Method for improving corn and soybean water utilization efficiency and intercropping yield under strip-shaped composite planting

Abstract

The invention discloses a method for improving corn and soybean water utilization efficiency and intercropping yield under strip-shaped composite planting, and belongs to the technical field of agriculture. Aiming at the superiority of light and heat resources in the Huang-Huai-Hai region, the limitation of water resources and the uncertainty of the influence on crop productivity, in a corn and soybean strip intercropping mode, a method of combining corn strip deep scarification with total wheat straw and soybean strip returning / total wheat straw uniform returning is adopted, the plow pan is broken, the volume weight is reduced, and the yield is increased. The volume of middle and lower layers of roots is increased; the vertical and horizontal distribution of the roots is optimized; the water competition between intercropping corn and soybean strips is reduced; the above-ground source library relationship is balanced; and detecting. The water utilization efficiency WUE is remarkably improved, the land equivalence ratio LER reaches 1.41, and the method has remarkable production advantages and is beneficial to high-yield, high-efficiency and high-quality production of corn and soybeans in the northwest Shandong region.

Description

Technical Field

[0001] This invention relates to the field of agricultural technology, specifically to a method for improving water use efficiency and intercropping yield of maize and soybeans in strip intercropping. Background Technology

[0002] Water is a critical element in agricultural production and a major factor limiting agricultural development. Water use efficiency (WUE) is a core indicator measuring the ability of plants or ecosystems to convert water into biomass (or economic yield). Maize, a C4 crop, has high photosynthetic efficiency and a significantly higher WUE than soybean, a C3 crop. Its root system exhibits a "deep-broad" distribution, with root length density (RLD) in the 0–100 cm soil layer accounting for approximately 70%, demonstrating a "deep-root advantage" in absorbing water from deeper soil layers. Soybean, on the other hand, has an RLD of approximately 95% in the 0–25 cm soil layer, exhibiting a "shallow-root limitation" in absorbing water from shallower soil layers. Particularly in the 0–40 cm soil profile, the RLD of the maize strip is consistently higher than that of the soybean strip, indicating strong water competitiveness. This leads to reduced surface soil moisture in the soybean strip, forcing the stomata of its leaves to close to reduce transpiration (a decrease in stomatal conductance), resulting in hindered CO2 absorption and a 30%–40% reduction in net photosynthetic rate (i.e., "photosynthetic midday depression"). This physiological stress directly limits the accumulation of photosynthetic products in soybeans, ultimately affecting yield. To compensate for the deficiency in the surface layer, soybeans accelerate the consumption of deep water, which reduces the amount of deep water that corn roots can absorb in the later stages (grain filling stage). This directly restricts the transport of dry matter to the grains, resulting in "hidden yield reduction".

[0003] The Huang-Huai-Hai region, a major grain-producing area in my country, is not only a core planting area for corn and soybeans but also a typical water-scarce region. Located in the warm temperate semi-humid continental monsoon climate zone, its unique regional hydrothermal conditions are a typical microcosm of the mismatch between water and heat resources and agricultural production needs in northern my country's monsoon climate zone. While the basic advantages of high temperatures and abundant rainfall in summer, with rain and heat occurring simultaneously, should benefit crop growth, the highly concentrated rainfall (frequent summer and autumn rainstorms, and drought in winter and spring) and extremely scarce water resources (the region's water resources account for only 8% of the national total) create a sharp contradiction with the high water consumption of agriculture. Irrigated area accounts for 42% of the national total, and agricultural water use accounts for as much as 70% of total water consumption, yet the region faces the predicament of frequent "rapid shifts between drought and flood." This fragile balance, combining "simultaneous rainfall and heat" with "concentrated rainfall, resource scarcity, and high water consumption," dictates that agricultural development in this region must follow a path of "prioritizing water conservation, addressing both drought and flood, and utilizing resources efficiently" to cope with the long-term challenges of climate change and water scarcity.

