不同土地利用模式与管理实践下的土地经济效益响应

农户土地利用要素投入具体表现在土地利用模式与管理实践的差异。不同的土地模式与管理实践不仅是农户对局地自然、社会、经济条件及土地政策的响应，而且还是诱发土地质量变化最直接的外部诱因。该研究以重庆市万洲区万洲居仙试验区作为研究区，选取5种土地利用模式及与之相应的土地管理实践，获取576个0～20 cm表层土壤样品，分析不同土地利用模式下土壤性质变化及其经济效益的响应。结果表明，2003－2005年，试验区紫色土的土壤肥力总体上有所上升，但不同土地利用模式对其贡献程度不一，其顺序为：粮、经、菜间、套土地利用模式（CEV）＞菜、经、菜间、套土地利用模式（VEV）＞果、粮、菜间、套土地利用模式（FCV）＞粮、豆、粮间、套土地利用模式（CBC）＞单一土地利用模式（MONO）；土地经济系数对土壤性质响应明显，其变化方向较一致，土壤保肥供肥能力越强，其土地经济系数越大；菜、经、菜间、套土地利用模式（VEV）更适合于试验区，是农户选择的最优土地利用模式。

Response of land economic benefit to land use pattern and land management practice

Land use pattern and difference of land management practice are representations as farmer's investment in land use element. It is a response to physical, social, economical conditions and land policy from farmers, and is a direct external cause influencing land quality at the scale level. Taking Juxian study area in Wanzhou County, Chongqin as an example, the paper chose five land use patterns, adopted different management practices, and gathered 576 samples of surface soil from 0 to 20 cm. This paper studied the effect of different land use patterns on soil characteristics, and the response of land economical benefit to soil characteristics. The results indicated that the situation of soil fertility rose constantly from 2003 to 2005. But there was a difference in land use patterns. The order was CEV (cereals, economical plant, and vegetable) >VEV (vegetable, economical plant, and vegetable) >FCV (fruit, cereals, and vegetable) >CBC (cereals, bean, and cereals) >MONO (mono-cropping). Meanwhile, influence of different land use patterns on changes of soil nutrient was diversities. Accordingly, the land economical coefficient correlated closely with soil fertility. Finally, VEV (vegetable, economical plant, and vegetable) is the optimal land use pattern in the study area.