菠萝-甘蔗轮作的土壤生态效应

通过2000～2002年进行菠萝-甘蔗轮作田间试验，研究了菠萝、甘蔗轮作对甘蔗土壤生态的影响。结果表明：菠萝甘蔗轮作田与甘蔗连作田比较，能明显地改善土壤的通气和蓄水性，加速速效性养分的释放；增强土壤酶活性；增加土壤微生物总量(一般好气性细菌、真菌、放线菌)；有益的氨化细菌和硝化细菌成倍增加，而无益的厌氧性细菌、反硝化细菌则受到抑制;固氮菌数量小且变化不大。菠萝-甘蔗轮作对甘蔗土壤生态环境的改善其实质在于：菠萝、甘蔗轮作后，由于其作物种类的不同导致土壤结构的改善和土壤微生物种类和数量增多，土壤生物活性增强，并导致土壤速效养分的增加。

Effects of the crop rotation of pineapples-sugarcane on soil ecology

Through the rotation field experiment with pineapple and sugarcane as the crop from the year 2000 to 2002, the effect of pineapple and sugarcane rotation on the ecosystem of the soil was been studied.The results showed that: compared with the continuous cropping of sugarcane- sugarcane field, the crop rotation of Pineapple- sugarcane could improve the capability of aeration and water storage, accelerate the release of the quick effective nutrient, strengthen soil enzyme activity and increase the total quantity of microbe of soil (general aerobic bacteria, fungi, actinomyce). The beneficial ammonifier and the nitrifying bacteria were doubled, while the unbeneficial anaerobic bacteria, denitrify bacteria were inhibited, the quantity of nitrogen-fixing bacteria was less and not changed more. The nature of sugarcane soil ecosystem improvement affected by the rotation of pineapple and sugarcane lies in that after the rotation of pineapple-sugarcane, because of different crops, leading to the improvement of soil structure and the increase species and number of soil micro-organism, and the increase of soil biological activity, and the increase of speedy nutrients.