. The amount of phosphate fertilizer was 60-120 kg hm-3 in terms of P2O5. -2 ; Calculated in terms of K2O, the amount of potash fertilizer is 90-150kg hm -2 .

[0015] Furthermore, in step (3), the nitrogen fertilizer, the phosphorus fertilizer and the potash fertilizer are urea, superphosphate and potassium sulfate, respectively.

[0016] Furthermore, in step (5), the sowing date is mid-October, and the winter wheat is irrigated with 100-500 mm of water before the jointing stage and during the grain filling stage by sprinkler irrigation.

[0017] Furthermore, the wheat is winter wheat with salt tolerance.

[0018] Beneficial effects of the present invention:

[0019] The present invention performs strip tillage treatment on production land before the wheat season in saline-alkali land, divides the field into pure rotary tillage strips and plowing strips, uses the previous corn straw as the field returning material, uses a straw concentrated field returning machine to collect all the straw in the plowing strips and then buries the straw, then applies nitrogen fertilizer in the two strips according to a formula, and finally prepares and rotary tills all the strips of the production land.

[0020] Under the coordinated migration of water and salt, saline-alkali ions will concentrate in the plowing strip, and nitrogen will also concentrate in the strip due to the coordinated migration of water and nitrogen. This will result in higher saline-alkali ions and nitrogen in the plowing strip, lower saline-alkali ions and nitrogen in the pure rotary tillage strip, and reduced wheat yields in both strips. The present invention tests multiple formulas with the same total nitrogen fertilizer dosage but different nitrogen distribution ratios between the two strips, and selects the formula that can maximize the potential of pure rotary tillage while not significantly reducing the potential of the plowing strip. By applying less nitrogen fertilizer in the plowing strip and more nitrogen fertilizer in the pure rotary tillage strip, the increase in the yield of the pure rotary tillage strip is higher than the decrease in the yield of the plowing strip, thereby achieving an overall increase in yield.

[0021] The salt collection method and nitrogen formula for saline-alkali land used in the present invention optimize the distribution of nitrogen fertilizers and improve the potential for increasing production while ensuring that the amount of nitrogen fertilizer used remains unchanged, compared with conventional farmland. The present invention achieves the goal of increasing the yield of winter wheat in saline-alkali land while avoiding the waste of nitrogen, and has no destructive effect on the physical and chemical properties of the soil. The present invention increases the production potential of pure rotary tillage strips without significantly reducing the potential for increasing production of concentrated straw tillage strips, ultimately achieving an increase in the overall yield potential of the plot. Compared with pure rotary tillage land with uniform straw return to the field and conventional nitrogen fertilizer application, the present method significantly increases the yield of winter wheat in saline-alkali land, providing a new way to promote the rational combination of fertilization and tillage methods and increase the grain output of coastal saline-alkali land in my country. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The distribution of tillage strips (straw burying strips) and rotary tillage strips; the left picture shows that all the straw is concentrated in the tillage strips, and the right picture shows the effect after the straw in the tillage strips is buried in the soil.

[0023] Figure 2 The diagram is a schematic diagram of the field test design of the method of the present invention and a schematic diagram of the plant, soil sampling points and field evapotranspiration monitoring points.

[0024] Figure 3 It is a schematic diagram of the effect of the method of the present invention on the distribution of soil moisture content in the range of 0-60 cm.

[0025] Figure 4 Schematic diagram of the effect of the method of the present invention on the total nitrogen content of each soil layer.

[0026] Figure 5 Schematic diagram of the effect of the method of the present invention on the salt content of each soil layer.

[0027] Figure 6 Schematic diagram of the effect of the method of the present invention on the pH of each soil layer. DETAILED DESCRIPTION

[0028] It should be noted that the following detailed descriptions are illustrative and are intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those commonly understood by those skilled in the art to which the present application belongs.

[0029] In order to enable those skilled in the art to more clearly understand the technical solution of the present application, the technical solution of the present application will be described in detail below in conjunction with specific embodiments.

[0030] In the strip tillage treatment of production land, it is generally believed that pure rotary tillage strips are dominant strips and plowing strips are inferior strips. Although the previous research of the prior art found that strip tillage treatment of production land is beneficial to increase yield, it ignores the different mobility of different elements in the soil. Nitrogen has high mobility in the soil, especially in sandy soil, where its fluidity is higher, but its ability to retain water and fertilizer is poor. Under drip irrigation conditions, the vertical movement distance of nitrogen can exceed 40cm. In addition, the irrigation amount and irrigation method will also affect the mobility of nitrogen. For example, under artificial irrigation conditions, the greater the irrigation amount, the more obvious the downward migration of nitrate nitrogen in the soil surface, and the longer the migration distance. Therefore, on the basis of increasing yield by strip tillage, this study strives to optimize the pure rotary tillage strip wheat yield increase, and invented a cultivation management method for pure rotary tillage strip nitrogen fertilizer application, thereby further reducing the key problem of decreased yield potential due to soil nitrogen deficiency.

