LU502342B1 - Fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium - Google Patents

Abstract

The invention provides a fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium, belonging to the technical field of fertilizers. Aiming at the problem of excessive application of chemical fertilizer caused by excessive pursuit of high crop yield in current agricultural production, the invention reduces the amount of fertilizer application, alleviates the shortage of potassium fertilizer resources, and further realizes agricultural production with more efficient utilization of straw and more friendly environment by returning the full amount of straw to the field and using potassium in straw to partially replace the potassium invested by chemical fertilizer. Experiments show that the fertilization method provided by the invention can not only improve the crop yield but also effectively improve the soil fertility compared with the methods of returning straw to the field and conventional straw to the field.

Description

DESCRIPTION LU502342

FERTILIZER APPLICATION METHOD FOR RETURNING STRAWS TO A WHEAT AND MAIZE DOUBLE-CROPPING GRAIN FIELD TO REPLACE POTASSIUM

TECHNICAL FIELD The invention belongs to the technical field of fertilizers, and in particular relates to a fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium.

BACKGROUND It is well known that the nutrient cycling process in farmland ecosystem is deeply influenced by human activities, and unreasonable human activities may have adverse effects on farmland ecosystem. The sustainable development of agriculture can not only rely on the input of chemical fertilizer and energy, but also must study the internal nutrient circulation law and balance characteristics of farmland ecosystem. Only through the study of nutrient cycle can the limited nutrients be utilized to the maximum extent. Only by knowing the balance of nutrients can people predict the development trend of soil nutrient level and take reasonable control measures.

More than 80% of the total potassium in crops exists in straw. As a large agricultural country, China produces a large amount of straw every year due to crop planting. According to statistics, the total amount of all kinds of crop straws is about 6.2x10° t, and the straw that can be collected and utilized is about 4.8x105 t, of which 2.4x10° t can be used for fertilizer production and returning to fields. With the vigorous promotion of straw returning to field in China in recent years, straw returning has played an important role in supplementing soil potassium and overcoming potassium deficit, and has become an effective way to alleviate the pressure caused by the shortage of potash resources in China and develop sustainable agriculture. However, for a long time, when people apply fertilizer to crops, especially potassium fertilizer, they often ignore the potassium supplement from straw returning to the field, resulting in excessive application of potassium fertilizer, especially in the case of shortage of potassium fertilizer resources in China, which leads to waste. With the popularization of straw returning technology, under the current situation of feasible mechanical operation, the parameter of how much potash fertilizer can be replaced and the supporting technology are urgently needed under the condition of strabd502342 returning in full, so as to realize the advocated purpose of reducing fertilizer application and provide technical support for agricultural production.

Patent CN105723905A discloses a method of applying potassium fertilizer in combination with wheat-corn rotation, in which the annual potassium nutrient input is set at the middle and high yield level of wheat and corn, and the amount of potassium fertilizer is 9-13 kg/mu, of which the application amount in wheat season accounts for 27%-45% and that in corn season accounts for 55%-73%. Patent CN104145586A discloses a fertilization technology to reduce the amount of potassium fertilizer applied to crops, specifically the research conclusion that the available potassium in soil is inexhaustible and can meet the normal growth needs of crops, in the patent, applying soil potassium at seedling stage without fertilization, increasing soil available potassium at the maximum fertilizer demand stage, and reducing the inhibition of exogenous potassium on soil potassium release, so as to reduce the amount of potassium fertilizer applied to crops. During the seedling stage of crops from sowing and planting to 1-2 months after planting, only the seedlings are allowed to absorb the available potassium in the natural state of the soil. About 10 days before and after the initial stage of flower bud differentiation (young spike differentiation), 30-120 kg of potassium fertilizer (KO) was applied per hectare, and the soil available potassium concentration was increased by 10%-40% (the average increase was about 25%), so as to ensure the available potassium supply of crops during the flower bud differentiation, booting and maturity periods of 2-3 months. At present, the excessive pursuit of high yield of crops and the lack of potassium in crop growth in agricultural production lead to the problem of excessive application of chemical fertilizers. However, at present, the method of reducing the application of potassium fertilizer by returning straw to field has not been put forward.

