秸秆还田形态和还田量对水稻氮素积累与转运及产量品质的影响

Effects of straw returning form and amount on nitrogen accumulation and translocation as well as yield and quality of rice

秸秆还田是目前广泛应用的秸秆处理方式,但存在腐解效率低、易发生病虫害和释放有机酸等问题。汽爆膨化技术具有破坏秸秆纤维间聚合力,增大秸秆比表面积,使其更易被微生物降解、消灭秸秆自身携带的病虫卵的作用。故采用膨化秸秆和常规秸秆两种形态还田,于2020—2021年进行盆栽试验,探究两种还田形态在不同还田量下对水稻氮素积累与转运、产量以及稻米品质的影响。以‘垦粳8号’水稻为供试材料,秸秆不还田作为对照(CK),以当地秸秆还田7500 kg·hm-2为基准,各还田形态分别设置4种还田量,即25%、50%、75%和100%,共9个处理,采用单因素完全随机设计。结果表明:氮素积累量在齐穗期表现为膨化还田>CK>直接还田,并随还田量的增加而降低,25%秸秆膨化还田2 a间较CK分别提高了10.92%和11.66%,秸秆直接还田较CK略有降低;在成熟期,25%秸秆膨化还田处理地上部氮素积累最多,2 a间分别较CK增加1.11%和10.54%,75%直接还田处理在2020年试验中较CK显著提高4.99%,在2021年50%直接还田处理最佳,较CK增加了8.51%。2 a间秸秆还田均提高了水稻产量,秸秆膨化还田表现为25%还田量处理增产效果最佳,较CK分别增加5.54%和8.93%;秸秆直接还田以75%还田量处理增产效果最佳,较CK分别增加6.65%和9.14%;2 a间秸秆膨化还田处理和秸秆直接还田处理均改善了稻米的加工品质、营养品质和食味品质,其中25%、50%秸秆膨化还田稻米的食味评分均高于同施用量下秸秆直接还田处理,但各处理间差异未达显著水平。综上,秸秆膨化还田量为25%的处理有利于水稻产量和品质的提高,秸秆直接还田量为75%的处理次之。

Straw returning to the field is a widely used straw treatment method at present.However,there are problems such as low decomposition efficiency,easy occurrence of pests and diseases,and release of organic acids.The steam explosion technology has an effect of destroying the cohesion between the straw fibers,increasing the specific surface area of the straw,making it easier to be degraded by microorganisms and eliminate the eggs of diseases and insects carried by the straw itself.In this study,two forms of straw returning to the field were used:extruded straw and conventional straw.A pot experiment was carried out in 2020 and 2021 to investigate effects of the two return methods on rice growth,yield,quality,nitrogen accumulation and translocation.A single-factor completely randomized design was adopted.The rice variety‘Kenjing 8’was used as the test material and with no straw returning to the field as the control(CK)and 7500 kg·hm-2 of local straw return to the field as the base.Four return rates for each return method of 25%,50%,75%and 100%were employed with a total of 9 treatments.The results show that nitrogen accumulation in the full heading stage was in the form of puffed straw return>CK>direct straw return,and decreased with the increase of returning amount.Compared with CK,the 25%puffed straw returning to the field increased by 10.92%and 11.66%respectively,and the direct straw return was slightly lower than that of CK.At the mature stage,25%extruded straw returning to the field increased 1.11%and 10.54%compared with CK in two years,respectively,and 75%straw returning to the field significantly increased 4.99%compared with CK in 2020.The treatment of 50%of 2021 straw returning to field was the best,which increased 8.51%compared with CK.Compared with CK,the straw returning treatment increased the yield of rice.Under different returning rates,the puffed straw return rate was the highest at 25%,increasing by 5.54%and 8.93%respectively compared with CK in two years.The direct straw return was highest at 75%,increasing by 6.65%and 9.14%respectively compared with CK in the two years.The processing quality,nutritional quality and eating quality of rice were improved by straw extruding treatment and direct straw returning treatment during the two years.The taste scores of rice with 25%and 50%extruded straw return were higher than that of rice with the same amount of straw,but the difference was not significant.In conclusion,the treatment of 25%extruded straw returning to the field was beneficial to improvement of rice yield and quality followed by the treatment of 75%direct straw returning to the field.The study provides a theoretical and technical reference for high yield and good quality of rice.