[0031] The experimental materials used in the examples of the present invention without specific description are all conventional experimental materials in the field and can be purchased through commercial channels. The values ​​marked with different letters in the same parameter in each table listed in the subsequent examples indicate significant differences between different treatments at the p<0.05 level, LSD data statistics.

[0032] Example 1

[0033] 1.1 Experimental design

[0034] The field experiment was conducted in Xiaobotou Town, Wudi County, Binzhou City, Shandong Province (N37°56′42.93″, E111°57′43.02″). This experiment adopted a randomized block experimental design. The winter wheat variety Taimai 198 was used as the test variety. The experimental treatment consisted of two continuously arranged planting strips, of which the width of the plowing strip was 1.8m and the width of the pure rotary tillage strip was 5.4m, which were combined into a test area with a width of 7.2m and a length of 50m. Each test area was repeated four times. The wheat sowing rate was 300kg hm -2 The previous summer corn stalks were used as the returning material. The stalks were concentrated in the tillage strips and buried. The amount of stalks returned to the field was 12255 kg hm -2 (The moisture content of corn stalks was 66.3% ± 2.7%). Winter wheat was irrigated with 250 mm of water before the jointing stage and during the grain filling stage.

[0035] When applying basal fertilizer and topdressing fertilizer at the sowing and jointing stages, the nitrogen fertilizer application rate per unit area of ​​the tillage strip and the pure rotary tillage strip was 120 kg hm -2 :120kg hm -2 (Formula 1-DRN1), 60kg hm -2 :140kg hm -2 (Formula 2-DRN2), 0kghm -2 :160kg hm -2 (Formula 3-DRN3), since the area of ​​pure rotary tillage strip is three times that of plowing strip, the total amount of nitrogen fertilizer applied in each experimental area (alternating plowing strip once) is the same, and the total amount of pure nitrogen applied in each treatment base (one plowing strip + one pure rotary tillage strip) is 240 kg hm -2 , see Table 1.

[0036] Table 1

[0037]

[0038] In addition, the amount of phosphorus fertilizer and potassium fertilizer applied during the sowing period was P2O5 90kg hm -2 , K2O 120kg hm -2 , and the nitrogen, phosphorus and potassium fertilizers were urea, superphosphate and potassium sulfate, respectively. Pure rotary tillage under the conditions of uniform straw return and conventional fertilization (R0) and pure rotary tillage under the conditions of uniform straw return and no nitrogen fertilizer application (R1) were set as controls. The soil samples and plant samples required by the present invention were progressively sampled at 0, 0.9, 1.8, 2.7 and 3.6 m horizontally from the symmetry axis of the tillage strip in each test area perpendicular to the strip direction ( Figure 2 ), repeated 3 times, in this test, soil samples were taken to 60cm, with a layer of every 20cm.

[0039] 1.2. Measurement items and methods

[0040] 1.2.1 Output and output components

[0041] In order to conduct relevant statistics, a 2×0.9m2 area was drawn in each experimental area during the winter wheat harvest period. 2 Community.

[0042] Number of ears per hectare: Number of ears per unit area (hm -2 )×10 4 , the calculation of the number of ears per unit area is as follows:

[0043]

[0044] Number of grains per ear: Before harvest, 30 single stems were randomly selected from each plot, and the number of grains per ear was counted and the average value was taken.

[0045] Thousand-grain weight: Samples were taken from the air-dried grains measured in the plot for a thousand-grain weight survey, and the data were converted to the thousand-grain weight of the standard 13.0% moisture content.

[0046] Output, that is, the actual output of the process (t hm -2 ), the calculation method is as follows: take 5×0.6m 2 Harvest in the plot, all wheat ears in the area are cut manually, threshed with a small seed thresher, and the grains are dried at 70℃ to constant weight. The grain yield is converted to yield based on 13% moisture content. Each treatment is repeated 3 times. The public notice is as follows:

[0047]

[0048] *0.13: Dried kernels are adjusted to a standard moisture content of 13%

[0049] 1.2.2 Soil nitrogen accumulation

[0050] The total nitrogen in the soil was determined using the semi-micro Kjeldahl method. Weigh 1.00 g of air-dried soil sample (passing a 100-mesh sieve) (containing about 1 mg of nitrogen). (1) Soil sample digestion; (2) Ammonia distillation; (3) 0.01 mol L -1 The distillate of the H2SO4 standard solution titration changes from blue-green to just purple-red. Record the volume V1 of the acid standard solution used. The volume V2 of the acid standard solution used in the blank determination should generally not exceed 0.4 mL.

