小麦||蚕豆间作提高间作产量的优势及其氮肥响应

Wheat and faba bean intercropping to improve yield and response to nitrogen

  • 摘要: 为探明小麦||蚕豆间作体系种间互补和竞争与产量优势的关系及其氮肥响应,为豆科禾本科间作最佳氮素管理提供指导,本研究通过为期2年(2015—2017年)的田间定位试验,在不施氮(N0)、低氮(N1,90 kg·hm-2)、常规施氮(N2,180 kg·hm-2)和高氮(N3,270 kg·hm-2)4个施氮水平下,研究小麦||蚕豆间作的产量优势及其相关种间关系。结果表明,与单作相比,两年的间作小麦产量平均显著增加23.50%,单、间作蚕豆的产量均维持在4 000 kg·hm-2左右,土地当量比均表现为N0 > N1 > N2 > N3 > 1的趋势,系统生产力平均达5 023 kg·hm-2。与单作相比,间作小麦和蚕豆的花后干物质累积比例、干物质转移率和贡献率均不同程度增加,增幅随着施氮量增加而降低。不同施氮水平下,小麦的种间相对关系指数均表现出明显的互利效应,相对种间竞争强度在低氮水平为种内竞争,常规氮和高氮水平为种间竞争;蚕豆的种间相对关系指数则表现出竞争效应,相对种间竞争强度表现为种内竞争。较蚕豆而言,小麦的相对种间竞争力表现出不同程度的竞争优势,在种间竞争力为0.629 2时可获得最大的间作体系混合干物质量16 093 kg·hm-2。综上,小麦||蚕豆间作降低了低氮水平下的种间竞争强度,扩大了小麦的互利效应和竞争优势,增加了间作作物的花后干物质累积比例以及干物质贡献率,表现出明显的间作产量优势。

     

    Abstract: The wheat and faba bean intercropping system improves crop yield. However, there are few systematic reports on the relationship between the yield advantage and the interspecific interaction and its response to nitrogen fertilizer. Nitrogen applications were tested to improve nitrogen management in intercropped legumes and grasses, gather information on efficient nutrient use, and determine the interspecific influence on wheat and faba bean yields. The field positioning test was conducted from 2015 to 2017 to study yield advantages and interspecies relationship of wheat||faba bean intercropping system under various nitrogen application levels:no nitrogen (N0), low nitrogen (N1, 90 kg·hm-2), conventional nitrogen (N2, 180 kg·hm-2), and high nitrogen (N3, 270 kg·hm-2). Compared with monocropped wheat, the intercropped wheat yield was significantly higher in all treatments2016:24.55% (N0), 20.71% (N1), 19.92% (N2), 16.77% (N3); 2017:35.89% (N0), 28.63% (N1), 23.32% (N2), 18.25% (N3). The mono and intercropped faba bean yields were both around 4 000 kg·hm-2. The land equivalent ratio of the intercropping system under different nitrogen levels was N0 > N1 > N2 > N3 > 1, and the average intercropping productivity reached 5 023 kg·hm-2 in two years. The intercropped wheat dry matter accumulation ratio after flowering, transfer rate, and contribution rate increased by 37.68%, 7.95%, and 10.59%, respectively, and the intercropped faba beans increased by 19.66%, 41.43%, and 17.64%, respectively, compared with the monocultured crops. The increase rate decreased as nitrogen increased, and the intercropped wheat dry matter accumulation ratio after flowering was significantly different at N2 and N3 levels in 2016. The average wheat relative interaction indexes were 0.13 (N0), 0.11 (N1), 0.10 (N2), and 0.08 (N3), showing mutually beneficial effects, but the faba bean indices were -0.008 (N0), -0.03 (N1), -0.08 (N2), and -0.08 (N3), indicating a competitive effect. The average wheat relative competition intensity values were -0.19 (N0), -0.08 (N1), 0.21 (N2), and 0.32 (N3), indicating intraspecific competition at low nitrogen levels (N0, N1) and interspecific competition at conventional (N2) and high (N3) nitrogen levels. All faba bean values indicated intraspecific competition:-0.75 (N0), -0.75 (N1), -0.66 (N2), and -0.65 (N3). The relative interspecific competitiveness values of wheat versus faba beans were 0.51 (N0), 0.54 (N1), 0.56 (N2), and 0.58 (N3), suggesting different degrees of competitive advantage. Competitiveness was significantly correlated (a quadratic curve) with the above-ground dry matter of the intercropping system. The maximum mixed dry matter mass of the intercropping system (16 093 kg·hm-2) was reached when the wheat versus faba bean interspecific competitiveness value was 0.629 2. Wheat and faba bean intercropping reduced the interspecific competition intensity in a low nitrogen environment (N0, N1). It also expanded the mutually beneficial effects and competitive advantages of wheat and increased the dry matter accumulation ratio after flowering and the dry matter contribution rate of intercropping crops. The maximum competitive advantage of intercropped wheat was at the conventional nitrogen level (N2, 180 kg·hm-2).

     

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