黄土塬区玉米大豆间作系统水分利用研究

发布时间：2019-06-14 07:15

【摘要】：粮食安全问题一直是人类社会可持续发展面临的首要挑战和亟待解决的问题之一。黄土塬区降水量少,时空分布不均,且土壤肥力较低,极大地限制了作物水分利用效率和生产力的提高。如何提高水分利用效率成为该地区农业研究的一个重要方向。玉米大豆间作可利用大豆的固氮作用为玉米提供氮肥,提高产量和水分利用效率的同时减少化肥使用量。因此,玉米大豆间作具有改善黄土塬区缺水又缺肥现状的潜力,从而为黄土塬区的农作物种植提供理论基础和实践指导。本研究通过田间试验,系统研究了不同作物品种(玉米:郑单958和豫玉22;大豆:中黄24和中黄13),密度梯度(低、中、高)、种植比例(单作玉米,玉米:大豆=2:2;玉米:大豆=2:4;玉米:大豆=4:2;单作大豆)对玉米-大豆生长发育、生理特征、产量、经济效益、养分和水分利用等的影响,为该区域作物合理种植方式的选择以及农业的可持续发展提供依据。主要结论如下:(1)相比单作,不同品种、密度和种植比例下玉米-大豆间作的土地当量比介于0.90-1.29。除2014年玉米与大豆以2:2间作外,其他间作的土地当量比大于1,表明黄土塬区合理的玉米-大豆间作能够提高间作产量和土地使用效率,具有间作优势。(2)玉米的竞争指数(侵占力和竞争比率)均高于大豆,表明玉米-大豆间作系统中玉米为优势种。玉米的实际产量损失(AYL)均为正值,表明间作系统中玉米表现为产量增加;而大多数间作方式下大豆AYL均为负值,表明间作系统中大豆产量表现为不同程度损失;间作系统AYL均为正值,表明玉米-大豆间作在产量上具有间作优势。系统生产力指数(SPI)是表征间作系统生产力和稳定性的一种指标,其结果表明所考虑的间作系统均具有较高的生产力和稳定性。玉米-大豆间作系统中玉米在经济上表现为收益增加(玉米的间作优势IA0),而大豆表现为收益减少(大豆IA0),综合作用下形成间作系统在经济上的收益优势(间作系统IA0)。货币优势指数为正值,表明玉米大豆间作系统具有经济优势。因此,玉米-大豆间作具有间作优势主要归因于玉米产量的提高和经济收益的增加。(3)相对于豫玉22与大豆间作,玉米品种郑单958与大豆品种(中黄24和中黄13)在产量和经济收益上具有更好的间作优势。间作中,郑单958的AYL、SPI和IA均高于豫玉22,表明在黄土塬区,抗旱品种——郑单958有利于提高间作优势。(4)玉米和大豆的产量构成要素随着种植密度的增加而减小。间作提高了玉米的穗重、穗长、穗粗、穗粒重、行粒数和千粒重,从而显著的提高了玉米的单株产量乃至群体产量。间作对大多数大豆的单株荚数和粒数、百粒重没有变化或者降低,导致大豆的单株产量乃至群体产量有所降低。所有种植比例下玉米AYL为正值,表明相对单作所有间作方式玉米产量均有所增加。大多数2:4种植比例的大豆AYL为正值,而2:2种植比例下大豆AYL为负值,表明2:4种植比例较2:2增加了大豆产量。(5)从地上部对光资源的相互竞争作用来看,间作对玉米和大豆的光合速率没有显著影响。从地下部对养分和水分相互竞争作用来看,间作增加了玉米作物对氮和磷的吸收量,降低了大豆作物对氮和磷的吸收量;间作通过影响根系输水能力而影响玉米和大豆的耗水量,从而提高作物的水分利用效率。(6)相比单作大豆和2个作物的平均水分利用效率(WUE),玉米与大豆间作提高WUE,玉米和大豆以4:2种植比例的WUE高于其他种植比例的间作方式。与单作相比,间作系统扩大了两种作物根系横向和纵向的空间分布(根长密度),改变了作物根系形态特性,增加了玉米和大豆根系吸收水分的生态位,从而提高了作物对水分的吸收和利用。(7)玉米-大豆间作的根长密度和土地当量比之间存在负相关关系。与其他种植比例的间作相比,玉米-大豆以2:2间作时产生了较多根系是以牺牲生殖生长中产量的积累为代价,这表明产量和WUE提高的主要原因是玉米与大豆间作时根系发育和产量形成之间存在合理的生长权衡。
[Abstract]:The issue of food security has been one of the main challenges and problems to be solved in the sustainable development of human society. The precipitation is small, the time-space distribution is not uniform, and the soil fertility is low, and the water use efficiency and the productivity of the crops are greatly limited. How to improve the water use efficiency becomes an important direction of agricultural research in the region. The corn-soybean intercropping can utilize the nitrogen fixation of the soybean to provide the nitrogen fertilizer for the corn, improve the yield and the water use efficiency, and simultaneously reduce the use amount of the fertilizer. Therefore, the corn-soybean intercropping has the potential to improve the water-deficient and fertilizer-free status of the crop region, so as to provide theoretical basis and practical guidance for crop cultivation in the region. In this study, field experiments were conducted to study different crop varieties (maize: Zhengdan 958 and Yuyu 22; soybean: medium yellow 24 and medium yellow 13), density gradient (low, medium and high), planting ratio (single cropping of corn, corn: soybean = 2:2; corn: soybean = 2:4; corn: The effects of soybean = 4:2; single-cropping soybean) on the growth and development, physiological characteristics, yield, economic benefit, nutrient and water utilization of maize-soybean, and provide the basis for the selection of reasonable planting methods of the crops and the sustainable development of agriculture. The main conclusions are as follows: (1) The land equivalent ratio of maize-soybean intercropping under different varieties, density and planting ratio is between 0.90 and 1.29. In addition to the 2:2 intercropping of the maize and the soybean in 2014, the land equivalent ratio of the other intercropping is greater than 1, indicating that the reasonable corn-soybean intercropping can improve the intercropping yield and the efficiency of the land use, and has the intercropping advantage. (2) The competition index (the occupation force and the competition ratio) of the corn were higher than that of the soybean, indicating that the corn-soybean intercropping system was the dominant species. The actual yield loss (AYL) in the intercropping system was positive, indicating that the yield of the maize in the intercropping system was increased, while the soybean AYL was negative in most intercropping systems, indicating that