【作者】 黄金辉；

【导师】 廖允成；

【作者基本信息】 西北农林科技大学 ， 生态学， 2009， 硕士

【摘要】 以洛川为代表的黄土高原中南部地区,因其特有的气候条件和土壤资源,适合优质苹果生产,苹果产业已成为当地发展经济、改善生态环境的支柱产业。但目前当地果园的耕作多采用传统的方式,形成裸露的地表,这样不仅使土壤水分大量蒸发而损失,而且土壤肥力逐年下降,同时由于该地区无补灌措施,且果树生长期间耗水量大,极易导致深层土壤的干燥化,土壤水分不足已制约着当地苹果产业的进一步发展。实践证明,将保护性耕作引入黄土高原果园生产中去,通过少耕、免耕及地表覆盖等综合配套措施,能减少农田土壤水分蒸发,保护农田生态环境,获得生态效益、经济效益和社会效益。本研究立足黄土高原果区的资源现状,以最具代表性的苹果园为研究对象,以全年有效抑制果园土壤水分蒸发为目标,系统地对比研究运用免耕、翻耕和旋耕三种耕作方式和生草、覆草、覆膜三种覆盖措施,以及不同耕作和覆盖组合,对黄土高原果园土壤水分、温度、容重和有机质的影响,探索其影响机理;分析单项保护性耕作措施的综合效应,并在此基础上对各种保护性耕作进行整合。主要研究结果如下:(1)黄土高原果园随着树龄的增加,土壤各层的水分含量呈逐步下降趋势。1a、5a、10a、15a、20a果园5m平均土壤干燥化指数依次为:133%(无干燥化)、105%(无干燥化)、99%(轻度干燥化)、78%(轻度干燥化)、66%(中度干燥化)。10a果树是果园发生土壤干燥化的界限。20a果园土壤分水在果树4-10月生育期间均表现出较严重的分水亏缺。(2)在4-10月果树生长期,不同耕作和覆盖1 m土层蓄水量变化总体趋势相一致,均呈“W”形;各处理在不同的果树生长时期保水效果不同。5月份果园土壤水分临界期不同耕作方式1 m土层土壤水分差异极显著,免耕14.28%﹥旋耕14.13%﹥翻耕13.57%,而在9月份土壤蓄水期其差异并不明显;不同覆盖处理中以覆草处理的土壤水分最高(5月为16.47%,9月为19.42%)且与其他处理差异极显著;在所有耕作和覆盖组合中,免耕覆草保水效果最好且比较稳定,黄土高原果园的保护性耕作体系应以免耕覆草为主。(3)生草、覆草、裸地和覆膜5-20 cm各土层昼平均地温覆膜﹥裸地﹥生草﹥覆草;地温昼变幅裸地﹥覆膜﹥生草﹥覆草。7月份各处理之间5-20 cm土层昼平均地温差异和地温变幅都与4月份一致。每个覆盖处理的蓄水量并不是与其地温都成负相关,而是由不同覆盖物的保水效果和保温性质共同决定的。(4)黄土高原果园三种不同耕作方式下,20cm土层容重翻耕、旋耕<免耕;不同覆盖处理之间,生草和覆草处理的土壤容重最小且它们之间差异不显著,裸地的土壤容重最大。果园总孔隙度和毛管孔隙度总体呈现出生草>覆草>覆膜>裸地的变化趋势。不同耕作和覆盖措施下土壤水分与容重有一定的负的线性相关关系,但这种相关性并不显著。(5)不同耕作方式下黄土高原7月土壤表层有机质免耕﹥旋耕﹥翻耕。不同覆盖处理之间覆草﹥生草﹥覆膜﹥裸地且差异极显著。果实膨大期黄高原果园耕层土壤有机质与1m土层平均土壤水分呈极显著相关关系。(6)不同耕作和覆盖措施下土壤容重、温度和有机质对土壤水分的相对重要性按直接通径系数(绝对值)从大到小,依次排列顺序为:有机质(1.0388)>土壤温度(0.5058)>土壤容重(0.2987)。本研究结果既能够有效指导提高黄土高原果园土壤水分利用效率,改善果园土壤干燥化状况,又能实现土壤水分生态环境的有效保护和土壤水分资源持续利用,建立科学合理的保护性耕作体系。将为黄土高原地区的果业的进一步发展,农民的持续增收提供坚实的技术保障。更多还原

