Study On Rational Fertilization Technology Of Low-medium Yielding Yellow-clayed Paddy Field In South China

Yellow-clayed paddy field is one main type of low-medium yielding farmland in south China. This research, in allusion to its low yield factors, focus on soil-ripening and high efficient utilization of water resources and fertilizer and mainly from three aspects, such as soil improvement, management of water and fertilizer and cultivation methods, studied the effect of different measures on rice growth, yield, absorption and utilization of nutrients and physical, chemical and biological properties of soil to evaluate their effect as well as to explore the mechanism through long term location experiment. The two year’s results showed:1. Chemical fertilizer, combined with organic materials, could archieve higher rice yield than single chemical fertilizer, but no significant difference appeared between different organic material treatments so far. The application of organic material could not only improve soil structure, but also increase soil available nutrients. Mushroom residue could significantly derease soil bulk density, increase total porosity and contents of soil alkali-hydrolyzable N; astragalus sinicus could significantly increase soil available kalium and CEC; fermented cow dung could significantly derease soil bulk density, increase total porosity and contents of soil total-N, alkali-hydrolyzable N and available phosphorus; straw could significantly increase available phosphorus and available kalium. In general, fermented cow dung performed best.2. Compared with traditional urea (PU100%), biochemical inhibited urea which added nitrapurin (NPU100%) increased yield of early rice by11.8%and2297Yuan·hm-2,9.2%and2144Yuan·hm-2of late rice, its nitrogen use efficiency (NUE), agricultural nitrogen use efficiency (ANUE), partial factor productivity of applied N (PFP-N) and N uptake efficiency (NUPE) increased by10.8%,4.1kg·kg-1,4.2kg·kg-1,0.11kg·kg-1, respectively. Besides, it increased soil available nutrients. Nitrogen of sulfur and polymer coated urea (SPCU100%) released slow at early stage which was not good for early rice growth. SPCU70%+PU30%could achieve similar effect to NPU100%, but it’s a little more expensive. Urea formaldehyde (UF100%) had poor effect.3. Compared with NPU100%, NPU80%could maintain rice yield with increased harvest index and NUE, but NPU60%lead to decreased yield and NUE for nitrogen deficiency. Therefore, we recommended that biochemical inhibited urea which added nitrapurinwith144kg·hm-2for basal application be the suitable N application pattern for yellow-clayed paddy field.4. Mechanical transplanting of rice with controlled release bulk blending fertilizer (CRBBF)(BBMT) could achieve rice yield of10673kg·hm-2, was16.3%and27.0%higher than traditional manual transplanting with traditional fertilizer (commenly used by local farmers, TFMT) and direct seeding with CRBBF (BBDS). Compared with TFMT, BBMT increased soil total-N, available N, available P, contents of microbial biomass C, activities of urease, sucrase and hydrogen peroxidase by21.5%,13.6%,41.2%,27.1%,50.0%,22.5%and46.2%, respectively. Therefore, BBMT, a simple high-efficiency rice cultivation method, should be widely promoted and adopted in this area.5. Under wide field trial condition, fertilization of organic fertilizer with CRBBF (BBM) worked best. Compared with single chemical fertilizer (F), BBM and chemical fertilizer with straw and inoculants (FS) could increase yield of early rice by26.9%and3.9%, respectively,16.0%and12.0%of late rice, and14.4%and7.8%of single cropping rice. The soil organic matter, total nitrogen and available nutrient were also increased to some extent.