CN111869388A - Method for determining application amount of farmland fertilizer - Google Patents

Abstract

The invention discloses a method for determining the application amount of chemical fertilizers in farmland, which includes determining typical crops, selecting representative fields, measuring the N/P content in the soil of the representative fields, and calculating the N/P applied per kilogram yield of the typical crops. Demand; comprehensively the proportion of N/P in chemical fertilizers, calculate the total amount of chemical fertilizer required by typical crops in the area and the total amount of chemical fertilizer required by all typical crops; judge whether the total annual chemical fertilizer demand is greater than the annual planned total amount, If yes, go to the next step, otherwise output the total annual chemical fertilizer demand and the total demand of each typical crop fertilizer; judge whether the typical crop planting area with the maximum and minimum N/P demand exceeds the planting limit, if so, go to the next step, otherwise , enter the final step; judge whether to adjust the typical crop planting area, if so, according to the N/P in the planned chemical fertilizer application amount, return to the step of the total amount of chemical fertilizer for each typical crop, and verify the planting area; otherwise, use organic fertilizer to replace the excess value Calculate the difference between the annual planned total and the annual fertilizer total.

Description

Determination method of fertilizer application amount in farmland

technical field

The invention relates to the field of agricultural planting and ecological environment, in particular to a method for determining the amount of chemical fertilizer applied in farmland.

Background technique

Agricultural non-point source pollution is the main factor of water environment pollution in my country. Because of its extensiveness, latentness, randomness and ambiguity, it is difficult to control agricultural non-point source pollution. Although the state promulgated the policy of "zero" growth in the amount of farmland chemical fertilizer application from 2015 to 2020, and most regions in my country have also achieved strict control of the total amount of farmland chemical fertilizer application in statistical data, the problem of agricultural non-point source pollution still remains. It is more serious. On the one hand, it is the release of the unused amount accumulated in the soil for a long time. On the other hand, the current total control and control is a kind of static management. It is difficult to comprehensively change the planting structure and sown area year by year, and to achieve reasonable control according to local conditions. Therefore, it is difficult to control the agricultural non-point source from the source only by controlling the total amount of farmland chemical fertilizer application only by the cultivated land area.

SUMMARY OF THE INVENTION

Aiming at the above-mentioned deficiencies in the prior art, the method for determining the application amount of farmland chemical fertilizer provided by the present invention can combine the planting structure to provide the required nitrogen/phosphorus elements to the crops on demand, realize the dynamic management and control of the total amount of the regional chemical fertilizer, and realize the agricultural chemical fertilizer Strict constraints on pesticide application rates.

In order to achieve the above-mentioned purpose of the invention, the technical scheme adopted in the present invention is:

Provided is a method for determining the amount of chemical fertilizer applied in farmland, comprising:

S1. Obtain the agricultural statistical data of the research area, and according to the agricultural statistical data, determine the crops with the sown area greater than the set proportion as typical crops;

S2. Obtain the main root length of each typical crop, collect soil samples within the set area and the depth is equal to the main root length of the typical crop, and measure and obtain the initial nitrogen/phosphorus content of the soil within the depth range of the crop root system per unit area;

S3. Select representative fields, adopt fertilization and non-fertilization planting methods, and obtain the nitrogen/phosphorus requirements applied per kilogram of yield of each typical crop;

S4. Calculate the total amount of chemical fertilizers required for planting typical crops in representative fields

Among them, Si, fi and Qi are the planting area of the _i - _th typical crop _, the estimated yield per unit area and the nitrogen/phosphorus demand required for each kilogram of yield; η is the amount of nitrogen/phosphorus in the fertilizer used. Utilization rate; q is the effective content of nitrogen/phosphorus per kilogram of fertilizer; 1≤i≤n, n is the total quantity of typical crops;

S5. According to the total amount of chemical fertilizer required by each typical crop, calculate the total amount of chemical fertilizer required for all typical crops under the planting structure of the representative field;

