A method for improving the yield of winter wheat dominant strips in saline-alkali land by allocating nitrogen fertilizer

Abstract

The present invention discloses a method for promoting the yield of winter wheat dominant strips in saline-alkali land by distributing nitrogen fertilizer, and belongs to the technical field of improving the quality and efficiency of winter wheat in saline-alkali land. Before sowing wheat in saline-alkali farmland, differential tillage treatment is carried out. By utilizing the different characteristics of plowing strips and pure rotary tillage strips, the lateral migration of water is artificially created, which drives salt to leave the pure rotary tillage area, so that the pure rotary tillage area forms a dominant strip to increase the yield of winter wheat. Nitrogen fertilizer is applied on this basis, and the characteristics of water migration that simultaneously drives nitrogen to leave the pure rotary tillage strips are utilized to tap the yield-increasing potential of the dominant strips and further optimize the utilization rate of nitrogen fertilizer. The farmland yield of the method of the present invention is increased by about 25% compared with the yield of conventional saline-alkali farmland, and is increased by about 9% compared with the yield of farmland treated with only concentrated straw burying and pure rotary tillage. The yield-increasing advantage is obvious and has a prospect for promotion.

Description

Technical Field

[0001] The present 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] my country has 99.13 million hectares of saline-alkali land. Fully utilizing this land could increase yields. However, research shows that when soil salinity exceeds 0.03%, wheat growth and development are affected by salinity stress, which is detrimental to wheat yields and improving arable land utilization efficiency.

[0003] Improving and optimizing saline-alkali land is a complex process. Generally, flood irrigation is the primary technical measure for reducing salinity in saline-alkali land. However, coastal saline-alkali land is characterized by shallow groundwater levels and high evaporation, making salinization a serious problem. Furthermore, it is difficult to maintain a stable freshwater irrigation source during the winter and spring. Saltwater irrigation after winter wheat sowing seriously affects seed germination and seedling growth. The paper "Effects of Straw Return Method and Strip Tillage Width Ratio on Soil Physical and Chemical Properties and Winter Wheat Yield in Coastal Saline-alkali Land" demonstrates that appropriate tillage methods and fertilizer application rates can improve soil structure, increase soil organic matter content, and enhance soil fertility and water and fertilizer retention capacity. However, while the paper proposes a combined tillage and rotary tillage method for soil improvement, strips with concentrated straw tillage reduce soil bulk density and increase soil evaporation. Water absorption by straw in the tillage layer causes water to migrate from the rotary tillage strips on either side to the tillage strips. Of the key plant nutrients, nitrogen, phosphorus, and potassium, potassium has the highest mobility in soil. Due to the coordinated migration of water and salt, saline ions concentrate in the plowing strips, and nitrogen also concentrates in these strips due to the coordinated migration of water and nitrogen. This has adverse effects on both pure rotary tillage strips and plowing strips: for pure rotary tillage strips, nitrogen in these strips decreases, reducing the soil's nitrogen supply capacity. Although soil salinity and alkalinity concentrations are reduced, the lack of nitrogen limits yield potential. For plowing strips, nitrogen accumulates in these strips, resulting in nitrogen waste and deterioration of soil physical properties. Therefore, improving production conditions to further overcome these disadvantages while maintaining the advantages of zoned tillage and increasing wheat yields is the key to further research. Summary of the Invention

[0004] In view of the above-mentioned prior art, the purpose 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 solutions:

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

[0007] (1) The farmland was divided into different strips: a 1.8 m wide plowing 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 and the straw is centrally burial;

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

[0010] (4) The entire 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 straw in the pure rotary tillage strip is crushed and concentrated in the plowing strip, so that the corn straw is mixed into the 30-40 cm soil layer of the plowing strip.

[0013] Furthermore, in step (3), when applying base fertilizer and topdressing during the sowing period and jointing period, the nitrogen fertilizer application rate per unit area of ​​the plowing 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 applied was 60-120 kg hm-3 in terms of P2O5. -2 Calculated in terms of K2O, the amount of potash fertilizer used is 90-150 kg 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 watered 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, utilizes a straw centralized field returning machine to collect all the straw in the plowing strips, and then buries the straw, then applies nitrogen fertilizer according to a formula on the two strips, and finally prepares the land for rotary tillage on all 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 without 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 yield of the pure rotary tillage strip is higher than the decrease in 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 fertilizer while ensuring that the amount of nitrogen fertilizer used remains unchanged, thereby improving the potential for increasing production, 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 having no destructive effect on the physical and chemical properties of the soil. The present invention improves the production potential of pure rotary tillage strips without significantly reducing the yield potential of concentrated straw plowing 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 grain production in my country's coastal saline-alkali land. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 The figure shows 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 figure shows the design of the field test of the method of the present invention and a schematic diagram of the plant and soil sampling points and the field evapotranspiration monitoring points.