[0004] Due to the unique hydrothermal conditions in the Huang-Huai-Hai Plain, the traditional maize-soybean intercropping pattern has significant drawbacks. Essentially, it suffers from intensified water competition, resource misallocation, and physiological stress leading to yield losses. In this pattern, the difference in root distribution between maize (a C4 crop with deep-root dominance) and soybean (a C3 crop with shallow-root limitation) triggers fierce water competition: maize's deep roots preferentially exploit deep-rooted water, while soybean's shallow roots first deplete surface water before being forced to penetrate deeper to compete for it. This directly conflicts with maize's deep-rooted water demand during the grain-filling stage (mid-August to September, the critical water requirement period), exacerbating resource scarcity under rapid shifts between drought and flood. Simultaneously, the combination of high temperatures (extreme temperatures of 35-38℃ in July and August) and water competition causes soybean leaves to close stomata, reducing net photosynthetic rate and pod number, ultimately impacting yield. Furthermore, soybean's "predatory consumption" of deep-rooted water also restricts the transport of dry matter to maize grains during the grain-filling stage, reducing grain weight and yield. In recent years, the promotion of the corn-soybean strip intercropping model has effectively alleviated the conflict of land competition in the same season, but its adaptability to the special hydrothermal conditions of the region still needs to be further explored. Summary of the Invention

[0005] The purpose of this invention is to provide a method for improving water use efficiency and intercropping yield in maize-soybean strip intercropping, addressing the superior light and heat resources and limited water resources in the Huang-Huai-Hai region and the uncertainty of their impact on crop productivity. By optimizing strip deep tillage and straw return methods, this invention explores the formation mechanism of water differences between strips in maize-soybean strip intercropping in the Huang-Huai-Hai region, clarifying the regulatory pathway of strip tillage and straw return through "water spatial balance—root distribution—dry matter source-sink relationship," providing theoretical support for the efficient and coordinated production of dryland grain crops in the same season in the Huang-Huai-Hai region.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A first aspect of the present invention provides a method for improving water use efficiency and intercropping yield of maize and soybean in strip intercropping, comprising the following steps: (1) Divide farmland into different strip areas: In the corn strip, the row spacing of corn is (0.3-0.5) m; in the soybean strip, the row spacing of soybean is (0.2-0.4) m; the row ratio of corn strip and soybean strip is (1-4):(1-4); (2) Deep loosening of the corn belt; (3) Centralized straw plowing and burying: Return all the wheat straw from the previous season to the soybean belt or return all the wheat straw from the previous season evenly to the corn belt and soybean belt; (4) After rotary tilling the farmland plots, sow the corn with a plant spacing of (0.10-0.12) m and the soybean with a plant spacing of (0.08-0.10) m.

[0007] Furthermore, in step (1), the row spacing for corn is 0.4m and the row spacing for soybeans is 0.3m.

[0008] Furthermore, in step (1), the row ratio of the corn strip and the soybean strip is configured as 2:4.

[0009] Furthermore, in step (1), the distance between the corn strip and the soybean strip is 0.7m.

[0010] Furthermore, in step (4), the corn plant spacing is 0.11m and the soybean plant spacing is 0.09m.

[0011] Furthermore, in step (4), a controlled-release compound fertilizer N-P2O5-K2O is applied once during the corn seedling stage at a rate of 750 kg / hm. 2 The contents of N, P and K are 26wt%, 10wt% and 12wt%, respectively.

[0012] Furthermore, in step (4), a controlled-release compound fertilizer N-P2O5-K2O is applied once during the soybean seedling stage at a rate of 300 kg / hm. 2 The contents of N, P and K are 15wt%, 15wt% and 15wt%, respectively.

[0013] Furthermore, in step (4), during the growing season, micro-sprinklers are used for unified irrigation based on soil moisture, drainage is carried out in a timely manner in case of flooding, and a unified plant protection plan is adopted for pest and disease control and chemical control.

[0014] Furthermore, the corn variety used was MY73, and the soybean variety used was Qihuang 34.

