为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm...为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm^(-2),设置3种施肥量水平,低肥料(low fertility,LF)、中肥料(medium fertility,MF)和高肥料(high fertility,HF)分别为450 kg hm^(-2)、525 kg hm^(-2)和675 kg hm^(-2)进行大田试验。结果表明:中密中肥(medium density and medium fertilizer,MDMF)处理的产量最高,与低密高肥(low density and high fertilizer,LDHF)相比,MDMF处理的产量2年平均增幅3.15%,显著增加了有效穗数,稳定了其他产量因素,但收获指数增幅不高,甚至降低。齐穗期前高密高肥(high density and high fertilizer,HDHF)处理的地上部干物质量最高,2年平均增幅0.17%,齐穗后MDMF处理的地上部干物质量最高,2年平均增幅0.16%。MDMF处理在各生育时期的叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD)与LDHF处理相差不大,但MDMF处理的SPAD衰减率和LAI衰减率维持在较高水平,2021年和2022年MDMF处理条件下水稻SPAD衰减率分别为12.65%和16.85%,LAI衰减率分别为6.42%和6.74%。随着移栽密度和肥料的增加水稻分蘖数增加。由以上可知,适当的增密减肥可增加有效穗数,构造较高的群体结构和地上部干物质量,增加齐穗期至成熟期籼型杂交稻群体光合物质的生产及转运能力,保持了源的稳定,增加了产量库容量而获得高产,籼型杂交稻生产上宜采用栽插密度为22万株hm^(-2)和施肥量为525 kg hm^(-2)的组合。展开更多
The linear instability analysis of the present paper shows that the thermocapillary convection in a half floating zone of larger Prandtl number has a steady instability mode ωi = 0 and m = 1 for a fat liquid bridge V...The linear instability analysis of the present paper shows that the thermocapillary convection in a half floating zone of larger Prandtl number has a steady instability mode ωi = 0 and m = 1 for a fat liquid bridge V = 1.2 with small geometrical aspect ratio A = 0.6. This conclusion is different from the usual idea of hydrothermal instability, and implies that the instability of the system may excite a steady and axial asymmetric state before the onset of oscillation in the case of large Prandtl number.展开更多
文摘为探究增密减肥对水稻地上部干物质积累、产量等的影响,在2021—2022年,采用有序机抛技术,设置3种移栽密度,低密度(low density,LD)、中密度(medium density,MD)和高密度(high density,HD)分别为18万株hm^(-2)、22万株hm^(-2)和27万株hm^(-2),设置3种施肥量水平,低肥料(low fertility,LF)、中肥料(medium fertility,MF)和高肥料(high fertility,HF)分别为450 kg hm^(-2)、525 kg hm^(-2)和675 kg hm^(-2)进行大田试验。结果表明:中密中肥(medium density and medium fertilizer,MDMF)处理的产量最高,与低密高肥(low density and high fertilizer,LDHF)相比,MDMF处理的产量2年平均增幅3.15%,显著增加了有效穗数,稳定了其他产量因素,但收获指数增幅不高,甚至降低。齐穗期前高密高肥(high density and high fertilizer,HDHF)处理的地上部干物质量最高,2年平均增幅0.17%,齐穗后MDMF处理的地上部干物质量最高,2年平均增幅0.16%。MDMF处理在各生育时期的叶面积指数(leaf area index,LAI)、叶绿素相对含量(soil and plant analyzer development,SPAD)与LDHF处理相差不大,但MDMF处理的SPAD衰减率和LAI衰减率维持在较高水平,2021年和2022年MDMF处理条件下水稻SPAD衰减率分别为12.65%和16.85%,LAI衰减率分别为6.42%和6.74%。随着移栽密度和肥料的增加水稻分蘖数增加。由以上可知,适当的增密减肥可增加有效穗数,构造较高的群体结构和地上部干物质量,增加齐穗期至成熟期籼型杂交稻群体光合物质的生产及转运能力,保持了源的稳定,增加了产量库容量而获得高产,籼型杂交稻生产上宜采用栽插密度为22万株hm^(-2)和施肥量为525 kg hm^(-2)的组合。
基金the National Natural Science Foundation of China under Grant No.19789201the Ministry of Science and Technology of China under project 95-Yu-34.
文摘The linear instability analysis of the present paper shows that the thermocapillary convection in a half floating zone of larger Prandtl number has a steady instability mode ωi = 0 and m = 1 for a fat liquid bridge V = 1.2 with small geometrical aspect ratio A = 0.6. This conclusion is different from the usual idea of hydrothermal instability, and implies that the instability of the system may excite a steady and axial asymmetric state before the onset of oscillation in the case of large Prandtl number.
