不同穗型籼稻群体小气候对氮肥的响应特征

Character research of micro-climate response on nitrogen fertilizer in different indicia rice field where planted with different panicle type

明确不同穗型籼稻群体小气候对氮肥的响应特征,对探索适宜的氮肥调控措施,提高氮肥利用效率具有重要的现实意义.研究以籼稻R498,R816和R499为材料,设置3个氮肥施用水平(N0:N 0 kg/hm2;N1:N 150 kg/hm2;N2:N 300 kg/hm2),采用TP1 000型温湿度记录仪和TASI-8720型光照度计等仪器设备分别观测齐穗期和齐穗后20 d的水稻群体温湿度和群体光照等,比较不同穗型籼稻群体的温湿度差异及光照差异,研究不同穗型籼稻田间小气候对氮肥的响应特征.结果表明:①随着氮肥用量的增加,不同穗型的群体上部、中部和底部的温度均表现为先降低后增加的趋势;穗型对籼稻群体温度的影响不仅与群体部位有关,同时也受氮肥肥力水平的影响.②齐穗期不同穗型水稻群体上部、中部和底部的相对湿度不仅在肥料处理间差异显著而且在不同穗型间差异显著.齐穗后20 d,所有穗型水稻群体中部和底部相对湿度在9:00-19:00随着氮肥的增加而增加;所有穗型群体上部的相对湿度在17:00-19:00随着氮肥的增加而增加.③不论是齐穗期还是齐穗后20 d,3种穗型水稻群体的光照强度均表现为自上而下逐渐下降的趋势,但下降的程度受穗型和氮肥影响显著,R499的降低幅度显著低于R498和R816;3种穗型的群体上部和中部的光照强度均表现为随着氮肥的增加而降低的趋势.④R498和R816的群体RIC值在N1和N2水平下均表现为从上部至下部逐渐降低的趋势;R499的群体RIC值在N1水平下,表现为自上部至下部逐渐降低的趋势;但在N2水平下,其RIC2U值比RIC2M值和RIC2L值显著降低.研究结果表明,直立穗型籼稻群体中部和下部的群体小气候对氮肥的响应显著优于弯曲穗型和半直立穗型;在高氮条件下直立穗型籼稻的单株有效穗数显著高于弯曲穗型,其稻谷产量、氮肥农学利用效率和氮肥增产效率显著高于弯曲穗型;与弯曲穗型相比,直立穗型籼稻更适宜在高氮条件下推广种植.

Micro-climate of rice population is one of the most important factors on nitrogen utilization.Clarifing the micro-climate response of indicia rice population on nitrogen fertilizer can help to optimize the nitrogen fertilizer management and to enhance the nitrogen using efficiency in indicia rice field. R498, R816 and R499 were selected to represent dropping panicle, semi-erect panicle and erect panicle, respectively;3 nitrogen fertilizer levels(N0: N 0 kg/hm^2;N1: N 150 kg/hm^2;N2: N 300 kg/hm^2) were applied for each panicle type.Temperature, relative humidity and luminous of indicia rice population during heading stage and 20 days after full heading were measured at different positions under different nitrogen fertilizer treatments, by Temperature &Humidity Data Logger(TP1000) and Luminometer(TASI-8720). Responsive characters of micro climate on nitrogen fertilizer were investigated by comparing temperature, relative humidity and light intensity of different panicle types at different positions of indicia rice populations. The results showed that: ① With the increase of nitrogen fertilizer, the temperature at upper, middle and lower position of indicia rice population all increased after decreasing;the response of micro climate on nitrogen fertilizer was not only affected by nitrogen fertilizer but also impacted by position in indicia rice population. ② Relative humidity at upper, middle and lower position of indicia rice population all showed a significant difference among different nitrogen fertilizer treatments and among different panicle types during the full heading stage;Relative humidity at middle and lower position of indicia rice population both performed an increasing trend from N0 to N2 at 9:00-19:00, the relative humidity at upper position increased from N0 to N2 at 17:00 to 19:00. ③ The luminous intensity of indicia rice population showed a down trend from top to bottom in rice population, while its decreasing rate varied significantly, the decreasing rate of luminous intensity of R499 was significantly lower than R498 and R816. ④ The response index of micro-climate on nitrogen fertilizer of R498 and R816 both performed a down trend from top to bottom at N1 and N2 fertilizer treatment;the response index of microclimate of R499 on nitrogen fertilizer increased from top to bottom under N1 fertilizer treatment, while it was significantly lower at top than it at middle and bottom position. According these results, we conclude that the comprehensive response of micro-climate of erect panicle indicia rice on nitrogen fertilizer is better than dropping panicle indicia rice. The effective panicle and the grain yield of erect panicle indicia rice is higher than dropping panicle indicia rice, its agronomic efficiency of applied nitrogen and increase rate of grain yield by nitrogen also was higher than dropping panicle indicia rice under higher fertilizer treatment.Comparing with dropping panicle indicia rice, erect panicle indicia rice is more appropriate for high fertilizer.Therefore, we suggest farmers to plant erect panicle indicia rice in heavy fertilizer area or used more fertilizer in moderate fertilizer area.