Temporal And Spatial Distribution Of Roots And Feasibility Study Of Fertilization In Soybean(Glycine Max L.Merril)

This experiment was conducted with frame and field tests during the period from 2009 to 2010 years at Lindian county, cultivar KenNong 4 was selected as the experimental material. In frame experiment, We studied the root spical distribution of soybean at different growth stage, and Compared the changing trend of root dry weight, root volume and root activity in different layers at horizontal and vertical directions.In field experiment, we studied the best fertilization of furrow and the effect of furrow fertilization on growth and development, physiological characteristics, yield and quality of soybean. The result can provide furrow fertilization theories for for higher yield, better quality, and more efficient production of soybean. The main results were:(1) In V5, R1 and R5 stages,the vertical root dry weight and root volume at different layers decreased from ridge center to furrow, and the horizontal increased from bottom to top. The vertical root dry weight mainly distributed 0¹3 cm layer of ridge center to furrow, and the horizontal root dry weight of different layers mainly distributed 0¹3 cm layer of surface. In V5, R1 and R5 stages,the root volume and root dry weight of 26³9 layer occupied total root volume of 6.71%, 6.28%, 7.32% and 8.97%, 11.45%, 11.90%.(2) In V5, R1 and R5 stages,the vertical activity in root at different layers were gradually increased from ridge center to furrow, and the horizontal of root activity at different layers were showed changing trend of down - up– down. In V5, R1 and R5 stages,the 26³9 cm layer of root vigor was significantly higher than other layers.(3) After furrow fertilization at R1 stage, the root dry weight, root volume and root vigor in R5 stage were significantly increased.(4) The furrow fertilization at R1 stage increased pod number per plant, seed number per plant, seed weight per plant, 100-seed weight and yield. The yield difference between treatment and control achieved 1% significant level, and the best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² respectively.(5) The furrow fertilization at R1 stage increased protein content and fat content in soybean seed. The best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² for improving the protein content, and the best results of nitrogen, phosphorus and potassium were 20 kg/hm², 30 kg/hm² and 20 kg/hm² for improving the fat content.(6) The furrow fertilization at R1 stage increased plant height, stem diameter, root volume and petiotle dry weight per plant of soybean, and the best results of nitrogen, phosphorus and potassium were 80kg/hm², 120 kg/hm² and 80kg/hm² respectively.(7) The furrow fertilization at R1 stage increased main-stem nodes, effective node, pod number, root dry weight, leaf dry weight, stem dry weight, pod dry weight, plant dry weight and crop growth rate of soybean, and the best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² respectively.(8) The furrow fertilization at R1 stage increased nitrogen, phosphorus and potassium content and accumulation of soybean root, stem, leaf, stem, pod and plant, and the best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² respectively (9) The furrow fertilization at R1 stage increased leaf area index, photosynthetic potential, specific leaf weight, chlorophyll content, photosynthetic rate, transpiration rate, stomatal conductance and water efficiency of soybean, and the best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² respectively.(10) The furrow fertilization at R1 stage increased starch content and soluble sugar content, cane sugar content and invertase activity of soybean leaf and the best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² respectively.(11) The furrow fertilization at R1 stage increased free amino acid content, NH₄⁺-N content, NO₃^--N content, soluble protein content, nitrate reductase (NR) activity, protease activity, glutamine synthetase (GS) activity, glutamate synthase (GOGAT) and glutamate dehydrogenase (GDH) activity of soybean leaf, and the best results of nitrogen, phosphorus and potassium were 50 kg/hm², 75 kg/hm² and 50 kg/hm² respectively.(12) The effect of interaction of nitrogen and potassium, square of nitrogen, phosphorus and potassium on protein content was marked and great marked. The effect of phosphorus, square of nitrogen, phosphorus and potassium, and interaction of phosphorus and potassium fertilizer on fat content was marked and great marked. We can forecast the best value of protein content and fat content is 42.86% and 23.80%.(13) Relationship between yield and nitrogen, phosphorus, potassium were parabola opening downwards, the effect of nitrogen, phosphorus and potassium on yield showed as phosphorus>potassium>nitrogen. In selecting of soybean fertilizer, Optimum nitrogen, phosphorus and potassium were 42.44～57.56kg/hm²,55.38～94.62kg/hm² and 36.92～63.08 kg/hm² respectively. In this range we will get ideal yield, and exceeding the range the yield will decline. We can forecast the best yield is 5247.85 kg/hm².