Method for increasing corn yield and / or reducing farmland ammonia volatilization

Abstract

The invention provides a method for increasing the corn yield and / or reducing farmland ammonia volatilization, and belongs to the technical field of corn planting. The method specifically comprises the following steps: (1) applying a nitrogen fertilizer and biochar in a planting land, and sowing corn and common vetch; (2) turning and pressing the common vetch in the full-bloom stage; (3) performing topdressing management on the corn, wherein the topdressing type is nitrogen fertilizer; and (4) harvesting the corn in a mature period. According to the method for improving the corn yield and / or reducing farmland ammonia volatilization through intercropping of the green manure, nitrogen reduction and combination of the biochar, the green manure crops and the biochar which are scientifically proportioned are jointly utilized in the corn planting process, and stable yield of the corn can be achieved under the condition that the nitrogen is reduced by 30%; meanwhile, on the premise that stable yield of corn is guaranteed, ammonia volatilization of farmland can be effectively reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of corn planting, and particularly to a method for increasing corn yield and / or reducing ammonia volatilization in farmland. Background Art

[0002] Ammonia volatilization is one of the main ways of nitrogen loss in farmland. The average proportion of ammonia volatilization loss in global farmland accounts for 18% of the total nitrogen application amount, and can reach up to 64%. Ammonia volatilization not only significantly reduces the nitrogen fertilizer utilization rate, but also causes serious pollution to water, atmosphere and soil environments. Corn is an important food crop and requires a large amount of fertilizer for growth and development. High application of nitrogen fertilizer ensures the corn yield, but also leads to problems such as increased nitrogen loss, decreased utilization rate and environmental pollution, and the problem of high ammonia volatilization is particularly prominent. Therefore, it is necessary to provide a method that can both increase the corn yield and reduce ammonia volatilization in farmland.

[0003] Planting green manure can absorb ammonia gas and ammonium ions, reduce nitrogen loss, and turning under green manure can increase the nitrogen content in the soil. On the premise of no yield reduction, it can replace part of chemical nitrogen fertilizer, reduce ammonia emissions and reduce environmental pollution. Biochar has large porosity and specific surface area, and strong adsorption ability, and is widely used in environmental pollution remediation, soil improvement and carbon sequestration. Applying biochar can improve the soil nutrient content, increase the diversity and richness of soil microbial communities, enhance the absorption and utilization of nutrients by crops, and ultimately improve the nitrogen utilization efficiency of crops. Compared with traditional fertilization, applying biochar can effectively promote crop growth and development, improve nitrogen fertilizer utilization rate and reduce the loss of reactive nitrogen gases. Whether applying biochar can reduce ammonia volatilization while ensuring nitrogen reduction and stable yield of green manure remains to be studied. Summary of the Invention

[0004] The purpose of the present invention is to provide a method for jointly using green manure crops and biochar to increase corn yield and effectively reduce ammonia volatilization in farmland under nitrogen reduction conditions.

[0005] In order to achieve the above invention purpose, the present invention provides the following technical solutions:

[0006] The present invention provides a method for increasing corn yield and / or reducing ammonia volatilization in farmland, including the following steps:

[0007] (1) Apply nitrogen fertilizer and biochar to the planting land, and sow corn and common vetch;

[0008] (2) Turn under common vetch in the full-bloom stage;

[0009] (3) Conduct topdressing management on corn, and the topdressing type is nitrogen fertilizer;

[0010] (4) Harvest corn at the maturity stage;

[0011] Among them, the total application amount of nitrogen fertilizer is applied in an amount that is 25% to 35% less than the conventional nitrogen application amount.

[0012] Preferably, before applying nitrogen fertilizer and biochar in step (1), the planting land is prepared, and the land preparation includes plowing and loosening the soil; the depth of plowing is 15 - 25 cm, and the depth of soil loosening is 30 - 40 cm.

[0013] Preferably, in step (1), the biochar is sesbania biochar, and the application amount of the biochar is 2500 - 3500 kg / hm 2 。

[0014] Preferably, before sowing corn and vetch in step (1), phosphate fertilizer is also applied to the planting land, and the application amount of the phosphate fertilizer is 130 - 170 kg / hm 2 。

[0015] Preferably, in step (1), the sowing density of the corn is 85000 - 95000 plants / hm 2 , and the sowing amount of the vetch is 50 - 70 kg / hm 2 ; the row number ratio of the corn and vetch during sowing is 2 - 4:3 - 5.

