CN-121614700-B - Dry land agriculture water-saving equivalent calculating method

Abstract

The invention belongs to the technical field of dry land agricultural water saving, and provides a dry land agricultural water saving equivalent calculating method which comprises the steps of S1, calculating average water productivity WP ave of a research area under the same type of soil and traditional management conditions, S2, obtaining actual crop yield Y a and actual crop evapotranspiration ET a after a target water saving technology is adopted in the research area, S3, calculating theoretical evapotranspiration ET Theo of production crop yield Y a according to the average water productivity WP ave and the actual crop yield Y a , and S4, calculating dry land agricultural water saving equivalent W sav after the water saving technology is adopted through unit conversion according to difference between the theoretical evapotranspiration ET Theo and the actual crop evapotranspiration ET a . The method for calculating the water-saving equivalent of the dry land agriculture provided by the invention breaks the technical defect that the physical water-saving amount cannot be calculated in the dry land rain-raising agriculture for the first time, so that the water-saving technology can be converted into the water-saving equivalent of an intuitive and physical index. Fills the gap that the direct water quantity index is lacking in the field for a long time.

Inventors

• LIU HAIJUN
• XU PEIWEN

Assignees

• 北京师范大学

Dates

Publication Date

20260508

Application Date

20251205

Claims (6)

1. 1. The dry land agricultural water-saving equivalent calculating method is characterized by comprising the following steps of: S1, acquiring a years average crop yield Y ave and a years average crop evapotranspiration ET ave of a research area, and calculating the average water productivity WP ave of the research area according to a formula WP ave = Y ave / ET ave , wherein the research area is a dry farming and rainy planting area; s2, obtaining the actual crop yield Y a and the actual crop evapotranspiration ET a after a target water-saving technology is adopted in the research area, wherein the target water-saving technology comprises one or a combination of a plurality of drought-resistant preparations, plastic film coverage, subsoiling cultivation, water-retaining agents or drought-resistant varieties; S3, calculating the theoretical evapotranspiration ET Theo of the production crop yield Y a according to the average water productivity WP ave and the actual crop yield Y a , wherein a calculation formula ET Theo = Y a / WP ave is adopted; S4, calculating the agricultural water-saving equivalent W sav of the arid region after adopting the water-saving technology according to the theoretical evapotranspiration ET Theo and the actual crop evapotranspiration ET a , wherein the calculation formula is W sav = k× (ET Theo - ET a ), and k is a unit conversion coefficient.
2. 2. The method for calculating the water-saving equivalent of dry land agriculture according to claim 1, wherein the calculation formula of the average crop yield of years Y ave is as follows ; The calculation formula of the average crop evapotranspiration ET ave for many years is as follows ; Wherein Y ave and Y i are respectively the average crop yield of years and the crop yield obtained by the ith, and the unit is kg/hm 2 ; N is the total number of crop yields obtained by consulting literature and investigation, and N is more than or equal to 5; ET ave and ET i are the average crop evapotranspiration over the years and the crop evapotranspiration obtained at the ith, in mm, respectively; m is the total number of the crop evapotranspiration obtained by consulting the literature, and M is more than or equal to 5.
3. 3. The method for calculating the water saving equivalent of dry land agriculture according to claim 1, wherein the actual crop evapotranspiration ET a after the target water saving technology is adopted in the research area is obtained by adopting a water balance method, a lysimeter method or a vorticity correlation method in the step S2.
4. 4. The method for calculating the water saving equivalent of dry land agriculture according to claim 1, wherein the actual crop evapotranspiration ET a obtained in the study area by adopting the target water saving technology adopts a water balance method, specifically, ET a =Δw+p, wherein Δw is the water consumption of soil in the crop growing period, and P is the precipitation in the crop growing period.
5. 5. The method for calculating the water saving equivalent of dry land agriculture according to claim 1, wherein the water amount Δw consumed by the soil during the growing period of the crop is calculated by the following formula: ; Wherein: Δw is the amount of water consumed by the soil during the crop growth period in cm, and can also be converted into mm; Z i is the thickness of the i-th layer of soil, and the unit is cm; Gamma i is the volume weight of the soil of the ith layer, and the unit is g/cm 3 ; And The average weight water content of the soil of the ith layer measured during crop sowing and harvesting is measured in g/g; N is the layering quantity of soil; i is the soil of the ith layer.
6. 6. The method for calculating the water saving equivalent of dry land agriculture according to claim 1, wherein after the water saving equivalent W sav is calculated in S4, the water saving ratio R is further calculated, and the calculation formula is R= (ET Theo - ET a ) /ET a ).

