不同粮草种植模式对四川紫色丘陵区水土流失的影响

Influence of Different Grain-forage Cropping Rotations on Runoff and Sediment in the Purple Hilly Area of Sichuan Province

把饲草作为主要作物引入耕作制,通过3年3重复随机区组定位试验,研究了紫色土丘陵区坡耕地不同粮草种植模式对水土流失的影响。研究表明,夏季牧草在雨季需刈割多次,造成土壤覆盖度急剧降低,栽种夏季牧草后加大了土壤侵蚀。刈割后再生力较强的墨西哥玉米较再生力较差的高丹草有利于减少土壤侵蚀。在冬季小麦预留空行增种禾本科牧草能在夏季残留大量根系,固定泥沙,显著减少土壤侵蚀。因此,从控制土壤侵蚀的角度考虑,在四川紫色丘陵区发展饲草种植,首先应考虑冬季小麦的空行利用,在栽培夏季牧草时应选择再生能力和分蘖力强的牧草品种。

A completely randomized block design was employed in this experiment with three replications and three-year study phases to investigate the influence of different forage rotations on runoff and sediment from the purple sloping arable lands.Results showed that large quantity of roots was left in soil when gramineous hay was inter-cropped with winter wheat,and this resulted in remarkable reduction in eroded sediments because soil particles were tightly held together by these roots.After several harvests of the summer forage crops in rain season,soil erosion become severe because of periodically loss of plant coverage.It was observed that zea mexicana had a stronger ratooning ability than sorghum,so as a better ability in soil erosion control.Therefore,from the angle of soil erosion control,planting winter wheat with reserved spacing for early summer forages in the next year should be adopted and screening the summer forage crops with strong ratooning ability after cutting is the key.