沼液替代化肥氮对水稻生长发育及稻米品质的影响

Effect of chemical fertilizer nitrogen substitution by biogas slurry on the growth and quality of rice

研究了沼液替代不同比例化肥氮对水稻生长发育特征(生育进程、株高动态、群体动态和干物质积累动态)、产量、稻米品质和重金属含量的影响。结果表明:在等氮量条件下,随着沼液替代化肥氮比例的增加,水稻各生长指标及产量呈现先增加后下降的趋势,以沼液替代70%化肥氮处理(70%Nbs)最高;施用沼液可改善稻米品质,稻米Cu、Zn、Pb和As含量稍有增加,Cd和Cr含量则有所降低;各处理稻米重金属含量均低于相应的污染物限量标准(GB 2762—2005);与全施化肥处理(Ncf)相比,沼液替代100%化肥氮处理(100%Nbs)水稻各生长指标都有下降趋势,有减产风险;沼液替代200%化肥氮处理(200%Nbs)由于水稻贪青晚熟,以及基部节间长度显著增长等原因可能导致倒伏减产和二次污染风险增加;在本试验条件下,稻田灌溉沼液替代化肥氮最佳比例为70%,约灌溉沼液278.56×10~3kg·hm^(-2)。

A field experiment was conducted to examine the effects of different rates of chemical fertilizer nitrogen substitution by biogas slurry on rice growth（ development progress,plant height dynamic,population dynamic,and dry matter accumulation dynamic）,yield,quality,and heavy metal content. The results showed that when the amount of nitrogen input was same,rice growth indices and yield first increased and then decreased with increasing rates of chemical fertilizer nitrogen substitution by biogas slurry,with rice growth indices and yield under the treatment with70% chemical fertilizer nitrogen substitution by biogas slurry（ 70%Nbs） being the highest. Biogas slurry could improve rice quality. With the increases of the proportion of biogas slurry application,the contents of Cu,Zn,Pb and As in grains increased slightly,while the contents of Cd and Cr in grains decreased slightly. The contents of heavy metals in grains of all treatments were lower than the critical levels of contaminants in foods（ GB 2762-2005）. Compared with the treatment of chemical fertilizer application alone（ Ncf）,the rice growth indices in the treatment with 100% chemical fertilizer nitrogen substitution by biogas slurry（ 100%Nbs） decreased,with a risk of yield reduction. The treatment with 200% chemical fertilizer nitrogen substitution by biogas slurry（ 200%Nbs） could lead to rice lodging and yield reduction and increase the risk of secondary pollution,due to the prolonged growth duration and the increased basal internode length.Therefore,the optimal proportion of chemical fertilizer nitrogen substitution by biogas slurry was70%,with the biogas slurry application level of 278.56×103 kg·hm-2.