The black soil region of northeast China is one of the most important grain-producing areas in China. Increasingly severe gully erosion in this region has destroyed much farmland and reduced grain production. We analy...The black soil region of northeast China is one of the most important grain-producing areas in China. Increasingly severe gully erosion in this region has destroyed much farmland and reduced grain production. We analyzed SPOT5 imagery from 2007 and TM imagery from 2008 to describe the distributions of gullies and farmland shelterbelts in Kedong County and to assess the effect of farmland shelterbelts on gully erosion. The ima- gery revealed 2311 gullies with average density of 418.51 m km-2, indicating very serious gully erosion. With increasing slope gradient there was an inverse trend between gully density and shelterbelt density, indicating that farmland shelterbelts can prevent gully erosion. The defense effect of farmland shelterbelts against gullyerosion varied with distance： for distances 〈120 m, the defense effect was consistent and very strong; for distances of 120-240 m, a weak linear decrease was found in the defense effect; and for distances 〉240 m, the defense effect of the shelterbelts was significantly weaker. We recommend an optimal planting density of farmland shel- terbelts for the prevention of gully erosion at 1100-1300 m km-2.展开更多
On the basis of landscape ecology, combining the Spot 5 high resolution satellite imagery with GIS, a method evaluating the spatial heterogeneity of shelterbelts distribution at landscape scale is put forward in this ...On the basis of landscape ecology, combining the Spot 5 high resolution satellite imagery with GIS, a method evaluating the spatial heterogeneity of shelterbelts distribution at landscape scale is put forward in this paper. The distance coefficients of reasonable and existing landscape indexes of farmland shelterbelt networks were com-puted, and then through the classification of the distance coefficients, and the establishment of evaluation rules, the spatial heterogeneity of farmland shelterbelts was evaluated. The method can improve the evaluating system of previ-ous studies on shelterbelts distribution, resolve the disadvantages of lacking spatiality of overall evaluation, and make the evaluation results have more directive significance for shelterbelt management. Based on this method, spatial het-erogeneity of shelterbelt networks was evaluated in the midwest of Jilin Province, China. The results show that the re-gions with fewer shelterbelts and no closed network account for 34.7% of the total area, but only 4.9% of the area has relative reasonable pattern of shelterbelt networks. Many problems exist in the distribution pattern of shelterbelts, therefore, much attention should be paid to construct farmland shelterbelts in the study area.展开更多
【目的】系统评价中国农田防护林对作物产量的影响。【方法】在中国知网和Web of Science公开发表的文献中,通过检索关键词“农田防护林和产量”构建目标数据库,利用整合分析研究农田防护林对作物产量的影响及其在不同环境条件下的变化...【目的】系统评价中国农田防护林对作物产量的影响。【方法】在中国知网和Web of Science公开发表的文献中,通过检索关键词“农田防护林和产量”构建目标数据库,利用整合分析研究农田防护林对作物产量的影响及其在不同环境条件下的变化。【结果】1)中国农田防护林对作物的平均增产率为16.4%,考虑林带占地因素后为5.6%;2)不同作物的增产效应有显著差异(Q_(M)=8.55,p=0.02),玉米(22.02%)增产率最大,小麦(14.36%)和水稻(11.15%)较低;3)不同气候类型(Q_(M)=1.8,p=0.79)和不同林网规格(Q_(M)=3.25,p=0.16)条件下农田防护林对作物产量的影响无显著差异;4)作物的增产效应和背景产量呈负相关,在产量低于9727.5 kg·hm^(-2)时具有显著增产效应。【结论】农田防护林可有效提高作物产量,是保障粮食安全和应对气候变化的有效途径,未来研究应适当关注政策工具的制定和综合经济效益的提升。展开更多
基金supported by the National Natural Science Foundation of China(31400612,41271305)the Key Technologies Research and Development Program of Henan Province(142102110147)
文摘The black soil region of northeast China is one of the most important grain-producing areas in China. Increasingly severe gully erosion in this region has destroyed much farmland and reduced grain production. We analyzed SPOT5 imagery from 2007 and TM imagery from 2008 to describe the distributions of gullies and farmland shelterbelts in Kedong County and to assess the effect of farmland shelterbelts on gully erosion. The ima- gery revealed 2311 gullies with average density of 418.51 m km-2, indicating very serious gully erosion. With increasing slope gradient there was an inverse trend between gully density and shelterbelt density, indicating that farmland shelterbelts can prevent gully erosion. The defense effect of farmland shelterbelts against gullyerosion varied with distance： for distances 〈120 m, the defense effect was consistent and very strong; for distances of 120-240 m, a weak linear decrease was found in the defense effect; and for distances 〉240 m, the defense effect of the shelterbelts was significantly weaker. We recommend an optimal planting density of farmland shel- terbelts for the prevention of gully erosion at 1100-1300 m km-2.
基金Under the auspices of Knowledge Innovation Programs of Chinese Academy of Sciences (No. KZCX1-YW-08-02)
文摘On the basis of landscape ecology, combining the Spot 5 high resolution satellite imagery with GIS, a method evaluating the spatial heterogeneity of shelterbelts distribution at landscape scale is put forward in this paper. The distance coefficients of reasonable and existing landscape indexes of farmland shelterbelt networks were com-puted, and then through the classification of the distance coefficients, and the establishment of evaluation rules, the spatial heterogeneity of farmland shelterbelts was evaluated. The method can improve the evaluating system of previ-ous studies on shelterbelts distribution, resolve the disadvantages of lacking spatiality of overall evaluation, and make the evaluation results have more directive significance for shelterbelt management. Based on this method, spatial het-erogeneity of shelterbelt networks was evaluated in the midwest of Jilin Province, China. The results show that the re-gions with fewer shelterbelts and no closed network account for 34.7% of the total area, but only 4.9% of the area has relative reasonable pattern of shelterbelt networks. Many problems exist in the distribution pattern of shelterbelts, therefore, much attention should be paid to construct farmland shelterbelts in the study area.
文摘【目的】系统评价中国农田防护林对作物产量的影响。【方法】在中国知网和Web of Science公开发表的文献中,通过检索关键词“农田防护林和产量”构建目标数据库,利用整合分析研究农田防护林对作物产量的影响及其在不同环境条件下的变化。【结果】1)中国农田防护林对作物的平均增产率为16.4%,考虑林带占地因素后为5.6%;2)不同作物的增产效应有显著差异(Q_(M)=8.55,p=0.02),玉米(22.02%)增产率最大,小麦(14.36%)和水稻(11.15%)较低;3)不同气候类型(Q_(M)=1.8,p=0.79)和不同林网规格(Q_(M)=3.25,p=0.16)条件下农田防护林对作物产量的影响无显著差异;4)作物的增产效应和背景产量呈负相关,在产量低于9727.5 kg·hm^(-2)时具有显著增产效应。【结论】农田防护林可有效提高作物产量,是保障粮食安全和应对气候变化的有效途径,未来研究应适当关注政策工具的制定和综合经济效益的提升。
