陕北几种农业生态经济系统生产力分析

本文将陕北黄土高原分为6个农业生态经济系统,笔者从土地利用结构、生物群落、产值结构、能量在食物链中流动和转化效率、粮田氮素循环、作物水分利用率、水土保持效益等方面来分析各系统的生产力,通过典型事例来论证观点,并指出今后发展的方向。从现状分析结果来看,以延安市庙沟为代表的梁状丘陵果林农牧系统,由于大力发展苹果生产,经济效益最高,1990年人均纯收入达1166.7元,比周围村高1.9倍,目前百亩果园供养44.6人,比百亩草地供养人数高8.3倍,至1995年可供养217人。以米脂县泉家沟为代表的峁状丘陵果粮副牧系统,由于大搞农田基本建设和退耕还林种草,年土壤侵蚀模数由60年代的16000t/km²降低到3000t/km²,1990年人均纯收入656.4元,比周围村增加1倍,目前百亩果园供养95人,比种粮食多供养9.1人,至1995年可供养190人。

An Analysis of the Productivity in Several Agro-ecological and Economic Systems in North Shaanxi

The Loess Plateau is divided into 6 agro-ecological and economic systems in this paper. The authors analysed the productivity in each system from many aspects including land use structures, bio-community, productive value structure, energy flow and conversion efficiency in food chains, N-cycle in farmlands, crop water use efficiency as well as water and soil conservation benefits. Also, they proved their viewpoints with the typical examples, and pointed out the directions for the future development. It can be seen from the analysis of the existing conditions that the system of fruit, forests, agriculture and animal husbandry developed in Liang and hill area represented by Miaogou village in Yanan Municipality has the high economic returns owing to a large scale development of apple production, In 1990, per capita net income reached 166.7 Yuan, being 1.9 times higher than that in the surrounding villages. At present, one hectare orchard can support 6.7 persons, being 8.3 times higher than one hectare grassland supports. Up till to 1995, one hectare orchard can support 32.6 persons. In the system of fruit food crops, sideline production and animal husbandry formed in mound and hill area represented by Qianjiagou village in Mizhi county, the modulus of soil erosion has been reduced from 16,000 t/(km²·a). in the 1960s to 3,000 t/(km²·a ). at present owing to a large scale basic farmland construction and conversion of sloping lands into planting trees and grasses. In 1990, per capita net income was 656.4 yuan, being more than double that in the surrounding villages. At present one hectare orchard can support 14.3 persons, being 1.4 persons higher than that supported by one hectare cultivated with food crops. Up till to 1995, one hecgare orchard can support 28.5 persons.