Phosphorus fertilization impacts on maize yield and nutritional status with emphasis on P and Zn in leaves and grain

摘要

Four field experiments with increasing rates of P fertilization (kg P_2 O_5/ha: up to 2000, 1000,1500, and 1500, for the exp. A, B, C and D, respectively) were started between spring of 2002 and 2004. The experiments were performed in four replicates(basic plot, depending on the trial, from 32 to 92 m~2). Monoammonium phoshate (MAP: 12% N + 52% P_2 O_5) in experiments A-C and triplephoshate enriched with sulphur and zinc (45% P_2 O_5 + 1,2% S + 0,06% Zn) in experiment D were used as P fertilizers. In general, P fertilization (the exp. A) had moderate yield effects probably due to acid soil reaction. Only application of the highest P rate had residual influences on maize yields for the 2003 growing season (7.74 and 8.38 t/ha, for the control and thehighest rate of P, respectively). In the experiment B, fertilization resulted in significant yield increases up to 16%. In the exp. C maize yields were similar for applied P treatments. However, maize responded drastically to P fertilizations by yield increasing up to 32% , 17%, and 40%, for 2004, 2005, and 2006, respectively (the exp. D). An acceptable range of P:Zn ratio from 15 to 180 was mainly found in our study. For example, leaf P:Zn ranged from 38 to 80 (the exp. A), from 77 to 100 (the exp. B), from 35 to 69 (the exp. C) and from 73 to 168 (the exp.D). Grain P:Zn ratios were higher than leaf P:Zn (from 151 to 194 and from 124 to 168, for the exp. B and D, respectively). Phosphorus fertilization mainly increased P:Zn.