Tomato Response to Starter Fertilizer, Polyethylene Mulch, and Level of Soil Phosphorus

Abstract

Unmulched and polyethylene-mulched tomatoes (Lycopersicon esculentum Mill.) were grown with and without starter fertilizer (SF) in four field experiments. The fields varied as to residual P level and the amount of P incorporated before planting. No benefits from SF were obtained on a soil with high residual P that was moderately fertilized with P before transplanting or on a soil with low residual P that was heavily fertilized with P. A positive effect from SF was observed only when residual P was low and no P was broadcast, and this was true in mulched and umnulched plots. No significant SF by mulch interaction was obtained in these experiments even though mulching consistently increased shoot P concentrations and fruit yield. The mulch was beneficial even under conditions where unmulched tomato leaves contained 0.4 % P 3 weeks after transplanting, indicating that factors in addition to improved P nutrition are also involved in the mulch effect.