[0015] The beneficial effects of this invention are: This invention addresses the challenges of abundant light and heat resources and limited water resources in the Huang-Huai-Hai Plain, as well as the uncertainty of their impact on crop productivity. In a maize-soybean strip intercropping pattern, it employs a method combining deep tillage of the maize strips with the return of all wheat straw to the soybean strips / uniform return of all wheat straw to the field. This breaks up the plow pan, reducing bulk density, which promotes root penetration, increases the volume of roots in the middle and lower layers, optimizes the vertical and horizontal distribution of roots, reduces water competition between the intercropped maize and soybean strips, balances the source-sink relationship in the aboveground parts, and improves yield and crop water use efficiency. Testing showed a significant improvement in water use efficiency (WUE), with a land equivalent ratio (LER) reaching 1.41, demonstrating significant production advantages and promoting high-yield, high-efficiency, and high-quality maize-soybean production in northwestern Shandong. Attached Figure Description

[0016] Figure 1 The data represents the rainfall, daily maximum temperature, and daily minimum temperature at the experimental site during the 2024 growing season.

[0017] Figure 2 This is a schematic diagram of the field layout for different experimental planting methods.

[0018] Figure 3 Schematic diagram of row spacing and soil and root sampling points for different planting methods. (A): Maize / soybean strip intercropping, (B): Soybean monoculture, (C): Maize monoculture. a1-a2 and c1-c2 calculate the root index and soil moisture content for intercropped maize and monoculture maize, respectively; a3 calculates the root index and soil moisture content in the middle of the intercropped maize / soybean row; a4-a7 and b1-b2 calculate the root index and soil moisture content for intercropped soybean and monoculture soybean, respectively.

[0019] Figure 4 The study investigated the effects of different tillage practices on soil moisture content in the 0-100 cm depth between soybean and corn strips at different stages in 2024. In this study, A represents the flowering stage and B represents the maturity stage.

[0020] Figure 5 The effects of different farming practices on aboveground parts and pod / ear dry matter of soybeans and maize at different post-flowering days in 2024 are shown. In this study, A represents soybeans and B represents maize.

[0021] Figure 6 The study investigates the impact of different farming practices on the source viability and storage demand of soybeans and maize at different post-flowering days in 2024, where A represents soybeans and B represents maize.

[0022] Figure 7 The impact of different farming practices on water use efficiency (WUE) of soybeans and maize in 2024. Detailed Implementation

[0023] It should be noted that the following detailed descriptions are illustrative and intended to provide further explanation of this application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0024] Strip tillage significantly increases precipitation infiltration rate and stabilizes topsoil moisture content by breaking up the plow pan and increasing capillary porosity. Simultaneously, the "mixed soil structure" created by deep tillage reduces unnecessary water loss in the deeper layers of corn strips. Straw mulch reduces topsoil evaporation, delays water depletion in soybean strips, and enhances soil water retention capacity during the later stages of growth through the humification of organic matter. However, the mechanism by which deep tillage and straw return synergistically improve soil structure and water transport pathways, mitigate moisture differences between strips, and balance post-flowering source-sink relationships in intercropping patterns remains unclear.

[0025] Dry matter accumulation and its distribution to grains (source-sink allocation) are determinants of crop yield. Under unfavorable environmental conditions that limit photosynthetic assimilation during the grain-filling stage (source < sink), carbohydrates accumulated before flowering may be transferred to developing grains. However, in the maize-soybean intercropping system, these two crops exhibit significant water competition and complementary effects, and the mechanisms of dry matter synthesis and distribution remain incompletely understood. Therefore, enhancing post-flowering dry matter accumulation and improving translocation efficiency during grain filling are key strategies for increasing crop yield.

[0026] To enable those skilled in the art to better understand the technical solution of this application, the technical solution of this application will be described in detail below with reference to specific embodiments.

[0027] The experimental materials used in the embodiments of this invention, unless otherwise specified, are all conventional experimental materials in the art and can be purchased through commercial channels. The maize variety used in this invention is MY73, a maize variety bred by Henan Yuyu Seed Industry Co., Ltd. and Henan Pengchuang Agricultural Technology Co., Ltd. using a hybrid combination of T1932 and T856, with an average growth period of 101 days in the Huang-Huai-Hai summer maize region. The soybean variety used is Qihuang 34, bred by the Crop Research Institute of Shandong Academy of Agricultural Sciences, with an average summer sowing growth period of 105 days.

