Using limited irrigation water - crops or pasture?

Abstract

The irrigation of perennial pasture and the growing of dryland summer forage crops are two common methods of increasing the supply of and nutritional value of home grown forage on dairy farms in south west Victoria. In recent years the amount and reliability of supply of irrigation water to dairy farmers in the region has decreased through drought and increased regulation. Over the last 8 years a series of studies have been conducted to investigate the most efficient use of unreliable irrigation water supplies. Perennial pasture was found to be particularly sensitive in terms of reduced productivity and water use efficiency (WUE) to poor irrigation practices. However, under good management and reliable water supply it is still likely to be the easiest and most economically efficient irrigation system. Irrigated summer forage crops were found to have a higher WUE, but responses were variable due to year to year seasonal differences. These crops were found to be more tolerant of poor irrigation management and were able to take advantage of reduced amounts of irrigation water and one off irrigations. Keywords: brassicas, forage crops, irrigated pasture, irrigation, water use efficiency.