SUMMARY In view of this, the purpose of the present invention is to provide a fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium, in this method, the full amount of straw is returned to the field, and the potassium in the straw is used to partially replace the potassium input by chemical fertilizer, so that the fertilizer application amount is reduced, the shortage of potassium fertilizer resources is relieved,

and then the agricultural production with more efficient utilization of straw and more friendls/502342 environment is realized.

The invention provides a fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium, comprising the following steps: The annual fertilization amount is as follows: 375-470 kg/hm? of N, 180-225 kg/hm? of P,0s, 120 kg/hm? of K20; In wheat season, crushing 50%-100% of the total weight of corn stalks, returning to the field and applying base fertilizer, wherein the application amount of base fertilizer is as follows: 90-120 kg/hm? of N, 75-120 kg/hm? of P,0s, 60 kg/hm° of K,O, and the application rate of topdressing is as follows: 90-120 kg/hm? of N, In corn season, crushing 50%-100% of the total weight of straw harvested after 0-15 cm stubble of wheat, returning to the field and applying base fertilizer, wherein the amount of base fertilizer is as follows: 60-80 kg/hm? of N, 90-105 kg/hm? of P,0s, 60 kg/hm? of K2O, and the application rate of topdressing is as follows: 135-150 kg/hm? of N; Optionally, the annual fertilization amount is as follows: 410 kg/hm? of N, 180 kg/hm” of P,0s, 120 kg/hm? K20; In wheat season, crushing 100% of the total weight of corn stalks, returning them to the field and applying base fertilizer, wherein the application amount of base fertilizer is as follows: 105 kg/hm? of N, 75 kg/hm? of P,Os, 60 kg/hm? of K3O, and the application rate of topdressing is as follows: 90 kg/hm? of N, In corn season, crushing 100% of the total weight of straw harvested after 10 cm stubble of wheat, returning to the field and applying base fertilizer, wherein the amount of base fertilizer is as follows: 75 kg/hm? of N, 90 kg/hm? of P,0s, 60 kg/hm? of KO, and the application rate of topdressing is as follows: 120 kg/hm° of N; Optionally, in the wheat season, the base fertilizer is applied as follows: spreading the fertilizer on the surface of the earth, plowing and turning into the soil; in the wheat season, the top dressing is as follows: when wheat is turning green, applying fertilizer with turning green water.

Optionally, in the corn season, the application method of base fertilizer is sowing seéd/502342 fertilizer at the same time; the method of topdressing is spreading it on the surface or ditching it; the period of topdressing is the big trumpet stage of corn.

Optionally, N fertilizer comprises urea.

Optionally, the P>Os includes superphosphate, heavy superphosphate, monoammonium phosphate or diammonium phosphate.

Optionally, the KO includes potassium sulfate or potassium chloride.

Optionally, the soil background available potassium content of the grain field exceeds 150.0 mg/kg.

The invention provides a fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium. The method adds potassium to the fields by returning crop straws to fields for wheat-and-corn-double-cropping fields, so as to control the total fertilization amount of N, P and K, the respective fertilization amounts in wheat and corn seasons, the types and fertilization amounts of base fertilizer and topdressing fertilizer, and ensure the demand of N, P and K and the balance of three elements in different growth periods of wheat and corn, thus promoting the full absorption of nutrients and increasing crop yield. Experiments prove that straw returning treatment can significantly improve the yield of corn and wheat, and at the same time, compared with the conventional straw returning treatment method, by controlling the amount of straw returning and the total quality of N, P and K fertilization, the amount of potassium fertilizer is reduced and the yield of wheat and corn is significantly increased. At the same time, compared with no straw returning treatment and conventional straw returning treatment methods, the present invention significantly improves the soil alkali-hydrolyzable nitrogen content, soil available phosphorus content, soil available potassium and total potassium content, and improves soil fertility.