S6. Obtain the total annual planned chemical fertilizer application planned by the Ministry of Agriculture or the local environmental protection department in the study area, and determine whether the total annual chemical fertilizer demand is greater than the annual planned total. If so, go to step S7, otherwise output the total annual chemical fertilizer demand and each type of fertilizer Total fertilizer requirements for typical crops

S7, determine whether the typical crop planting area corresponding to the maximum and minimum nitrogen/phosphorus demand reaches the planting lower limit and the planting upper limit respectively, if both are not established, then go to step S8, otherwise go to step S9;

S8. Reduce the planting area of the typical _crop corresponding to the maximum nitrogen/phosphorus demand Qi according to a set proportion, and use the reduced area to plant the typical _crop corresponding to the minimum nitrogen/phosphorus demand Qi, and then calculate and adjust the planting area. The total amount of chemical fertilizers of the two typical crops, and return to step S5;

S9. Calculate the difference between the annual planned total amount and the annual planned total amount of chemical fertilizer, and use 3 to 6 times the difference of fermented animal manure to replace part of the chemical fertilizer with the difference, and output the organic fertilizer amount and the annual planned total amount.

The beneficial effects of the present invention are as follows: in this scheme, by clarifying the monitoring results of soil nitrogen/phosphorus content and typical crop nitrogen/phosphorus demand, combined with the nitrogen/phosphorus content and fertilizer utilization rate of commonly used compound fertilizers in my country, the entire growth rate of each typical crop is determined. The total amount of chemical fertilizer in the cycle, and then combined with the fertilizer amount planned by the Ministry of Agriculture to adjust the total amount of chemical fertilizer for all crops in the entire growth cycle.

This scheme basically realizes the supply of nitrogen/phosphorus to typical crops on demand through the nitrogen/phosphorus available in the soil combined with the nitrogen/phosphorus provided by the compound fertilizer, so as to avoid a large amount of nitrogen/phosphorus entering the soil during the fertilization process and enriching in the soil. Non-point source pollution occurs; through the adjustment of the fertilizer application amount in this plan, to achieve dual control of the total amount of fertilizer application and application intensity, improve the utilization efficiency of agricultural chemical fertilizer application amount, reduce non-point source pollution, and at the same time meet the planning requirements of the Ministry of Agriculture.

Description of drawings

FIG. 1 is a flow chart of an embodiment of a method for determining the amount of fertilizer applied in farmland.

Detailed ways

The specific embodiments of the present invention are described below to facilitate those skilled in the art to understand the present invention, but it should be clear that the present invention is not limited to the scope of the specific embodiments. For those of ordinary skill in the art, as long as various changes Such changes are obvious within the spirit and scope of the present invention as defined and determined by the appended claims, and all inventions and creations utilizing the inventive concept are within the scope of protection.

Referring to FIG. 1 , FIG. 1 shows a flow chart of a method for determining the application amount of chemical fertilizers in farmland. As shown in FIG. 1 , the method S includes steps S1 to S9 .

In step S1, obtain the agricultural statistical data of the research area, and determine the crops whose planting area is larger than the set ratio according to the agricultural statistical data as typical crops;

In step S2, obtain the main root length of each typical crop, collect soil samples within the set area and the depth is equal to the main root length of the typical crop, and measure and obtain the initial nitrogen/phosphorus content of the soil within the depth range of the crop root system in the unit area;

In one embodiment of the present invention, a soil sample within a set area and a depth equal to the length of a typical crop taproot is collected, and the method for obtaining the initial nitrogen/phosphorus content per unit area includes:

Preparation of collection bucket: Select a circular collection bucket with a height equal to the length of the main root of a typical crop and without upper and lower bottom plates, and grind one side wall of the collection bucket into a chamfered surface inclined from outside to inside;

Soil sample collection: Select flat land in the test field, turn the chamfered surface of the collection bucket down, and place a force transmission plate on the top of it. Take out the collection bucket and the soil in it to obtain the soil sample required for measurement;