[0028] Example 1 1.1 Experimental Methods The field trial was conducted in 2024 at the Agronomic Experiment Station of Shandong Agricultural University, Tai'an City, Shandong Province (36°10′19″N, 117°9′03″E). The experimental site has a warm temperate monsoon climate with four distinct seasons, abundant sunshine, an average annual temperature of 12.9℃, an average annual accumulated temperature ≥0℃ of 4731℃, and an average frost-free period of 195 days. Temperature and rainfall data for the experimental site during the 2024 growing season are available in [link to relevant data]. Figure 1 The tested soil was brown soil, with a deep soil layer. The annual soil properties of the topsoil (0-20 cm) were: pH 6.8, organic matter 14.26 g / kg, and total nitrogen 1.12 g / kg. -1 The available nitrogen content was 61.5 mg / kg, available potassium was 100.26 mg / kg, and available phosphorus was 27.6 mg / kg. Crop rotation was practiced at this experimental site, with wheat sown after the corn and soybean harvest, and no fertilizer applied during the wheat season.

[0029] The experiment employed a split-plot design. The main plot included two strip deep tillage patterns: maize strip deep tillage (SM) and soybean strip deep tillage (SS). The subplot included three straw return methods: uniform return of all wheat straw (CA), uniform return of all wheat straw to maize strip (CM), and uniform return of all wheat straw to soybean strip (CS). Additionally, there were maize monoculture (SM), soybean monoculture (SS), and a conventional intercropping management pattern—rotary tillage and uniform return of wheat straw (FP). A total of nine treatments were included. Figure 2 Each treatment was repeated in triplicate. The subsoiling depth was 0.35 m and the rotary tillage depth was 0.2 m.

[0030] The row ratio for maize-soybean strip intercropping is 2:4, with intercropping densities of 67,500 plants / hm² for maize and soybean. 2 Soybean density 165,000 plants / hm 2 Leave one seedling per hole. Each plot (22×10.8m) 2 It includes 4 production units. The monoculture soybean row spacing is 60 cm, and the density is 165,000 plants / hm². 2 Leave two seedlings per hole. For monoculture corn, the row spacing is 60 cm, and the density is 67,500 plants / hm². 2 .from Figure 2 As shown in the planting pattern diagram, the plant spacing for intercropped corn and soybeans is 0.11m and 0.09m, respectively, while the actual plant spacing for monoculture corn and soybeans is 0.25m and 0.20m, respectively. The farmland was tilled as a whole before sowing. Seeds were carefully selected before sowing to ensure purity and uniform emergence. A single application of controlled-release compound fertilizer N-P2O5-K2O7 (50 kg / hm²) was applied during the seedling stage in both the corn and soybean strips. 2 (26%-10%-12%), 300 kg (15%-15%-15%). During the growing season, use micro-sprinklers for unified irrigation based on soil moisture, and drain water promptly in case of flooding. Use a unified plant protection program for pest and disease control and chemical control.

[0031] 1.2 Measurement Items 1.2.1 Output and its components For soybeans, harvest in 2-meter four-row fields with uniform growth during the soybean harvest period. After natural air drying, indoor seed testing was conducted to measure the number of plants per unit area, the number of effective pods per plant, the number of grains per pod, the 100-grain weight, and the grain moisture content, and the yield per hectare (13% moisture content) was calculated. For maize, harvest in 5-meter double-row fields with uniform growth during the maize harvest period. The number of plants per unit area, the number of ears, and the double-ear rate were counted. After natural air drying, indoor seed testing was conducted to measure the number of rows per ear, the number of grains per row, the 1000-grain weight, and the grain moisture content, and the yield per hectare (14% moisture content) was calculated. Each treatment was replicated three times.

