Abstract:

The ratoon crop of ratoon rice, after the mechanical harvesting of the main crop, often faces issues such as low yield and high broken rice rates. Foliar nitrogen application is a simplified fertilization technique that effectively supplements the crop's nitrogen requirements, enhancing both quality and yield. This study investigated the effects of different foliar nitrogen application rates on the growth, yield, and quality of ratoon crop rice, aiming to provide a theoretical basis for achieving high yields through mechanical harvesting and simplified fertilization in ratoon rice production. A field split-plot design with two factors was employed following the main crop rice harvest in both high-fertility (HF) and low-fertility (LF) fields. The main plot factor was rolling status (rolled and non-rolled), and the sub-plot factor was foliar nitrogen application rate, with six nitrogen gradients: 0 (N0), 1.0 (N1), 3.0 (N3), 5.0 (N5), 7.0 (N7), and 9.0 kg/hm²(N9). The results showed that, in HF, foliar nitrogen application treatments increased yields by 13.6%-37.4% in rolled areas and 35.1%-39.7% in non-rolled areas compared to N0, with the highest yields in N9 and the lowest in N1. In LF, yields increased by 15.6%-38.8%(rolled areas) and 22.3%-38.6%(non-rolled areas), respectively. Specifically, in the rolled area, the highest yield was observed in N9 and the lowest in N1, while in the non-rolled area, the highest yield was in N3 and the lowest in N1. Compared to the N0 treatment, foliar nitrogen application improved both milling and appearance quality of the ratoon crop rice to varying degrees. In rolled areas of HF, foliar nitrogen treatments significantly increased milled rice rate and head milled rice rate by 31.6%-37.5% and 65.3%-71.5%, respectively, and significantly reduced chalkiness by 20.4%-35.3%. In non-rolled area of HF, milled rice rate and head milled rice rate increased significantly by 27.2%-32.2% and 46.7%-57.0%, respectively, with chalky grain rate significantly decreased by 22.8%-38.5%. In rolled area of LF, milled rice rate and head milled rice rate increased significantly by 31.8%-37.9% and 53.4%-70.3%, respectively, with chalky grain rate significantly decreased by 20.5%-35.5%. In non-rolled area of LF, milled rice rate and head milled rice rate increased significantly by 34.9%-40.8% and 49.4%-60.2%, respectively, with chalky grain rate significantly decreased by 22.8%-38.5%. Based on the results, the optimal foliar nitrogen application rates for the ratoon crop rice under mechanical harvesting conditions of the main crop were recommended as 4.1 kg/hm² for rolled areas and 3.0 kg/hm² for non-rolled areas.

Key words: ratoon rice, mechanical harvesting, urea, foliar fertilizer, yield, quality

摘要：

再生稻头季机收条件下再生季存在产量低和碎米率高等问题。叶面喷施氮肥是一种轻简化施肥技术，能有效补充作物对氮肥的需求且提质增效。于头季稻机收后分别在高施肥田块（HF）和低施肥田块（LF）采用大田裂区双因素试验设计，碾压状况为主区，包括碾压和非碾压，叶面施氮量为副区，包括0（N0）、1.0（N1）、3.0（N3）、5.0（N5）、7.0（N7）和9.0 kg/hm²（N9）等6个氮肥梯度，探讨了不同叶面施氮量对再生季水稻生长、产量和品质的影响，以期为再生稻机收高产和轻简化施肥提供理论依据。结果表明，在HF碾压区和非碾压区，叶面施氮处理较N0处理分别增产13.6%~37.4%和35.1%~39.7%，并均以N9处理产量最高、N1处理产量最低。在LF碾压区和非碾压区，叶面施氮处理处理较N0分别增产15.6%~38.8%和22.3%~38.6%，其中碾压区以N9处理产量最高、N1处理产量最低，非碾压区则是N3处理产量最高、N1处理产量最低。与N0处理相比，叶面施氮均能不同程度提高再生季的碾磨品质和外观品质，在HF碾压区，叶面施氮处理的精米率和整精米率较N0处理分别显著提高31.6%~37.5%和65.3%~71.5%，垩白粒率显著降低20.4%~35.3%；在非碾压区，叶面施氮处理精米率和整精米率较N0处理分别显著提高27.2%~32.2%和46.7%~57.0%，垩白粒率显著降低22.8%~38.5%。在LF碾压区，叶面施氮处理的精米率和整精米率较N0处理分别显著提高31.8%~37.9%和53.4%~70.3%，垩白粒率显著降低20.5%~35.5%；在非碾压区，叶面施氮处理精米率和整精米率较N0处理分别显著提高34.9%~ 40.8%和49.4%~60.2%，垩白粒率显著降低22.8%~38.5%。根据试验结果，提出了头季机收条件下再生季适宜叶面施氮量，碾压区为4.1 kg/hm²、非碾压区为3.0 kg/hm²。

关键词: 再生稻, 机收, 尿素, 叶面肥, 产量, 品质