Description

Dry land agriculture water-saving equivalent calculating method Technical Field The invention belongs to the technical field of dry land agriculture water saving, and relates to a dry land agriculture water saving equivalent calculating method. Background The dry land agriculture is to depend on natural precipitation completely, and has no irrigation input, thereby realizing crop growth and obtaining yield. In order to promote the development of dry land agriculture and improve the crop yield and the utilization efficiency of water, various water-saving technologies have been developed from the fields of breeding, cultivation, water and fertilizer management and the like at home and abroad, such as drought-resistant preparations, plastic film mulching, subsoiling cultivation, water-retaining agent application, water-saving drought-resistant crop varieties and other water-saving measures are commonly adopted in production. The current evaluation method for the technical means mainly comprises the following steps: (1) And the yield comparison method is to measure the yield difference between the treatment area and the control area through field test so as to measure the technical effect of the yield increase. (2) The water utilization efficiency method is to measure the actual evapotranspiration quantity ET while obtaining the yield, and calculate WUE=yield/ET so as to improve the efficiency and evaluate the technical advantages and disadvantages. (3) The physiological and biochemical index method is to measure the relative water content, SOD activity, MDA content, etc. of leaf and to infer the drought resistance of crop indirectly. In order to further distinguish whether various technical means are high-yield and multi-consumption or water-saving and high-yield, and realize accurate dry-area agricultural water resource management and planning, evaluation and investigation and research benefits, the water-saving equivalent of various technical means needs to be further evaluated, and the calculation concept of the water-saving equivalent is clear and the method is direct in irrigation agriculture in the prior art, namely, the water-saving amount is directly quantified by comparing the reduction value of irrigation water before and after the application of the water-saving irrigation technology on the premise of ensuring the same yield, as is clear in GB/T50363-2018 Water-saving irrigation engineering technical standard. However, for dry farming and rainy farming, there has long been a general technical prejudice in the art that since there is no irrigation water input throughout the crop growth, there is no way to define and calculate a physically significant water saving equivalent as in irrigation agriculture. This prejudice has led to scientific and practical work that generally takes the improvement of water utilization efficiency as the sole or final indicator for evaluating the effectiveness of water saving techniques. The water utilization efficiency is a ratio representing the water conversion efficiency, and although the efficiency of the system is improved, the water utilization efficiency has inherent defects that the water utilization efficiency is an efficiency index, not a water quantity index, and can mask the actual water resource consumption condition, for example, a technology for realizing small improvement of WUE by greatly increasing the yield and the water consumption simultaneously, and the water utilization efficiency is not water-saving from the point of view of the total water resource consumption. Therefore, under the inertia thinking, the technical prejudice of the general existence of the technology for indirectly and qualitatively describing the water-saving effect by using the water utilization efficiency is widely satisfied by the person in the art, and the general technical prejudice seriously hinders the accurate assessment of the water-saving benefit of the agriculture in the arid region, the transverse comparison among different technologies, and the effective connection of the water-saving result with policies such as water resource management, ecological compensation and the like. With the rapid development of dry land rain-raising agricultural technology, a calculation method capable of breaking the technical prejudice and directly quantifying water-saving equivalent is urgently needed to fill the blank of the prior art in the key field. The invention provides a dry land agriculture water-saving equivalent calculating method, which breaks the technical prejudice that the dry land rain-raising agriculture cannot calculate the physical water-saving amount for the first time, so that the water-saving technology can be converted into the water-saving equivalent with visual and physical indexes. Fills the gap that the direct water quantity index is lacking in the field for a long time. The technical scheme of the invention is realized as follows: A dry land agriculture water-