[0016] Preferably, in step (2), the incorporation amount of the vetch is 1200 - 1500 kg / mu, and the incorporation depth is 17 - 23 cm.

[0017] Preferably, in step (3), the method of topdressing management is topdressing and irrigation, the number of topdressing management is 2 times, and the timing of topdressing management is the large flare - opening stage and the filling stage of corn.

[0018] Preferably, in step (4), the signs of corn maturity are the disappearance of the milk line of the kernels and the appearance of the black layer.

[0019] Preferably, the total application amount of the nitrogen fertilizer is 210 - 245 kg / hm 2 , and the base fertilizer application amount: topdressing amount at the large flare - opening stage: topdressing amount at the filling stage = 3.5 - 4.5:2.5 - 3.5:2.5 - 3.5.

[0020] The present invention provides an application of the above - mentioned method in increasing corn yield and / or reducing ammonia volatilization in farmland.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] The present invention provides a method for increasing maize yield and / or reducing ammonia volatilization in farmland by intercropping green manure, reducing nitrogen, and combining with biochar. In the process of maize planting, the present invention jointly utilizes scientifically proportioned green manure crops and biochar, and can achieve stable maize production under the condition of reducing nitrogen by 30%. At the same time, on the premise of ensuring stable maize production, it can effectively reduce ammonia volatilization in farmland. Compared with monoculture of maize under conventional nitrogen application rate, the present invention can make the maize yield not significantly reduced, but the ammonia volatilization in farmland is significantly reduced. The present invention provides technical support for nitrogen reduction and yield increase of maize and efficient utilization of nitrogen in soil, and has broad application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the drawings in the following description are only the embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained according to the provided drawings.

[0024] Figure 1 Statistical results of maize yields for different treatment groups;

[0025] Figure 2 Statistical results of the cumulative annual ammonia volatilization emissions in farmland for different treatment groups. DETAILED DESCRIPTION OF THE INVENTION

[0026] The present invention provides a method for increasing maize yield and / or reducing ammonia volatilization in farmland, comprising the following steps:

[0027] (1) Applying nitrogen fertilizer and biochar to the planting land, sowing maize and Vicia sativa;

[0028] (2) Incorporating Vicia sativa at the full flowering stage;

[0029] (3) Conducting topdressing management for maize, and the topdressing type is nitrogen fertilizer;

[0030] (4) Harvesting maize at maturity;

[0031] Among them, the total application amount of nitrogen fertilizer is applied according to the amount of reducing nitrogen by 25% - 35% of the conventional nitrogen application rate.

[0032] In the present invention, the conventional nitrogen application rate = (total nitrogen amount required for maize to reach the expected yield - available nitrogen content in soil × soil nitrogen utilization rate) ÷ fertilizer nitrogen utilization rate.

[0033] In the present invention, before applying nitrogen fertilizer and biochar in step (1), the planting land is also prepared, and the land preparation includes ploughing and loosening the soil; the depth of ploughing is 15 - 25 cm, preferably 18 - 22 cm, and more preferably 20 cm; the depth of soil loosening is 30 - 40 cm, preferably 32 - 38 cm, and more preferably 35 cm. The purpose of land preparation is to break the plough pan, increase soil aeration and water permeability, and create a good soil environment for seed germination and root growth.

[0034] In the present invention, the biochar in step (1) is sesbania biochar, and the application rate of the biochar is 2500 - 3500 kg / hm 2 , preferably 2800 - 3200 kg / hm 2 , more preferably 3000 kg / hm 2 .

[0035] In the present invention, before sowing maize and vetch in step (1), phosphate fertilizer is also applied to the planting land, and the application rate of the phosphate fertilizer is 130 - 170 kg / hm 2 , preferably 140 - 160 kg / hm 2 , more preferably 150 kg / hm 2 .

