水葫芦富集水体养分及其农田施用研究

采用自然水体养殖及农田施用试验方法,对水葫芦(Eichhornia crassipes)的N、P、K吸收能力及其在农田施用效果进行了研究.结果表明,在研究试验条件下,水葫芦对N、P、K的富集系数分别达到N6641倍、P16 667倍、K6 560倍,42 d对N、P、K的吸收量可高达40.57、6.95和81.14 g·m~(-2).与常规施肥处理相比,施用水葫芦处理(等量的N、P投入)的土壤速效N除了苗期显著降低外,其他各时期无显著筹异,而速效P和速效K从苗期开始一直表现为不同程度的升高,说明施用水葫芦可促进土壤速效P、K的增加.但要获得较高的产量水平,应适当增加前中期氮肥施用水平.采用水葫芦控制性种养既可实现养分在水体与农田间的循环,还可减少农田化肥的施用量和农业面源污染,是一种良性的循环模式.

Absorption of Water Nutrients by Hyacinth and Its Application in Wheat Production

Water hyacinth(Eichhornia crassipes) has been widely used in recovery of eutrophicated waters. However, few studies have been focused on use of the harvested hyacinth and its integrated technologies. The objectives of this paper were to study hyacinth's ability to adsorb N P K and the effects of hyacinth as an organic fertilizer on wheat production. The results showed that hyacinth had high growth and N P K ab-sorption rates in eutrophicated water. At our experimental conditions, hyacinth could absorb 40.57 g·m~(-2) N, 6.95 g·m~(-2)P and 81.14 g·m~(-2) K from the water during a 42-day period. Compared with pure chemical fertilizer treatment, the combination of the hyacinth mulching and chemi-cal fertilizer treatment did not cause significant difference in soil available N concentration, except that it caused a significant decrease at wheat seedling stage( 56 days after the application of hyacinth mulching). The soil treated with combination of hyacinth mulching and chemical fertilizer showed higher available P and K concentrations during the entire growth period. Our results suggested that more chemical nitrogen should be applied at the early and middle stages of wheat growth to achieve high yield. The nutrient translocation from eutrophicated water to a-gricultural fields can be realized by controlled cultivation of hyacinth in eutrophicated water and its direct application as organic fertilizer in crop fields. This mode can also decrease amount of fertilizer applicated, thus reduce the non-point pollution and alleviate water eutrophication.