水稻不同生育期类型品种精确定量施氮参数的初步研究

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。

Preliminary Study on Parameters of Precise and Quantitative Nitrogen Application in Rice Varieties with Diflferent Growth Period Durations

The objective of this study was to expose the change law of the three parameters of the precise and quantitative N application based on the Stanford equation in different growth types of rice. Three levels of N fertilizer application rates of 0, 225, and 300 kg ha^?1 N were designed in a field experiment with early (125–135 d), medium (136–145 d), late-maturing (146–155 d) medium japonica and early (156–165 d), medium-maturing (166–175 d) late japonica rice in 2007 and 2008 on the farm of Yangzhou university, Jiangsu province, China. The results were as follows: (1) Under zero N application, soil basal N application (N accumulation for basal yield) increased with the extension of the rice growth duration, in which the parameter of calculating N accumulation for basal yield was the N requirement for 100 kg grains. There were only small differences in N requirement for 100 kg grains between medium, late-maturing medium japonica and early-maturing late japonica rice. For an average yield of 6 t ha^?1 (4.87–6.58), the N requirement for 100 kg basal yield was 1.58 kg (1.50–1.63). (2) Under N application, the N requirements for 100 kg grains were rather stable in medium，late-maturing medium Japonica and early-maturing late Japonica rice. With the average yield of 7.5 t ha^?1, N requirement for 100 kg grains was 1.86 kg (1.85–1.87) under 225 kg ha^?1 N level and 2.01 kg (1.98–2.05) under 300 kg ha^?1 N level, respectively. With the average yield of 9 t ha^?1, N requirement for 100 kg grains was 1.94 kg (1.91–2.04) under 225 kg ha^?1 N level and 2.08 kg (2.01–2.19) under 300 kg ha^?1 N level, respectively. With the average yield of 10.5 t ha^?1, N requirement for 100 kg grains was 1.95 kg (1.93–2.01)under 225 kg ha^?1 N level and 2.09 kg (2.08–2.10) under 300 kg ha^?1 N level, respectively. These results suggested that N requirement for 100 kg grains increased with the rising of N application rates. Correlation analysis showed that there existed highly significantly positive conic correlation between yield and N requirement for 100 kg grains, and the correlation coefficients for early-maturing medium japonica and medium-maturing late Japonica were less than those for the other three types. (3)The N use efficiency decreased with the increase of N application rate, and increased with the extension of the growth duration except in the medium-maturing late japonica. N use efficiency was 31.32%, 37.64%, 38.5%, 41.08%, and 38.11% under 225 kg ha^?1 N level , and 28.74%, 36.13%, 37.16%, 40.15%, and 39.42% under 300 kg ha^?1 N level, for the five types of rice with extended growth duration respectively. (4) The parameters of N application displayed larger differences in early-maturing medium japonica and medium-maturing late japonica rice which were less suitable for local cultivation, compared with the other three types, while these parameters values of the prevailing varieties (headed varieties) were higher and more stable than those of common varieties. These results demonstrated that the changes of the parameters of N application were much larger, it is feasible for the N quantity required for target yield to be calculated accurately by using Stanford equation under the condition of reasonable variety selection and planting location.