[0036] In the present invention, the sowing density of the maize in step (1) is 85000 - 95000 plants / hm 2 , preferably 88000 - 92000 plants / hm 2 , more preferably 90000 plants / hm 2 ; the sowing rate of the vetch is 50 - 70 kg / hm 2 , preferably 55 - 65 kg / hm 2 , more preferably 60 kg / hm 2 ; the row number ratio of the maize and vetch during sowing is 2 - 4:3 - 5, preferably 3:4.

[0037] In the present invention, the row spacing of the maize during sowing is 30 - 40 cm, preferably 32 - 38 cm, and more preferably 35 cm, and the plant spacing is 15 - 25 cm, preferably 18 - 22 cm, and more preferably 20 cm; the row spacing of the vetch during sowing is 12 - 18 cm, preferably 15 cm.

[0038] In the present invention, in step (2), the incorporation amount of Vicia sativa is 1200 - 1500 kg / mu, preferably 1250 - 1400 kg / mu, and more preferably 1300 kg / mu; the incorporation depth is 17 - 23 cm, preferably 19 - 21 cm, and more preferably 20 cm. During incorporation, it should be ensured that Vicia sativa is evenly distributed in the soil. Mechanical tillage or manual tillage can be used, and the tillage depth is 17 - 23 cm, which is beneficial to the decomposition and transformation of green manure in the soil, increasing the soil organic matter content, improving the soil structure, enhancing the soil fertility, and providing nutrients for the growth of maize.

[0039] In the present invention, in step (3), the method of topdressing management is topdressing and irrigation. The number of times of topdressing management is 2 times, and the timing of topdressing management is the large flare stage and the filling stage of maize.

[0040] In the present invention, the irrigation is carried out by flood irrigation. The irrigation amount should be adjusted according to the soil moisture and weather conditions to ensure that the soil is moist but not waterlogged. The irrigation amount makes the moist depth of the soil reach 30 - 40 cm, preferably 32 - 38 cm, and more preferably 35 cm.

[0041] In the present invention, in step (4), the signs of maize maturity are the disappearance of the milk line of the grains and the appearance of the black layer.

[0042] In the present invention, the conventional nitrogen application rate is 300 - 350 kg / hm 2 preferably 310 - 340 kg / hm 2 and more preferably 330 kg / hm 2

[0043] In the present invention, the total application amount of nitrogen fertilizer is 210 - 245 kg / hm 2 and the base fertilizer application amount: topdressing amount at the large flare stage: topdressing amount at the filling stage = 3.5 - 4.5: 2.5 - 3.5: 2.5 - 3.5, preferably 4: 3: 3.

[0044] In the present invention, the nitrogen fertilizer is preferably urea, and the phosphate fertilizer is preferably triple superphosphate.

[0045] The present invention provides an application of the above - mentioned method in increasing maize yield and / or reducing ammonia volatilization in farmland.

[0046] The technical solutions provided by the present invention are described in detail below in conjunction with the embodiments, but they should not be construed as limiting the protection scope of the present invention.

[0047] Example 1

[0048] A method for increasing maize yield and / or reducing ammonia volatilization in farmland comprises the following steps: ​

[0049] (1) Between the end of April and the beginning of May, plow the farmland to a depth of 15 cm, loosen the soil to a depth of 30 cm, and apply nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 130 kg / hm 2 ), and apply sesbania biochar at a rate of 2500 kg / hm 2 (Sesbania biochar is obtained by carbonizing the above-ground straw of sesbania at 680 °C for 20 minutes, and the particle size of sesbania biochar is 60 mesh), and then sow corn and common vetch;

[0050] (2) Sow according to a row spacing of 35 cm for corn and 20 cm for plant spacing, a row spacing of 15 cm for common vetch. The row ratio of corn to common vetch in the intercropping plot is 2:3, and the planting density of corn is 90000 plants / hm 2 , and the seeding rate of common vetch is 60 kg / hm 2 ; After common vetch grows to the full bloom stage, turn over and plow the fresh grass of common vetch into the farmland soil, and the turning-over amount is 1200 kg / hm 2 , and the plowing depth is 17 cm;

[0051] (3) Apply nitrogen fertilizer at the large flare stage and filling stage of corn respectively; After each topdressing, irrigate by flooding, and the irrigation amount makes the wetting depth of the soil reach 30 cm;

[0052] (4) After the corn matures in early October (the milk line of the grain disappears and the black layer appears), harvest;

[0053] Among them, the total application amount of the nitrogen fertilizer is 247.5 kg / hm 2 (25% nitrogen reduction, calculated based on the conventional nitrogen application rate of 330 kg / hm 2 ), and apply it according to the ratio of base application: large flare: filling = 4:3:3, that is, the nitrogen application amount in step (1) is 99 kg / hm 2 , and the nitrogen application amounts at the large flare stage and filling stage in step (3) are 74.25 kg / hm 2 .