[0051]

[0052] *14.0: Relative molecular mass of nitrogen

[0053] 1.2.3 Field evapotranspiration

[0054] Choose a clear and cloudless day, use a transparent acrylic box (light transmittance ≈ 96%, 30×30×120cm) to completely cover the wheat plant area with uniform growth in each treatment, forming a closed room. Use absorbent cellulose (water absorption ≈ 33%) to absorb moisture in the box, replace the absorbent cellulose and ventilate every 2 hours, and measure it continuously for 24 hours for a total of 12 times. Each time the absorbent cellulose is taken out, immediately put it into a self-sealing bag, return to the laboratory, and use a one-thousandth balance to weigh it and record Wa1......Wa 12 Then open the ziplock bag and put it in the oven to dry until constant weight is reached. Weigh the total weight and record it as Wb1......Wb 12

[0055]

[0056] i: 1...12;

[0057] *30 2 : Evapotranspiration box bottom area (cm 2 ).

[0058] 1.2.4 Soil moisture content

[0059] The sampling depth was 60 cm during the jointing, flowering, filling and maturity stages of wheat, with one layer every 20 cm. Three replicates were used for each treatment. The fresh weight of the soil sample was weighed immediately after collection and then dried at 75°C to constant weight. The calculation formula for soil moisture content is as follows:

[0060] Soil moisture content (%) = (fresh weight - dry weight) / dry weight × 100%

[0061] 1.2.5 Soil salt content

[0062] Weigh 4g of air-dried soil sample (passing through a 1mm sieve) and place it in a test tube. Add 20ml of water (1:5 soil leachate), cover with a leather stopper, shake for 3min, let stand to clarify, and filter. Use a conductivity meter (DDSJ-308) to measure the conductivity of the soil sample. The total amount of water-soluble salt in the soil is determined by the residue drying method, and the regression equation is calculated in combination with the corresponding soil leachate conductivity determined by the conductivity method to finally obtain the soil salt content.

[0063]

[0064] EC 5:1 :Soil sample conductivity value

[0065] *3.1781: Regression coefficient of the conductivity-salinity linear regression equation

[0066] *0.2853: Constant term obtained by the linear regression equation of conductivity-salinity

[0067] 2. Results and Analysis

[0068] Table 2 Winter wheat yield and yield components

[0069]

[0070] As shown in Table 2, the tillage measures of alternating rotary strips can increase winter wheat yield by 14% compared with conventional rotary tillage fields. After adding the nitrogen fertilizer formula distributed in two strips on the basis of alternating rotary tillage, Formula 2 (DRN2) achieved further improvement in yield potential, increasing yield by 25% compared with conventional selective tillage fields. The yield of Formula 3 (DRN3) was significantly lower than that of other treatments. As shown in Table 5, the yield of the tillage strips of Formula 3 was significantly lower than that of other formulas. The increase in wheat yield in pure rotary tillage strips was not enough to compensate for the decrease in the yield of the tillage strips, resulting in an overall yield lower than that of the conventional treatment (R). The reason for this can be found in Figure 5 The analysis showed that the nitrogen content in the tillage strips of the formulation 3 treatment was always significantly lower than that of the other formulations during the entire sampling growth period. The lack of nitrogen content inhibited the growth and development of wheat and the formation of yield.

[0071] Figure 3 The results showed that there was an obvious difference in soil moisture content between the concentrated straw tillage strips and the pure rotary tillage strips. The moisture content of the tillage strips was always higher than that of the pure rotary tillage strips in all periods and treatments. Figure 3 The difference in salt content between the plowed strips and the pure rotary tillage strips has the same trend as the difference in water content, with the content in the plowed strips being higher than that in the pure rotary tillage strips, indicating that water drives the salt to migrate to the plowed strips.

[0072] Depend on Figure 4 It can be seen that the nitrogen content of the soil in the plowing strip of Formula 1 (plowing DRN1) was always higher than that in the pure rotary tillage strip (rotation DRN1) during the four sampling periods, but this formula did not participate in nitrogen distribution, which shows that the alternating tillage measures can lead to the lateral movement of nitrogen in the soil layer. Formula 3 allocated excessive nitrogen fertilizer to the pure rotary tillage strip, and the water and nitrogen movement in the soil layer was not enough to move all the excess nitrogen in the pure rotary tillage strip to the plowing strip. As a result, the soil in the plowing strip of Formula 3 was always in a nitrogen-deficient state.