【Abstract】 Luochuan which represented in the Loess Plateau in central-southern area, has unique climatic conditions and soil resources, suitable for high-quality apple production. Apple production has become the pillar industries, which development the local economic, and improve ecological environment. However, they also used the traditional farming in orchard production and management, the soil surface is bare, so that not only makes a large number of soil moisture evaporation loss, and an annual decline in soil fertility; There have no irrigation and the fruit trees consume large amount of water during the growth, that’s easily lead to the desiccation of deep soil. Lack water has confined the development of apple industry. Practice has proved that,introduction of conservation tillage in the Loess Plateau orchard production, through less tillage or no-tillage, and mulching, to reduce soil moisture evaporation, protection of agricultural ecological environment, access to eco-efficiency, economic and social benefits .This study based on the resources of the Loess Plateau, study the typical apple orchard, to effectively control the orchard soil moisture evaporation in all year, systematically and comparatively study the effects, which used no-tillage, rotary tillage, plow tillage, sod mulch, straw mulch, film mulch and the combination to soil moisture, soil temperature, bulk density and soil organic matter, and explore the mechanism; Analysis and integrated the combined effect of all individual treatment. The main finding follows:(1)The soil moisture were gradually declining with the apple tree age increase in Loess Plateau Orchards .The average SDI (soil desiccation index) of 1a, 5a, 10a, 15a, 20a in 5m soil layer were as follows: 133% (without desiccation), 105% (without desiccation), 99% (mild desiccation), 78% (mild dry of), 66% (moderate desiccation). After 10 years the orchard will occur desiccation. 20a Orchard showed a serious deficit of water during apple trees growth.(2)During the apple trees growth from April to October, there have the same water storage trend in different tillage and mulching in 1m soil layer, both "W"-shaped; They have different water storage capacity in different growth periods.The difference of different tillage soil moisture was extremely Significant in May in 1m layer, no-tillage 14.28%> rotary tillage 14.13% > plow tillage13.57%; but it was not significant in September; the straw mulch treatment was the higher and extremely significantly soil moisture in all mulching ,was 16.47% in May and 19.42% in September; In all combination of tillage and mulching ,the no tillage- straw mulch have the highest soil moisture and stable, the Loess Plateau orchard conservation tillage system should be based on no tillage- straw mulch.(3)The average soil temperature at day in 5cm to 20cm soil layer were that film mulch﹥bare﹥sod mulch﹥straw mulch; The temperature difference at day were that bare﹥film mulch﹥sod mulch﹥straw mulch . It’s similar which average soil temperatures and temperature difference at day between April and July in 5-20cm soil layers in all treatments.It’s not negatively correlated between soil temperature and water storage capacity in all mulch, the soil moisture which in different mulch is the comprehensive results, which effect on soil temperature change, soil moisture hold or consume with mulch.(4)The surface soil bulk density in Loess Plateau Orchard was: plow tillage and rotary tillage<no-tillage; The treatment sod mulch and straw mulch were smaller than bare, and no significant difference between them, the bare was the largest. The total porosity and capillary porosity born general showing the trend that sod mulch > straw mulch> film mulch > bare. The soil moisture and soil bulk density have a negative correlation in different tillage and mulching, but this correlation is not significant.(5)The surface soil organic matter in different tillage in July was that no-tillage﹥rotary tillage﹥plow tillage; the surface soil organic matter in different mulching in July was that straw mulch﹥sod mulch﹥film mulch > bare, and the difference was extremely significant. It was a significant correlation between surface soil organic matter and 1m layer soil moisture in July.(6)The arrangement, which the relative importance of soil bulk density, temperature and organic matter for soil moisture in different tillage and mulching, by the direct path coefficient (absolute value) was that organic matter(1.0388)>soil temperature(0.5058)>soil bulk density(0.2987).The results of this study is able to effectively improve the Loess Plateau water use, Improve the situation of soil desiccation,Effective protect the ecological environment of soil moisture, Used the soil water resources sustainably and establishment scientific and rational system of conservation tillage. It will provide a solid technical support for fruit industry development in Loess Plateau region and farmers income increase.更多还原