Air-drying soil samples: Put the collected columnar soil samples on a wooden tray or clean paper, disperse them into clods smaller than the set size, and spread them out in the room to ventilate and dry. crumb;

Soil sample crushing and sieving: After the soil sample is air-dried, pick out the plant residues and stones in the soil sample, pour it into a clean wooden tray, grind it finely with a wooden stick, and make it all pass through a 1.5mm nylon sieve;

Ultrasonic extraction: Weigh a set amount of soil and place it in a conical flask, add the extractant, stir, and ultrasonically extract in batches for 50 minutes;

Sample determination: After filtering or centrifuging the contents of the conical flask, the supernatant was taken and melted with sodium hydroxide to measure phosphorus in the soil, and the semi-micro Kjeldahl method was used to measure the nitrogen in the soil.

In this scheme, the soil sample collection depth is set to the length of the main root of a typical crop, so that it can be accurately determined that typical crops can obtain nitrogen/phosphorus at the corresponding depth in the soil. The nitrogen/phosphorus that the soil of each typical crop can provide ensures the accuracy of the nitrogen/phosphorus introduced when the subsequent compound fertilizer is added, so as to avoid the accumulation of nitrogen/phosphorus in the soil and the occurrence of non-point source pollution.

The collection bucket made in this scheme can realize the collection of soil samples evenly at each depth within the set area, so as to avoid too many or too few soil samples at the same depth, which will affect the nitrogen/nitrogen ratio of soil samples per unit area. Accuracy of Phosphorus Calculations.

The setting of the chamfered surface on one side of the collecting bucket can form a beveled edge surface, so that when the collecting bucket is knocked into the soil, the difficulty of entering the collecting bucket into the deeper soil can be reduced; the setting of the force transmission plate can make the top of the collecting bucket The force is relatively uniform in all positions of the surface.

In step S3, select a representative field, adopt the planting methods of fertilization and no fertilization, and obtain the nitrogen/phosphorus demand applied per kilogram of output of each typical crop;

In one embodiment of the present invention, step S3 further comprises:

Obtain the yield of each typical crop with and without fertilization, and record the amount of chemical fertilizer applied to each typical crop throughout the growth cycle;

Select a typical plot corresponding to a typical crop planting structure as a fertilization formula test field, collect soil samples with the test field after harvesting within the set area and the depth equal to the length of the main root of a typical crop, and measure the post-planting nitrogen/phosphorus per unit area. by content;

Calculate the N/P requirement applied per kg of yield based on typical crop yield and post-plant N/P content;

Among them, c _i is the amount of chemical fertilizer applied to the ith typical crop, s is the test field area; a _1i and a _2i are the nitrogen/phosphorus content per unit area of the ith typical crop before and after planting without fertilization; a _3i is the first Nitrogen/phosphorus content per unit area of i typical crop after fertilization; b _1i and b _2i are the yield of i-th typical crop without fertilization and fertilization, respectively.

以此对后续作物对土壤中氮/磷的提供量进行准确计算。In this scheme, the nitrogen/phosphorus content collected before and after fertilization in the experimental field can accurately know the use of nitrogen/phosphorus applied in the process of planting and fertilization, whether it is more or less fertilized, so as to accurately obtain the nitrogen consumed per kilogram of yield. / Phosphorus; through the yield of fertilized and unfertilized, we can get the absorption rate of trace amounts in the soil by typical crops during the growth process, namely

In this way, the supply of nitrogen/phosphorus in the soil by subsequent crops can be accurately calculated.

In step S4,

Calculate the total amount of fertilizer required to grow a typical crop in a representative field

Among them, Si, fi and Qi are the planting area of the _i - _th typical crop _, the estimated yield per unit area and the nitrogen/phosphorus demand required for each kilogram of yield; η is the amount of nitrogen/phosphorus in the fertilizer used. Utilization rate; q is the effective content of nitrogen/phosphorus per kilogram of fertilizer; 1≤i≤n, n is the total quantity of typical crops.

