陇中半干旱地区不同地类轮作周期土壤水分动态研究

本文通过对陇中旱农地区梯田、川台、坡地轮作周期土壤水分动态的定位研究指出：在当地夏作→秋作→豆类的轮作过程中，３种土地类型的土壤水分都有一个微弱的下降→下降→升高的变化趋势。从土壤水分的年变化和垂直变化入手，分析产生这一变化的原因认为，在除自然因素降水和蒸发外，作物和地类对土壤水分有很大影响。作物的利用能力和利用范围是造成这一现象的根源，在制订该地轮作方案时，把主栽作物（春小麦）放在豆茬后是一个基本原则；轮作效益应以协调水分、平衡肥力、防除病虫草害等方面综合评价。

A Study on Soil Moisture Dynamics of Rotation Period on Different Field Type in Semi-arid Area of Central Gansu

In this paper the soil moisture dynamics of rotation period(Summer crops→Autumn crops→legume crops)on terrace field,frank fieldand slop field in semi-arid area of central Gansu has been studied.Therule of soil moisture of rotation period in all of the threc field types isfrom slightly decrease to decrease then increase. Based on yearly andvertical difference of the soil moisture,we have concluded that the cropand the field type have more influence on soil moisture than other factorsbesides rainfall and transpiration,especially the water use ability andextention of the crops.Thus the main crop(Spring wheat)planted afterthe legume crop in the rotation system is the basic principle