【作者】 云雷；

【导师】 朱清科； 毕华兴；

【作者基本信息】 北京林业大学 ， 复合农林学， 2011， 博士

【摘要】 农林复合经营作为解决水土流失、恢复生态平衡、提高土地利用率和增加经济效益的最有效的措施和途径之一,在黄土区被广泛的应用。但农林复合系统内部存在着一定程度的种间竞争,对农林复合系统种间关系的研究有助于更深层次地理解生态系统结构和功能的稳定性,探索资源合理和高效的利用方式,为经营种间关系协调的高产、高效和稳定的农林复合系统提供理论依据。为了提出黄土高原区适宜的间作模式和经营管理措施,本文以黄土高原地区典型果农间作系统为研究对象,针对间作系统地下部分土壤水分、土壤养分、果树根系,地上部分光合有效辐射、净光合速率以及产量和经济收入进行研究,分析研究树木与农作物种群界面中土壤水分、土壤养分和光分布特征,旨在使树木和农作物之间的资源竞争最小化,资源利用最大化,为该地区农林复合系统调控和管理技术的研究提供重要的基础理论依据和决策依据。研究结果表明：(1)果农间作系统土壤水分分布特征：时间上,果农间作系统土壤水分在不同物候期变化极为显著。空间上,在垂直方向上,核桃间作和苹果间作土壤含水量变化规律存在差异,但土壤水分的变异系数随着土壤深度的增加而减小,且为中等变异程度；在水平方向上,土壤含水量变化与离果树行的距离有关,均是离树行越近,土壤含水量越少。苹果间作土壤含水量明显小于相应的核桃间作土壤含水量,且其二维分布明显要比核桃间作复杂很多。根据移动窗口法,判定3种核桃间作模式的土壤水分影响域,其0～20cm和20～40cm土壤水分的边界影响域宽度在4.0m～5.5m。(2)果农间作系统土壤养分分布特征：在垂直方向上,土壤养分随土层深度的增加而减少,并且距果树行越远,土壤养分的垂直变化梯度越小；在水平方向上,在果树区内,离果树行越近,土壤养分越少、在农作物区,离果树行越远,土壤养分越大,养分水平变化越小。在典型物候期,观测范围内果树和农作物存在养分竞争。(3)果农间作系统果树根系分布特征：在所研究范围内,不同径级根生物量分布规律基本一致。作为土壤水分、养分吸收和传输作用的细根,核桃和苹果细根垂直方向集中在0～40cm和0～60cm的土层,分别占细根总量的68.51%和94.39%；水平方向集中在离树0.5～1.5m范围内和0～1.5m范围内,分别占细根总量的56.15%和83.85%。根系消弱系数反映出的根系分布特点与根系的实际分布情况相符,可以作为描述果树根系垂直变化的参数。(4)果农间作系统光照空间分布特征：核桃间作的遮荫区域多取决于单株核桃树遮荫区的累加,群体遮荫时间段相对较少,遮荫程度相对较轻；苹果间作光照分布较为复杂,其受到多重遮荫影响,地面受光相对有限,遮荫程度相对较重。受到果树的影响,农作物的光合有效辐射、净光合速率均出现不同程度的降低,并且离树行越近,影响越大。(5)果农间作系统土壤水分效应和养分效应均表现为核桃×花生>核桃×大豆>苹果×花生>苹果×大豆：当土壤层次取0～40cm时,其土壤水分效应依次为-5.33%、-5.66%、-10.54%和-12.81%,土壤养分效应依次是-8.68%、-15.00%、-21.77%和-22.12%；当土壤层次取0～100cm时,其土壤水分效应依次为-4.08%、-5.25%、-11.20%和-16.83%,土壤养分效应依次是-10.19%、-16.85%、-23.40%和-25.69%。果农间作系统光效应表现为核桃×花生>核桃×大豆>苹果×大豆>苹果×花生,其光效应依次为-16.62%、-18.12%、-21.89%和-26.39%。从土地利用效率和经济效益来看,核桃×花生、核桃×大豆、苹果×花生和苹果×大豆间作模式可以作为该区的主要果农间作模式,推荐模式土地利用效率平均提高约70%,经济效益平均提高约14%,适合该地区实践推广的。更多还原

