西南丘陵山区土地整理方案比选研究

新增耕地潜力是土地整理项目立项决策的重要依据，而新增耕地率是新增耕地潜力的反映，直接影响项目工程布局、投资预算以及效益问题。该文以重庆市忠县拔山土地整理项目为例，依据国土资源部不同土地开发整理项目新增耕地的两种最低门槛值10%和3%，进行土地整理方案比选设计，计算得到两种土地整理方案的新增耕地率分别为10.3%和4.02%，并从经济、生态和社会3方面，分别采用动态投资评估法、可拓物元分析法、综合指数法对两方案进行比选分析。结果表明：旱地坡改梯工程布局是造成两种土地整理方案新增耕地面积差异的主要原因；农田水利、道路工程以及防护林工程布局差异不大，只存在布局力度上的差异；从方案的系统效益看，新增耕地率10.3%的方案无论是动态投资回收年、生态环境关联度、社会效益指数，还是系统效益指数均优于新增耕地率为4.02%的方案；通过典型田块采用加权算法计算净耕地系数，可以作为西南丘陵山区土地整理项目净耕地系数的计算方法，但该方法中修正系数确定需要经过实地勘测和类比，这样可避免典型田块选择的主观性。

Comparisons of land consolidation projects in the hilly and mountainous, southwestern China

Newly-increased cultivated land potential is an important foundation of decision-making for land consolidation projects, and is reflected by newly-increased cultivated land ratio. Based on 10% and 3% of newly-increased cultivated land ratio from criterion of the Ministry of Land and Resources, two schemes whose newly-increased cultivated land ratio were 10.3% and 4.02% in Bashan land consolidation project were designed; meanwhile, dynamic investment evaluation method, extension element model and comprehensive index method were used to comparatively analyze their integrative benefits separately. The results indicate that newly-increased cultivated land area is greatly dependent on terracing slope fields in dryland and there are no significant difference among irrigation and drainage engineering, road engineering and shelter-belt engineering except their layout intensity. Scheme, that newly-increased cultivated land ratio is 10.3%, is much better in payback period for dynamic investment, annual net benefits, eco-environment correlation value, social benefit index and systemic benefit index than another one which cultivated land ratio is 4.02%. Choosing representative farmlands and using weighted algorithm are effective methods to calculate net cultivated land coefficient, thus providing scientific foundation for studying newly-increased cultivated land in hilly and mountainous, southwestern China. And using analogism and field survey, the subjectivity of choosing representative farmlands could be avoided.