Evaluation of early mature naked oat varieties as a summer-seeded crop in dryland northern climate regions

Increased land degradation and shortage of forage resources for animal production over-winter have accentuated the need for alternative cropping systems in northeast China. While short frost-free period and cool temperatures are major limitations to cereal grain production in the northern regions of China (45 degrees N, 122 degrees E), crop varieties that are able to produce food and feed in short growing season and tolerant to low temperature may extend the total cropping period. Three hulless oat (Avena sativa L.) lines, Baiyan 9015, Baiyan 9017 and Baiyan 9044, were bred and tested for 3 years (2004-2006) to determine their suitability for summer seeding in a double cropping system. The new lines were sown both in the spring and summer to provide growers with opportunities to harvest two grain-crops in a year. Averaged across 3 years, Baiyan 9044 produced 2.5 and 1.6 Mg ha(-1) yr(-1) grain yield when sown in spring and summer, respectively. The new lines seeded in 20th or 21st July and harvested in early October allowed utilization of an average of over 1500 growing degree days (GDDs). For grain yield alone, the net income for two oat crops a year was up to 1390 Chinese yuan (RMB) ha(-1), more than that of growing a single oat crop in 3 years, or in most cases, equivalent to monocultured corn (Zea mays L.) production, the dominant crop in the region. In addition, an average of 5 Mg ha(-1) of oat straw was produced as valuable forage fodder for the livestock industry, which was in great demand for over-wintering animals. Furthermore, in the traditional single small grain cereal cropping system, bare ground after harvest leads to severe water and wind erosions. Our results indicate that the new oat lines could be a potential crop for summer seeding, particularly when spring-seeded crops fail due to abiotic (hail, drought, etc.) or biotic (e.g. insects) stresses. The double cropping system provides growers with a potential opportunity to facilitate the farming strategy of food, cash crops and control soil erosion in the region. (c) 2007 Elsevier B.V. All rights reserved.