小麦秸秆生物质炭对水稻产量及晚稻氮素利用率的影响

选择湖南长沙红黄泥水稻土和江西进贤红壤性水稻土为供试土壤,研究小麦秸秆制生物质炭在20、40t.hm-2施入量水平下与氮肥配施对早、晚稻产量及晚稻氮素利用率的影响。结果表明,生物质炭与氮肥配施情况下,2个试验点不同生物质炭施用量处理间早稻产量均无显著差异,但进贤试验点生物质炭施用量为20和40t.hm-2处理晚稻产量分别比未施生物质炭对照提高5.18%和7.95%,而长沙试验点3个处理间晚稻产量无显著差异。在相同氮素水平下,当生物质炭施用量为40 t.hm-2时,2个试验点土壤有机碳含量与未施生物质炭对照相比最高增幅均在55%以上;施用生物质炭可提高酸性或弱酸性土壤pH值,降低土壤容重;施用生物质炭也可显著提高水稻氮肥利用率,在40 t.hm-2施用水平下,长沙和进贤试验点水稻氮肥吸收利用率分别提高20.33和17.58百分点,进贤试验点氮肥农学效率提高39.81%。在酸性土壤中施用生物质炭可提高氮肥利用率,保持水稻产量稳定或有一定的增产效果。

Effects of Wheat-Straw-Based Biochar on Yield of Rice and Nitrogen Use Efficiency of Late Rice

Biochar prepared out of wheat straw was applied in reddish yellow paddy soil in Changsha of Hunan and red paddy soil in Jinxian of Jiangxi in a field experiment to explore for effects of biochar applied at a rate of 20 and 40 t·hm-2,separately on yields of early and late rice and nitrogen recovery efficiency of late rice.It was found that the early rice didn′t respond much in yield to the combined application of nitrogen fertilizer and biochar,regardless of rate,in the two experiment sites,and neither the late rice in the experiment site of Changsha did,but the late rice at the experiment site of Jinxian did,increasing by 5.18% and 7.95%,separately,in the two treatments of 20 and 40 t·hm-2 biochar.With the same N application rate,the treatments of 40 t·hm-2 biochar in both experiment sites increased soil organic carbon by 55% or more over the control.Application of the biochar was found to increase pH in acid or weakly acid soil,lower soil bulk density and also increase nitrogen use efficiency of rice by 20.33 and 17.58 percentage point in the treatments of 40 t·hm-2 biochar in the experiment sites of Changsha and Jinxian,respectively and nitrogen agronomic efficiency by 39.81% in Jinxian.The experiment demonstrates that biochar amendment in acid soil can stabilize or even increase rice yield and improve nitrogen use efficiency.