生草对渭北苹果园土壤微生物量碳、氮的影响

摘 要

果园生草栽培是欧美等国家普遍采用的果园可持续发展的土壤管理模式，我国于1988年将果园生草栽培作为绿色果品生产主要技术措施在全国推广。有关果园生草栽培方面的研究主要集中在生草对果园土壤理化性质的影响、生草微气候效应、以及生草对果树产量与果实品质影响等效益方面，基本上是针对果园生草现状及互作效果进行评价，而对产生互作效应机制方面的研究则鲜有报道。本研究以本研究以渭北苹果园生草为对象，通过田间试验和室内分析相结合，研究了不同生草处理对渭北苹果园土壤微生物量碳、土壤微生物量氮等一系列表征土壤肥力特征指标的影响。探讨了微生物量碳、氮对生草栽培的响应及其反馈作用，为进一步探讨果园生草复合系统组分间的互作机制提供了理论依据，主要研究结果如下：

1、生草明显改善了苹果园土壤结构，有效降低了土壤0~40 cm土层的土壤容重。生草提高了土壤表层养分的含量，土壤全氮和有机碳含量显著增加。土壤有机碳含量较清耕增幅为13.4%~68.6%。土壤全氮含量较清耕增幅为10.4%~43.4%。不同生长季节总体趋势表现为夏季>秋季>春季，在垂直分布上，各处理间表现为表层（0~5 cm）土壤有机碳和全氮含量最高，随土层加深逐渐降低。

2、生草有效地提高了土壤过氧化氢酶、土壤脲酶、土壤蔗糖酶及土壤纤维素酶的活性，以白三叶和百脉根处理效果最好，土壤酶活性随季节变化表现为先提高后降低的变化趋势对，夏季达到最高，土壤酶活性随着土层增加呈现逐渐降低的规律。

3、果园生草显著增加土壤微生物量碳、氮含量和微生物碳熵及氮熵，提高微生物对有机碳和全氮的利用效率。各土层不同处理在各季节表现为夏季>秋季>春季，不同土层分布表现为随土层深度的增加而降低。在表层0~5cm，白三叶处理的土壤微生物量碳含量最高，在春、夏、秋三个季节其含量分别较对照提高175.2%，144.9%，175.4%。微生物碳熵分布在各土层变化各异，整体以白三叶、百脉根和鸡脚草提高效果最为明显。土壤微生物量氮含量在0~20 cm土层的3个季节中均以白三叶处理最高，春、夏、秋三个季节平均较清耕分别提高62.4%，、65.3%和72.6%。微生物氮熵在各土层各季节分布规律不明显，主要以白三叶和百脉根最高。各季节生草处理的微生物量碳氮比尤以表层（0~5 cm）最大，0~40cm土层的微生物量碳氮比垂直变化规律总体也表现为随着土层加深呈现递减的趋势。

4、相关分析表明，土壤微生物量碳与土壤微生物量氮极显著相关，且均与土壤有

机碳、全氮，蔗糖酶、脲酶和纤维素酶极显著相关，与过氧化氢酶不相关。通径分析表明有机碳、全氮和纤维素酶是影响土壤微生物量碳的重要因子，而全氮和脲酶是影响土壤微生物量氮的重要因子。

关键词：果园生草；土壤微生物量碳；土壤微生物量氮；土壤酶活性

THE EFFECTS OF INTERPLANTING HERBAGE ON SOIL MICROBIAL BIOMASS CARBON AND NITROGEN IN WEIBEI

APPLE ORCHARD

ABSTRACT

Weibei Loess Plateau is one of the high quality apple producing areas in China the world. Interplanting herbages is a soil management mode commonly employed for orchard development in developed countries. It has been promoted as a measure of green fruit producing in China since 1988. Current research on intercropping herbages in orchard mainly focus on the effects of growing herbage on fruit yield, fruit quality, microclimate, and soil environment, while little work was done on the mechanisms. Intercropping herbages in apple orchard in Weibei Area was studied. Through field experiments and laboratory analysis, soil microbial biomass carbon (SMBC), soil microbial biomass nitrogen (SMBN) were analyzed, and responses of them to intercropping herbages were discussed. This research provided a scientific basis for studying the interaction mechanisms between fruit trees and herbages in the fruit orchard-growing herbage complex system. The main results showed that:

1．Interplanting herbages significantly improved the soil structure in apple orchards, effectively reducing the soil of soil bulk density in 0~40cm. Interplanting erbage improved the nutrient content of topsoil, and significantly increased the content of soil organic carbon and total nitrogen. Compared with clear tillage, the content of soil organic carbon and total nitrogen in interplanting herbages could improve by 13.4%~68.6% and 10.4%~43.4%. In different growing seasons, the overall trend showed summer>autumn>spring, in the vertical distribution among treatments, the content of soil organic carbon and total nitrogen was highest in topsoil (0~5cm), which was decreased with depth.

