淮北地区麦茬机插优质食味粳稻氮肥减量的精确运筹

当前"减氮"成为优质食味粳稻种植措施之一,但减氮后的氮肥科学运筹方案尚不够明确,需进一步研究。2018—2019年,选用优质食味粳稻品种‘南粳505’和‘南粳2728’为材料,前茬麦秸秆全量还田,采用机插方式,在总施氮量较当地常规施氮量减少20%条件下,设置基蘖肥和穗肥比例分别为5∶5、6∶4、7∶3和8∶2四种氮肥运筹比例,研究了淮北地区麦茬机插优质食味粳稻氮肥减量精确运筹。结果表明,随着基蘖肥占总施氮量比例增加,产量呈先增后降趋势, 7∶3处理产量最高, 2年达11,134.80～11,280.19 kg hm–2,较CK增产1.23%～2.54%,但差异不显著; 7∶3处理群体高产,在于能获得充足的群体颖花量、较高的结实率和千粒重。随着基蘖肥比例增加,有效分蘖临界叶龄期、拔节期群体干物质积累量呈增加趋势;抽穗期、成熟期、抽穗至成熟期的干物质积累量、最终氮素积累量及氮素利用率,呈先增后降趋势,均以7∶3处理最高。与常规施氮处理相比,减氮处理通过增加前期施氮肥比例(7∶3),能确保群体后期获得较高的干物质积累量;成熟期氮素积累量较小,但显著提升了氮素吸收利用率,较CK高14.10%～...

Nitrogen fertilizer reduction and precise application model on mechanical transplanting japonica rice with good taste quality under straw returning in Huaibei Area

At present,"nitrogen reduction" has become one of the planting measures for good eating quality japonica rice,but the scientific management plan of nitrogen fertilizer after nitrogen reduction is unclear and further studies are needed.From 2018 to 2019,good eating quality japonica rice varieties including Nanjing 505 and Nanjing 2728 were planted as materials,and four ratios of basic and tillering to panicle fertilizer including 5:5,6:4,7:3,and 8:2 were arranged with nitrogen application 20% less than conventional nitrogen application(CK) for mechanical transplanting rice under wheat straw returning.Yield,rice quality,and nitrogen utilization were investigated to determine the effects under nitrogen reduction for good eating quality japonica rice.The results were as follows:With the increase of the proportion of the basic and tillering fertilizer in the total nitrogen application,the yield increased first and then decreased.The 7:3 treatment had the highest yield,reaching 11,134.80–11,280.19 kg hm^-2 for two years.Compared with CK,the yield increased by 1.23%–2.54% and there was no significant difference.The 7:3 treatment group could obtain sufficient population spikelet,higher seed-setting rate,and 1000-grain weight.With the increase of the proportion of nitrogen application in the previous period,the dry matter weight of the population at(N-n) stage and jointing stage displayed an increasing trend,while the dry matter weight at heading stage and maturity stage,the dry matter accumulation from heading to maturity,the final nitrogen accumulation and the nitrogen efficiency increased first and then decreased,and reached a peak in the 7:3 treatment.Compared with CK,nitrogen reduction treatment could ensure higher dry matter accumulation of the population at the later stage by increasing the proportion of nitrogen fertilizer application(7:3) at the early stage,which significantly improved nitrogen absorption and nitrogen use efficiency of the population by 14.10%–15.48%,and significantly higher than CK.For eating quality of japonica rice under nitrogen reduction,the processing quality deteriorated with the increase proportion of basic and tillering nitrogen,the appearance quality became better,the cooking and eating quality improved,and rice RVA profile was optimized.Under the condition of the whole wheat straw to the field,nitrogen was reduced by 20% compared with conventional fertilization.To achieve the comprehensive planting goal of high-yield,high-quality,and high-efficiency for good eating quality rice to a certain extent,nitrogen application with the ratio of basic and tillering fertilizer to panicle fertilizer 7:3 could stabilize or slightly increase the yield of good eating quality japonica rice,greatly increase nitrogen use efficiency,and improve the appearance and taste quality in rice.