DESCRIPTION OF THE INVENTION The invention provides a fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium, comprising the following steps: The annual fertilization amount is as follows: 375-470 kg/hm? of N, 180-225 kg/hm? of P,0s, 120 kg/hm? of KO;

In wheat season, crushing 50%-100% of the total weight of corn stalks, returning to thé/502342 field and applying base fertilizer, wherein the application amount of base fertilizer is as follows: 90-120 kg/hm? of N, 75-120 kg/hm? of P,0s, 60 kg/hm? of K:O, and the application rate of topdressing is as follows: 90-120 kg/hm? of N, In corn season, crushing 50%-100% of the total weight of straw harvested after 0-15 cm stubble of wheat, returning to the field and applying base fertilizer, wherein the amount of base fertilizer is as follows: 60-80 kg/hm? of N, 90-105 kg/hm? of P,0s, 60 kg/hm? of K2O, and the application rate of topdressing is as follows: 135-150 kg/hm? of N; In this invention, the annual fertilization amount 1s related to the quality of straw returned to the field. When the amount of straw returned to the field is large, the annual fertilization amount is relatively reduced, and when the amount of straw returned to the field is small, the annual fertilization amount is relatively high. The annual fertilization amount is preferred as follows: 410 kg/hm? of N, 180 kg/hm” of P,Os, 120 kg/hm? of KO; in wheat season, crushing 100% of the total weight of corn stalks, returning them to the field and applying base fertilizer, wherein the application amount of base fertilizer is as follows: 105 kg/hm? of N, 75 kg/hm? of P,0s, 60 kg/hm? of K2O, and the application rate of topdressing is as follows: 90 kg/hm? of N; in corn season, crushing 100% of the total weight of straw harvested after 10 cm stubble of wheat, returning to the field and applying base fertilizer, wherein the amount of base fertilizer is as follows: 75 kg/hm? of N, 90 kg/hm? of P,0s, 60 kg/hm? of K:O, and the application rate of topdressing is as follows: 120 kg/hm? of N. The N fertilizer preferably includes urea. The POs preferably includes superphosphate, superphosphate, monoammonium phosphate or diammonium phosphate. The K:O preferably includes potassium sulfate or potassium chloride. The application amount of urea was calculated by dividing the application amount of N by 0.46 (the percentage of N in urea). The application amount of other fertilizers can be calculated in the same way according to the above method.

In the present invention, in the wheat season, the application method of the base fertilizer is preferably that the fertilizer is spread on the ground and plowed into the soil; in the wheat season, the top dressing method is preferably to flush fertilizer with green water; the top dressing period is preferably the turning green period of wheat. According to the invention, the specific operation of the base fertilizer and top dressing is not particularly limited, and the well-known fertilization method in the field can be adopted. Experiments have proved that topdressing in the turnit&/502342 green period of wheat is more beneficial to increase wheat yield than topdressing in other periods.

In the present invention, in the corn season, the use method of base fertilizer is preferably sowing seed fertilizer at the same time; the top dressing method is preferably spreading on the surface or furrowing; the top dressing period is preferably the big bell mouth period of corn. According to the invention, the specific operation of the base fertilizer and top dressing is not particularly limited, and the well-known fertilization method in the field can be adopted. The experiment proved that topdressing in the big trumpet stage of corn was more beneficial to increase the yield of corn than in other periods.

In the invention, the available potassium in the soil background of the grain field is more than 150.0 mg/kg, and the preferred areas are Dezhou, Dongying, Binzhou and other places. Using the above method to return straw to field and reduce potassium fertilizer application can not only reduce the production cost, but also ensure the yield of wheat and corn.

The following examples will be used to explain in detail the fertilizer application method of straw returning to wheat and jade double cropping grain fields provided by the present invention, but they should not be understood as limiting the protection scope of the present invention.

Embodiment 1

1. Test site and Soil properties: The test site is located in Zhanghua Town, Pingyuan County, Dezhou City, located in the alluvial plain of the Yellow River in northwest Shandong Province, with Mount Tai in the south and Beijing and Tianjin in the north, 30 kilometers away from Dezhou City, belonging to the continental monsoon climate of warm temperate zone, with flat terrain, deep soil layer, well-developed planting industry, and implements the planting system of wheat and corn twice a year. The local soil type is fluvo-aquic soil, and its basic physical and chemical properties are shown in Table 1.

