Organic production of horticultural crops with green manure, composted farmyard manure and organic fertiliser

AbstractA three-year organic crop rotation was set up in a field with sandy loam soil, with a cover crop of rye and vetch grown over the three autumn/winter seasons for green manure, followed by potato and lettuce (1st year), Swiss chard and turnip (2nd year), and Portuguese cabbage and carrot (3rd year). Nitrogen (N) mineralisation was determined by field incubation in response to green manure (GM), GM with 20 and 40 t ha−1 farmyard manure (FYM) compost (C20 and C40) and GM with 1 and 2 t ha−1 of commercial organic fertiliser (CF1 and CF2). The second season crops (lettuce, turnip and carrot) yields were higher for the treatment C40 compared to all other treatments because most of the commercial fertiliser was mineralised during the previous crop. Swiss chard, grown in a short season (54 days), produced higher yield for CF2 compared with C40. However, this was not true for potato (1st year), probably because of increased compost mineralised N recovery during the longer growing season for the potatoes (12...