AN ALTERNATIVE PLASTIC MULCHING SYSTEM FOR IMPROVED WATER MANAGEMENT IN DRYLAND MAIZE PRODUCTION

Plastic mulching has become a well established technique for increasing the profitability of many horticultural crops. Large yield increases have also been achieved by using plastic mulching on rainfed maize, often more than doubling yields. At current grain prices, however, the increase in maize yields obtained through the use of plastic mulching have not been sufficient to cover the cost of the traditional mulching system where the plastic mulch is replaced annually. It has also not generally been considered technologically nor agronomically practical to reuse plastic mulch under the traditional mulching systems. For these reasons a new system referred to as 'semi-permanent plastic mulching' is proposed here. This system which leaves the plastic mulch in situ for a period of years, combines improved water management, decreased risk of soil erosion, higher yields, and improved sustainability, all in an economically viable system. Semi-permanent plastic mulching is most suitable for regions where the shortage and unreliability of rainfall are the greatest constraints to increasing yields. The system has been tested using rainfed maize in a semi-arid region of Mexico and resulted in yields which were significantly higher than the control non-mulching treatment and which were similar to those achieved using traditional plastic mulching systems.