Growth and Yield of Tomatoes in Hairy Vetch-Incorporated and-Mulched Field

For the establishment of a tomato cropping system with hairy vetch (Vicia villosa Roth), effectiveness of incorporation and mulch (no-till) of hairy vetch and nitrogen fertilizer effect on tomato (Lycopersicon esculentum Mill.) growth and yield were examined, compared with tomatoes conventionally grown in a tilled field without hairy vetch (conventionally-tilled field), in 1997 and 1999. The NO3- concentration in the petiole sap was highest 42 days after transplanting. Though it decreased to below 1, 000ppm in tomatoes grown in conventionally-tilled field 56 days after transplanting, it remained more than 2, 000ppm in tomatoes grown in the hairy vetch-incorporated field (HV-incorporated field) and hairy vetch-mulched field (HV-mulched field). The growth index (GI) was higher in the HV-incorporated and HV-mulched fields than in the conventionally-tilled field. No difference in GI was observed among the rates of nitrogen fertilizer applied to HV-incorporated and HV-mulched fields and GI in these fields reached the recommended levels for obtaining average tomato yield at the beginning of the harvest even with no nitrogen fertilizer. The NO3- concentration in the petiole sap and GI in HV-mulched field was larger than those in HV-incorporated field in early period of tomato growth. Higher total tomato yields were shown in HV-incorporated and HV-mulched fields than conventionally-tilled field in both years, especially, HV-mulched field added 0-60kg/ha nitrogen fertilizer showed similar yield obtained in conventionally-tilled field with 120kg/ha nitrogen fertilizer. Yield-increase was recognized in early and middle harvest. Though tomato yield increased as nitrogen fertilizer added in conventionally-tilled field, there were no differences in yield among rates of nitrogen fertilizers applied in HV-incorporated and HV-mulched fields. Hairy vetch used for incorporation and dead mulch contributed to the increase in NO3- concentration in the petiole sap, and promoted tomato growth and yield, especially in HV-mulched field, compared with the conventionally-tilled field. There is a possibility to reduce the nitrogen fertilizer in the tomato cropping system with hairy vetch-incorporation and hairy vetch-mulch.