氮素对哈尼梯田水稻冠层温、光生态因子及稻瘟病的影响

为了研究氮素对云南哈尼梯田水稻冠层昼温、光合有效辐射截获率及稻瘟病的影响，探索水稻冠层光合有效辐射截获率与稻瘟病发生的相关性，构建合理健康的群体冠层结构。以当地种植的常规水稻品种‘月亮谷’为试验材料，采取单因素随机区组设计，共6个处理，包括5个不同施氮处理和1个传统施肥对照处理。研究结果表明，高施氮水平下(125.0 kg/hm²)齐穗期的冠层昼温最低，冠层光合有效辐射最大截获率最大。中等施氮(75.0 kg/hm²)和高施氮水平下穗颈瘟的病情指数最高，中等施氮水平下的发病率最高，为51.0%。穗颈瘟发病率和病情指数均和冠层光合有效辐射最大截获率存在正相关性 (r=0.6696^*和r=0.7130^**)，发病率与1级病穗百分比呈正相关性(r=0.7511^**)，而和2级至5级病穗百分比的关系不大，病情指数分别与5级、1级病穗百分比呈正相关性(r=0.6324^**、r=0.4936^*)，而和2级至4级病穗百分比关系不大。

Effects of Different Nitrogen Application Amounts on Canopy Temperature, Solar Radiation and Blast of Rice in Yunnan Hani Terrace

We conducted tests on the Hani terraced rice ‘Yuelianggu’ in order to study the effect of nitrogen on canopy day temperature, photosynthetic active radiation interception rate and rice blast, and to explore the relationship between canopy photosynthetic active radiation interception rate and rice blast, then construct the health canopy structure. The experiment consisted of six treatments, which were five different nitrogen levels and a traditional fertilization management, and carried out as a random block design experiment in field. The results showed that rice canopy day temperature reached the minimum at heading stage at the highest level of nitrogen conditions (125.0 kg/hm²), then the maximum interception ratio of canopy photosynthetic active radiation reached the maximum. The disease index of neck blast reached the maximum at medium (75.0 kg/hm²) and high level of nitrogen conditions (P＞0.05), and morbidity reached the maximum at medium level of nitrogen conditions. The morbidity, disease index and the maximum interception ratio of canopy photosynthetic active radiation had a positive correlation, and the correlation coefficients were 0.6696^* and 0.7130^**. Morbidity had a positive correlation with level 1 of diseased panicle proportion (r=0.7511^**), but had no relationship with level 2 to level 5 of diseased panicle proportion. Disease index had a positive correlation with level 5 and level 1 of diseased panicle proportion, and the correlation coefficients were 0.6324^** and 0.4936^*, respectively, but had no relationship with level 2 to level 4 of diseased panicle proportion.