Physiological changes in soybean (Glycine max) Wuyin9 in response to N and P nutrition |
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Authors: | YINBO GAN INEKE STULEN HERMAN van KEULEN PIETER J C KUIPER |
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Institution: | Laboratory of Plant Physiology, University of Groningen, P O Box 14, 9750 AA Haren, The Netherlands;Cash Crops Institute, Hubei Academy of Agricultural Sciences, Wuhan 430064, Hubei, China;Agrosystems Department, Plant Research International, Wageningen University and Research centre, P O Box 16, 6700 AA Wageningen, The Netherlands |
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Abstract: | Phosphorus deficiency is a very common problem in the acid soil of central China. Previous research has shown that starter N and N topdressing at the flowering stage (Rl) increased soybean (Glycine max) yield and N2 fixation (Gan et al, 1997, 2000). However, there is little information available concerning soybean response to P‐fertiliser in soybean production in central China (Gan, 1999). A field experiment was conducted to investigate the response to P (0 kg P ha?1, 22 kg P ha?1, 44 kg P ha?1 before sowing) and N fertiliser application (N1: 0 kg N ha?1, N2: 25 kg N ha?1 before sowing, N3: N2 + 50 kg N ha?1 at the V2 stage and N4: N2 + 50 kg N ha?1 at the R1 stage) on growth, yield and N2 fixation of soybean. Both N and P fertiliser increased growth and seed yield of soybean (P < 0.01). Application of basal P fertiliser at 22 kg P ha?1 or 44 kg P ha?1 increased total N accumulation by 11% and 10% (P < 0.01) and seed yield by 12% and 13% (P < 0.01), respectively, compared to the zero P treatment. Although application of starter N at 25 kg N ha?1 had no positive effect on seed yield at any P level (P > 0.05), an application of a topdressing of 50 kg N ha?1 at the V2 or R1 stage increased total N accumulation by 11% and 14% (P < 0.01) and seed yield by 16% and 21% (P < 0.01), respectively, compared to the zero N treatment. Soybean plants were grown on sterilised Perlite in the greenhouse experiment to study the physiological response to different concentrations of phosphate (P1: 0 mM; P2: 0.05 mM; P3: 0.5 mM; P4:1.0 mN) and nitrate (N1: 0 mM with inoculation, N2: 20 mM with inoculation). The result confirmed that N and P nutrients both had positive effects on growth, nodulation and yield (P < 0.01). The relative importance of growth parameters that contributed to the larger biomass with N and P fertilisation was in decreasing order: (i) total leaf area, (ii) individual leaf area, (iii) shoot/root ratio, (iv) leaf area ratio and (v) specific leaf area. The yield increase at N and P supply was mainly associated with more seeds and a larger pod number per plant, which confirmed the result from the field experiment. |
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Keywords: | Phosphorus deficiency nitrogen fertilisation biomass seed yield nodulation N2 fixation |
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