In order to explore the effects of different silicon fertilizers and their application rates on grain quality, Zhuang-xiangyou Baijin5,the main indica hybrid rice variety in Guangxi, was used as the test material in 2021,and the two-factor split-plot experiment was conducted.The main area of silicon fertilizer application rate was 4 levels: Si0（0 kg/hm~2）,Si1（90 kg/hm~2）,Si2（180 kg/hm~2） and Si3（270 kg/hm~2）,the silicon fertilizer varieties were the secondary area, including two silicon fertilizer varieties: Xianyinong（K1,SiO 2 ＞25%）and Guozhenggui（K2,SiO 2 ＞29%）.The results showed that the application of silicon fertilizer significantly improved the appearance and eating quality of Zhuangxiangyou Baijin5 grain, and its chalkiness rate and chalkiness degree decreased.The content of protein increased slightly; with the decrease of amylose content, the peak viscosity, trough viscosity, final viscosity, breakdown viscosity and setback viscosity in RVA spectrum of grain decreased, and the pasting temperature increased, but no significant influence on the processing quality.The effect was better when the amount of silicon fertilizer was low, and the suitable amount of silicon fertilizer for Zhuangxiangyou Baijin5 was 90 kg/hm~2（Guozhenggui）.

为明确施氮量和种植密度对优质稻稻米品质的影响，科学合理地调控氮肥和种植密度，改善稻米品质提供一定的理论实践、基础。本研究于2020年和2021年以广西主栽籼型三系杂交水稻品种壮香优白金5为材料进行大田试验，设置 90 kg N/ha（N1）、180 kg N/ha（N2）2个氮水平和27.2万穴/ha（PD1）、23.8万穴/ha （PD2）和20.6万穴/ha （PD3） 3个移栽密度，收获后测定稻米品质及RVA谱特征值。结果表明，施氮量显著或极显著影响稻米峰值粘度、崩解值、糊化温度、蛋白质和直链淀粉含量等品质性状，种植密度显著影响稻米峰值时间。高施氮量下，稻米蛋白质含量在2020年和2021年分别提高15.10%和16.67%，直链淀粉含量分别降低7.83%和9.31%，垩白率分别降低30.45%和24.26%，垩白度分别降低34.24%、25.88%。种植密度对稻米加工、外观、营养品质性状均没有明显影响。稻米RVA谱特征值受施氮量及施氮量与种植密度互作的共同影响，较高的施氮量和种植密度降低了峰值粘度、最低粘度、崩解值，增加了糊化温度、回复值，较高的种植密度增加了峰值时间。大部分RVA谱特征值与稻米直链淀粉和蛋白质含量呈显著或极显著相关。本研究结果说明试验条件下，壮香优白金5优质种植方案为20.6万穴/ha与180 kg N/ha的组合。

The number of seedlings per hill and the configuration of plant row spacing are important management measures to improve rice yield. In the present study, we evaluated the impact of various seedlings per hill (1, 3, 6, and 9 seedlings hill−1) under four different rice verities (two conventional rice, two hybrid rice) on allometric characteristics, nitrogen use efficiency (NUE) and yield in 2020 at early and late season. Results showed that compared with nine seedlings per hill (wide row spacing), the number of effective panicles, yield, grain biomass allocation, grain-to-leaf ratio, grain nitrogen accumulation, nitrogen dry matter production efficiency (NDMPE), N harvest index (NHI) of 1 seedling per hill increased by 21.8%, 10.91%, 10.5%, 32.25%, 17.03%, 9.67%, 6.5%, respectively. With the increase of seedlings per hill and the expansion of row spacing, stem biomass (SB) and reproductive biomass (RB) increased with the increase of above-ground biomass, mainly showing the relationship of isometric growth. Leaf biomass (LB) increased with above-ground biomass, mainly showing the relationship of allometric growth. The results suggested that under the same basic seedlings, transplanting 1 seedling per hill and dense planting was the most beneficial to improve rice yield.

Sink capacity, nitrogen (N), and dry matter accumulation (DMA) all play essential roles in promoting high rice grain yield, but their relationship is unclear. Here, a field experiment was conducted from 2020 to 2021 with Zhuangxiangyou Baijin 5 as the test cultivar. Two rates of N (T1 = 90 kg ha−1 N and T2 = 180 kg ha−1 N) and three transplanting densities (272,000 hills ha−1 (M1), 238,000 hills ha−1 (M2), and 206,000 hills ha−1 (M3)) were used to investigate rice grain yield and corresponding yield attributes. The results showed significant differences in rice yield, sink capacity, N and DMA, and the leaf area index (LAI) at the heading stage among the different treatments. The results showed that the output of T2M1 was the highest in 2020, increasing by 16.6% compared with the lowest output, while the output of T2M2 was the highest in 2021, increasing by 11.9% compared with the lowest output. During 2020, the highest sink capacity, LAI at the heading stage, and maximum dry matter accumulation at the maturity stage of rice were recorded in T2M1, while the highest N accumulation was recorded in T2M2. Furthermore, the sink capacity, as well as levels of N and DMA, of rice in 2020 was higher in T2M2, and the LAI was higher in T2M1 at the heading stage. Correlation analyses showed that yield was significantly positively correlated with N and DMA. In addition, a significant positive correlation between sink capacity and DMA was observed during both years, while a significant positive correlation between sink capacity and N accumulation was observed in 2021. Thus, we conclude that a high sink capacity can increase rice yield by increasing N and DMA because a high sink capacity is the internal driving force of high rice grain yield. In conclusion, the T2M1 regimen is a promising approach for improving the grain yield of paddy rice.