[0024] Figure 3 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 showing 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 intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as 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 with reference to 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 previous studies of the prior art have found that strip tillage treatment of production land is beneficial to increasing yields, the different mobility of different elements in the soil has been ignored. Nitrogen has high mobility in the soil, especially in sandy soils, 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 40 cm. In addition, the amount of irrigation and the method of irrigation will also affect the mobility of nitrogen. For example, under artificial irrigation conditions, the greater the amount of irrigation, the more obvious the downward migration of nitrate nitrogen in the soil surface, and the longer the migration distance. Therefore, based on the use of strip tillage to increase yield, this study strives to optimize the pure rotary tillage strip wheat yield increase and invents a cultivation and management method for pure rotary tillage strips to increase nitrogen fertilizer, 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, not specifically described, are all conventional experimental materials in the field and can be purchased through commercial channels. In the tables listed in the subsequent examples, the values ​​of the same parameter marked with different letters indicate significant differences between different treatments at the p < 0.05 level, using LSD statistics.

[0032] Example 1

[0033] 1.1 Experimental Design

[0034] A field experiment was conducted in Xiaobotou Town, Wudi County, Binzhou City, Shandong Province (N37°56′42.93″, E111°57′43.02″). A randomized block design was used. The winter wheat variety Taimai 198 was used as the test variety. The experimental treatment consisted of two consecutive planting strips: a 1.8-m wide ploughing strip and a 5.4-m wide rotary tillage strip, forming a 7.2-m wide and 50-m long experimental plot. Each plot was replicated four times. The wheat sowing rate was 300 kg hm2. -2 The straw from the previous summer corn crop was used as the returning material. The straw was concentrated in the tillage strips and buried. The amount of straw returned to the field was 12255 kg hm -2 (The moisture content of corn straw was 66.3% ± 2.7%). Winter wheat was irrigated with sprinkler irrigation at a depth of 250 mm before the jointing stage and during the grain filling stage.

[0035] When applying basal fertilizer and topdressing during the sowing and jointing stages, the nitrogen fertilizer 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 ​​the pure rotary tillage strip is three times that of the plowing strip, the total amount of nitrogen fertilizer applied to each experimental area (alternating tillage once) was the same, and the total amount of pure nitrogen applied to each treatment base (one plowing strip + one pure rotary tillage strip) was 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 , nitrogen, phosphorus and potassium fertilizers were urea, superphosphate and potassium sulfate respectively. The control group was set up under the conditions of uniform straw return and conventional fertilization and pure rotary tillage (R0) and uniform straw return and no nitrogen fertilizer application and pure rotary tillage (R1). The soil samples and plant samples required by the present invention were progressively sampled at the horizontal distance of 0, 0.9, 1.8, 2.7 and 3.6 m from the symmetry axis of the tillage strip in each test area perpendicular to the strip direction ( Figure 2 ), repeated 3 times, in this experiment, 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 its 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] Grain number 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 obtained.

[0045] Thousand-grain weight: Samples of air-dried grains from the yield measurement plots were collected 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, actual output (t hm -2 ), the calculation method is as follows: take 5×0.6m 2 Harvest plots were made. All wheat ears in the plot were manually cut and threshed using a small seed thresher. The grains were dried at 70°C to a constant weight. Grain yield was calculated based on a moisture content of 13%. Each treatment was replicated three times. The following is the public notice:

[0047]

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

[0049] 1.2.2 Soil nitrogen accumulation

[0050] Total soil nitrogen was determined using the semi-micro Kjeldahl method. 1.00 g of air-dried soil (passing a 100-mesh sieve) was weighed (containing approximately 1 mg of nitrogen). (1) The soil was boiled; (2) Ammonia was distilled; (3) 0.01 mol L -1 Titrate the distillate with H2SO4 standard solution until the color changes from bluish-green to just purple-red. Record the volume of acid standard solution used (V1). The volume of acid standard solution used in the blank measurement (V2) should generally not exceed 0.4 mL.

[0051]

[0052] *14.0: Relative molecular mass of nitrogen

[0053] 1.2.3 Field evapotranspiration

[0054] On a clear, cloudless day, a transparent acrylic box (light transmittance ≈ 96%, 30×30×120 cm) was used to completely cover the uniformly growing wheat plants selected for each treatment, forming a closed chamber. Water-absorbing cellulose (water absorption capacity ≈ 33%) was used to absorb moisture within the box. The absorbent cellulose was replaced and ventilated every 2 hours, and measurements were taken continuously for 24 hours, a total of 12 times. Each time the absorbent cellulose was removed, it was immediately placed in a ziplock bag and returned to the laboratory. The weight was then weighed using a 1 / 1000 scale and recorded as Wa1...Wa 12 Then open the ziplock bag and put it into the oven to dry until constant weight is reached. The total weight is recorded as Wb1......Wb 12

[0055]

[0056] i: 1...12;

[0057] *30 2 : Evaporation tank bottom area (cm 2 ).