[0054] Example 2

[0055] A method for increasing corn yield and / or reducing ammonia volatilization in farmland, the steps are as follows:

[0056] (1) Between the end of April and the beginning of May, plow the farmland to a depth of 25 cm, loosen the soil to a depth of 40 cm, and apply nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 170 kg / hm 2 ), and apply sesbania biochar at a rate of 3500 kg / hm 2 (Sesbania biochar is obtained by carbonizing the above-ground straw of sesbania at 680 °C for 20 minutes, and the particle size of sesbania biochar is 60 mesh), and then sow corn and common vetch;

[0057] (2) Sow according to a maize row spacing of 35 cm, plant spacing of 20 cm, and a vetch row spacing of 15 cm. The row ratio of maize to vetch in the intercropping plot is 4:5, and the maize planting density is 90,000 plants / hm 2 , and the sowing rate of vetch is 60 kg / hm 2 ; after the vetch grows to the full-bloom stage, turn under the fresh vetch forage and plow it into the farmland soil. The turning-under amount is 1,500 kg / hm 2 , and the plowing depth is 23 cm;

[0058] (3) Top-dress nitrogen fertilizer at the large flare opening stage and filling stage of maize respectively; after each top-dressing, use flood irrigation for irrigation, and the irrigation amount makes the soil wetting depth reach 40 cm;

[0059] (4) After the maize matures in early October (the milk line of the grain disappears and the black layer appears), harvest it;

[0060] Among them, the total application amount of the nitrogen fertilizer is 214.5 kg / hm 2 (reducing nitrogen by 35%, calculated based on the conventional nitrogen application amount of 330 kg / hm 2 ), and apply it according to the ratio of basal application: large flare opening: filling = 4:3:3, that is, the nitrogen application amount in step (1) is 85.8 kg / hm 2 , and the nitrogen application amounts at the large flare opening stage and filling stage in step (3) are 64.35 kg / hm respectively 2 .

[0061] Example 3 (N70S-IMC)

[0062] A method for increasing maize yield and / or reducing ammonia volatilization in farmland, the steps are as follows:

[0063] (1) Between the end of April and the beginning of May, plow the farmland by 20 cm, loosen the soil to a depth of 35 cm, spread nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 150 kg / hm 2 ), and spread sesbania biochar in an amount of 3,000 kg / hm 2 (sesbania charcoal is obtained by carbonizing the above-ground straw of sesbania at 680 °C for 20 minutes, and the particle size of sesbania charcoal is 60 mesh), and then sow maize and vetch;

[0064] (2) Sow according to a maize row spacing of 35 cm, plant spacing of 20 cm, and a vetch row spacing of 15 cm. The row ratio of maize to vetch in the intercropping plot is 3:4, and the maize planting density is 90,000 plants / hm 2 , and the sowing rate of vetch is 60 kg / hm 2 ; after the vetch grows to the full-bloom stage, turn under the fresh vetch forage and plow it into the farmland soil. The turning-under amount is 1,300 kg / hm2 , the plowing depth is 20 cm;

[0065] (3) Apply nitrogen fertilizer respectively at the large trumpet stage and the filling stage of maize; after each topdressing, irrigate by flood irrigation, and the irrigation amount makes the wetting depth of the soil reach 35 cm;

[0066] (4) After the maize is mature in early October (the milk line of the grain disappears and the black layer appears), harvest it;

[0067] Among them, the total application amount of the nitrogen fertilizer is 231 kg / hm 2 (with a 30% reduction in nitrogen, calculated based on the conventional nitrogen application rate of 330 kg / hm 2 ), and apply it according to the ratio of base application: large trumpet: filling = 4:3:3, that is, the nitrogen application amount in step (1) is 92.4 kg / hm 2 , and the nitrogen application amounts at the large trumpet stage and the filling stage in step (3) are 69.3 kg / hm respectively 2 .

