Evaluation of Agronomic and Economic Effects of Nitrogen and Phosphorus Additions to Green Pepper with Drip Fertigation
2010
Zhang, T. Q. | Liu, K. | Tan, C. S. | Hong, J. P. | Warner, J.
Drip fertigation is an effective way in splitting soluble fertilizer application to simultaneously meet water and nutrient demands of multi-harvested green pepper (Capsicum annuum L.). However, fruit yield and the profitability of green pepper can be constrained, if nutrients are either insufficiently or excessively supplied. A 3-yr experiment was conducted to assess both agronomic and economic effects of fertilizer N and P addition for green pepper grown under drip fertigation. Both fruit yields, including total and marketable, and net economic return responded quadratically to fertilizer N rate. The 3-yr average maximum marketable yield of 38 Mg ha⁻¹ was achieved at the N rate of 227 kg N ha⁻¹ The economic optimum N rate was identical to the one required for the production of maximum marketable yield, due to the large price ratio of green pepper to fertilizer N. Nitrogen use efficiency and N agronomic efficiency decreased as N rate increased. The amount of fertilizer N required for production of each megagram of marketable fruit yield increased with the level of yield, with an average of 6.0 kg N Mg⁻¹ fruit across the 3 yr at the maximum marketable yield. Fertilizer P did not affect selected variables, except for both total and marketable fruit yields that increased linearly with increases in P rate in one of the 3 yr. The results suggested that an increase in the optimum N rate to 227 kg N ha⁻¹ is needed to maximize the profitability of green pepper production with drip fertigation
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