2．Interplanting herbages effectively improved the soil enzyme activity of catalase, urease, sucrose and cellulose. Interplanting Trifolium repens L. and Lotuscorniculatus L. were better than other treatments. With the season change, the trends of soil enzyme activity showed that it decreased at first and increased at last, and it reached maximum in summer. The activity of soil enzyme was decreased with soil depth.

3．Interplanting herbages significantly increased the content of soil microbial biomass carbon (SMBC) and nitrogen (SMBN), ratio of SMBC to soil organic carbon (qSMBC), ratio

of SMBN to soil total nitrogen (qSMBN). It improved the utilization efficiency of soil organic carbon and total nitrogen for microbe. In different seasons, the overall trend showed summer>autumn>spring. The contents of them were decreased with soil depth. In the topsoil of 0~5cm, the content of soil microbial biomass carbon in the interplanting Trifolium repens L. treatment was highest among of all treatments. In spring, summer and autumn, its contents were increased by 175.2 percent, 144.9 percent and 175.4 percent. The distributions of qSMBC was different in different treatment. The most obvious effect arose in interplanting Trifolium repens L. and Lotuscorniculatus L.and Dactylis glomerata L. treatmens. In the topsoil of 0~20cm, the content of soil microbial biomass nitrogen in the interplanting Trifolium repens L. treatment was highest among of all treatments. In spring, summer and autumn, compared with clear tillage, its contents were increased by 62.4 percent, 65.3 percent and 72.6 percent.Like the qSMBC, the distributions law of qSMBN was not obvious in different treatment. Interplanting Trifolium repens L. and Lotuscorniculatus L. were higher than other treatments. In the topsoil (0~5cm), the ratio of soil microbial biomass carbon to soil microbial biomass nitrogen were the highest in the all treatments. In the 0~40cm soil layer, the ratio of soil microbial biomass carbon to soil microbial biomass nitrogen were decreased with soil depth.

4．Correlation analysis showed that soil microbial biomass carbon had significant correlation extremely with soil microbial nitrogen, and it had significant correlations with soil organic carbon, total nitrogen, sucrase, urease and cellulase, but it had no significant correlation with soil catalase. Path analysis indicated that soil organic carbon, total nitrogen and cellulase were the important factors that affected the soil microbial biomass carbon, and soil total nitrogen and urease were the important factors that affected the microbial biomass nitrogen.

KEY WORDS: Interplanting herbage in apple orchard; Soil microbial biomass carbon, Soil

microbial biomass nitrogen; Soil enzyme activity

目 录

第一章 文献综述 ................................................................................................................................. 10 1.1背景与目的意义 ......................................................................................................................... 10 1.1.1 研究背景 ............................................................................................................................. 10 1.1.2 研究目的意义 ..................................................................................................................... 10 1.2国内外研究进展 ......................................................................................................................... 11 1.2.1 果园生草对土壤理化性质的影响 ..................................................................................... 11 1.2.2 果园生草对土壤酶活性的影响 ......................................................................................... 12 1.2.3 果园生草对土壤微生物量碳的影响 ................................................................................. 13 1.2.4 果园生草对土壤微生物量氮的影响 ................................................................................. 15 第二章 研究内容与方法 ..................................................................................................................... 17 2.1试验区概况 ................................................................................................................................. 17 2.2试验设计 ..................................................................................................................................... 17 2.3 样品的采集与分析 .................................................................................................................... 17 2.4 研究内容 .................................................................................................................................... 18 2.4.1生草对果园土壤理化性质和土壤酶活性的影响 .............................................................. 18 2.4.2生草对果园土壤微生物量碳、土壤微生物量氮的影响 .................................................. 18 2.4.3土壤微生物量碳、氮与土壤养分和土壤酶活性之间的关系 .......................................... 18 2.5 技术路线 .................................................................................................................................... 19 第三章 生草对苹果园土壤理化性质和酶活性的影响 ..................................................................... 20 3.1 生草对土壤理化性质的影响 .................................................................................................... 20 3.1.1 生草对土壤容重的影响 ..................................................................................................... 20 3.1.2 生草对土壤有机碳的影响 ................................................................................................. 21 3.1.3 生草对土壤全氮的影响 ..................................................................................................... 22 3.2 生草对土壤酶活性的影响 ........................................................................................................ 23 3.2.1 生草对土壤过氧化氢酶的影响 ......................................................................................... 24 3.2.2 生草对土壤蔗糖酶的影响 ................................................................................................. 25 3.2.3 生草对土壤脲酶的影响 ..................................................................................................... 26 3.2.4 生草对土壤纤维素酶的影响 ............................................................................................. 27 3.3 讨论 ............................................................................................................................................ 29