When implemented, the preferred method for obtaining the estimated yield per unit area of each typical crop in this scheme is:

Obtain the actual output per unit area in consecutively set years before the current year, and calculate the growth rate of the actual output in each year; the set year is preferably 5 years, such as 2015 to 2019, then the calculation will get 4 growth rates.

According to all growth rates, calculate the average growth rate of consecutively set years to obtain the estimated growth rate; when the set year is 5, the estimated growth rate is obtained by averaging the four growth rates.

When the estimated growth rate is less than or equal to the growth rate in the previous two years of the current year, a correction factor greater than 1 is used to correct the estimated growth rate to obtain the final growth rate;

When the estimated growth rate is greater than the growth rate in the previous two years of the current year, a correction factor less than 1 is used to revise the estimated growth rate to obtain the final growth rate;

Calculate the estimated yield per unit area of each typical crop by using the final growth rate and the actual yield per unit area of the current year and previous year;

The value of the correction coefficient e greater than 1 is 1<e<1.3, and the value of the correction coefficient e less than 1 is 0.9<e<1.

This scheme achieves the estimated yield per unit area in this way, which can make the estimated results relatively reasonable, and will not exceed the load of the land, ensuring the benign use of the land.

In step S5, according to the total amount of chemical fertilizer required by each typical crop, the total amount of chemical fertilizer required for all typical crops under the planting structure of the representative field is calculated.

In step S6, obtain the total annual planned chemical fertilizer application amount planned by the Ministry of Agriculture or the local environmental protection department in the study area, and judge whether the total annual chemical fertilizer demand is greater than the annual planned total amount, if so, go to step S7, otherwise output the annual total chemical fertilizer demand and total fertilizer requirements for each typical crop

In step S7, it is judged whether the typical crop planting area corresponding to the maximum and minimum nitrogen/phosphorus demand reaches the planting lower limit and the planting upper limit respectively, if both are not established, then go to step S8, otherwise go to step S9;

In step S8, the typical _crop corresponding to the maximum nitrogen/phosphorus demand Qi is reduced in the planting area according to a set ratio, and the reduced area is used to plant the typical _crop corresponding to the minimum nitrogen/phosphorus demand Qi, and then the adjustment is calculated and adjusted. The total amount of chemical fertilizers of the two typical crops after the planting area, and return to step S5;

In step S9, the difference between the annual planned total amount and the annual total amount of chemical fertilizer is calculated, and the organic fertilizer after fermentation of animal manure of 3 to 6 times the difference is used to replace the difference part of the chemical fertilizer, and the organic fertilizer amount and the annual planned total amount are output. quantity.

In one embodiment of the present invention, after adopting the organic fertilizer, the scheme also includes calculating the respective application rates of the organic fertilizer and chemical fertilizer for each typical crop:

Among them, R _i and P _i are the actual amount of compound fertilizer and organic fertilizer of the ith typical crop, respectively; x is the difference; u is the total amount of organic fertilizer;

Then output the total amount of chemical fertilizer application of each typical crop and the amount of organic fertilizer application of typical crops.

The adjustment of compound fertilizers and the division of organic fertilizers are carried out according to the method of planting area, which can be applied regardless of the number of typical crops. The division of organic fertilizers in this way can make the compound fertilizer of each crop in the growth cycle to a small extent. It can be reduced and then supplemented by organic fertilizers, which can ensure that the planting can meet the planning of the Ministry of Agriculture without affecting the normal growth of crops, so as to ensure the normal yield of crops.

During implementation, this scheme preferably sorts the nitrogen/phosphorus requirements of typical crops in descending order when the number of typical crops is greater than or equal to t, and adjusts the compound fertilizer usage of the previous t typical crops:

Among them, R _j and P _j are the actual amount of compound fertilizer and organic fertilizer of the jth typical crop respectively; 1≤j≤t, t=5 is the upper limit of the value of j, x is the difference; u is the total amount of organic fertilizer quantity;

Then output the total amount of chemical fertilizer for each typical crop and the amount of organic fertilizer for the typical crop to which organic chemical fertilizer is allocated.