[0032] 1.2.2 Soil moisture content and differences Soil moisture content (SWC, %) was measured every 10 cm at a depth of 0-40 cm and every 20 cm at a depth of 40-100 cm, and dried using a soil dryer with a diameter of 5.5 cm. Four sampling points were selected for the intercropping pattern. Figure 3 a1, a3, a5, a7). In single-operation mode, two sample points are selected ( Figure 3Soybean b1-2 and corn c1-2). Soil moisture difference is calculated four times each crop growing season—before sowing, at flowering, at maturity, and after harvest. The following formula is used to calculate the soil moisture difference between soybean and corn intercropping. ΔS=SWS S -SWS M (1) SWS=SWC h ρ 10 (2) In the formula, SWS S and SWS M ΔS represents soil moisture storage (SWS, mm) in the soybean and corn belts, respectively. h represents soil depth. A ΔS greater than 0 indicates that the soil moisture on the soybean side is higher than that on the corn side; the opposite is true if ΔW is less than 0.

[0033] 1.2.3 Source-repository relationship Five soybean and maize plants were randomly selected every 7–10 days after flowering. Leaves, stems, pods, or ears (when present) were separated, dried at 105°C for 30 min, and then dried at 80°C to constant weight for dry weight determination. The source-sink relationship of aboveground and grain dry matter during the maize grain-filling stage was quantified. Source and sink parameters were distinguished by the subscripts o and i, respectively. The model describes source parameters based on aboveground biomass data, while sink parameters are estimated based on pod (soybean) / ear (maize) biomass measured on different sampling dates during the grain-filling stage.

[0034] Aboveground dry matter mass (W) at a certain time (t) during the grouting period o The calculation is as follows: (3) In the formula W b,o For W o In t b The initial value at [location]. In this study, W [is used]. o and W i t b They are the same because we take the start of grain filling as the initial time point, so t b =0; W x,o For the growth rate to drop to zero (t) e,o W o The maximum value of t; m,o It is W o The moment when the maximum growth rate is reached.

[0035] Source vitality rate (S) o g / m 2 / d) Calculate using the reverse S-shaped formula: S o = (4) In the formula, S max,o Indicates t m,o The maximum source vitality rate at time t is calculated using the following formula: S max,o = (5) Pod / ear dry matter (W) i The dynamics of ) are represented by a sigmoid function: W i = (6) In the formula W b,i For W i In t b Initial value at; W x,i When the grain filling rate drops to zero (t) e,i The maximum value W i ;t m,i This refers to the moment when the grains reach their maximum filling rate.

[0036] The rate of demand for the library at any time (t) (S) i g / m 2 / d), can be represented as: S i = (7) In the formula, S max,i Indicates t m,i The maximum library demand rate at any given time can be expressed as: S max,i = (8) The average source vitality rate (S_) during the grouting stage o , g / m 2 / d), average rate of reservoir vitality (S_ i , g / m 2 / d) and total source supply (g / m 2 ) and total inventory requirements (g / m 2 This can be expressed by the following formula: S_ o = (9) S_ i = (10) Total source supply (g / m 2 )= W x,o -W b,o (11) Total inventory demand (g / m³) 2 )= W x,i -W b,i(12) The above parameters can be estimated by fitting the observed data of aboveground dry matter and pod / ear dry matter W to formulas (1) and (4), respectively. This experiment used Shao et al 2021 and Fang et al The 2024 method introduces two dummy variables, Z1 and Z2. Z1 = 1 and Z2 = 0 are set for the aboveground dry matter W, and Z1 = 0 and Z2 = 1 are set for the pod / ear dry matter W, as shown in the following formula: W = Z1W o + Z2W i (13) We used formulas (3), (6), and (13) to comprehensively fit the observed data on aboveground and pod / ear biomass changes over time, estimating source and sink parameters. Dummy variables were used to examine whether the total source supply during the crop grain-filling stage met the total sink demand. To achieve this, we formulated a null hypothesis (H0) stating that the total sink growth equals the total source supply: W x,i = W x,o -W b,o + W b,i (14) We can compare the sum of squared residuals and degrees of freedom of the two combinations and perform an F-test to determine whether there is a significant difference between total source supply and total sink demand. If the F-value is not significant (P>0.05), we accept the null hypothesis. Conversely, if the F-value is significant, it indicates an imbalance between source supply and sink demand during the grouting period.

