黄土母质生土当年施肥对谷类作物生产力与根际土壤营养及生物活性的影响

Effect of fertilization in immature loess subsoil on productivity and rhizospheric soil nutrient and biological activity of cereal crops

连续3年试验研究了黄土母质生土当年施肥对谷类作物生产力与根际土壤营养及生物活性的影响。结果表明:黄土母质生土当年施肥促进了作物根系生长、生产力增加,强大的根土系统又促进了微生物的繁衍、酶活性及土壤营养的提高。黄土母质生土的熟化利用过程需用地养地相结合,重视生物改土。本研究表明,高粱、玉米均可作为生土改良沃化的先锋作物,高粱根系强壮,入土深,生物量大;而玉米虽根重、最大根长、一级节根数低于高粱,但根际土壤微生物数量多,酶活性高。而黍子根系柔弱,根际土壤生物活性较低,与高粱、玉米相比,不宜作为生土改良的先锋谷类作物。黄土母质生土对外源的辅助能(当年施肥)反应十分敏感,施肥的增产效应与土壤培肥都十分显著。黄土母质生土熟化沃化过程既是一个生土培肥改良过程,也是一个物质能量(营养)投入转化过程,并经植物物质生产过程、土壤微生物分解矿化过程及土壤生物化学酶系统促进过程三者互动,共同构成根土苗微生物物质能量转化的生态系统。

An experiment was conducted to study the effect of immature loess subsoil fertilization in current year on productivity and rhizospheric soil nutrient and biological activity of cereal crops. The results show that fertilization promotes crop root growth and productivity. A strong root-soil system in turn promotes the multiplication of microbes, enzyme activity, and increases soil nutrient. Aging of immature loess subsoil should adopt measures of both utility and maintenance, with emphasis on soil biological conditions. The study indicates that sorghum and maize could be planted as the pioneer crops to improve immature subsoil conditions. Sorghum owns strong and deep root system, and great biomass. Although the root weight, maximum root length, and number of adventitious root are not as high as those of sorghum, microbe amount and enzyme activity in rhizospheric soil of maize are high enough. Com-pared with sorghum and maize, broomcorn is not suitable for the improvement of immature subsoil due to its weak root system and low biological activity in rhizospheric soil. Immature losses subsoil is sensitive to fertilization. Since fertilization of immature loess subsoil is achievable with high annual yields, it serves as a significant aging factor of immature subsoil. Aging of immature loess subsoil is both an input and transformation process of matter and energy among plants, soils, microorganisms, including fertilization, crop production, resolving and mineralization of soil microbes, and catalysis of soil enzymes.