水氮管理及品种对冬小麦光能利用率的影响

Effects of water and nitrogen management on radiation use efficiency of different varieties of winter wheat

提高光能利用率（RUE）是作物获得高产的重要因素之一。遗传特性和栽培管理措施等因素通过影响作物冠层结构及冠层形成过程,进而影响作物的光能利用率。为探讨不同冬小麦品种在不同水氮管理条件下的光能利用率,于2012—2013年,在中国科学院栾城农业生态系统试验站,进行了3个冬小麦品种（‘冀麦585’、‘科农199’和‘石新828’）在3个氮水平[135 kg（N）·hm^-2,180 kg（N）·hm^-2,225 kg（N）·hm^-2]和3个灌溉水平（70 mm,140 mm,210 mm）下的大田试验,对关键生育期光合有效辐射截获、生物量和叶面积等参数进行了测定和分析。结果表明：不同冬小麦品种的光能利用率存在显著差异（P〈0.05）,‘冀麦585’、‘科农199’和‘石新828’的光能利用率分别为2.10 g·MJ^-1、2.05 g·MJ^-1和1.93 g·MJ^-1。不同水氮处理对冬小麦光能利用率有一定的影响,其值为1.80~2.20 g·MJ^-1;水氮因素对冬小麦光能利用率的影响不同,随着施氮水平的增加,光能利用率增加,适度的水分亏缺会产生较高的光能利用率。光能利用率增加与生物量形成呈正相关,但当生物量增加到一定程度后冬小麦产量并不随生物量的增加而增加,这与干物质量转移率随着生物量增加而降低有关。结果还显示：从拔节期到灌浆期冬小麦的光能利用率与气温存在明显的曲线关系,其在水氮条件下表现不一致。综合上述分析结果,需要适宜水氮供应才能获得适度干物质积累,提高光能利用率和有效干物质运转,最终提升冬小麦产量。

Radiation use efficiency （RUE） is critical for improving crop yield. It is not only related to crop canopy intercepted radiation, but also to the distribution of radiation within the canopy. The characteristics and forming processes of crop canopy are affected by genetic characteristics, management practices and other related factors. Various canopy characteristics have different end-effects on crop RUE. Winter wheat is a major crop grown in the North China Plain （NCP）, accounting for about 50% of wheat production in China. Thus keeping high yields and improving resources use efficiency of winter wheat are critical in the NCP region. To explore the effects of varieties, water and nitrogen supplies on RUE of winter wheat, a field experiment was conducted at Luancheng Agro-Ecosystems Experimental Station, Chinese Academy of Sciences in the winter wheat growing season from 2012 to 2013. Three winter wheat varieties （＇Jimai585＇, ＇Kenong199＇ and ＇Shixin828＇） were used in the experiment — the main wheat varieties grown in the study area. Three water supply levels [70 mm irrigation in jointing stage （serious deficit irrigation）, total 140 mm irrigations in jointing and booting stages （moderate deficit irrigation） and total 210 mm irrigations in jointing, booting and grain-filling stages （normal irrigation）] were applied, and three nitrogen supply levels [135 kg（N）·hm-2, 180 kg（N）·hm-2 and 225 kg（N）·hm-2] used as fertilizer management in the study. Biomass, leaf area index and photosynthetically active radiation （PAR） were measured every 7 days. RUE was calculated using biomass and intercepted radiation during the respective growth periods of winter wheat. The results showed that RUE was significantly different for different wheat varieties. RUE was 2.10 g·MJ-1 for ＇Jimai585＇, 2.05 g·MJ-1 for ＇Kenong199＇ and 1.93 g·MJ-1 for ＇Shixin828＇. RUE under different water and nitrogen levels was also different, and ranged within 1.80-2.20 g·MJ-1. RUE increased with increasing nitrogen supply. However, RUE was higher for moderate water deficit irrigation than others treatments. There was no significant difference in RUE for water and nitrogen interaction. This suggested that genetic characteristics, water and nitrogen supplies significantly influenced wheat RUE. Although increasing RUE obviously increased biomass, winter wheat yield did not significantly increase after a certain increase in biomass due to lower dry matter transfer rate. The results also showed a significantly relationship between RUE and air temperature for the period from stem-elongation to grain-filling. Given the above, it was concluded that the appropriate nitrogen and water supply for winter wheat was beneficial for dry matter accumulation and improvement of RUE, eventually resulting in high winter wheat yield.