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|作者:||Hsiang, Yang Chi|
The transformations of organic materials in soil environment greatly affect physical, chemical, and biological of soils. The aim of this study was to investigate the changes of some selected physical and chemical properties of the soils of a field plots after 3 to 5years of paddy-upland crop rotations with various fertilizations. The applications of the organic materials were easily decomposable green manure, compost of decomposable agriculture waste, and peat of resistant decomposition. Other than the applications of various organic materials to the plots of experimental field, the amounts of 1/3 and 2/3 of chemical fertilizer N were complemented. Spring rice and autumn corn were rotated to plant in the field. After the harvests of rice in July 1998, of corn in January of 1999 and 2000, and of rice in July 2000, the surface soils were collected from the four replicated plots of the field. The soil samples were subjected to the measurements of pH and electrical conductivity (EC) values, and the determinations of water content at 1/30 MPa, bulk density, and contents of organic C and water-stable aggregate of soils with particle-size of 2-1 and 1-0.5 mm. The results showed that the applications of organic materials to the plot soils prevented soils from the decrease of pH value, and increased the amounts of soluble salts to provide plant nutrients. The applications of organic materials increased organic C contents of plot soils. The organic C content of soil with particle-size of 2-1 mm amended with peat was highest (0.93%) and 1.86 times of that of the check. The organic C content of the soil amended with compost was the next and then that of the soil amended with green manure. The organic C content of soil with particle-size of 1-0.5 mm had the similar trend. After the harvest of spring rice, the water contents of the plot soils at 1/30 MPa tension, amended with organic materials were higher then that of the plot soils amended with chemical fertilizer and the check. This is probably due to the increase of soil organic C content. After the planting of corn, the organic C content of the plot soils followed the same trend except for that of the plot soils amended with green manure . There was no significant difference between the organic content of the soil amended with green manure and the check. This may be attributed to faster decomposition rate of green manure during the growth of upland corn. After the planting of rice, the contents of water-stable aggregate of the plot soils with particle-size of 2-1 mm, amended with peat and compost were significantly higher then that of the plot soils amended with chemical fertilizer and the check. The content of water-stable aggregate of the plot soils amended with peat was the highest (93.3%) and 1.05 times of that of the check. That of the plot soil amended with compost was the next and that of the check was the least. Similarly, the contents of water-stable aggregate of the plot soils with particle-size of 1-0.5 mm followed the same trend. After the planting of upland-corn, other then the plot soil amended with green manure, the content of water-stable aggregate of the plot soil had the same trend as that after the planting of paddy-rice. There was no significant difference between the content of water-stable aggregate of the plot soil amended with green manure and that of the plot soils amended with chemical fertilizer and the check. This is attributed to highly oxidized state of the plot soil of upland-corn, changing from highly reduced state of that of paddy-rice. Further, green manure is easily decomposable in soil environment. After the planting of rice, the bulk density of the surface soils of field plots amended with the organic materials significantly higher then that of the check. This is probably because of the increase of soil organic C by the amendment of organic materials to the field plots. However, after the planting of corn, the differences of the bulk density of the surface soils among the 7 treatments became insignificant. It is due to highly oxidized state of upland-corn changing from highly reduced state of paddy-rice, resulting in greater decomposition rate of organic matter. The impact influence of the applications of organic materials to soils in improving soil physical properties is the increase of soil organic C content, resulting in the formation of soil aggregates, which in turn results in potential water-holding capacity and lowering soil bulk density. Chemically, the applications of organic materials prevent soil from decreasing pH and increase the amounts of soluble salts. Therefore, the applications of organic materials to soils improve physicochemical properties of soils, leading to suitable environment for plant growth. For the maintenance of crop production as well as quality and soil physicochemical properties, fertilization and cultivation strategies merit more close attention.|
摘要 有機材質於土壤中之轉變影響土壤之物理、化學及生物性質甚鉅。 本研究之目的，在探討田間三至五年之水旱輪作及不同施肥處理對土壤一些物化性質的影響。 施用至土壤之有機材質包括極易分解之綠肥、易分解之農業廢棄物堆肥及不易分解之泥炭。 試驗田除了添加有機材質外，再添加不同氮肥量之處理，其用量為化肥處理氮量之1/3或2/3。 試驗田種植之作物為水稻與玉米。 於87年7月以及89年七月水稻收穫後；88年1月以及89年1月玉米收穫後，採集田間各不同處理之土壤，測定其表土之pH、EC、含水量、總體密度、以及2-1 mm與1-0.5 mm粒徑土壤之有機碳含量與水穩定團粒含量。 結果顯示，施用有機材質於土壤中，可避免土壤pH值降低；增加土壤中可溶性鹽類含量，提供作物生長所需養分；提高土壤有機碳含量，粒徑1-2 mm土壤之有機碳含量以泥炭處理者最高達0.93 ﹪為對照處理者之1.86倍，其次為堆肥處理者，綠肥處理者最小；粒徑0.5-1 mm土壤之有機碳含量，其結果與粒徑1-2 mm土壤之有機碳含量相似。 在水稻收穫後，表土於1/30 MPa水分張力時之含水量，施用有機材質處理者，均較對照區及化肥區高，這是因為表土之有機碳含量增加的緣故。 種植玉米後，除了綠肥處理者外亦有相同之趨勢，綠肥處理和對照組者無顯著差異，應是綠肥分解較速之緣故。 水稻收穫後，粒徑2-1 mm土壤之水穩定團粒含量，泥炭處理及堆肥處理者與對照及化肥處理者達顯著差異，以泥炭處理最高達93.3﹪為對照處理之1.05倍，其次為堆肥處理，綠肥處理最小；粒徑1-0.5 mm土壤之結果相似；在玉米收穫後，表土之水穩定團粒含量，除了綠肥處理者外，結果和水稻收穫後相似，綠肥處理之水穩定團粒含量和對照及化肥處理者未達顯著差異，其原因為土壤水分境況由水田轉換為旱田，土壤由還原變為氧化狀態，加上綠肥較易分解，故其對土壤水穩定團粒百分比之增進效果不明顯。水稻收穫後，施用有機材質處理者，其表土總體密度均較對照組低，應是表土之有機碳含量因為施用有機材質增加的緣故；玉米成熟後，表土總體密度在各處理間之差異，變得不顯著應是土壤境況由還原狀態轉變為氧化狀態，有機質分解較速。 施用有機材質於土壤，對土壤物理性質的影響，應是增加土壤中的有機碳含量，促進土壤團粒之形成；團粒的增加，可增加土壤保水力及降低土壤的總體密度。 在化學性質方面，施用有機材質於土壤可抑制土壤之pH值之下降及增加可溶性鹽類含量。因此，施用有機材質於土壤，可使土壤之物化性質變佳，而為作物良好之生長環境。為兼顧作物之產量與品質以及土壤物化性質之維續，最適當之施肥及耕作策略值得進一步思維。
|Appears in Collections:||土壤環境科學系|
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