化肥减施对土壤肥力、木薯产量及种植效益的影响

Effects of Chemical Fertilizer Reduction on Soil Fertility,Cassava Yield and Planting Benefit

为探讨木薯化肥减量增效技术对木薯土壤肥力、木薯产量及种植效益的影响,于2019-2020年开展木薯化肥减施种植技术示范。以木薯新品种"桂热10号"为材料,以化肥减量(25%)配施生物有机肥+地膜覆盖处理为示范种植模式,以常规种植(仅施化肥)和不施肥为对照,比较分析各处理土壤速效养分、土壤酶活性、木薯养分、产量及种植效益差异。结果表明:木薯种植会导致土壤有效养分和生物活性下降,示范种植模式可显著缓解木薯种植后土壤养分的降幅,并提高土壤速效磷、速效钾含量和土壤微生物量碳,显著提高土壤蔗糖酶活性,氮肥和钾肥的利用率分别提高12.8和40.4个百分点;不施肥和常规施化肥情况下木薯种植后土壤微生物量碳显著降低;施肥显著促进木薯植株生长,增加木薯生物量,显著提高木薯鲜薯产量和淀粉产量,常规种植和示范种植鲜薯产量和淀粉产量均显著高于不施肥处理,但施肥对植株氮磷钾含量并无显著影响;示范地块磷肥利用率偏低,应适当减少磷肥施用量;2019年和2020年示范种植较常规种植效益分别增加1532.45元/hm^(2)和1284.45元/hm^(2)。因此,化肥减量配施生物有机肥+地膜覆盖示范种植模式能有效保持土壤肥力,提高木薯产量从而提高木薯种植效益。

To explore the effects of chemical fertilizer reduction on soil fertility,cassava yield and planting benefit,a cassava planting demonstration was carried out from 2019 to 2020.A new cassava variety GR10 was used as material,with chemical fertilizer reduction(25%)combined with biological organic fertilizer and plastic film mulching as the demonstration planting pattern,and the conventional planting pattern with chemical fertilizer and no fertilizer as the control,the differences in soil available nutrients,soil enzyme activities,cassava nutrients,yield and planting benefits of each treatment were compared and analyzed.Cassava planting could lead to the decrease of soil available nutrients and biological activity.The demonstration model could significantly alleviate the decrease of soil nutrients after cassava planting,and increase the contents of soil available phosphorus,available potassium,soil microbial biomass carbon and soil sucrose activity.The utilization rates of nitrogen and potassium were increased by 12.8%and 40.4%,respectively.Soil microbial biomass carbon decreased significantly after cassava planting under the conditions of no fertilization or only chemical fertilizer application.Fertilization significantly promoted the growth of cassava plant,increased the biomass,fresh root yield and starch yield of cassava.The yields of fresh root and starch in conventional and demonstration planting pattern were significantly higher than that in no fertilization treatment.Fertilization had no significant effect on the contents of N,P and K in plant.Phosphate fertilizer with low utilization rate should be appropriately reduced in the demonstration plot.The benefits of demonstration planting in 2019 and 2020 increased by 1532.45 yuan/hm^(2) and 1284.45 yuan/hm^(2) respectively than that of the conventional planting.Therefore,the planting pattern of fertilizer reduction combined with biological organic fertilizer and plastic film mulching can effectively maintain soil fertility,improve cassava yield and increase planting benefit.