【作者】 秦安振；

【导师】 黄高宝； 柴强；

【作者基本信息】 甘肃农业大学 ， 作物栽培学与耕作学， 2013， 博士

【摘要】 间作种植是河西绿洲灌区一种常见的提高农田产出的农作模式，其多样化配置是农业可持续发展的基础。然而，间作系统在干旱绿洲灌区是否能降低农田碳排放还有待研究。通常情况下，高产出的农作模式也伴随着高CO₂排出，间作系统对土壤呼吸及碳排放的调控作用亦鲜见报道。为探索间作系统下产量，土壤呼吸和环境因子的动态及其与因子间的相互关系，在甘肃农业大学武威试验站（37o96′N,102o64′E）进行了三年的定位试验（2009，2010和2011年）。试验共设置九个处理，其中四个间作处理，分别是玉米–小麦间作，玉米–豌豆间作，玉米–油菜间作和小麦–大豆间作，及五个单作处理，分别是单作油菜，单作小麦，单作豌豆，单作大豆和单作玉米。本试验的主要结果如下：1.作物生长（干物质累积）是影响农田土壤呼吸的主要因子，当作物干物质开始累积时，土壤呼吸随之增加，到开花期（早播作物）或吐丝期（晚播作物），干物质累积速率最大时，土壤呼吸速率亦达最大，随后开始降低。将土壤呼吸和干物质累积的二次方程（y=a×x₂+b×x+c）与土壤呼吸和土壤温度的指数方程（y=a×ek×t）结合建立的复合模型可以较好地模拟农田土壤呼吸变异，干物质累积与土壤温度可以解释土壤呼吸38%到58%的变异。玉米间作系统，如玉米–小麦(0.52g CO^-22mhr^-1)，玉米–豌豆(0.51g CO₂2m–hr^-1)和玉米–油菜(0.44g CO^-22mhr^-1)较单作玉米(0.74g CO₂m^-2hr^-1)显著降低了土壤呼吸季变化的最大值。单作玉米的碳排放量最高(4,233kg C ha^-1)，单作油菜的最低(1,260kg C ha^-1)。玉米间作系统(1,701kg C ha^-1到3,108kg C ha^-1)较单作玉米或单作小麦显著降低了碳排放量。玉米是单位水碳排放最高的作物，豌豆和小麦次之，油菜和大豆最低。玉米间作系统较单作玉米减少了42%（2009），52%（2010）和45%（2011）的单位水碳排放量。2.单作种植中，玉米的产量最高，为11,724kg ha^-1，小麦次之，为6,467kg ha^-1，豌豆最小，为2,830kg ha^-1。单作玉米的产量由2009年的12,677kg ha^-1降至2011年的10,624kg ha^-1，减少了19%。玉米–小麦间作系统中，玉米产量由2009年的7,404kg ha^-1升至2011年8,123kg ha^-1，提高了10%。玉米间作系统表现出较高的水分利用效率(15.9^-19.8kg ha^-1mm^-1)和土地当量比(1.16^-1.48)，表明间作系统存在高效水分利用及增产的优势。3.豌豆与玉米共生时，土壤水分移动势最小，表明豌豆带从玉米带汲取的水分最小。小麦是最强的水分竞争者。小麦与玉米或大豆共生时，可从玉米带或大豆带中竞争11^-20mm的土壤水分。豌豆由于根系分布较浅，与玉米带不存在水分竞争关系，为玉米后期恢复生长提供较多的土壤水分。小麦带在收获后通过休闲期雨水或灌溉补给，涵养最大量的土壤水分，为玉米带补给19^-21mm的土壤水分。4.间作系统早播作物干物质最大累积速率(57g m^-2d^-1)高于单作作物的(51g m^-2d^-1)，最大速率出现在播种后72到77天；间作系统晚播作物的最大干物质累积速率低于单作作物，在31.6到44.9g m^-2d^-1之间，较单作玉米降低了30%到43%。单作玉米干物质最大累积速率出现在播种后80到96天，间作玉米的最大累积速率出现的时间较单作玉米推迟了6到10天。玉米–豌豆间作系统中，玉米干物质最大累积速率为43g m^-2d^-1，分别较单作玉米，玉米–油菜间作和玉米–小麦间作系统中的玉米，提高了15%，21%和40%，表明玉米–豌豆间作系统对间作玉米的干物质累积是有利的。更多还原

