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首页> 外文学位 >Evaluating the impact of Gliricidia sepium on soil organic matter in maize-based cropping systems in southern Malawi.
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Evaluating the impact of Gliricidia sepium on soil organic matter in maize-based cropping systems in southern Malawi.

机译：在南部马拉维以玉米为基础的种植系统中，评估君子兰对土壤有机质的影响。

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摘要

There is considerable interest in soil organic matter technologies and fertility sources in intensified maize-based cropping systems in Southern Africa. This study investigated the effect of the Gliricidia sepium (Jacq.) Walp and maize intercrop on soil organic matter (SOM) fractions and soil fertility indices in southern Malawi. Part 1 investigated the response of SOM fractions to the intercrop, inorganic nitrogen (N), and phosphorus (P) on a long-term trial established in 1991 on a Ferric Lixisol in southern Malawi. Soil was sampled to a 20 cm depth in July of 2006. SOM, available P, exchangeable K+, and CEC were determined on whole soil samples. Particulate organic matter (POM) was separated from the soil by size and density fractionation and analyzed for C and N. The intercrop had a positive effect on all SOM fractions. With the intercrop, POM was increased by 37%, carbon in POM by 60% and nitrogen in POM by 78% compared to sole maize. C/N ratio of POM decreased from 17.9 with sole maize to 15.5 with the intercrop. After 14 years, predictors of soil fertility and SOM fractions were significantly greater under the intercrop than under sole maize. In part 2, an on-farm study in the same district described characteristics of intercrop users and their placement of the intercrop on different soils. Thirty-seven households using the intercrop and 28 households not using the intercrop were interviewed in June and July of 2006. Questionnaires were completed with each household concerning demographic statistics and the soil types found and cropping systems used in their fields. In female-headed households use of the intercrop was 66% compared to 49% in households headed by males. Intercrop use was 50% among households in the lower half of the socioeconomic scale and 63 % in the upper halt. Households using the intercrop had an average of 0.4 hectares of land, while those not using the intercrop had an average of 0.83 hectares. Placement of the gliricidia/maize intercrop on sandy M'chenga soils was less common than on Katondo and Makande soils. In part 3, the SOM and soil nutrient effects of the intercrop were compared to prevailing soil management practices in smallholder's fields. Soil samples were taken from the 2005/6 planting rows from the fields with and without the gliricidia intercrop. Soil samples were analyzed for SOM, sand content, available P, exchangeable K + and CEC. Soil organic matter values associated with the intercrop were not significantly different from those for other cropping systems. When the gliricidia/maize intercrop fields were analyzed separately, soil type, elevation, and their interaction affected trends in soil organic matter. A positive relationship between soil organic matter and elevation was evident in the two finer-textured soil types, Makande and Katondo. The addition of pigeonpea, Cajanus cajan (L.), to the maize cropping system at elevations below 877 meters was associated with an increasing trend in SOM compared to the sole maize cropping system. The emergence of increasing trends in SOM correlated with increasing elevation and fineness of soil texture in fields with the gliricidia/maize intercrop may indicate that a SOM benefit will develop over time in fields at relatively higher elevations with finer soil textures.
机译：在南部非洲，以玉米为基础的集约化耕作系统对土壤有机质技术和肥力来源有相当大的兴趣。这项研究调查了 Gliricidia sepium （Jacq。）Walp和玉米间作对马拉维南部土壤有机质（SOM）组分和土壤肥力指数的影响。第一部分研究了1991年在马拉维南部的Lixisol铁上进行的一项长期试验，研究了SOM馏分对间作，无机氮和磷的响应。在2006年7月对土壤取样到20厘米深度。对整个土壤样品进行了SOM，有效磷，可交换K + 和CEC的测定。通过大小和密度分级从土壤中分离出颗粒有机物（POM），并分析其C和N。间作对所有SOM组分均具有积极作用。与单独的玉米相比，通过间作，POM增加了37％，POM中的碳增加了60％，POM中的氮增加了78％。 POM的C / N比从单一玉米的17.9降至间作的15.5。 14年后，间作下的土壤肥力和SOM分数的预测值明显高于单独玉米下的。在第2部分中，同一地区的农场研究描述了间作作物使用者的特征及其在不同土壤上的间作作物位置。 2006年6月和2006年7月，对37个使用间作作物的农户和28个不使用间作作物的农户进行了访谈。对每个住户进行了问卷调查，涉及人口统计数据，发现的土壤类型和田间使用的耕作制度。在以女性为户主的家庭中，间作套种的使用率为66％，而以男性为户主的家庭为49％。在社会经济规模的下半部分家庭中，间作作物的使用率为50％，在上半部分为63％。使用间作作物的家庭平均土地面积为0.4公顷，而不使用间作作物的家庭平均土地面积为0.83公顷。麦地那沙质土壤上的 gliricidia /玉米间作的放置比在Katondo和Makande土壤上的放置少。在第3部分中，将间作的SOM和土壤养分效应与小农户田间的现行土壤管理实践进行了比较。土壤样品取自2005/6种植有和没有草皮的田间种植行。分析土壤样品的SOM，含沙量，有效磷，可交换的K + 和CEC。间作相关的土壤有机质值与其他种植系统的有机质值没有显着差异。分别对麦草/玉米间作田进行分析时，土壤类型，海拔及其相互作用影响土壤有机质的趋势。在两种质地较细的土壤中，Makade和Katondo，土壤有机质与海拔之间呈正相关。与单独的玉米种植系统相比，在877米以下海拔高度的玉米种植系统中添加木豆 Cajanus cajan （L.）与SOM的增加趋势有关。 SOM增加趋势的出现与 gliricidia /玉米间作的田间土壤质地的高度和细度的增加有关，这可能表明随着时间的推移，在土壤相对较细的较高海拔的田间，SOM效益将逐渐提高。纹理。

著录项

  • 作者

    Beedy, Tracy L.;

  • 作者单位

    Michigan State University.;

  • 授予单位 Michigan State University.;
  • 学科 Agriculture Agronomy.;Agriculture Soil Science.
  • 学位 Ph.D.
  • 年度 2009
  • 页码 125 p.
  • 总页数 125
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类
  • 关键词

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