Cover crops and mulches influence weed management and composition in strip-tilled tomato 1 (Solanum lycopersicon L.)

Abstract

This study was carried out in the Mediterranean environment of central Italy from 2011 to 2013 in order to evaluate the effects of winter cover crops and their residues on the weed composition in a cover crop-tomato sequence. The treatments consisted in: (i) 5 soil managements {3 cover crop species [hairy vetch, phacelia, white mustard]}, winter fallow mulched with barley straw before tomato transplanting, and conventionally tilled soil, (ii) 2 levels of nitrogen fertilization [0 and 100 kg N ha-1], and (iii) 2 levels of weed management [weed-free and weedy] on tomato. The cover crop residues were left on the soil surface and arranged in strips which were used as beds for tomato seedlings transplanted in paired rows. The tomato was strip tilled between the tomato paired rows. Hairy vetch was the most suppressive species as cover crop and as dead mulch with the highest production of residues (634 g m-2 of DM). Phacelia and mustard were not suitable for controlling weeds and, as dead mulches, showed values of weed aboveground biomass, weed density and composition similar to the bare soil (on average 85.6 n m-2, 403.1 g m-2 of DM, and 6.3 n. species m-2, respectively). The use of strip mulches caused a change in weed species composition which was mainly composed of perennial ruderal weeds, while in tilled soil the weed flora was dominated by annual photoblastic weeds.