[0037] Source-liquid difference (g / m 2 = Total supply - Total demand (15) Source / Stock = Total Source Supply / Total Stock Demand (16) Contribution rate of pre-flowering inventory to the total inventory (%) = Source inventory difference / Total inventory demand × 100 (17) When the source-sink difference is zero or positive (source / sink ≥ 1) during the grain-filling stage, it indicates that the carbohydrates accumulated by the crop through photosynthesis during this stage are sufficient to meet the sink requirements. Conversely, when the source-sink difference is negative (source / sink < 1) during the grain-filling stage, the plant needs to mobilize the carbohydrates accumulated before flowering to ensure the sink requirements.

[0038] 1.2.4 Relative interspecific competition (predatory power) Predatory power is an indicator of the relative competitive ability among intercropping species. This invention will use A... MS Defined as the aggressiveness of corn relative to soybean during intercropping, the calculation formula is as follows: A MS =Y IM / Y SM -YIS / Y SS (18) In the formula Y IM and Y IS These represent the yields of intercropped corn and soybeans, respectively. SM and Y SS Let A be the yield of monoculture corn and soybeans, respectively. MS A value > 0 indicates that corn is more competitive than soybean in intercropping. The opposite is true if AMS < 0.

[0039] 1.2.5 Land Equivalent Ratio Land equivalent (LER) reflects the productivity and efficiency of intercropping versus monoculture. The LER is calculated as follows: LER = pLER S + pLER M =Y IS / Y SS +Y IM / Y SM (19) In the formula, pLER S and pLER M This represents the partial land equivalent ratio of intercropped soybeans and corn. A LER > 1 indicates that the intercropping system achieved a yield advantage over monoculture.

[0040] 1.2.6 Water use efficiency Calculate the total actual evapotranspiration over the entire growing season using the water balance equation: ET = (SM) +R+I −Q (20) In the formula, S and M represent the soil moisture content (mm) of the 0-100 cm soil layer during the sowing and maturity periods, respectively. R is the total rainfall during the growing season (mm), I is the total irrigation quota (mm), and Q is the surface runoff (mm). Since the soil surface of each experimental plot is flat and there is no water accumulation, the value of Q can be ignored.

[0041] WUE is calculated using the following formula: WUE = Y / ET (21) Where Y represents yield (kg / ha) and ET (mm) represents evapotranspiration. The calculation method for evapotranspiration is the same for both monoculture and intercropping systems.

[0042] Test Example 1: 1. Soil moisture content Strip deep tillage and straw return to the field significantly affect the soil moisture content in the 0-100 cm soil layer for soybeans and corn. Figure 4As shown in the figure, the water content of the monoculture treatment was significantly higher than that of the intercropping treatment, and the soil water content of soybean was higher than that of corn, indicating that corn consumes more water than soybean during its growth period. Compared with the flowering stage, the water content at maturity was significantly lower, mainly due to the larger rainfall during the flowering stage. In the intercropping treatment, both deep tillage and straw mulching can increase the water content of the 0-100 cm soil layer. The treatment of deep tillage combined with straw mulching (S S C S / S M C M This significantly increased the moisture difference between strips. Soybean row mulching or full-field mulching combined with deep tillage of maize rows (S... M C S / S M C A During the flowering period, S S C S / S M C M The treatment reduced the soil moisture content by 98.32% and 95.13% respectively, effectively balancing the soil moisture content in the soybean and corn belts.

[0043] 2. The dynamics of source activity and library demand, and the relationship between source and library. The model using formulas (3) and (6) accurately describes the aboveground biomass. Figure 5 Compared to monoculture, intercropping significantly reduces the W of soybeans and corn. x,o / i W b,o / i S_ o / i Significantly improved t e,o / i , t m,o / i This indicates that intercropping reduced dry matter but prolonged the growing season. In the intercropping treatment, deep tillage of soybeans significantly reduced W compared to non-deep tillage. x,o / i and S_ o / i Significantly improved W b,o Conversely, deep tillage of corn rows had the opposite effect; under conditions without deep tillage, straw mulching reduced W. x,o / i W b,o / i S_ o / i This is conducive to increasing production.