[0068] Control 1 (N100-MM)

[0069] A conventional nitrogen application method for monoculture of maize, the steps are as follows:

[0070] (1) Between the end of April and the beginning of May, plow the farmland by 20 cm, loosen the soil to a depth of 35 cm, spread nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 150 kg / hm 2 ), and then sow maize;

[0071] (2) Sow maize according to a row spacing of 35 cm, a plant spacing of 20 cm, and a planting density of 90,000 plants / hm 2 ;

[0072] (3) Apply nitrogen fertilizer respectively at the large trumpet stage and the filling stage of maize; after each topdressing, irrigate by flood irrigation, and the irrigation amount makes the wetting depth of the soil reach 35 cm;

[0073] (4) After the maize is mature in early October (the milk line of the grain disappears and the black layer appears), harvest it;

[0074] Among them, the total application amount of the nitrogen fertilizer is 330 kg / hm 2 (conventional nitrogen application rate), and apply it according to the ratio of base application: large trumpet: filling = 4:3:3, that is, the nitrogen application amount in step (1) is 132 kg / hm 2 , and the nitrogen application amounts at the large trumpet stage and the filling stage in step (3) are 99 kg / hm respectively 2 .

[0075] Control 2 (N70-MM)

[0076] A method for monoculture of corn with 30% nitrogen reduction, the steps are as follows:

[0077] (1) Between the end of April and the beginning of May, plow the farmland to a depth of 20 cm, loosen the soil to a depth of 35 cm, apply nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 150 kg / hm 2 ), and then sow corn;

[0078] (2) Sow corn according to a row spacing of 35 cm, a plant spacing of 20 cm, and a planting density of 90,000 plants / hm 2 ;

[0079] (3) Top-dress nitrogen fertilizer at the large bell-mouth stage and filling stage of corn respectively; after each top-dressing, irrigate by flooding, and the irrigation amount makes the soil wetting depth reach 35 cm;

[0080] (4) After the corn matures in early October (the milk line of the grain disappears and the black layer appears), harvest;

[0081] Among them, the total application amount of the nitrogen fertilizer is 231 kg / hm 2 (with a 30% nitrogen reduction, calculated based on the conventional nitrogen application amount of 330 kg / hm 2 ), and apply it according to the ratio of basal application: large bell-mouth: filling = 4:3:3, that is, the nitrogen fertilizer application amount in step (1) is 92.4 kg / hm 2 , and the nitrogen fertilizer application amounts at the large bell-mouth stage and filling stage in step (3) are 69.3 kg / hm 2 respectively.

[0082] Control 3 (N70-IMC)

[0083] A method for intercropping corn and vetch with 30% nitrogen reduction, the steps are as follows:

[0084] (1) Between the end of April and the beginning of May, plow the farmland to a depth of 20 cm, loosen the soil to a depth of 35 cm, apply nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 150 kg / hm 2 ), and then sow corn and vetch;

[0085] (2) Sow corn according to a row spacing of 35 cm, a plant spacing of 20 cm, and a planting density of 90,000 plants / hm 2 ;

[0086] (3) Top-dress nitrogen fertilizer at the large bell-mouth stage and filling stage of corn respectively; after each top-dressing, irrigate by flooding, and the irrigation amount makes the soil wetting depth reach 35 cm;

[0087] (4) After the corn matures in early October (the milk line of the grain disappears and the black layer appears), harvest;

[0088] Among them, the total application amount of the nitrogen fertilizer is 231 kg / hm 2 (with a 30% reduction in nitrogen, calculated based on the conventional nitrogen application amount of 330 kg / hm 2 , and applied in the ratio of base application: large flare opening: filling = 4:3:3, that is, the nitrogen application amount in step (1) is 92.4 kg / hm 2 , and the nitrogen application amounts in the large flare opening stage and filling stage in step (3) are 69.3 kg / hm 2 respectively).