[0073] Table 3 Yield and yield components of each sampling point of formula 1

[0074]

[0075] Table 4 Yield and yield components of each sampling point of formula 2

[0076]

[0077] Table 5 Yield and yield components of each sampling point of formula 3

[0078]

[0079] From Tables 3 to 5, it can be seen that the yield of pure rotary tillage strips in each formula is significantly higher than that of plowing strips. As the amount of nitrogen applied to pure rotary tillage strips increases, the yield difference between plowing strips and pure rotary tillage strips in each treatment gradually increases. In each formula treatment, the 0.9-2.7 area is the area with the highest local yield. Figure 5 , Figure 6 It can be seen that the salt content of the soil in this area is lower than that in other areas, and the pH value is closer to normal farmland without saline-alkali, and the salt-alkali stress is the mildest. The yield of pure rotary tillage strips in formula 2 is 6.6% higher than that in formula 1 and 31.94% higher than that in formula 3. However, there is no significant difference in the yield of the plowing strips between formula 1 and formula 2. This is because the plowing strips have limited yield-increasing potential as inferior strips for salt collection, and the amount of nitrogen fertilizer cannot significantly affect the formation of yield. In formula 3, no nitrogen fertilizer was applied to the plowing strips, and the nitrogen content in the soil became a limiting factor, which seriously affected the formation of yield. The advantage of formula 2 in significantly increasing yield mainly lies in the increase in the number of ears per hectare and the number of grains per ear, and the thousand-grain weight does not have a significant advantage compared with other formulas.

[0080] Based on the above analysis, the agronomic measure of alternating rotation can significantly change the state of lateral water migration. In the process of lateral water migration, not only salt is taken away, but part of the nitrogen is also accumulated in the inferior strips with the water. This leads to nitrogen waste. For this reason, this study explores the reasonable distribution of nitrogen fertilizers and the improvement of nitrogen utilization efficiency in response to the existing problem of nitrogen accumulation and waste. The present invention uses conventional salt-alkali tolerant wheat varieties, and deeply analyzes the effects of nitrogen fertilizer distribution and concentrated straw burial on the water and nitrogen movement law of coastal saline-alkali land and winter wheat yield regulation, in order to promote the rational combination of fertilization and farming methods, and provide a new method to increase the grain output of coastal saline-alkali land in my country.

[0081] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. For those skilled in the art, the present application may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for increasing the yield of winter wheat dominant strips in saline-alkali land by distributing nitrogen fertilizer, characterized in that: The steps include: (1) The farmland was divided into different strips: a 1.8 m wide tillage strip and a 5.4 m wide pure rotary tillage strip, with the two strips arranged continuously and alternately; (2) Centralized straw burial: The straw on the pure rotary tillage strip is concentrated in the adjacent tillage strip for centralized straw burial; (3) Fertilizing the farmland: Apply different amounts of nitrogen fertilizer to the tilled strips and pure rotary tillage strips; (4) The farmland is tilled and then sown.

2. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution as claimed in claim 1, characterized in that: In step (1), the width of the farmland plot is a positive integer multiple of 7.2 m.

3. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution as claimed in claim 1, characterized in that: In step (2), after the previous crop corn is harvested, the corn stalks in the pure rotary tillage strip are crushed and concentrated in the plowing strip, so that the corn stalks are mixed into the 30-40 cm soil layer of the plowing strip.

4. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution as claimed in claim 1, characterized in that: In step (3), when applying basal fertilizer and topdressing fertilizer at the sowing period and jointing period, the nitrogen fertilizer application rate per unit area of ​​the tillage strip and the pure rotary tillage strip is (30-90) kg hm -2 :(70-280)kg hm -2 ; Phosphate and potash fertilizers were applied evenly in two strips during the sowing period. The amount of phosphate fertilizer was 60-120 kg hm-3 in terms of P2O5. -2 ; Calculated in terms of K2O, the amount of potash fertilizer is 90-150kg hm -2 .

5. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution as claimed in claim 1, characterized in that: In step (3), the nitrogen fertilizer, the phosphorus fertilizer and the potash fertilizer are urea, superphosphate and potassium sulfate respectively.

6. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution as claimed in claim 1, characterized in that: In step (5), the sowing date is mid-October, and the winter wheat is irrigated with 100-500 mm of water before the jointing stage and during the grain filling stage by sprinkler irrigation.

7. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution as claimed in claim 6, characterized in that: The wheat is winter wheat with salt tolerance.

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