耕作方式对黑土理化性状季节变化的影响

发布时间：2018-04-25 19:02

本文选题：保护性耕作 + 传统耕作　；参考：《中国科学院研究生院(东北地理与农业生态研究所)》2016年博士论文

【摘要】：以少免耕为代表的保护性耕作被国内外证明是有利于土壤可持续利用的有效措施,在全球得以广泛推广应用。近年来,东北黑土区保护性耕作对土壤性状影响研究已有很多,但对土壤理化性状季节动态变化报道较少。本论文利用典型黑土区保护性耕作长期定位实验,选取平地(8年)和坡耕地(坡度为5°,5年)2种土地利用方式,系统的研究免耕、少耕和传统耕作土壤理化性状季节变化,同时比较3种耕作方式之间差异性。主要研究的结果如下:平地与坡耕地土壤容重结果均表明,在0-10 cm与10-20 cm深度,免耕土壤容重季节变化小,垄台与垄沟差异也较小;少耕雨季前深松处理,6月垄沟土壤容重显著低于其他月份;传统耕作垄台土壤容重随时间推移呈现增加的趋势,而垄沟容重季节变化小。免耕垄台土壤容重高于传统耕作,少耕垄台土壤容重介于免耕与传统耕作之间;对于垄沟土壤容重,少耕6月容重显著低于其他耕作方式,而其他月份差异均不显著。随着深度增加,各耕作方式土壤容重逐渐增加,且平地免耕土壤容重低于坡耕地。在0-20 cm深度,土壤含水量主要由降雨量大小决定。与少耕和传统耕作相比,免耕无论是平地还是坡耕地均能够维持较高的垄台和垄沟土壤含水量,尤其在降雨较少的情况下。各耕作方式2-10 mm与0.5-1 mm粒级团聚体存在较为明显季节变化,而其他粒级团聚体季节差异小。在0-40 cm土层,免耕土壤团聚体季节变化差异较大,8月2-10 mm粒级团聚体含量和平均重量直径(MWD)高于其他月份;少耕和传统耕作的2-10 mm粒级团聚体含量及MWD呈现降低趋势。各耕作方式0.25mm团聚体含量随着时间推移呈现降低趋势,但免耕0.25mm团聚体含量与MWD高于少耕、传统耕作,表明免耕土壤团聚度高,稳定性强。在平地与坡耕地,免耕垄台与垄沟8月土壤初始入渗速率高于其他月份,少耕垄台入渗速率逐渐降低,而6月垄沟初始土壤入渗速率最高;传统耕作初始入渗速率逐渐降低。免耕与传统耕作垄台与垄沟土壤稳定入渗速率则逐渐降低,而少耕垄沟6月土壤稳定入渗速率高于其他月份。3种耕作方式在5月差异小,少耕在6月的土壤初始和稳定入渗速率高于免耕与传统耕作,而随着时间推移,免耕土壤渗透特性优于其他耕作。土壤有机碳季节变化与全氮含量相似。在0-20cm深度,免耕8月土壤有机碳和全氮含量最高,少耕与传统耕作土壤有机碳和全氮随着时间推移逐渐降低。在0-100cm深度,3种耕作方式土壤有机碳及全氮季节变化无显著差异性。传统耕作在0-20cm土层土壤有机碳和全氮含量低于少耕与免耕。在40-100cm深度,各耕作方式有机碳差异较小。随着深度增加,土壤有机碳和全氮含量呈现降低趋势,且免耕在平地0-20cm土层平均土壤有机碳和全氮含量高于坡耕地。在20-100cm土层,各测定深度平地与坡耕地土壤全氮含量差异均较小。在0-20cm土层,各耕作方式土壤铵态氮与全磷含量季节变化表现为先增加后降低,6月的土壤铵态氮和全磷含量最高。耕作方式之间比较发现,在0-15cm,平地免耕和少耕土壤铵态氮含量高于传统耕作,而坡耕地免耕在0-5cm土层铵态氮含量低于传统耕作。传统耕作土壤全磷含量在0-10cm深度高于免耕,但差异未达到显著。平地和坡耕地之间比较,平地免耕和少耕表层0-10cm土壤铵态氮含量略高于坡耕地,而平地传统耕作则略低于坡耕地;在10-20cm土层,免耕在平地与坡耕地差异较小,而少耕和传统耕作土壤铵态氮含量则低于坡耕地。各耕作方式平地土壤全磷含量高于坡耕地。坡耕地水土流失监测结果表明,免耕在作物生育期基本未产生较大的地表径流及输沙过程,而少耕及传统耕作在降雨量最高的7月,其径流及输沙次数、径流量与侵蚀模数均高于其他月份。免耕地表产流次数及输沙次数小于少耕和传统耕作,其土壤总径流量和土壤侵蚀模数也远低于少耕和传统耕作,说明三种耕作方式免耕水土保持效果最好。综上述结果表明,不同耕作黑土土壤理化性状季节变化多集中在0-20cm土壤表层。免耕在作物生育期内维持良好的土壤结构和渗透特性,维持较高含水量及有机碳和全氮含量,生育期水土流失量少;少耕雨季前深松,有效改善垄沟土壤结构,降低土壤侵蚀几率,而传统耕作土壤结构、渗透特性、有机碳及养分等均随时间推移降低趋势。在0-20 cm土层,相比较少耕与传统耕作,免耕能够维持稳定的土壤结构,提高团聚体稳定性及土壤有机碳、全氮、土壤养分含量,且在坡耕地由良好的水土保持效果;少耕雨季前垄沟深松处理,提高大孔隙含量,增加垄沟土壤入渗速率,少耕在作物生育期径流量与侵蚀量低于传统耕作,但仍显著高于免耕,并未显示出很好的水土保持效果。因此,在东北黑土区推广免耕为代表的保护性耕作具有重要意义,尤其在坡耕地。
[Abstract]:Conservation tillage, represented by less and less no tillage, has been proved to be an effective measure for the sustainable utilization of soil at home and abroad, and widely popularized in the world. In recent years, many studies have been made on the effects of conservation tillage on soil properties in northeastern black soil area, but few reports on seasonal dynamic changes of soil physical and chemical properties. The long-term location experiment of conservation tillage in soil area was carried out, and 2 kinds of land use methods were selected for flat land (8 years) and slope farmland (5 degrees, 5 years). The seasonal changes of soil physical and chemical properties were systematically studied, and the differences between the 3 tillage methods were compared. The main results were as follows: the results of soil bulk density in flat land and slope land were both results. The results showed that in the depth of 0-10 cm and 10-20 cm, the seasonal variation of bulk density in no tillage soil was small, and the difference between ridge and ridge was smaller. The soil bulk density of the ridge and furrow soil in June was significantly lower than that