[0089] Control 4 (N70S-MM)

[0090] A method for planting maize monoculture + sesbania biochar with a 30% reduction in nitrogen is as follows:

[0091] (1) Between the end of April and the beginning of May, plow the farmland to a depth of 20 cm, loosen the soil to a depth of 35 cm, apply nitrogen fertilizer (urea) and phosphate fertilizer (triple superphosphate, 150 kg / hm 2 ), apply sesbania biochar at a rate of 3000 kg / hm 2 (the sesbania biochar is obtained by carbonizing the above-ground straw of sesbania at 680 °C for 20 minutes, and the particle size of the sesbania biochar is 60 mesh), and then sow maize;

[0092] (2) Sow according to a maize row spacing of 35 cm, plant spacing of 20 cm, and vetch row spacing of 15 cm. The row ratio of maize to vetch in the intercropping plot is 3:4, the maize planting density is 90000 plants / hm 2 , and the sowing rate of vetch is 60 kg / hm 2 ; after the vetch grows to the full flowering stage, turn over the fresh vetch grass and plow it into the farmland soil, with a turning-over amount of 1300 kg / hm 2 , and the plowing depth is 20 cm;

[0093] (3) Top-dress nitrogen fertilizer at the large flare opening stage and filling stage of maize respectively; after each top-dressing, irrigate by flood irrigation, and the irrigation amount makes the soil moistening depth reach 35 cm;

[0094] (4) After the maize matures in early October (the milk line of the grain disappears and the black layer appears), harvest;

[0095] Among them, the total application amount of the nitrogen fertilizer is 231 kg / hm 2 (with a 30% reduction in nitrogen, calculated based on the conventional nitrogen application amount of 330 kg / hm 2 , and applied in the ratio of base application: large flare opening: filling = 4:3:3, that is, the nitrogen application amount in step (1) is 92.4 kg / hm 2 , and the nitrogen application amounts in the large flare opening stage and filling stage in step (3) are 69.3 kg / hm 2 respectively).

[0096] Experimental Example

[0097] 1. Yield determination

[0098] At the maize harvest stage, the yields of Example 3 and Comparative Examples 1-4 were determined, and each treatment group was harvested separately. An electronic scale with a precision of 0.1 kg was used to weigh the fresh weight of the maize harvested in each treatment group. Then, some maize ears were randomly selected to measure their moisture content, and the dry yield was calculated according to the formula "dry yield = fresh yield × (1 - moisture content)".

[0099] The results are as Figure 1 shown. It can be seen that compared with the conventional nitrogen application treatment for monoculture maize (Comparative Example 1, N100-MM), the maize yields of the intercropping treatment with a 30% nitrogen reduction (Comparative Example 3, N70-IMC) and the intercropping treatment with a 30% nitrogen reduction combined with the application of sesbania biochar (Example 3, N70S-IMC) increased by 3.77% and 1.51% respectively, indicating that under the condition of a 30% nitrogen reduction, intercropping vetch with the application of sesbania biochar can achieve stable maize yields.

[0100] 2. Measurement of soil NH3 volatilization

[0101] Soil NH3 volatilization was measured by the aeration method. The capture device was made of rigid polyvinyl chloride plastic pipe with an inner diameter of 15 cm and a height of 10 cm. After two sponges with a thickness of 2 cm and a diameter of 16 cm were evenly soaked with 15 mL of phosphoric acid glycerol solution (50 mL phosphoric acid + 40 mL glycerol, made up to 1 L), they were placed in the rigid plastic pipe. The lower sponge was 5 cm from the bottom of the pipe, and the upper sponge was flush with the top of the pipe. When sampling, the lower sponge of the aeration device was taken out, quickly sealed in a plastic bag, and at the same time, another sponge just soaked with phosphoric acid glycerol was replaced. The upper sponge was replaced every 3-7 days depending on its dryness and wetness. The taken sponge was brought back to the laboratory, placed in a plastic bottle, and 150 mL of 1 mol / L KCl solution was added to completely immerse the sponge in it. After shaking for 1 h, the ammonium nitrogen content in the leaching solution was measured by a flow analyzer. In the first week after the basal fertilizer and top dressing of maize, samples were taken once a day; in the second week, samples were taken once every two days; in the third week, samples were taken once every three days. Sampling was completed before 9:00 every morning, and 10 samples were taken in each cycle.