【Abstract】 Agroforestry management is widely applied in China Loess Plateau as one of effective measures to reduce soil and water loss, restore ecological balance, raise land utilization rate and increase economic benefits. However, interspecific competition exists in agroforestry system to some extent, the sduty on the relationship among different species in agroforestry system could contribute to intensively understanding the stability of ecosystem structure and function, explore reasonable and efficient utilization ways of resource, provide theoretical basis for managing agroforestry system with high-yield, high-efficiency and stabilization. In order to find suitable intercropping models and management in Loess Plateau, typical economic tree and crop intercropping models in loess region of western Shanxi Province were selected as research objects to study the underground for soil moisture, soil nutrient and walnut roots, the aboveground for photosynthetic active radiation and net photosynthetic rate, yield and economic benefit, and soil moisture, soil nutrient and light distribution at tree-crop interface were analyzed. The objectives of the paper are:1) to minimize the competition between trees and crops and maximize resource utilization,2) to provide a theoretical basis for the agroforestry control and management in this region. The results showed that:(1) Soil moisture distribution in economic tree and crop intercropping system showed that:In temporal, the soil moisture variation of economic tree and crop intercropping was very significant in different phonological phases; In spatial, the variation of soil moisture was different between walnut-crop intercropping and apple-crop intercropping in vertical direction. However, the variation coefficient of soil moisture decreased with soil depth, and soil moisture in the system of walnut-crop intercropping and apple-crop intercropping belonged to intermediate variability; In horizontal direction, soil moisture was related to distance from tree row. The closer to trees sampling points, the lower the soil moistures. The soil moisture in applet-crop intercropping was much less than that in walnut-crop intercropping, and two-dimension isogram of soil moisture content in applet-crop intercropping was more complicated than that in walnut-crop intercropping. By using moving split-window techniques, the distance of edge influence of compound boundary to soil moisture content at soil depth of 0-20 cm and 20-60 cm were [4.0 m,5.5 m] in walnut-crop intercropping.(2) Soil nutrient distribution in economic tree and crop intercropping system showed that:In vertical direction, soil nutrient decreased with increasing soil depth, and vertical decrease gradient of soil nutrient decreased with the increase of the distance from the tree row. In horizontal direction, soil nutrient decreased with the decrease of the distance from the tree row in economic tree area. Soil nutrient increased and its horizontal variation decreased with the increase of the distance from the tree row in crop area. It showed soil nutritent competition between crops and trees of observation range in typical phonological phase.(3) Economic tree roots distribution in economic tree and crop intercropping system showed that: Roots biomass distributions of different diameters were consistent in research ranges. As the main organ of absorption of soil moisture and nutrient, fine roots of walnut trees and apple trees concentrated within the depth of 0-40 cm and 0-60 cm in vertical direction, which accounted for 68.51% and 94.39% of total fine roots biomass respectively. In horizontal direction, fine roots concentrated at [0.5 m,1.5 m] and [0 m,1.5 m] distance from the trees, which accounted for 56.15% and 83.85% of total biomass of fine roots respectively. The root extinction coefficient could be used as a parameter revealing the vertical distribution characteristics of economic tree roots.(4) Light distribution in economic tree and crop intercropping system showed that:The shading areas more depended on accumulation of shading area of per walnut tree in walnut-crop intercropping, and time quantum of canopy shading was relative short. Therefore, shading degree was relative slighter. The light distribution was relative more complicated in apple-crop intercropping, which was influnenced by multiple shading, there was less light on the ground. Therefore, shading degree was relative stronger. The crops were influenced by trees, the photosynthetic active radiation and net photosynthetic rate of crops were significantly decreased by trees, and the decreasing degree is decreased with the increasing of distance from tree rows.(5) The values of EM in economic tree and crop intercropping system were -5.33%,-5.66%, -10.54%, and -12.81% for walnut-peanut, walnut-soybean, apple-peanut and apple-soybean in layer of 0-40 cm respectively, while that were -4.08%,-5.25%,-11.20%, and -16.83% in layer of 0-100 cm respectively, and the values of EN in intercropping with crops were -8.68%,-15.00%,-10.54%, and-12.81% for walnut-peanut, walnut-soybean, apple-peanut and apple-soybean in layer of 0-40 cm respectively, while that were -10.19%,-16.85%,-23.40%, and -25.69% in layer of 0-100 cm respectively. The values of EM in economic tree and crop intercropping were -16.62%,-18.12%,-21.89%, and -26.39% for walnut-peanut, walnut-soybean, apple-soybean and apple-peanut respectively. According to land use efficiency and economic benefits, walnut-peanut, walnut-soybean, apple-peanut, and apple-soybean intercropping models could be used as the main models of economic tree and crop intercropping, and they should be extended in the Loess Plateau. The average value of land use efficiency increased by 70%, and the average economic benefits increased by 14%.更多还原