山西省农牧生产体系磷流动空间变异特征

为揭示山西省农牧生产体系磷流动空间分布特征,进一步为养分资源综合管理提供科学建议,本研究使用食物链养分流动模型(NUFER)与Arc GIS相结合,以2011年山西省11个地市农牧生产体系为研究对象,计算了农牧生产体系中的磷流动、损失及账户平衡,并对各个生产体系的磷利用效率(PUE)、有机废弃物中磷的循环利用效率、磷的损失途径等重要指标进行了综合评价,描述了2011年山西省各地市农牧生产体系与区域尺度的磷流动变化特征。研究结果表明,山西省各地市农牧体系磷的投入和损失差异较大,农田生产体系投入范围在22.5~83.0 kg·hm~(-2),而整个农牧生产体系损失区间在2.7~8.8 kg·hm~(-2);磷的投入和损失均总体呈现东南部高、西北部低的空间分布格局;各地市农田磷素均有盈余但程度不均,为9.4~48.4 kg·hm~(-2)。农田生产系统的磷素利用效率(PUEc)高于全国平均水平;农牧生产体系的磷利用效率(PUEc+a)较低,全省平均水平仅为30.3%,主要是由于农牧分离较为严重;有机废弃物的循环利用效率较低(60%)。省域东南部存在潜在环境风险,晋城、晋中等地市有大量的粪尿磷未得到回收利用,可作为周边农业主产区的农田养分资源。因此通过提高农牧生产体系的养分管理水平和区域间养分资源协同管理,能够大幅提高磷的利用效率,同时有效降低环境风险,实现山西农业可持续发展。

Spatial characteristics of phosphorus flow in crop-livestock production systems in Shanxi, China

A quantitative understanding of phosphorus (P) flow, loss and use efficiency is critical for improving the productivity and sustainability of agriculture while minimizing environment impact. However, most studies have focused primarily on either crop systems or livestock systems. Hence the analysis of P flow in integrated crop-livestock production systems has been largely lacking and the spatial characteristics of P flow has not been entirely known. Here, we quantified P flow, loss and use efficiency (PUE) in crop-livestock production systems in Shanxi Province, China, using the NUFER (nutrient flows in food chain, environment and resources use) simulation model and ArcGIS. We collected the data from a statistical database in 2011, consisting of 11 municipalities in Shanxi Province, to explore the spatial characteristics of P flow in the crop-livestock systems and propose scientific regional nutrient management. Our results showed large variations in P input and loss under crop/livestock systems in different cities of Shanxi Province. P input under crop production system was within 22.5–83.0 kg×hm-2 and P loss under crop-livestock system was within 2.7–8.8 kg×hm-2. Both P input and loss were significantly higher in the southeast than in the northwest regions. For crop systems, surplus P was within 9.4–48.4 kg×hm-2, which largely varied with region. PUE under crop systems (PUEc) in Shanxi was 45.6%, significantly higher than the national average (37.0%). Then PUE under livestock system (PUEa) was low (7.6%), mainly because of the large amount of draught cattle in livestock systems (581×103 heads). As a result, PUE under crop-livestock systems (PUEc+a) was relatively low (30.3%). This was mainly due to the separation between crop and livestock systems and the resulting low recycling rate of P (< 60%) from animal excreta and crop residues to croplands. Spatially, the southeast region had the largest potential risks of environmental pollution. Hence there was an urgent need to improve P management in crop-livestock production systems in the province. Large amounts of animal manure were not recycled and reused in Jincheng and Jinzhong, which could be used as nutrient input in croplands. In conclusion, PUE in crop-livestock systems in Shanxi Province was relatively low. This was in part due to the separation and de-coupling of crop and livestock systems within regions. It also related to the specialization of crop and livestock production in various regions, which resulted in large spatial variations. P loss under crop production systems was large in the south than in the north. There was also a large room for animal manure recycling. Hence significant improvements in P management were realizable via optimizing P flow between crop and livestock systems, and also via improving P flow among regions. P management needed optimization in crop-livestock production systems and among regions to significantly improve PUE at large scale and production system scale. This significantly reduced the risk of environmental pollution and ensured sustainable development.