of other months, and the soil bulk density of traditional tillage ridges increased with time, while the bulk density in the ridge and furrow was small. Compared with traditional tillage, the soil bulk density of the ridge platform was between no tillage and traditional tillage. In the furrow soil bulk density, the bulk density in June was significantly lower than that in other tillage methods, but the other months were not significant. With the depth increasing, the soil bulk density increased gradually, and the soil bulk density of no tillage soil was lower than that in the sloping field. In the 0-20 cm depth, the soil bulk density was lower than that in the slope. Degree, the soil water content is determined mainly by the size of the rainfall. Compared with the low tillage and traditional tillage, no tillage can maintain high ridge and furrow soil water content in both flat and sloping fields, especially in the case of less rainfall. 2-10 mm and 0.5-1 mm particle clusters have obvious seasonal changes, and other grains. In the 0-40 cm soil layer, no tillage soil aggregates vary greatly in season, and the content of aggregate and the average weight diameter (MWD) of 2-10 mm in August are higher than those of other months, and the content of 2-10 mm grain aggregate and MWD in less tillage and traditional tillage are lower in August. There was a decreasing trend, but no tillage 0.25mm aggregate content and MWD were higher than less tillage. Traditional tillage showed that no tillage soil had high agglomeration degree and strong stability. In plain and slope farmland, the initial infiltration rate of soil initial infiltration rate in August of no tillage ridge platform and ridge furrow was higher than that of other months, and the infiltration rate of little tillage ridge platform decreased gradually, but the initial infiltration rate of ridge and furrow in June was the highest. The initial infiltration rate of the traditional tillage decreased gradually. The soil stable infiltration rate of no tillage and traditional tillage ridge and ridge was gradually reduced, while the soil stable infiltration rate in June was higher than that of the other months of.3 cultivation in May, and the initial and stable infiltration rate of soil in June was higher than that of no tillage and traditional tillage in June, but the soil initial and stable infiltration rate of less tillage in June was higher than that of no tillage and traditional tillage. Soil organic carbon (organic carbon) and total nitrogen (organic carbon) and total nitrogen (organic carbon) and total nitrogen (organic carbon) and total nitrogen (organic carbon) and total nitrogen (organic carbon and total nitrogen) decreased gradually at 0-20cm depth in August. At 0-100cm depth, soil organic carbon and total soil organic carbon and total soil organic carbon and total soil carbon and total nitrogen in the soil were 3. There was no significant difference in the seasonal variation of nitrogen. The organic carbon and total nitrogen content of soil in the 0-20cm soil layer was lower than that of no tillage and no tillage in the soil layer. The organic carbon and total nitrogen content of the soil decreased with the depth of 