Table 1 Basic physical and chemical properties of soil LU502342 matter% e nitrogen mg/kg phosphorus potassium mg/kg mg/kg

1.34 65.1 23.4 156.0 8.47

2. Test time: Long-term positioning test was conducted from October 2013 to October 2016.

3. Experimental design: There are three treatments in the test, namely: (1) Control: the straw is not returned to the field, 410 kg/hm? of N (among them, the basal fertilizer of wheat season is 105 kg/hm”, and the topdressing amount is 90 kg/hm?; the basal fertilizer of corn season is 75 kg/hm?, and the topdressing amount is 120 kg/hm?.), 180 kg/hm? of P,0s (among them, the basal fertilizer of wheat season is 105 kg/hm”, and the basal fertilizer of corn season is 75 kg/hm”.), 180 kg/hm? of K:O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?.) (2) Farmers' habit: mash 100% corn straw and return it to the field, and leave Ocm of wheat straw as stubble and return it to the field, 410 kg/hm? of N (the basal fertilizer of wheat in season is 105 kg/hm?, and the topdressing amount of wheat in green turning period is 90 kg/hm?; the basal fertilizer of corn in season is 75 kg/hm?, and the topdressing fertilizer in big trumpet stage is 120 kg/hm?), 180 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 105 kg/hm?, and the basal fertilizer of corn season is 75 kg/hm”.), 180 kg/hm? of K,O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?) (3) Optimal treatment: 100% corn straw is crushed and returned to the field, and wheat straw with stubble of 0 cm is returned to the field, 410 kg/hm? of N (the basal fertilizer of wheat in season is 105 kg/hm? and the topdressing amount of wheat in green turning period is 90 kg/hm?; the basal fertilizer of corn in season is 75 kg/hm?, and the topdressing fertilizer in big trumpet stage is 120 kg/hm?), 180 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 105 kg/hm”, and the basal fertilizer of corn season is 75 kg/hm?)), 120 kg/hm? of K2O (among them, the basal fertilizer of wheat season is 60 kg/hm?, and the basal fertilizer of corn season is 60 kg/hm?.)

4. Test results: LU502342 (1) Effect on the average yield of corn and wheat Table 2 Effects of Different Treatments on Corn-Wheat Yield Treatment Season yield of corn (kg/hm?) Wheat season yield (kg/hm?) Control 8124.9+132.8 7600.3+54.5 Farmers' habit 9449 1+112.1 8175.3+ 75.8 Optimal treatment 10241.9+ 203.1 8600.4+ 49.9 It can be seen from Table 2 that different treatments can significantly affect the yield of com and wheat. For corn, compared with the control treatment, the corn yield of farmers' habitual and preferred treatment increased by 16.3% and 26.1% respectively; for wheat, compared with the control treatment, the wheat yield of farmers' customary and preferred treatment increased by

19.4% and 25.0% respectively. On the one hand, straw returning can increase crop yield; on the other hand, under the condition of straw returning, the input of potassium fertilizer can be reduced without decreasing crop yield. (2) Effects on soil nutrients Table 3 Effects of different treatments on soil nutrients Alkali-hydrolyza Available Available Total potassium Treatment ble nitrogen phosphorus potassium (<10*mg/kg) (mg/kg) (mg/kg) (mg/kg) Control 71.17#1.35 28.33+2.51 104.67+2.31 1.810+0.04 Farmers' 77.60+2.21 31.83+2.12 117.00+4.36 1.817+0.01 habit Optimal 80.17+1.25 32.40+0.53 123.67+6.66 1.822+0.02 treatment It can be seen from Table 3 that, compared with the control, in terms of soil alkali-hydrolyzable nitrogen content, straw returning increased the soil alkali-hydrolyzable nitrogen content, and the soil alkali-hydrolyzable nitrogen of farmers' habit and preferred treatment increased by 6.43 mg/kg and 9.00 mg/kg respectively; in terms of available phosphorus in soil, the available phosphorus in the soil that farmers used to and preferred to treat increased by 3.50 mg/kg and 4.07 mg/kg respectively; In terms of soil potassium, the available potassium in the soil that farmers used to and preferred to treat increased by 12.33 mg/kg and

19.00 mg/kg respectively, The soil total potassium of farmers' customary and preferred treatments increased by 0.007x104 mg/kg and 0.012x104 mg/kg respectively. The reason may b&J502342 that the straw contains more potassium, so the available potassium and total potassium contributed to the soil after the straw is returned to the field are more than those of the control. However, although the optimal treatment reduces the potassium fertilizer input, the farmers' habit of fertilization may be due to the excess potassium fertilizer input and nutrient imbalance, which affects the release of nutrients instead. The proportion of nitrogen, phosphorus and potassium nutrient input under the optimal treatment of straw returning to the field is more appropriate, and the purpose of increasing potassium content in soil and increasing crop yield is achieved.

