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以长江中下游地区早熟中粳、中熟中粳、迟熟中粳、早熟晚粳和中熟晚粳5种类型品种为材料,设置3种施氮水平(0、225和300kghm-2纯氮),研究精确定量施氮3个参数的变化规律。结果表明:(1)不施氮条件下的土壤基础供氮量即基础产量吸氮量,随水稻品种生育期的延长而增加,计算基础产量吸氮量的参数即100kg稻谷吸氮量,在中熟中粳、迟熟中粳和早熟晚粳3种类型间差异较小,产量为6thm-2(4.87～6.58)时为1.58kg(1.50～1.63)。(2)施氮条件下,100kg籽粒吸氮量在中熟中粳、迟熟中粳和早熟晚粳间的变化较稳定,平均为7.5thm-2产量时,225kghm-2氮素水平为1.86kg(1.85～1.87),300kghm-2氮素水平为2.01kg(1.98～2.05);9thm-2的产量时,225kghm-2氮素水平为1.94kg(1.91～2.04),300kghm-2氮素水平为2.08kg(2.01～2.19);10.5thm-2的产量时,225kghm-2氮素水平为1.95kg(1.93～2.01),300kghm-2氮素水平为2.09kg(2.08～2.10)。说明随着施氮量的增加100kg籽粒吸氮量呈增加趋势。相关分析表明,100kg籽粒吸氮量与产量呈极显著的二次曲线关系,其中早熟中粳和中熟晚粳的相关系数小于其他3种类型。(3)氮肥利用率随施氮量的增加基本呈下降趋势,除中熟晚粳外表现为随生育期的延长而增加,即在225kghm-2氮素水平下分别为31.32%、37.64%、38.5%、41.08%和38.11%,300kghm-2氮素水平下分别为28.74%、36.13%、37.16%、40.15%和39.42%。(4)欠适宜种植的早熟中粳和中熟晚粳的施氮参数相对于其他类型变异较大;相对于非主推品种,主推品种(当家品种)的施氮参数值较高且更趋稳定。说明在合理的品种选择和布局条件下,施氮参数变化规律较强,生产上利用斯坦福方程精确计算水稻目标产量施氮量是可行的。
Three types of nitrogen application (0,225 and 300 kghm-2 pure nitrogen) were set up in the middle and lower reaches of the Yangtze River with five types of early-maturing medium japonica rice, middle-maturing medium japonica rice, late maturing medium japonica rice, early maturing late japonica rice and medium maturing late japonica rice as materials. ), To study the rules of quantitatively quantifying the three parameters of nitrogen application. The results showed that: (1) The nitrogen uptake of soil basal nitrogen under no nitrogen application increased with the prolongation of rice growth period. The parameter to calculate the nitrogen uptake of basal yield was the nitrogen uptake of 100 kg rice. The middle-maturing medium japonica rice, the late maturing medium japonica rice and the early maturing late japonica rice had little difference among the three types. The yield was 1.58kg (1.50-1.63) when the yield was 6thm-2 (4.87 ~ 6.58). (2) Under the condition of nitrogen application, the nitrogen uptake of 100 kg grain was more stable in medium maturity medium japonica rice, late maturing medium japonica rice and early maturing late japonica rice. The average nitrogen yield of 225 kghm-2 was 1.86 (1.85 ~ 1.87), and the nitrogen level of 300kghm-2 was 2.01kg (1.98 ~ 2.05). The nitrogen level of 225kghm-2 was 1.94kg (1.91 ~ 2.04) and the nitrogen level of 300kghm-2 Was 2.08kg (2.01-2.19). The yield of 225kghm-2 nitrogen was 1.95kg (1.93-2.01) at 10.5thm-2 and 2.09kg (2.08-2.10) at 300kghm-2. The results showed that with the increase of nitrogen application, the nitrogen uptake of 100 kg grains increased. Correlation analysis showed that there was a very significant quadratic curve between the nitrogen uptake of 100 kg grain and yield, of which the correlation coefficients of early maturity medium maturity japonica rice and late maturity japonica rice were lower than the other three types. (3) Nitrogen utilization rate decreased with the increase of nitrogen application rate, except for middle late japonica rice, it increased with growth period, ie, it was 31.32% and 37.64% at 225kghm-2 nitrogen level respectively, 38.5%, 41.08% and 38.11%, respectively, which were 28.74%, 36.13%, 37.16%, 40.15% and 39.42% under 300kghm-2 nitrogen level. (4) The nitrogen application parameters of mature and medium late japonica cultivars were larger than those of other cultivars. Compared with the non-main varieties, the nitrogen application parameters of the main cultivar (cultivars) were higher and more stable . The results showed that under the conditions of rational variety selection and layout, the variation of nitrogen application parameters was strong, and it was feasible to use Stanford equation to calculate accurately the target nitrogen yield of rice in production.