NO-TILL VEGETABLE PRODUCTION USING ORGANIC MULCHES

Conventional tillage practices and the use of polyethylene mulch has led to the loss of soil organic matter and increasing problems of erosion, water logging and soil compaction. A no-till system using permanent beds, permanent sub-surface irrigation and organic mulches grown in-situ, based on that developed by Abdul–Baki & Teasdale (1993) has been implemented as an alternative to conventional production. The system uses a tropical legume, Centrosema pubescens ‘Cavalcade’, or the C₄ grasses Bothriochloa pertusa ‘Keppel’ or ‘Hatch’ as cover crops over summer and fall. Cover crops are killed using glyphosate (1440g ai/Ha) and the residues left on the soil surface. Vegetable seedlings are then planted through the mulch residues and grown using conventional agronomic techniques. Following harvest, crop residues are macerated and the following cover crop direct seeded through the mulch residues. The development and implementation of this no-till system of vegetable production has resulted in significant improvements in soil aggregate stability, soil bulk density and soil biological activity, compared to polyethylene mulch and cultivation while crop yields are similar or improved.