the yield of the soybean in the intercropping system was different and the intercropping system AYL was positive, It is shown that maize-soybean intercropping has intercropping advantage in yield. The system productivity index (SPI) is an index to characterize the productivity and stability of intercropping systems. The results show that the intercropping system considered has higher productivity and stability. In the maize-soybean intercropping system, the economic performance of the corn is increased (the intercropping advantage of the corn is IA0), and the soybean performance is the yield reduction (the soybean I0), and the economic benefit advantage of the intercropping system under the comprehensive action (the intercropping system IA0) is formed. The monetary advantage index is positive, indicating that the corn-soybean intercropping system has the economic advantage. Therefore, the intercropping advantage of maize-soybean intercropping is mainly due to the increase of corn yield and the increase of economic benefit. (3) With respect to Yuyu 22 and soybean intercropping, the corn variety Zheng single 958 and soybean variety (middle yellow 24 and medium yellow 13) have better intercropping advantage in the yield and economic benefit. In the intercropping, the AYL, SPI and IA of Zhengdan 958 were higher than that of Yuyu 22, indicating that the drought-resistant variety, Zhengdan 958, was beneficial to the improvement of intercropping. (4) The composition of the yield of corn and soybean decreased with the increase of planting density. The intercropping increased the ear weight, the ear length, the ear length, the ear weight, the number of grains and the 1000-grain weight of the corn, thereby obviously improving the yield of the single plant and the yield of the group of the corn. The number and the number of grains per plant of most of the soybean were not changed or decreased by intercropping, and the yield of single plant and the yield of the population decreased. The corn AYL was positive at all planting rates, indicating an increase in the yield of maize in all intercropping patterns. The majority of the 2:4 ratio of the soybean AYL was positive, while the 2:2 ratio of the soybean AYL was negative, indicating that the 2:4 planting ratio was 2:2 and the yield of the soybean was increased. (5) The intercropping of intercropping has no significant effect on the photosynthetic rate of maize and soybean. the intercropping increases the absorption of the nitrogen and the phosphorus by the corn crops, and the water consumption of the corn and the soybean is influenced by the intercropping through the influence of the water transport capacity of the root system, So as to improve the water use efficiency of the crops. (6) Compared with the average water use efficiency (WUE) of single-cropping soybean and 2 crops, the intercropping of maize and soybean increased the intercropping of WUE, maize and soybean at the ratio of 4:2. Compared with the single cropping system, the intercropping system enlarges the spatial distribution (root length density) of the lateral and longitudinal directions of the root systems of the two crops, changes the morphological characteristics of the root system of the crops, and increases the ecological position of the corn and the soybean root system to absorb water, thereby improving the absorption and utilization of the water by the crops. (7) There was a negative correlation between the root length density and the land equivalence ratio of maize-soybean intercropping. when intercropping with other planting ratios, the corn-soybean produced more roots when intercropping with 2:2, at the expense of the accumulation of the yield in the sacrifice of reproductive growth, This indicates that the main reason for the increase in yield and WUE is that there is a reasonable trade-off between the development of the root system and the formation of the yield between the corn and the soybean.
【学位授予单位】：中国科学院研究生院(教育部水土保持与生态环境研究中心)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S513;S565.1

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