[0058] 1.2.4 Soil moisture content

[0059] Sampling was conducted at a depth of 60 cm, with a layer of 20 cm per soil, during the wheat jointing, flowering, grain filling, and maturity stages. Three replicates were used for each treatment. Fresh weight of soil samples was measured immediately after collection and then dried at 75°C to constant weight. Soil moisture content was calculated as follows:

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

[0061] 1.2.5 Soil salinity

[0062] Weigh 4 g of air-dried soil sample (passing a 1 mm sieve) into a test tube, add 20 ml of water (1:5 soil leachate), secure with a leather stopper, and shake for 3 minutes. Allow to settle, then filter. The soil sample's electrical conductivity is measured using a conductivity meter (DDSJ-308). The total amount of water-soluble salts in the soil is determined by the residue drying method. Combined with the corresponding soil leachate conductivity measured by the conductivity method, a regression equation is calculated to determine the soil salinity.

[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 the yield of winter wheat by 14% compared with conventional rotary tillage fields. After adding the nitrogen fertilizer formula to the two strips on the basis of alternating rotary tillage, formula 2 (DRN2) achieved further improvement in yield potential, with a 25% increase 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 formula 3 in the tillage strips 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 in the tillage strips, resulting in an overall yield lower than that of the conventional treatment (R). The reason for this can be found in the following table: 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 formulation treatments during the entire sampling growth period. The lack of nitrogen content inhibited the growth, development and yield formation of wheat.

[0071] Figure 3 The results showed that there was a significant difference in soil moisture content between the concentrated straw tillage strips and the pure rotary tillage strips. The soil moisture content in the tillage strips was always higher than that in 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, which indicates that water drives the salt to migrate to the plowed strips.

[0072] Depend on Figure 4 As can be seen, the soil nitrogen content in the ploughed strips (DRN1) of Formulation 1 was consistently higher than that in the pure rotary tillage strips (DRN1) across all four sampling periods. However, this formulation did not participate in nitrogen distribution, indicating that alternating ploughing and rotary tillage can lead to lateral nitrogen movement within the soil layer. Formulation 3 distributed excess nitrogen fertilizer to the pure rotary tillage strips, but the water and nitrogen movement within the soil layer was insufficient to fully transfer the excess nitrogen from the pure rotary tillage strips to the ploughed strips. This resulted in the soil in the ploughed strips of Formulation 3 being consistently nitrogen-deficient.

[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 3-5, we can see that the yield of the pure rotary tillage strips in each formula is significantly higher than that of the plowing strips. As the amount of nitrogen applied to the pure rotary tillage strips increases, the yield difference between the plowing strips and the 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 The results show that the soil salinity in this area is lower than in other areas, and the pH value is closer to normal non-saline farmland, resulting in the mildest saline-alkali stress. The yield of the pure rotary tillage strip in Formulation 2 was 6.6% higher than that of Formulation 1 and 31.94% higher than that of Formulation 3. However, the difference in yield between the plowing strips in Formulations 1 and 2 was not significant. This is because the plowing strips, as inferior strips for salt collection, have limited yield-increasing potential, and the amount of nitrogen fertilizer applied cannot significantly affect yield formation. In Formulation 3, no nitrogen fertilizer was applied to the plowing strips, and the soil nitrogen content became the limiting factor, seriously affecting yield formation. The advantage of Formulation 2 in significantly increasing yield is mainly due to the increase in the number of ears per hectare and the number of grains per ear. The thousand-grain weight did not have a significant advantage over the other formulations.

[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 migration, water not only takes away salt, but also some nitrogen is carried away with the water and accumulated in the inferior strips. This leads to nitrogen waste. To this end, this study explores the rational 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 and winter wheat yield regulation in coastal saline-alkali land, providing a new method for promoting the rational combination of fertilization and tillage methods and increasing grain yield in my country's coastal saline-alkali land.

[0081] The above description is merely a preferred embodiment of the present application and is not intended to limit the present application. Various modifications and variations are possible for those skilled in the art. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present application shall be included within the scope of protection of the present application.

Claims

1. A method for increasing the yield of dominant strips of winter wheat in saline-alkali soil by distributing nitrogen fertilizer, characterized in that: The steps include: (1) The farmland was divided into different strips: a 1.8 m wide plowing 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 and the straw is centrally burial; (3) Fertilizing the farmland: applying different amounts of nitrogen fertilizer to the tilled strips and pure rotary tillage strips; (4) The entire farmland is tilled and then sown; In step (3), when applying basal fertilizer and topdressing during the sowing and jointing stages, 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 applied was 60-120 kg hm-3 in terms of P2O5. -2 Calculated in terms of K2O, the amount of potash fertilizer used is 90-150 kg hm -2 .

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 according to claim 1, characterized in that: In step (2), after the previous crop corn is harvested, the corn straw in the pure rotary tillage strip is crushed and concentrated in the plowing strip, so that the corn straw is 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 soil by nitrogen fertilizer distribution according to 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.

5. The method for increasing the yield of winter wheat dominant strips in saline-alkali land by nitrogen fertilizer distribution according to 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.

6. The method for increasing the yield of dominant strips of winter wheat in saline-alkali land by nitrogen fertilizer distribution according to claim 5, characterized in that: The winter wheat is salt-tolerant winter wheat.

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