Embodiment 2 The experiment was conducted in a field with an area of 12 hm? in Zhanghua Town, Pingyuan County, Dezhou City. The experiment was set up in three treatments, and the area of each treatment field was 4 hm?, which were: (1) Control: the straw is not returned to the field, 470 kg/hm? of N (among them, the basal fertilizer of wheat season is 120 kg/hm”, and the topdressing amount is 80 kg/hm?; the basal fertilizer of corn season is 80 kg/hm?, and the topdressing amount in big trumpet period is 120 kg/hm?.), 180 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 105 kg/hm°, and the basal fertilizer of corn season is 75 kg/hm?), 180 kg/hm? of K:O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?) (2) Farmers' habit: mash 100% corn straw and return it to the field, and leave 0 cm of wheat straw as stubble and return it to the field, 470 kg/hm° of N (the basal fertilizer of wheat in season is 120 kg/hm°, and the topdressing amount of wheat in green turning period is 120 kg/hm?; the basal fertilizer of corn in season is 80 kg/hm?, and the topdressing fertilizer in big trumpet stage is 150 kg/hm?), 225 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 120 kg/hm?, and the basal fertilizer of corn season is 105 kg/hm?), 180 kg/hm° of K:O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?) (3) Optimal treatment: 50% corn straw is crushed and returned to the field, and wheat straw with stubble of 15 cm is returned to the field, 470 kg/hm? of N (the basal fertilizer of wheat in season is 120 kg/hm?, and the topdressing amount of wheat in green turning period is 120 kg/hm?; the basal fertilizer of corn in season is 80 kg/hm? and the topdressing fertilizer in big trumpet stage is 150 kg/hm?), 225 kg/hm? of P,Os (among them, the basal fertilizer of wheat season 18502342 120 kg/hm°, and the basal fertilizer of corn season is 105 kg/hm?), 150 kg/hm? of K:O (among them, the basal fertilizer of wheat season is 75 kg/hm?, and the basal fertilizer of corn season is 75 kg/hm?) Test results: Effect on the average yield of corn and wheat Table 4 Effects of Different Treatments on Corn-Wheat Yield ____ Treatment Season yield of corn (kg/hm®) Wheat season yield (kg/hm’) _ Control 8415.5+56.8 8112.9+70.2 Farmers' habit 9508.2+142.1 8639.1+93.8 Optimal treatment 10589.7+64.3 9143.9+41.5 It can be seen from Table 4 that different treatments can significantly affect the yield of com and wheat. For corn, compared with the control treatment, the corn yield of farmers' habitual and preferred treatment increased by 12.98% and 25.841% respectively; for wheat, compared with the control treatment, the wheat yield of farmers' customary and preferred treatment increased by

6.49% and 12.71% respectively.

Comparative example 1 The experiment was conducted in a field with an area of 12 hm? in Zhanghua Town, Pingyuan County, Dezhou City. The experiment was set up in three treatments, and the area of each treatment field was 4 hm?, which were: (1) Control: the straw is not returned to the field, 410 kg/hm? of N (among them, the basal fertilizer of wheat season is 105 kg/hm”, and the topdressing amount is 90 kg/hm?; the basal fertilizer of corn season is 75 kg/hm?, and the topdressing amount in big trumpet period is 120 kg/hm?.), 180 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 105 kg/hm°, and the basal fertilizer of corn season is 75 kg/hm?), 180 kg/hm? of K:O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?) (2) Farmers' habit: mash 100% corn straw and return it to the field, and leave 0 cm of wheat straw as stubble and return it to the field, 410 kg/hm? of N (the basal fertilizer of wheat in season is 105 kg/hm?, and the topdressing amount of wheat in green turning period is 90 kg/hm?; the basal fertilizer of corn in season is 75 kg/hm?, and the topdressing fertilizer in big trumpet stage is 120 kg/hm?), 180 kg/hm? of P,Os (among them, the basal 75 kg/hm?.), 180 kg/hm? of K,O

