钵苗机插密度对不同类型水稻齐穗期株型及冠层微环境的影响

Effects of planting density on plant form and micrometeorology in different types of rice with potted seedlings by mechanical-transplanting method

在南方稻区大面积应用的常规粳稻、杂交粳稻、杂交籼稻中各选两个代表性品种为材料,根据钵苗机插不同穴距设置高、中、低3种密度处理,并以塑盘毯状育苗机插为对照,比较研究钵苗机插不同密度对水稻株型及田间小气候的影响。结果表明:不同类型水稻品种剑叶与倒2叶叶枕距、倒3叶与倒4叶叶枕距、有效叶面积率、高效叶面积率、剑叶夹角、倒2叶长、倒3叶长及叶夹角、穗长及穗下两个节间长均随着栽插密度的减小而增大;冠层内部温湿度随栽插密度降低而降低,常规粳稻和杂交粳稻以中低密度透光性好,杂交籼稻透光性差;钵苗机插水稻较常规盘育毯苗机插苗株型整齐,群体内部温湿度降低;钵苗机插常规粳稻、杂交粳稻、杂交籼稻适宜穴距设置分别为12、14和16 cm,有利于实现省工节本和高产高效的统一,可为大面积生产提供参考。

In order to study the impacts of planting density of potted rice seedlings by mechanical transplanting method on plant form and micrometeorology, a field experiment was conducted using conventional japonica rice （Nanjing 44, Wuyunjing 24 ）, japonica hybrid rice （Yongyou 8, Changyou 5）, and indica hybrid rice （Liangyoupeijiu, II You 084）, which have been widely grown in the southern China, with high, medium and low density treatments of different hole spacing in potted seedling mechanlcal-transplanting （12, 14, and 16 cm） , and the conventional blanket seedling mechanical-transplanting as control. The results showed that the distances of leaf occiput between flag leaf and top 2nd leaf and between top 3rd leaf and top 4th leaf, effective leaf area ratio, highly effective leaf area ratio, angle of flag leaf, lengths of top 2nd and 3rd upper leaves, leaf angle, lengths of panicle and uppermost two internodes increased with reducing the planting density, while canopy temperature and humidity decreased with reducing the planting density. Conventional japonica rice with the low density and japonica hybrid rice with the medium density had higher canopy light intensities, while indica hybrid rice presented an opposite trend. Compared with the control, rice plants with potted seedlings by mechanical transplanting exhibi-ted a uniform plant form, and canopy temperature and humidity decreaseu, t^omom~ variation characteristics of plant form, conventional japonica rice planting with 12 cm hole spac- ing could make better use of the resources of temperature and light, japonica hybrid rice planting with the hole spacing of 14 cm could effectively improve the light and ventilation conditions, co- ordinate grain contradiction, and hybrid indica rice planting with 16 cm hole spacing was not only suitable for mechanical cultivation, but also improved the percentage of spike-forming tillers.