[0102]

[0103] Among them, NH3-N refers to the NH3 volatilization flux (kgN ha -1 d -1 );M NH3-N is the average amount of NH3 measured by the NH3 collection device in each plot (NH3-N, mg); 0.075 is the radius of the PVC pipe (m); T is the time interval between each gas collection point (d).

[0104] The measurement results are as Figure 2 shown. It can be seen that, compared with the conventional nitrogen application maize monoculture treatment group (Comparative Example 1, N100-MM), the cumulative ammonia volatilization amounts of the other treatment groups are all significantly reduced. Compared with the conventional nitrogen application maize monoculture (Comparative Example 1, N100-MM), the annual cumulative ammonia volatilization amounts of the intercropping treatment with 30% nitrogen reduction (Comparative Example 3, N70-IMC) and the intercropping treatment with 30% nitrogen reduction and combined application with sesbania biochar (Example 3, N70S-IMC) are significantly reduced by 29.15% and 46.47% respectively. Compared with the intercropping treatment with 30% nitrogen reduction (Comparative Example 3, N70-IMC), the annual cumulative ammonia volatilization amount of the intercropping treatment with 30% nitrogen reduction and combined application with sesbania biochar (Example 3, N70S-IMC) is further reduced by 33.42%.

[0105] In summary, it can be seen that the combined use of 30% nitrogen reduction, vetch and biochar in the present invention can not only ensure high yield of maize, but also significantly reduce ammonia volatilization in farmland.

[0106] The above are only the preferred embodiments of the present invention. It should be pointed out that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can still be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for increasing maize yield and / or reducing ammonia volatilization in farmland, characterized in that, It includes the following steps: (1) Apply nitrogen fertilizer and biochar to the planting land, and sow corn and vetch; (2) Incorporate vetch at the full-bloom stage; (3) Conduct topdressing management on corn, and the type of topdressing is nitrogen fertilizer; (4) Harvest corn at the maturity stage; Among them, the total application amount of nitrogen fertilizer is applied according to the amount of reducing nitrogen by 25% - 35% of the conventional nitrogen application rate.

2. The method according to claim 1, characterized in that Before applying nitrogen fertilizer and biochar in step (1), the planting land is also subjected to soil preparation treatment, and the soil preparation treatment includes plowing and loosening the soil; the depth of plowing is 15 - 25 cm, and the depth of loosening the soil is 30 - 40 cm.

3. The method according to claim 1, characterized in that The biochar described in step (1) is Sesbania biochar, and the application rate of the biochar is 2500 - 3500 kg / hm 2 .

4. The method according to claim 1, wherein Before sowing maize and vetch, phosphate fertilizer is also applied to the planting land, and the application rate of the phosphate fertilizer is 130 - 170 kg / hm 2 .

5. The method according to claim 1, characterized in that, The seeding density of the corn described in step (1) is 85,000 - 95,000 plants / hm 2 , and the seeding rate of the common vetch is 50 - 70 kg / hm 2 ; the row ratio of the corn and the common vetch during sowing is 2 - 4:3 - 5.

6. The method according to claim 1, characterized in that, In step (2), the incorporation amount of vetch is 1200 - 1500 kg / mu, and the incorporation depth is 17 - 23 cm.

7. The method according to claim 1, wherein In step (3), the method of topdressing management is topdressing and irrigation, the number of topdressing management is 2 times, and the timing of topdressing management is the large bell-mouth stage and the filling stage of corn.

8. The method according to claim 1, wherein In step (4), the signs of corn maturity are the disappearance of the milk line of the grains and the appearance of the black layer.

9. The method according to claim 7, wherein The total application rate of the nitrogen fertilizer is 210 - 245 kg / hm 2 , and the application rate of the base fertilizer: the topdressing rate at the large flare opening stage: the topdressing rate at the filling stage = 3.5 - 4.5: 2.5 - 3.5: 2.5 - 3.

5.

10. Use of the method according to any one of claims 1 to 9 in increasing corn yield and / or reducing ammonia volatilization in farmland.

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