This scheme divides organic fertilizers according to the size of nitrogen/phosphorus demand, which can effectively control the total amount of fertilizers. The adjustment of this method will not affect all typical crops, and only a small amount of crop nitrogen/phosphorus control is required. The introduced organic fertilizer can supply nutrients to crops that control the total amount of fertilizer, and can also avoid non-point source pollution.

Nitrogen/phosphorus is basically an essential element for plant growth, and the normal growth of crops can be met by determining the amount of these substances.

To sum up, this scheme can determine the amount of chemical fertilizer applied to crops through the determination of nitrogen/phosphorus usage, so as to achieve on-demand supply, improve the utilization efficiency of agricultural chemical fertilizer application amount, and then realize the total amount and application intensity of chemical fertilizer application. The comprehensive control of non-point source pollution can also promote the utilization of organic fertilizers.

Claims (6)

1. the determination method of farmland chemical fertilizer application amount, is characterized in that, comprises: S1. Obtain the agricultural statistical data of the research area, and according to the agricultural statistical data, determine the crops with the sown area greater than the set proportion as typical crops; S2. Obtain the main root length of each typical crop, collect soil samples within the set area and the depth is equal to the main root length of the typical crop, and measure and obtain the initial nitrogen/phosphorus content of the soil within the depth range of the crop root system per unit area; S3. Select representative fields, adopt fertilization and non-fertilization planting methods, and obtain the nitrogen/phosphorus requirements applied per kilogram of yield of each typical crop; S4. Calculate the total amount of chemical fertilizers required for planting typical crops in representative fields

Among them, Si, fi and Qi are the planting area of the _i - _th typical crop _, the estimated yield per unit area and the nitrogen/phosphorus demand required for each kilogram of yield; η is the amount of nitrogen/phosphorus in the fertilizer used. Utilization rate; q is the effective content of nitrogen/phosphorus per kilogram of fertilizer; 1≤i≤n, n is the total quantity of typical crops; S5. According to the total amount of chemical fertilizer required by each typical crop, calculate the total amount of chemical fertilizer required for all typical crops under the planting structure of the representative field; S6. Obtain the total annual planned chemical fertilizer application planned by the Ministry of Agriculture or the local environmental protection department in the study area, and determine whether the total annual chemical fertilizer demand is greater than the annual planned total. If so, go to step S7, otherwise output the total annual chemical fertilizer demand and each type of fertilizer Total fertilizer requirements for typical crops

S7, determine whether the typical crop planting area corresponding to the maximum and minimum nitrogen/phosphorus demand reaches the planting lower limit and the planting upper limit respectively, if both are not established, then go to step S8, otherwise go to step S9; S8. Reduce the planting area of the typical _crop corresponding to the maximum nitrogen/phosphorus demand Qi according to a set proportion, and use the reduced area to plant the typical _crop corresponding to the minimum nitrogen/phosphorus demand Qi, and then calculate and adjust the planting area. The total amount of chemical fertilizers of the two typical crops, and return to step S5; S9. Calculate the difference between the annual planned total amount and the annual planned total amount of chemical fertilizer, and use 3 to 6 times the difference of fermented animal manure to replace part of the chemical fertilizer with the difference, and output the organic fertilizer amount and the annual planned total amount. 2. the determination method of farmland chemical fertilizer application rate according to claim 1, it is characterized in that, after adopting organic fertilizer, also comprise the organic fertilizer and chemical fertilizer application rate respectively of calculating each kind of typical crop respectively:

Among them, R _i and P _i are the actual amount of chemical fertilizer and organic fertilizer of the ith typical crop, respectively; x is the difference; u is the total amount of organic fertilizer; Then output the total amount of chemical fertilizer application of each typical crop and the amount of organic fertilizer application of typical crops. 3. the determination method of farmland chemical fertilizer application rate according to claim 1, is characterized in that, when typical crop quantity is more than or equal to t, the nitrogen and phosphorus demand of typical crop is sorted in descending order, and the front t kind of typical crop is sorted in descending order. Adjust the amount of fertilizer application:

Among them, R _j and P _j are the actual amount of compound fertilizer and organic fertilizer of the jth typical crop respectively; 1≤j≤t, t=5 is the upper limit of the value of j, x is the difference; u is the total amount of organic fertilizer quantity; Then output the total amount of chemical fertilizer for each typical crop and the amount of organic fertilizer for the typical crop to which organic chemical fertilizer is allocated. 4. The determination method of farmland chemical fertilizer application amount according to claim 1, is characterized in that, described step S3 further comprises: Obtain the yield of each typical crop under fertilized and unfertilized conditions, and record the amount of chemical fertilizer applied to each typical crop throughout the growth cycle; Select a typical plot corresponding to a typical crop planting structure as a fertilization formula test field, collect soil samples with the test field after harvesting within the set area and the depth equal to the length of the main root of a typical crop, and measure the post-planting nitrogen/phosphorus per unit area. by content; Calculate the N/P requirement applied per kg of yield based on typical crop yield and post-plant N/P content;

Among them, c _i is the amount of chemical fertilizer applied to the ith typical crop, s is the test field area; a _1i and a _2i are the nitrogen/phosphorus content per unit area of the ith typical crop before and after planting without fertilization; a _3i is the first Nitrogen/phosphorus content per unit area of i typical crop after fertilization; b _1i and b _2i are the yield of i-th typical crop without fertilization and fertilization, respectively. 5. the determination method of farmland chemical fertilizer application rate according to claim 1, it is characterized in that, collect the soil sample in the set area and the depth is equal to the length of the main root of typical crops, measure and obtain the initial nitrogen and phosphorus content in the soil in the unit area. Methods include: Preparation of collection bucket: Select a circular collection bucket with a height equal to the length of the main root of a typical crop and without upper and lower bottom plates, and grind one side wall of the collection bucket into a chamfered surface inclined from outside to inside; Soil sample collection: Select flat land in the test field, turn the chamfered surface of the collection bucket down, and place a force transmission plate on the top of it. Take out the collection bucket and the soil in it to obtain the soil sample required for measurement; Air-drying soil samples: Put the collected columnar soil samples on a wooden tray or clean paper, disperse them into clods smaller than the set size, and spread them out in the room to ventilate and dry. crumb; Soil sample crushing and sieving: After the soil sample is air-dried, pick out the plant residues and stones in the soil sample, pour it into a clean wooden tray, grind it finely with a wooden stick, and make it all pass through a 1.5mm nylon sieve; Ultrasonic extraction: Weigh a set amount of soil and place it in a conical flask, add the extractant, stir, and ultrasonically extract in batches for 50 minutes; Sample determination: After filtering or centrifuging the contents of the conical flask, the supernatant was taken and melted with sodium hydroxide to measure phosphorus in the soil, and the semi-micro Kjeldahl method was used to measure the nitrogen in the soil. 6. according to the determination method of the arbitrary described farmland chemical fertilizer application amount of claim 1-5, it is characterized in that, the acquisition method of every kind of typical crop estimated output per unit area is: Obtain the actual output per unit area in consecutively set years before the current year, and calculate the growth rate of actual output in each year; According to all the growth rates, calculate the average growth rate for consecutively set years to obtain the estimated growth rate; When the estimated growth rate is less than or equal to the growth rate in the first two years of the current year, a correction factor greater than 1 is used to correct the estimated growth rate to obtain the final growth rate; When the estimated growth rate is greater than the growth rate in the previous two years of the current year, a correction factor less than 1 is used to revise the estimated growth rate to obtain the final growth rate; Calculate the estimated yield per unit area of each typical crop by using the final growth rate and the actual yield per unit area of the current year and previous year; The value of the correction coefficient e greater than 1 is 1<e<1.3, and the value of the correction coefficient e less than 1 is 0.9<e<1.

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