关键词: 生物量, 生物量

Abstract: This study combined inventorying and census to investigate the use of pesticides, fertilizers, agricultural films and straw handling of typical farmer who was determined based on a percentage of sampling, and the statistical analysis of the survey results had been done, in order to learn about the existing conditions, characteristics and the rules of Xi’an farmland area-source pollution and put forward precaution measures. The results showed that: proportional application of nitrogen, phosphorus and potassium nutrition (N:P:K=1: 0.71:0.19) in Xi’an crops was unreasonable obviously compared with the optimal proportion (N:P:K=1:0.32: 0.59) of nutrient requirement on upland crops. The phosphate and nitrogen was high, and the potash was low on the utilization of fertilizer, these problems mainly lied in fertilizers of crops, vegetables and fruits. Pesticides dosage exceeded 7.3%-33.3% compared to the recommendations. The annual production of crop straw reached around 3.2 million tons, about 22% of the straw was burned in the fields or as a fuel; The annual consumption of mulch was 1800.16 tons, and amount of residue and residual rate respectively was 531.93 tons and 29.5%. From the investigation and analysis results, the fertilization structure, dosage and proportion were unreasonable obviously, the pesticides dosage exceeded the limit, crop straw comprehensive utilization rate was not high, agricultural film recovery rate was low, All of these problems was the important factor which led to the farmland area-source pollution, some effective measures must be taken to get rid of pollution.