长期定位施肥对土壤养分与作物产量的影响

 【目的】研究探讨长期施用有机肥、化肥、有机无机结合等不同施肥条件下的作物增产效果与土壤养分演变规律。【方法】以在山东禹城连续22年的长期施肥定位试验为依据,对历年土壤养分和作物产量测试结果进行系统总结。试验采用冬小麦－夏玉米一年二熟栽培制度,分别设置①无肥对照,②常量有机肥无机肥配施,③常量有机肥,④常量化肥,⑤高量有机肥,⑥高量化肥,共6个施肥处理。【结果】在作物产量方面,试验之初的8～10年间表现为化肥对冬小麦的增产作用优于有机肥,而在夏玉米上则表现出相反结果,有机无机结合处理大部分年份作物产量处于较高水平;随着试验时间的延长,各施肥处理产量逐渐趋于一致;22年间土壤有机质含量始终表现出随有机肥施用量的增加而增高,且有逐年增长之趋势;化肥在提高土壤有机质、全氮等营养方面受生物产量和根茬残留量影响而与施肥量无明显关系,增施化肥可以迅速提高速效养分含量,并在一定水平上保持相对稳定。【结论】长期施用有机肥与化肥均表现出持续提高作物产量的良好作用,且二者效果不相上下,常规栽培条件下,当产量提高到一定水平后,继续高量施肥无助于作物产量的提高;有机肥与化肥均表现出持续提高土壤有机碳、氮含量之作用,有机肥效果明显优于化肥,且表现出随有机肥用量的增加而增加。而继续提高化肥施用量无助于土壤有机碳、有机氮的积累;一向被认为钾素含量的黄淮海平原土壤在连续施用氮磷化肥5～8年左右作物即表现明显缺钾现象,由此揭示出高产条件下氮磷钾平衡施肥的重要作用;在对提高土壤速效养分效果方面的差异表现在,化肥可以迅速提高速效养分含量并在这一水平上保持相对稳定,而有机肥则具有持续提高土壤速效养分含量的作用。

Effects of Organic Manure and Fertlizers Long-Term Located Application on Soil Fertility and Crop Yield

【Objective】 To evaluate the effect of organic manure and fertilizers long-term located application on soil nutrients and crop yield. 【Method】 The results of crop yields and soil nutrients were measured and collected based on a 22-year long-term located application of organic manure and fertilizers experiment in Yucheng city of Shandong Province. 【Result】 The effect of chemical fertilizers on winter wheat yield was better than organic manure during the first 8-10 years, but the reverse result was observed in summer maize yield. The combined effect of chemical fertilizers with organic manure on wheat and maize yields was very obvious. However, with prolonged application, the yields of each treatment, no matter with organic manure or chemical fertilizer or combined, turned out similar. Soil organic matter content increased with time and application level of organic manure during the 22 years. Soil organic matter and total nitrogen contents were found unrelated to the application rate of chemical fertilizers in this long-term experiment. Increased application of chemical fertilizer could enhance soil available nutrient contents and at the same time be kept relatively stable to some extent. 【Conclusion】 The effect of chemical fertilizer on winter wheat yield was better than organic manure during the first 10 years, however, a reverse result was observed in summer maize yield, and after that the crop yields of all treatments were found similar. Therefore, increased application of fertilizer did not improve the crop yield. The effect of organic manure on soil organic C and N content increase was much better than chemical fertilizer, and the soil organic C and N content increased with the application rate of organic manure. Soil organic C and N content could not be improved by application increase of chemical fertilizer. With prolonged application, organic manure could improve soil available nutrients content continually, and its effect was found much obvious than that of chemical fertilizer.