(among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of cott#/502342 season is 90 kg/hm?.) (3) Optimal treatment: 100% corn straw is crushed and returned to the field, and wheat straw with stubble of 0 cm is returned to the field, 410 kg/hm? of N (the basal fertilizer of wheat in season is 105 kg/hm?, and the topdressing amount of wheat in green turning period is 90 kg/hm?; the basal fertilizer of corn in season is 75 kg/hm?, and the topdressing fertilizer in big trumpet stage is 120 kg/hm?), 180 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 105 kg/hm”, and the basal fertilizer of corn season is 75 kg/hm°.), 100 kg/hm? of K2O (among them, the basal fertilizer of wheat season is 50 kg/hm?, and the basal fertilizer of corn season is 50 kg/hm?.) Test results: Effect on the average yield of corn and wheat Table 5 Effects of Different Treatments on Corn-Wheat Yield ____ Treatment Season yield of corn (kg/hm®) Wheat season yield (kg/hm’) _ Control 8124.9+132.8 7600.3+54.5 Farmers' habit 9449. 1+112.1 8175.3+ 75.8 Optimal treatment 10035.5+ 52.6 8435.9+ 80.0 It can be seen from Table 5 that different treatments can significantly affect the yield of corn and wheat. For corn, compared with the control treatment, the corn yield of farmers' habitual and preferred treatment increased by 16.30% and 23.52% respectively; for wheat, compared with the control treatment, the wheat yield of farmers' customary and preferred treatment increased by

7.57% and 10.99% respectively.

Comparative example 2 The experiment was carried out in a 12hm2 field in Tingluo Town, Lijin County, Dongying City. The test site is located in the plain of the Yellow River Delta, adjacent to the estuary in the north, isolated island in the east and Chen Zhuang in the south. The average annual temperature is 14.2°C and the average annual precipitation is 534.4mm. Although the site is a plain, due to the frequent breaches of the Yellow River in history, it is repeatedly punched by floods, forming a complex micro-landform with hills, slopes and depressions. The land resources are vast, and hundreds of thousands of acres of saline-alkali land need to be developed and utilized. The soil type is coastal saline-alkali land, and its basic physical and chemical properties are shown in Table 6.

Table 6 Basic physical and chemical properties of soil LU502342 “Organic Alkali-hydrolyzabl Available Available pH value matter% e nitrogen mg/kg phosphorus potassium mg/kg mg/kg

0.78 21.5 8.21 392.0 8.85 The experiment was set up in three treatments, and the area of each treatment field was 4 hm”, which were: (1) Control: the straw is not returned to the field, 470 kg/hm? of N (among them, the basal fertilizer of wheat season is 120 kg/hm”, and the topdressing amount is 80 kg/hm?; the basal fertilizer of corn season is 80 kg/hm?, and the topdressing amount in big trumpet period is 120 kg/hm?.), 180 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 105 kg/hm°, and the basal fertilizer of corn season is 75 kg/hm?), 180 kg/hm? of K:O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?) (2) Farmers' habit: mash 100% corn straw and return it to the field, and leave 0 cm of wheat straw as stubble and return it to the field, 470 kg/hm° of N (the basal fertilizer of wheat in season is 120 kg/hm°, and the topdressing amount of wheat in green turning period is 120 kg/hm?; the basal fertilizer of corn in season is 80 kg/hm?, and the topdressing fertilizer in big trumpet stage is 150 kg/hm?), 225 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 120 kg/hm?, and the basal fertilizer of corn season is 105 kg/hm?), 180 kg/hm° of K:O (among them, the basal fertilizer of wheat season is 90 kg/hm?, and the basal fertilizer of corn season is 90 kg/hm?) (3) Optimal treatment: 50% corn straw is crushed and returned to the field, and wheat straw with stubble of 15 cm is returned to the field, 470 kg/hm? of N (the basal fertilizer of wheat in season is 120 kg/hm?, and the topdressing amount of wheat in green turning period is 120 kg/hm?; the basal fertilizer of corn in season is 80 kg/hm? and the topdressing fertilizer in big trumpet stage is 150 kg/hm?), 225 kg/hm? of P,Os (among them, the basal fertilizer of wheat season is 120 kg/hm°, and the basal fertilizer of corn season is 105 kg/hm?), 150 kg/hm? of K:O (among them, the basal fertilizer of wheat season is 75 kg/hm?, and the basal fertilizer of corn season is 75 kg/hm?) Test results: Effect on the average yield of corn and wheat

Table 7 Effects of Different Treatments on Corn-Wheat Yield Treatment Season yield of corn (kg/hm®) Wheat season yield (kg/hm’) _ Control 6943 5+69.8 3843.6+39.8 Farmers' habit 7447,5+57.1 4633.2+ 78.5 Optimal treatment 8809.6+ 101.3 5067.0+64.2 It can be seen from Table 7 that different treatments can significantly affect the yield of com and wheat. For corn, compared with the control treatment, the corn yield of farmers' habitual and preferred treatment increased by 7.26% and 26.88% respectively; for wheat, compared with the control treatment, the wheat yield of farmers' customary and preferred treatment increased by

20.54% and 31.83% respectively.

