香根草在土壤改良和水土保持中的作用

A STUDY ON VETIVER GRASS IN SOIL AMELIORATION,AND SOIL AND MOISTURE CONSERVATION

香根草作为一种理想的水土保持植物具有许多优良特性，目前正在热带和亚热带地区广泛推广种植。本文通过盆栽和大田两方面试验观测了香根草在土壤改良和水土保持中的作用。结果表明，种植香根草后可使强酸性土壤的可交换性铝含量下降，并使土壤ｐＨ值、有机质、全氮、速效氮和钾以及总孔隙度等都有不同程度的增加。与对照区相比，香根草区的径流量和土壤侵蚀量分别下降了６０％和９３％，而土壤含水量上升４％～４２％不等。香根草还可较好地改善果园小气候，使果园生态系统内的士温、气温和空气湿度等都朝着有利于果树生长发育的方向变化。

etiver grass (Vetiveria zizanioides) is a very ideal hedgerow for the vegetative system of soil and moisture conservation, and being widely planted in tropical and sub-tropical regions. The pot and field trials indicated that this plant could efficiently ameliorate soil characteristics. It was capable of lowering acidity and the content of exchangeable Al of strongly acid soil by 0. 5-0. 7 and 0. 3-0. 6cmol. kg-1, respectively. Distinct increments of organic matter, total N, available N and K, and total porosity in the soils were found after vetiver was established for 29 months.The vetiver treatment averaged 60% and 93% less runoff and soil loss, and 4 %-42% more soil moisture, than the control, respectively. Furthermore, this plant effectively improved the microclimates of fruit garden ecosystem, including an increase of relative humidity by approximately 4 %-5 %, and a decrease of air temperature by 1-3 degrees centigrade.