沼液替代化肥氮对冬小麦产量、品质及生长发育的影响

研究了沼液替代不同比例化肥氮对冬小麦产量、生长发育特征（生育进程、株高动态、群体动态和干物质积累动态）、品质和重金属含量的影响。结果表明：随着沼液施用量的增加，小麦产量显著增加（P<0.05），以沼液替代50%化肥氮（50% Nbs）处理产量最高，为7.75 t·hm^-2，比全施化肥（Ncf）处理增产18.14%；以沼液替代100%化肥氮（100% Nbs）处理与Ncf处理产量差异不显著（P>0.05）；籽粒千粒重呈显著下降趋势（P<0.05）；穗粒数和收获指数呈先上升后下降趋势。随着沼液替代化肥氮比例的增加，小麦各生育期株高、分蘖数和干物质积累量都呈现逐渐增加的趋势；成熟期，100% Nbs处理地上部干物质积累量显著高于Ncf处理（P<0.05）；以沼液替代200%化肥氮（200% Nbs）处理的小麦株高、分蘖数和地上部干物质积累量都显著高于Ncf处理（P<0.05）。施用沼液可改善小麦品质；提高小麦籽粒的Cu和Zn含量，显著降低Cd和Cr含量（P<0.05），对Pb和As含量影响不显著（P>0.05）。各处理籽粒重金属含量均低于相应的污染物限量标准。当沼液替代化肥氮比例达到50%以上，由于贪青晚熟，以及基部节间长度显著增长等原因可能导致倒伏、减产，施入大量沼液也可能导致二次污染风险。因此，本研究初步认为，在本试验条件下，麦田灌溉沼液替代化肥氮最佳比例为50%。

Effects of chemical fertilizer nitrogen substitution by biogas slurry on yield, quality and growth charac-teristics of winter wheat

A field experiment was conducted to study the effects of different ratios of chemical fertilizer nitrogen substitution by biogas slurry on yield, growth characteristics(development progress, plant height dynamic, population dynamic and dry matter accumulation dynamic), quality and heavy metal content of winter wheat. The results showed that winter wheat yield increased significantly(P<0.05), with the increase of the ratios of chemical fertilizer nitrogen substitution by biogas slurry, and the yield of the treatment with 50% chemical fertilizer nitrogen substitution by biogas slurry(50%Nbs) was the highest, about 7.75 t·hm^-2, 18.14% higher than the treatment with total chemical fertilizer nitrogen(Ncf). There were no significant differences between the yields of 100%Nbs and Ncf(P>0.05). The 1000-kernels weight presented a significant declining trend(P<0.05); the grains number per spike and harvest index increased at first and then decreased, with the increase of the ratios of chemical fertilizer nitrogen substitution by biogas slurry. The plant height, tiller number and dry matter accumulation in different stages presented the gradual increment trend; in maturity, the above ground dry matter accumulation of 100%Nbs was significantly higher than that of Ncf(P<0.05), The plant height, tiller number and dry matter accumulation of 200%Nbs were significantly higher than these of Ncf(P<0.05). Biogas slurry could improve wheat quality, and increase grain Cu, Zn contents, decrease grain Cd, Cr contents, significantly(P<0.05), and had no significant influences on grain Pb, As contents (P>0.05). The contents of these grain heavy metal of each treatment were lower than the maximum levels of contaminants in foods. When the ratio of chemical fertilizer nitrogen substitution by biogas slurry raised above 50%, because of the prolonged growth duration and the increased basal internode length could lead to lodge and yield reduction, and because of greater use of biogas slurry could lead to the risk of secondary pollution. Therefore, in our preliminary study, in this experiment, the optimal ratio of chemical fertilizer nitrogen substitution by biogas slurry was 50%.