冬小麦-夏玉米“双晚”种植模式的产量形成及资源效率研究

为了进一步明确黄淮平原冬小麦晚播、夏玉米晚收的“双晚”增产及资源高效的效应，选用2个中熟冬小麦品种和2个中晚熟夏玉米品种，于2006—2008年先后在河南温县和焦作进行大田试验，研究作物群体物质生产、产量形成参数定量指标及光温资源的分配利用。结果表明，冬小麦晚播产量降低不明显，夏玉米晚收产量显著提高747~2 700 kg hm^-2，“双晚”周年产量21 891~22 507 kg hm^-2，比对照提高442~2 575 kg hm^-2。冬小麦晚播平均叶面积指数、每平方米穗数和穗粒数降低，但平均净同化率、收获指数和粒重提高达5%显著水平；夏玉米晚收平均叶面积指数、收获指数、生育期天数和粒重均显著提高。“双晚”栽培优化了周年资源分配，提高生育期与光、温资源变化的吻合度，其生产效率分别提高2.22%~10.86%和0.47%~11.56%。小麦和玉米品种的遗传类型是影响“双晚”栽培技术的关键。因此，选用小麦晚播早熟高产和玉米长生育期晚熟品种，通过有效调节资源配置，将小麦冗余的光温资源分配给C₄高光效作物玉米，是提高周年高产高效的重要途径。

Yield Performance and Resources Use Efficiency of Winter Wheat and Summer Maize in Double Late-Cropping System

The winter wheat (Triticum aestivum L.)–summer maize (Zea mays L.) rotation is the main crop system in North China plain. In recent years, with continuous increase of air temperature, the double late-cropping system (late sowing for winter wheat and late harvested for summer maize) has of importance for whole-year high yield in this area. Proper scheme of light and heat in the double late-cropping system can provide high resource use efficiency (RUE) and high yields of both wheat and maize. To quantitatively analyze the yield performance and the effect of “double late” we need, two cultivars of winter wheat and two cultivars of summer maize in field experiments in Wen county and Jiaozuo of Henan province in 2006–2007 and 2007–2008 respectively. The dry matter production, grain yield, yield performance quantitative parameters, and energy (light and accumulated temperature) used efficiency were investigated in the double late-cropping system and compared with those in traditional cropping system (control). The results showed that the whole-year yield was 21 891–22 507 kg ha^-1 in the double late-cropping system with 442–2 575 kg ha^-1 more than that in control. In wheat cropping season, the yield of FS230 was slightly reduced with no significant difference form that of the control, but the yield of Yumai 49 significantly (P < 0.05) decreased by 291–305 kg ha^-1. In the maize cropping season, yield increased by 747–2 700 kg ha^-1, which highly compensated the yield loss of winter wheat. In the yield performance quantitative parameters, although the mean leaf area index, spike number, and grain number per spike of winter wheat decreased in the double late-cropping system, the mean net assimilation rate, harvest index, and grain weight were significantly (P < 0.05) promoted. Similarly, the mean leaf area index, harvest index, growth duration, and grain weight of maize significantly increased in the double late-cropping system. The light and temperature use efficiency were 2.22%–10.86% and 0.47%–11.56% higher in the double late-cropping system than in control. The results imply that the double late-cropping system has good performances on grain yield and resource use efficiency. The high whole-year yield and high production efficiency in double late-cropping system are mainly subject to the cropping season of maize, a C₄ plant with high photosynthetic efficiency. Thus, based on late sowing, early-maturing wheat cultivars are suggested to be used in the double cropping system in North China, resulting in longer grain-filling period of the following maize crop and ultimately higher yield.