Study On The Measuring Technology Of Environmental Efficiency Of Variable-rate Fertilization

In the work, the ecology benefit of the Variable-rate Fertilization (VRF) in precise agriculture were mainly analyzed and evaluated. Systematically analysis was made. And the work introduced the inevitability of the chemical fertilization in agricultural production. Fertilization has some positive function, while unreasonable fertilization will take some negative effects to the environment.We analyzed the situation of the environmental pollution brought by the fertilizer, and brought forward the measuring technology of the VRF to this question. On corn VRF, took the field in Gongpengzi town, Yushu city as the trial field. Using the data of 2002 and 2003, we analyzed the environmental load of the corn VRF by the numbers based on the LCA theory, and measured the environmental efficiency of the crop VRF, at last drew the conclusion of the environmental efficiency value. Using radial DEA and non-radial DEA, we evaluated the validity of the Decision Making Units. Finally the work measured the dynamic change of the environmental efficiency of the VRF based on the Malmquist index, and demonstrated that VRF can save the fertilizer and materiel, reduce the environmental pollution and increase the crop yield than traditional fertilization in theory. At the same time, the application of VRF becomes more and more maturely and the efficiency continues increasing, which will bring much economic benefit and social benefit.The main studies and conclusions are as follows:(1)Analysis of the situation of the environmental pollution brought by the fertilizer. Fertilization has some positive function, such as increasing the crop yield, improving the soil fertility, exerting well-bred potential, compensating infield shortage, adding organic fertility quantity, growing green resource; while unreasonable fertilization will take some negative effect to the environment, for example, excessive fertilization not only will waste the resource, increase the cost of the agriculture, but also the nitrogen which is not absorbed by the crop will volatilize to the air, adding the greenhouse gases, resulting the temperature increasing. And it can also prick up excessive nutrition of the water by eluviations. It decreases the soil absorbency of other elements so that it will destroy the internal balance of the soil polluting the environment, and so on.(2)Life Cycle Assessment (LCA)of VRF of corn. The work used LCA to VRF of corn. LCA has been widely used in industry production but it is seldom used in agricultural system. We introduced the LCA system, and analyzed the LCA frame and the phase plot of the corn LCA. At last it confirmed the environmental load index. In this trial, the input factors are mainly diesel oil, fertilizer, and pesticide. The output factors are the corn yield and the environmental load index such as NO3—,NOX,SOX,CO2,N2O.( 3 ) Measurement of the environmental efficiency of VRF. Environmental efficiency (EE) shows the extent of the whole development and the zoology rule. The development is of the economic social and cultural connotation which is achieved by the people. EE is the entia of the economic benefit, social benefit and the environmental benefit. EE embodies sustainable development. So the sustainable development can not be independent of EE. Without EE, there is no sustainable development. The value can be calculated by the economic value of the product and service dividing environmental load, i.e. the economic value of every environmental load unit. The functional unit of the trial is 1hm2.The ELU is calculated based on LCA. The economic value of the corn of one hm2 is the price multiplying the yield (the price is 0.85RMB/kg). According to the formula it got the environmental efficiency of VRF.From the result, we can see that the whole yield of 2003 is a bit less than that of 2002. But the environmental load of 2003 is much less than that of 2002. So the EE of 2003 is 40.04RMB/ELU, while the EE of 2002 is 39.33RMB/ELU. It shows that the technical efficiency has been improved, taking less pollution gradually, which is the inevitable effect.In addition, we ignored some input factors in this LCA which certainly will take much environmental load. Consequently the environmental load value in Table5-1 is smaller than the actual data, and the EE calculated based on the data is greater. The data should be more accurate with the full data collection.(4)The Environment efficiency of VRF is assessed based on the DEA model. The environmental pollution indexes are looked on as input factors, so it can calculate the environmental validity of VRF using the evolutive DEA model. The BCC model is the technical efficiency assessment model. By analysis, 59.4% of the grids which applied VRF were technical efficient. While only 42.8% of the grids which applied traditional fertilization were BCC effective.This result indicated that VRF is more efficient than traditional fertilization from the view of technology, the proportion of NPK is more reasonable, and the waste and the pollution are all much less. The trial validated the advantage of VRF.The CCR model is carries on the synthesis assessment to the technical validity and the scale validity. The CCR efficient grids are less than that of the BCC to both VRF and traditional fertilization. Because the technical and scale validity contain technical validity. The ratio of the technical and scale validity of VRF is 12.5%, while the ratio of traditional fertilization is 7.14%. By comparison it showed that VRF was more pertinent and made the NPK proportion more reasonable thus the crop could absorb the fertilizer more amply, take less environmental pollution and get ideal yield due to reasonable fertilization decision based on the different grid soil nutrient distribution situation.(5)The Environment efficiency of VRF is assessed using the non-radial DEA. The paper got the technical efficiency value of the DMUs based on the input and output data of 2002 with the Farrell input DEA model and the CCF non-radial DEA model separately. the non-radial DEA model uses the projection vector is: g x= [15.61 0.71 4.48 8.09 3.07 10.85 7.11]T, g y= [880.49 ]T.The DEA efficiency value was equal to 1 or the non- radial DEA efficiency value is equal to 0, both indicate the decision-making unit is effective. Sees by the result, DMU10, DMU16, DMU18, DMU22,DMU23, DMU25, DMU26 and DMU32 DEA efficiency value are all equal to 1, the non- radial DEA efficiency value are all equal to 0.This result indicated these 8 decision-making units were effective, simultaneously it explained the radial direction projection and the non- radial directional projection which along ( g x, g y) could get the same effective and non- effective DMUs, just the degree were different.For instance, under the Farrell input distance function, the DMU5 is the third one by the degree of the non- efficiency, while it is the second by the technical efficiency along ( g x, g y) projection. Other DMUs have the analogue. The two kinds of sort orders are incompletely consistent. The reason is that the degree of approaching to the production frontier along the radial direction projection and non- radial direction projection of the same DMU is different.Simultaneously the non- radial direction model considers both input and output factors, which also possibly is the reason that some decision-making units which along non-radial direction has lower efficiency than that of the radial direction.(6)The dynamic changes of the Environment efficiency of VRF was assessed based on the Malmquist index. The result showed that, 75% of the VRF DMUs raised their production boundary and made technical progress. 34.37% of the DMUs approached the production frontier much and the relative technical efficiency had been enhanced. Thus it can be seen that VRF technology has made progress and the technical application has made the certain result, and gotten certain experience. It may provide certain reference and the instruction to the next step of experiment.VRF technology becomes more and more mature during the application process. And the deficiency has been consummated day after day. It improved the technical efficiency of the VRF, saved the fertilizer and the materiel input, reduced the environmental pollution, enhanced the output and optimized the resource collocate. To the producer it can save the cost and increase the income; to the society it can protect the people's health and enhance the agricultural product quality.The efficiency of 2003 compared with 2002 has grown, which confirmed the former conclusion, showing that the VRF can save the fertilizer and the materiel input, reduce the environmental pollution, enhance the output. At the same time, VRF technology becomes more and more mature and the efficiency is increasing. All can take much economic and social efficiency to both the agricultural production and the social life.