有机肥替代对京郊夏播青贮玉米土壤养分动态与平衡的影响

通过田间试验设置4个处理,100%化肥、70%化肥+30%有机肥、40%化肥+60%有机肥和100%有机肥,研究青贮玉米生产中施用有机肥替代化肥对土壤养分动态和平衡的影响。通过测定生育期内表层土壤速效N、P、K养分、土壤微生物量C与N、1 m土体NO_3-含量和青贮玉米N、P、K吸收量发现,在大喇叭口期,有机肥替代化肥处理降低表层土壤无机N的供应水平,提高有效P和速效K的供应水平;在收获期,有机肥替代显著提高土壤微生物量C、N,显著降低81～100 cm土层NO_3-含量和1 m土体NO_3-累积量。有机肥替代提高养分生产力和养分回收量,加剧土壤养分的亏缺。本研究条件下,30%有机肥替代化肥处理土壤N、P、K养分供应水平高,养分回收率高,加剧土壤养分的亏缺,需考虑长期的养分平衡问题。

Effects of Organic Fertilizer Substitution on Soil Nutrient Dynamics and Balance in Summer Silage Maize in Beijing Suburbs

The purpose of this study was to provide an experimental basis for OFS in the silage maize production via field experiment. There were 4 treatments in the experiment, 100% chemical fertilizer N, 70% chemical fertilizer N +30% organic fertilizer N, 40% chemical fertilizer N +60% organic fertilizer N, and 100% organic fertilizer N. During the experiment, soil available N, P, K in the surface layer, soil microbial biomass C and N, nitrate along 1 m soil profile, and N, P, K in harvested biomass were measured. The results showed that, for soil nutrients, at flared stage, OFS reduced the supply level of mineral N in the surface layer, but improved the supply level of available P and K; at harvest, OFS increased soil microbial biomass C and N, significantly reduced nitrate concentration in the 80-100 cm layer and the nitrate amount in the 1 m soil profile; for nutrients recovery, OFS improved the productivity and recovery ratios of the nutrients and intensify the deficiency of soil nutrients. This research showed that 30% OFS could not only provide more available N, P, K for silage maize, but also recover more nutrients from soil. On the other hand, 30% OFS intensified the deficiency level of soil residual nutrients, which should be paying more attention advanced.