多元化种植模式下秸秆还田配合水氮管理对水稻产量形成与氮素吸收利用的影响

Effects of straw returning to field combined with water and N management on rice yield formation and N uptake and utilization under diversified cropping patterns

研究多元化种植模式下,不同前茬秸秆还田与水氮管理对水稻产量形成、干物质积累分配及氮素吸收利用的影响。2018—2019年以杂交稻F优498为材料,采用三因素裂裂区设计,主区设置油菜-水稻(Py)、小麦-水稻(Px)、青菜-水稻(Pq)3种种植模式秸秆还田,裂区设置常规淹水灌溉(W_(0))和干湿交替灌溉(W_(1))2种水分管理方式,裂裂区设置不施氮处理(N_(0))、常规施氮处理(N_(1))、精量减氮处理(N_(2))3个施氮水平,分析测定了拔节期、齐穗期和成熟期不同处理下秸秆还田的腐解率、氮素释放率、水稻各器官的干物质积累分配、植株氮素吸收利用以及籽粒产量。结果表明,Py的平均产量分别较Px、Pq增加2.55%、13.99%,主要原因是其有效穗数和千粒重较高;Py可促进各营养器官干物质和氮素积累,有利于干物质分配、提高茎鞘氮素贡献率和氮肥利用率,Py各时期的平均干物质积累总量、氮素积累总量分别比Px和Pq增加5.25%、7.48%和14.60%、17.30%,Py的氮肥偏生产力较Pq显著增加24.90%,但Py的秸秆腐解率和氮素释放率较低。3种模式下W1处理的水稻产量分别比W0处理增加5.10%(Py)、1.76%(Px)和4.80%(Pq),W1处理可促进秸秆腐解和氮素释放,促进干物质积累和氮素吸收转运,有利于Py和Px模式下的干物质分配,进而提高氮肥利用率。同一秸秆还田和水分管理下,N2处理可促进秸秆腐解和氮素释放,有利于干物质分配和氮素转运,提高了齐穗期、成熟期茎鞘和叶片氮素积累量,进而提高氮肥利用率,N2处理的产量、干物质积累量较N1处理略有下降,但二者差异不显著。综合考虑分析,油-稻种植模式下,油菜秸秆还田配合干湿交替灌溉与精量减氮(120 kg hm^(-2))有利于干物质积累分配、氮素吸收转运,进而提高氮肥农学利用率、氮肥偏生产力,并可节约20%氮肥投入,实现水稻稳产高效生产。

To study the effects of different precrop straw return and water and N management on rice yield formation,dry matter accumulation and distribution,and N uptake and utilization under diversified cropping patterns.In 2018–2019,hybrid rice F you 498 was used as the experimental material,and a three-factor split plot design was adopted.The main plot was conducted with three planting modes of rape-rice(Py),wheat-rice(Px),and cabbage-rice(Pq).In the field,the split area was equipped with two water management methods including conventional flooding irrigation(W_(0))and alternating wet and dry irrigation(W_(1)).The split area was equipped with three N levels including no N treatment(N_(0)),conventional N application treatment(N_(1)),and precise N reduction(N2).The decomposition rate,N release rate,dry matter accumulation,and the distribution of various rice nutrient organs,plant N uptake and utilization of straw returned to the field under different treatments at jointing,heading,and maturity stages,and grain yield were analyzed and measured.The results showed that the average yield of Py increased by 2.55%and 13.99%,respectively,compared with Px and Pq,mainly due to its higher effective panicles and 1000-grain weight.Py promoted the accumulation of dry matter and N in various nutrient organs,which was beneficial to dry matter distribution,to improve the stem sheath N contribution rate and N fertilizer utilization rate,the average total dry matter accumulation and total N accumulation at each stage of Py increased by 5.25%,7.48%,and 14.60%,17.30%,respectively,compared with Px and Pq.The partial factor productivity of N increased significantly by 24.90%compared with Pq,but the straw decomposition rate and N release rate of Py were lower.The rice yield of W1 treatment under the three modes increased by 5.10%(Py),1.76%(Px),and 4.80%(Pq),respectively,compared with W_(0) treatment.W1 treatment promoted straw decomposition and N release,promote dry matter accumulation and N uptake and transport are beneficial to dry matter distribution in Py and Px modes,thereby improving N fertilizer utilization efficiency.Under the same straw return and water management,N_(2) treatment promoted straw decomposition and N release,which was beneficial to dry matter distribution and N transport,and increased N accumulation in stem sheaths and leaves at heading and maturity stages,thus improving N fertilizer utilization efficiency.However,the yields and dry matter accumulations in N2 treatment decreased slightly compared with those in the N1 treatment,but there was significant difference between them.Comprehensive analysis showed that under the rape-rice planting model,returning rapeseed straw to the field combined with alternating dry and wet irrigation and precise N reduction(120 kg hm^(-2))was beneficial to dry matter accumulation and distribution,N uptake and transport,and thus improving the agronomic efficiency of N,and partial factor productivity of N,and can save 20%of N fertilizer input to achieve stable and efficient rice production.