Đất Microfauna: Đa dạng và ứng dụng của Protozoans trong đất Nhà máy sản xuất nông nghiệp phụ thuộc vào phân hủy tàn dư thực vật và động vật, cũng như phân bón, thành các hợp chất đơn giản, nhiều trong số đó được chuyển thành vi khuẩn và động vật nguyên sinh vật. Những vật liệu hữu cơ cuối cùng khoáng hóa thành các hợp chất đơn giản, chẳng hạn như CO2, ammonia, phosphate, được hấp thu bởi rễ cây | CHAPTER 2 Soil Microfauna Diversity and Applications of Protozoans in Soil Stuart S. Bamforth CONTENTS Introduction Role of Soil Protozoa Measuring Protozoan Biodiversity Protozoan Diversity in Agroecosystems Applications Conclusions References INTRODUCTION Agricultural plant production depends upon the decomposition of plant and animal residues as well as fertilizers into simpler compounds many of which are transformed into microbial and animal protoplasm. These organic materials are eventually mineralized into simpler compounds such as CO2 ammonia and phosphate which are absorbed by plant roots. ROLE OF SOIL PROTOZOA Microarthropods and larger fauna especially earthworms increase the rate and amount of mineralization by comminution of organic matter and by redistribution of hot spots of activity through movements. However mineralization and return 1999 by CRC Press LLC. of nutrients to plants occur in the water films covering soil aggregates and filling their pores. Here bacteria and fungi decompose organic matter and immobilize the extracted nutrients into their bodies but grazing by the microfauna protozoa and nematodes regulates and modifies the size and composition of the microbial community and enhances microbial growth through microfaunal excretions. Nematodes also graze fungi Chapter 1 but protozoa especially amoebae can graze bacteria in tiny pore spaces unavailable to nematodes. The degree of nutrient recycling is influenced by external factors of climate and soil management . inputs of fertilizers and biocides compaction by farm machinery and internally by the community of protozoa and nematodes reflected in their biodiversity. Most of the microfauna are located in small hot spots scattered through the soil mosaic which is soil aggregates of 1 mm or smaller containing bits of organic matter detritus and the overlying litter rhizosphere and the drillosphere parts of the soil influenced by earthworm secretions and castings. The microbial-feeding .