40-100cm, and the average soil organic carbon and total nitrogen content in the flat soil layer of 0-20cm soil was decreased with the depth increasing. In the 20-100cm soil layer, the total nitrogen content of soil nitrogen and total phosphorus in the soil on the 0-20cm soil layer was first increased and then decreased, and the content of ammonium nitrogen and total phosphorus in the soil in June was the highest. The ammonium nitrogen content of cultivated land and less tillage soil was higher than that of traditional tillage, while the content of ammonium nitrogen in the soil layer of 0-5cm soil was lower than that of traditional tillage. The soil total phosphorus content in the traditional tillage was higher than that of no tillage at 0-10cm depth, but the difference was not significant. The content of ammonium nitrogen in 0-10cm soil in flat ground and sloping farmland was slightly higher than that between slope land and sloping land. Cultivated land, while conventional tillage was slightly lower than slope farmland; in the 10-20cm soil layer, no tillage had a small difference between flat land and sloping land, while the content of ammonium nitrogen in the soil of small tillage and traditional tillage was lower than that in the sloping field. In July with the highest rainfall, the runoff and sediment transport times, runoff and erosion modulus were higher than those of other months. The number of runoff and sediment transport times of no tillage and the number of sediment transport were less than that of less tillage and traditional tillage, and the total soil runoff and soil erosion modulus were much lower than that of less tillage and transmission. The above results showed that the seasonal changes of soil physical and chemical properties of different tillage soils were mostly concentrated on the surface of 0-20cm soil. No tillage maintained good soil structure and permeability in the growth period of crops, maintained high water content and organic carbon and total nitrogen content, and the growth period water in the growth period of the three tillage black soil. The soil loss was less; the soil structure of furrow soil was improved and the soil erosion probability was reduced effectively. The traditional tillage soil structure, permeability, organic carbon and nutrients were reduced with time. In the 0-20 cm soil layer, less tillage and traditional tillage could maintain stable soil structure and increase the stability of aggregate. The soil organic carbon, total nitrogen, soil nutrient content and good soil and water conservation effect on sloping land, the ridge and furrow deep loosening treatment before the rainy season, increase the macropore content, increase the infiltration rate of the ridge furrow soil, and reduce the runoff and erosion in the growth period of the crop less than the traditional tillage, but still significantly higher than the no tillage, and do not show good soil and water soil. Therefore, it is important to popularize conservation tillage in the black soil region of Northeast China, especially in sloping fields.

【学位授予单位】：中国科学院研究生院(东北地理与农业生态研究所)
【学位级别】：博士
【学位授予年份】：2016
【分类号】：S34;S151.9

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