【Abstract】 Intercropping systems have been shown to boost crop productivity and provide potentialfor biodiversity in development of sustainable agriculture. Main concern is that higher yieldingsystems usually are associated with higher soil respiration while soil respiratory responses tocropping systems are limited to know on arid land. Field experiments were conducted atWuwei Experimental Station of Gansu Agricultural University, China （37o96′N,102o64′E）in2009,2010, and2011. Four intercropping systems, including maize （Zea mays）–wheat（Triticum aestivum）, maize–rape （Brassia campestris）, maize–pea （Pisum sativum） andsoybean （Glycine max）–wheat intercropping, along with the respective five sole crops, weredesigned in a randomized, complete block design with three replicates to investigate the effectof intercropping systems on yield–and environment–related factors, and the contributions ofcontrolling factors to those related factors. Main results are summarized as follows:（1） Crop growth （dry matter accumulation） is a major factor controlling soil respirationfarmland. With the increase of dry matter accumulation, soil respiration rate increased,reached a peak at the early flowering stage for earlier sown crops and at the silking stage formaize, and then declined. A quadratic function for dry matter accumulation combined with anexponential function for soil temperature was fit the measured results, showing thecombination of dry matter and soil temperature accounted for38%to58%of variances insoil respiration. Maize based intercropping such as maize–wheat (0.52g CO^-22mhr^-1),maize–rape (0.44g CO₂m^-2hr^-1) and maize–pea (0.51g CO₂m^-2hr^-1) intercropping systemssignificantly reduced seasonal maximal soil respiration as compared to sole maize (0.74g CO₂m^-2hr^-1). Sole maize emitted the highest carbon (4,233kg C ha^-1) in each year, whereas solerape released the least amount (1,260kg C ha^-1). Intercropping (1,701to3108kg C ha^-1)significantly reduced carbon emission compared to sole maize or sole wheat. Maize was thegreatest emitter of carbon per unit of water, followed by pea and wheat, whereas rape andsoybean were the least. Maize based intercropping emitted42%,52%, and45%less carbonper unit of water in2009,2010, and2011, respectively, compared to sole maize.（2） Maize produced the greatest grain yield at11,724kg ha^-1, followed by wheataveraging at6,467kg ha^-1, and pea the lowest at2,830kg ha^-1. Sole maize had the grain yielddecreased from12,677kg ha^-1in2009to10,624kg ha^-1in2011, or by19%, whereas themaize in the maize–wheat intercropping had its grain yields increased from7,404kg ha^-1in 2009to8,123kg ha^-1in2011, or by10%. Although, intercropping consumes more watercompared to sole cropping, maize based intercropping systems had greatest water useefficiency with a land equivalent ratio of1.16to1.48, showing significant advantages in wateruse and yield over the rest of the cropping systems.（3） Pea showed least soil water competition with the intercropped maize in the maize–peaintercropping during the co–growth period. Wheat was the greatest competitor for soil water,and competed for11to20mm soil water from neighboring maize or soybean strips inmaize–wheat or soybean–wheat intercropping systems. Pea was a least competitive crop withshallow rooting system. Wheat recharged greatest amount of soil water from wheat harvestthrough maize harvest, having a potential to compensate19to21mm soil water to the maizestrips, which is favorable to the recovery of maize growth in maize–wheat intercropping.Maize based intercropping, especially maize–pea intercropping, is a promising croppingoption in arid areas, as soil water extraction of two species in intercropping can be temporallystratified.（4） Intercropping had a co–growth period of50–80d, allowing the two intercroppedspecies to complete their life cycles. Maximum dry matter rate for the earlier sown crops in themaize based intercropping systems was significantly greater than that for sole earlier sowncrops (57vs.51g m^-2d^-1) which occurred at around72to77days after sowing （DAS）,whereas the maximum dry matter rate for the later sown crops in the maize basedintercropping systems was between31.6to44.9g m^-2d^-1, or30to43%lower than that ofsole later sown crops. The time to reach maximum dry matter was80–96DAS for sole maize,and the corresponding time for the intercropped maize was delayed by6to10days. Amongmaize based intercropping, maximum accumulation rate of maize in maize–pea intercroppingsystem was43g m^-2d^-1, or15%,21%and40%higher than those of sole maize, maize inmaize–rape and maize in maize–wheat intercropping systems, respectively.更多还原