Nitrogen and phosphorus application to processing tomatoes grown with drip fertigation.
Zhang, T.Q., Tan, C.S., Liu, K., and Warner, J.T. (2009). "Nitrogen and phosphorus application to processing tomatoes grown with drip fertigation.", Acta Horticulturae (ISHS), 823, pp. 109-114.
Sufficient nutrient and water supplies are vital for processing tomato production. Excessive N and P supplies, however, can reduce farmers' profitability and cause adverse impacts on environmental quality. A 3-year study was conducted to evaluate agronomic and environmental consequences of applied fertilizer N and P to processing tomato (Lycopersicon esculentum Mill.) under drip fertigation in southwestern Ontario, Canada. Nitrogen application significantly affected total fruit yields, which, however, were not affected by addition of fertilizer P. Fertilizer N rates required for the production of maximum yield were estimated at 254, 302, and 322 kg N ha⁻¹, for 2003, 2004, and 2005, respectively. Addition of fertilizer N above the rates required for the maximum yield production caused significant increases of post-harvest soil residual NO₃-N, which may increase leaching losses during the non- growing season. Total N uptake was averaged at 265 kg N ha⁻¹ and total P uptake averaged 44 kg P ha⁻¹. The results demonstrate that with the improved production of fruit yield under fertigation N application rate needs to be increased to satisfy the optimum growth under prevailing conditions.