The above are only the preferred embodiments of the present invention, and it should be pointed out that for those of ordinary skill in the technical field, without departing from the principle of the present invention, several improvements and embellishments can be made, and these improvements and embellishments should also be regarded as the protection scope of the present invention.

Claims (9)

CLAIMS LU502342

1. A fertilizer application method for returning straws to a wheat and maize double-cropping grain field to replace potassium, characterized by comprising the following steps: the annual fertilization amount is as follows: 375-470 kg/hm? of N, 180-225 kg/hm° of P,0s, 120 kg/hm? of KO; in wheat season, crushing 50%-100% of the total weight of corn stalks, returning to the field and applying base fertilizer, wherein the application amount of base fertilizer is as follows: 90-120 kg/hm? of N, 75-120 kg/hm? of P,0s, 60 kg/hm? of K2O, and the application amount of topdressing is as follows: 90-120 kg/hm? of N, in corn season, crushing 50%-100% of the total weight of straw harvested after 0-15 cm stubble of wheat, returning to the field and applying base fertilizer, wherein the amount of base fertilizer is as follows: 60-80 kg/hm? of N, 90-105 kg/hm? of P,Os, 60 kg/hm? of K2O, and the application amount of topdressing is as follows: 135-150 kg/hm? of N, wherein the soil type of the grain field is fluvo-aquic soil or coastal saline-alkali land, and the content of available potassium is higher than 150 mg/kg.

2. The fertilizer application method according to claims 1, characterized in that the annual fertilization amount is as follows: 410 kg/hm? of N, 180 kg/hm? of P,0s, 120 kg/hm? of KO; in wheat season, crushing 100% of the total weight of corn stalks, returning to the field and applying base fertilizer, wherein the application amount of base fertilizer is as follows: 105 kg/hm? of N, 75 kg/hm? of P2Os, 60 kg/hm? of K20, and the application amount of topdressing is as follows: 90 kg/hm” of N, in corn season, crushing 100% of the total weight of straw harvested after 10 cm stubble of wheat, returning to the field and applying base fertilizer, wherein the amount of base fertilizer is as follows: 75 kg/hm? of N, 90 kg/hm? of P,Os, 60 kg/hm? of K2O, and the application amount of topdressing is as follows: 120 kg/hm? of N.

3. The fertilizer application method according to claims 1, characterized in that in the wheat season, the base fertilizer is applied as follows: spreading the fertilizer on the surface of the earth, ploughing into the soil; in the wheat season, the top dressing is as follows: when wheat is turning green, applying fertilizer with green water.

4. The fertilizer application method according to claims 1, characterized in that in the cokt)502342 season, the application method of base fertilizer is sowing seed and fertilizer at the same time; the method of topdressing is spreading on the surface or ditching; the period of topdressing is the big trumpet stage of corn.

5. The fertilizer application method according to any one of claims 1-4, characterized in that N fertilizer comprises urea.

6. The fertilizer application method according to any one of claims 1-4, characterized in that the P,Os includes superphosphate, heavy superphosphate, monoammonium phosphate or diammonium phosphate.

7. The fertilizer application method according to any one of claims 1-4, characterized in that the K,O includes potassium sulfate or potassium chloride.

8. The fertilizer application method according to any one of claims 1-4, characterized in that the soil components of the grain field include: 0.78-1.34% of organic matter, 21.5-65.1 mg/kg of alkali-hydrolyzable nitrogen, 8.21-23.4 mg/kg of available phosphorus and 156.0-392.0 mg/kg of available potassium, and the pH value of the soil is 8.47-8.85.

9. The fertilizer application method according to claim 1, characterized in that the grain fields include Shandong.