[0044] At the beginning of the grouting period, source activity exceeds sink demand. Subsequently, source activity declines, while sink demand rises rapidly to its maximum value and then begins to decline. Figure 6It can be seen that deep tillage of soybean rows significantly reduced source vitality and significantly increased sink vitality, while deep tillage of corn rows had the opposite effect. The relationship between the total source supply, represented by Equation (11), and the total sink demand, represented by Equation (12), changes with the cropping pattern. In the intercropping pattern, deep tillage of soybean rows reduced the total source supply and total sink demand of soybeans and corn, and the source / sink ratio of soybeans required mobilizing 10% of pre-flowering carbohydrates to meet the sink demand; deep tillage of corn rows reduced the source / sink ratio of corn, where deep tillage of corn rows combined with corn row straw mulching could meet the sink demand without mobilizing pre-flowering carbohydrates, which is conducive to increasing yield.

[0045] 3. Output, Land Equivalent Ratio (LER), and Encroachment Potential (A) MS ) Tillage practices and straw return significantly affected soybean and maize yields (Tables 1-3). Monoculture soybean yield was significantly higher than intercropping by 119.16%, mainly due to the significantly higher number of effective plants and effective grains per plant in monoculture compared to intercropping. In the intercropping treatment, deep tillage and straw return altered the number of effective plants per unit area and the number of effective grains per plant, thus affecting soybean yield. Compared to deep tillage with maize, deep tillage with soybeans reduced yield by 18.29%. In the deep tillage treatment of soybeans, S... S C S Production compared to S S C A S S C M Yields decreased by 10.63% and 18.76% respectively; in the deep tillage treatment of corn belts, S M C S Production compared to S M C A S M C M Yields increased by 22.93% and 1.09%, respectively. Monoculture maize yield was significantly higher than intercropping by 12.7%, mainly due to the significantly higher number of ears, kernels per ear, and thousand-kernel weight compared to intercropping. In the intercropping treatment, deep tillage and straw return altered the number of ears per unit area, affecting maize yield. Compared to soybean with deep tillage, maize with deep tillage treatment increased yield by 4.26%; in the maize with deep tillage treatment, S... M C M Production compared to S M C A S M C S Yields decreased by 5.27% and 5.91%, respectively. In the deep tillage treatment of soybeans, S S C M Production compared to S S C A S S C SYields increased by 3.55% and 6.83% respectively. Compared to other methods such as deep tillage and straw return to the field, S... M C S and S M C A The treated LERs increased by 13.95% and 13.17% respectively, mainly due to S M C S and S M C A LER processing M LER S They increased by 6.90%, 5.71%, 3.09%, and 13.17% respectively, A MS The reductions of 16.3% and 16.3% respectively are due to the increased production.

[0046] Table 1. Impact of different farming practices on soybean yield and yield components in 2024 Table 2. Impact of different farming practices on maize yield and yield components in 2024 Table 3. Effects of different farming practices on land equivalent ratio (LER) and erosion rate (A) in 2024 MS The impact of 4. Water use efficiency (WUE) Strip deep tillage and straw return to the field significantly affect water use efficiency (WUE) of soybeans and corn. Figure 7 The WUE of monoculture maize was significantly higher than that of monoculture soybean. In the soybean treatment, the WUE of monoculture soybean was significantly higher than that of intercropped soybean by 123.37%; in the intercropped soybean treatment, the WUE of soybean with deep loosening was significantly lower than that of deep loosening in maize rows by 15.16%; compared with maize row straw mulching (C M Soybeans with straw mulch (C) S ) and uniform straw mulching throughout the field (C A The WUE of intercropped maize significantly increased by 8.02% and 10.30%, respectively. The WUE trend of intercropped maize was consistent with that of intercropped soybean. Under the intercropping pattern, the WUE of the system with deep tillage of maize rows combined with straw mulching of soybean rows or uniform straw mulching throughout the field was significantly higher than that of other treatments.

