“稻-再-油/肥”轮作和施氮对水稻产量及籽粒灌浆特性的影响

为探究稻-再-油/肥轮作和施氮对水稻产量及籽粒灌浆特性的影响，于2015-2017年在湖北省武穴市进行稻-再-油/肥轮作定位试验，设置4个处理。T1:稻-再-油轮作，三季均不施氮；T2:稻-再-油轮作，三季施氮量为165、120和180 kg·hm^-2；T3:稻-再-肥轮作，三季施氮量与T2相同；T4:稻-再-闲轮作，前两季施氮量与T2相同。研究各处理水稻产量及产量构成因子的变化，并利用Richards方程拟合水稻强、弱势粒的灌浆过程。结果表明：①2015-2017年头季稻和再生稻产量均表现为T3＞T2＞T4＞T1。与T4相比，2016-2017年T2处理的头季稻和再生稻分别增产8.4%和14.4%、22.2%和17.7%，T3分别增产12.7%和17.9%、25.1%和244%；与T1相比，2015-2017年T2处理的头季稻和再生稻分别增产35.1%和22.0%、36.4%和30.3%、651%和65.6%。②在稻-再-油/肥轮作和施氮条件下，2017年头季稻和再生稻籽粒灌浆特性表现一致。与T4相比，T2、T3均能提高头季稻和再生稻强势粒起始势和弱势粒达到最大灌浆速率的干物质量；与T1相比，T2延长头季稻和再生稻强、弱势粒有效灌浆期，从而实现头季稻和再生稻籽粒粒重增加，产量提高。

Impact of Rice-Ratoon Rice-Rapeseed/Green Manure Rotation Cropping System and Nitrogen Application on Yield and Grain-Filling Properties of Rice

In order to investigate the effect of nitrogen (N) application on rice yield and grain filling characteristics under the rotations of rice-ratoon rice-rapeseed (R-R-R) and/or green manure (R-R-G), this paper conducted field experiment during the period of 2015—2017 in Wuxue city, Hubei province. Four treatments were: N application of 0, 0 and 0 kg·hm^-2 under the R-R-R rotation (T1); N application of 165, 120 and 180 kg·hm^-2 under the R-R-R rotation (T2); N application of 165, 120 and 180 kg·hm^-2 under the R-R-G rotation (T3); and N application of 165, 120 and 0 kg·hm-2 under the rotation of rice-ratoon rice-fallow (T4), respectively. The changes of rice yield and yield components under different treatments were studied, and the Richards equation was used to fit the strong and weak grain filling process of rice. The results showed that: ① Yields of the first-season rice and ratoon rice in 2015—2017 were T3>T2>T4>T1. Compared with T4, the yield of first-season rice and ratoon rice under T2 increased by 8.4% and 14.4%, 22.2% and 17.7% respectively in 2016—2017, and T3 increased by 12.7% and 17.9%, 251% and 244%, respectively. Compared with T1, the yield of first-season rice and ratoon rice under T2 in 2015—2017 increased by 35.1% and 22.0%, 36.4% and 30.3%, 65.1% and 65.6%, respectively. ②Under rice-ratoon rice-rapeseed/green manure rotation cropping system and nitrogen application conditions, the grain-filling characteristics of the first-season rice and ratoon rice were consistent in 2017. Compared with T4, T2 and T3 could increase the initial potential of strong grain and the dry matter quality of weak grain at the maximum grain filling rate. Compared with T1, T2 prolonged the active period of grain filling and increased effective grain filling time of first-season rice and ratoon rice, respectively. Therefore, the grain weight and yield of first-season rice and ratoon rice were increased.