Organic mulch and nitrogen affect spring and fall collard yields

Abstract

Fall and spring collards (Brasslea oleraceu L. Acephala Group) weregrown under one of three mulches (black plastic, ground newspaper, woodchips) and in a bare soil control. Mulch treatments were arranged in afactorial design with five rates of N fertilizer: 0, 67, 134, 201, or 268 kgN/ha. All fertilizer was preplant-incorporated into the bed before applyingmulches and transplanting collards. Season did not affect collard yield, andthere was no significant season x N rate interaction. Collard yieldsincreased with increasing rates of N, with a maximum yield at 163 kg N/ha.Mulch type significantly affected collard yield, with fall collard yieldshighest under bare ground or wood chip mulches and spring yields highestunder black plastic mulch. Collards produced under newspaper mulch producedthe lowest yields in the fall and yields equal to bare soil and wood chips inthe spring. Collards produced under newspaper mulch had less tissue N atharvest than those of any of the other treatments in both seasons. Collardsproduced on black plastic produced the lowest plant populations in bothseasons. Wood chips and newspaper offer some appeal as low-input, small-scalemulches, but additional research to explore fertility management isnecessary.