Production and Resource Use of Winter Feed Crops in New Zealand

In the South Island of New Zealand (NZ), dairy cow numbers have increased from 1.4 to 2.1 million since 2005 (Statistics, New Zealand, 2014). This has led to a strong demand for winter feed crops in place of pasture, and also for supplementing pasture during lactation. Yields of 19–35 t DM/ha are reported for fodder beet (Beta vulgaris L.) in NZ (Chakwizira et al., 2014) compared with 14–25 t DM/ha for forage kale (Brassica oleracea L.) (Chakwizira et al., 2009) and 18–25 t DM/ha for maize (Zea mays L.). Fodder beet has only recently been widely adopted for its ease of feeding and provision a high energy feed (Matthew et al., 2011). Choice of crop is based on yield potential, feed value and suitability for winter feed management. Nitrogen fertiliser and irrigation practices affect the productivity, profitability, and dynamics of resource use during crop growth; and losses of N during winter in situ feeding. Optimized systems with high water and N use efficiency are sought to reduce potential adverse environmental effects. The objectives were to compare efficiency of water and N use of fodder beet, kale and maize and assess their value to growers