[0047] In this experiment, the land equivalent ratio (LER) of intercropping was greater than 1 in all cases, indicating that intercropping has a yield advantage. Among the intercropping patterns, deep tillage combined with full wheat straw return to the field along the soybean strip / uniform return of full wheat straw to the field (S... M C S / S M CA Breaking up the plow pan reduces bulk density, which is beneficial for root penetration, increases the volume of roots in the middle and lower layers, optimizes the vertical and horizontal distribution of roots, reduces water competition between intercropped corn and soybean strips, balances the source-sink relationship in the aboveground parts, and improves yield and crop water use efficiency. In summary, deep tillage of corn strips combined with the return of all wheat straw to the soybean strip / uniform return of all wheat straw to the field results in a land equivalent ratio of 1.41 > 1 for intercropped crops, which has significant production advantages and is conducive to high-yield, high-efficiency, and high-quality corn and soybean production in northwestern Shandong.

[0048] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A method of improving water use efficiency and intercropping yield of corn and soybean under strip intercropping, characterized in that, It comprises the following steps: (1) dividing the farmland plot into different strip regions: corn strip with corn row spacing (0.3-0.5) m; soybean strip with soybean row spacing (0.2-0.4) m; the row ratio of corn strip and soybean strip is (1-4):(1-4); (2) deep scarification for the corn strip; (3) straw centralized burying: burying the whole amount of wheat straw of the last season to the soybean strip or evenly burying the whole amount of wheat straw of the last season to the corn strip and soybean strip; (4) after whole rotary tillage for the farmland plot, sowing is performed, with corn strip plant spacing (0.10-0.12) m and soybean plant spacing (0.08-0.10) m.

2. The method of improving water use efficiency and intercropping yield of corn and soybean under strip intercropping of claim 1, characterized by, In step (1), the corn row spacing is 0.4 m and the soybean row spacing is 0.3 m.

3. The method of improving water use efficiency and intercropping yield of corn and soybean under strip intercropping of claim 1, wherein, In step (1), the row ratio of corn strip and soybean strip is 2:

4.

4. The method of increasing water use efficiency and intercropping yield of corn and soybean under strip intercropping of a complex according to claim 1, characterized in that, In step (1), the distance between corn strip and soybean strip is 0.7 m.

5. The method of increasing water use efficiency and intercropping yield of corn and soybean under strip intercropping of a complex according to claim 1, characterized in that, In step (4), the corn strip plant spacing is 0.11 m and the soybean plant spacing is 0.09 m.

6. The method of increasing water use efficiency and intercropping yield of corn and soybean under strip intercropping of composite planting according to claim 1, characterized in that, In step (4), the controlled-release compound fertilizer N-P2O5-K2O is applied once at the corn seedling stage, with a dosage of 750 kg / hm 2 , wherein the N, P, and K contents are 26 wt%, 10 wt%, and 12 wt%, respectively.

7. The method of increasing water use efficiency and intercropping yield of corn and soybean under strip intercropping of composite planting according to claim 1, characterized in that, In step (4), the controlled-release compound fertilizer N-P2O5-K2O is applied once at the soybean seedling stage, with a dosage of 300 kg / hm 2 , wherein the N, P, and K contents are 15 wt%, 15 wt%, and 15 wt%, respectively.

8. The method of increasing water use efficiency and intercropping yield of corn and soybean under strip intercropping of a complex according to claim 1, characterized in that, In step (4), during the growth period, unified spray irrigation is performed according to the soil moisture condition, timely drainage is performed when waterlogging occurs, and unified plant protection scheme is adopted for disease and pest control and chemical prevention.

9. The method of increasing water use efficiency and intercropping yield of corn and soybean under strip intercropping of composite planting according to claim 1, wherein The corn used is MY73 and the soybean used is Zihuang 34.

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