Đang chuẩn bị liên kết để tải về tài liệu:
ORGANIC SOILS and PEAT MATERIALS for SUSTAINABLE AGRICULTURE - CHAPTER 3

Không đóng trình duyệt đến khi xuất hiện nút TẢI XUỐNG Tải xuống

Bảo tồn đất hữu cơ được sử dụng cho nông nghiệp đòi hỏi phải quy định và phân vùng của dòng chảy trong môi trường. Chương này đánh giá vật lý tài sản liên quan đến việc giữ nước và chuyển giao hữu cơ trong đất thoát nước. | CHAPTER 3 Water-Related Physical Attributes of Organic Soils Tomasz Brandyk Jan Szatylowicz Ryszard Oleszczuk and Tomasz Gnatowski CONTENTS Abstract I. Introduction II. Basic Physical Properties III. Soil Water Characteristic A. Methods of Determination B. Water Retention of Peat and Moorsh Materials IV. Saturated Hydraulic Conductivity A. Methods of Determination B. Anisotropy C. Seasonal Variation V. Unsaturated Hydraulic Conductivity VI. Shrinkage Characteristic VII. Water Repellency A. Methods of Determination B. Water Repellency of Organic Soils VIII. Spatial Variability IX. Conclusion References ABSTRACT Conservation of organic soils used for agriculture requires proper regulation and partitioning of water flow in the environment. This chapter reviews the physical 2003 by CRC Press LLC properties involved in water retention and transfer in drained organic soils. Basic physical properties are bulk density specific density porosity and ash content. Water retention characteristics of organic soils are influenced by the degree of peat decomposition. Water retention characteristics can be derived from other soil properties using pedotransfer functions. The results of saturated and unsaturated hydraulic conductivity measurements must be interpreted in reference to factors influencing their determination. Relationships between concomitant changes in soil moisture and volume during shrinkage are illustrated by characteristic curves. For converting volume changes into crack volume and subsidence a dimensionless shrinkage geometry factor can be used. The authors investigated 1. The influence of moisture content on water repellency 2. The effect of repellency on field moisture distribution patterns 3. The spatial variability of bulk density hydraulic conductivity moisture retention characteristics and moisture content at plot scale Shrinkage characteristics the shrinkage geometry factor and parameters describing water repellency should be incorporated into hydrological