干旱区生态环境知识资源中心

Increased frequency of drought and shortage of irrigation water has challenged forage production in arid and semiarid regions. Farmers have shifted from corn (Zea mays L.), as their primary source of forage, to more drought-tolerant species such as millet (Pennisetum glaucum L.); however, protein content of millet may be too low to meet the needs of high-producing animals. A 2-yr field experiment was conducted to determine if mixtures of millet with soybean (Glycine max L.) could produce acceptable forage and protein yield and at the same time maintain farmers’ profit level. Main plots consisted of nitrogen (N) rates of 0, 37, and 74 kg N ha(-1), and subplots were assigned to intercropping ratios (50: 50, 60: 40, and 40: 60 millet-soybean) along with sole crops. Nitrogen application increased total dry matter yield, and millet sole crop had the highest yield (13.6 t ha(-1)) followed by 60: 40 millet-soybean (13.1 t ha(-1)). The land equivalent ratio (LER) was highest (1.17) in 60: 40 millet-soybean intercrops, indicating 17% more efficient use of land than sole crops. On the basis of the results from LER, relative crowding coefficient, and monetary advantage index, 60: 40 millet-soybean was superior to the other intercropping ratios and sole crops. Also, the highest protein yield (2.49 t ha(-1)) was obtained from 60: 40 millet-soybean intercrops. Considering both yield and nitrogen use efficiency, 60: 40 millet-soybean intercropping ratio, fertilized at 74 kg N ha(-1), was advantageous and could be recommended as an alternative to millet sole crop to produce forage of high quality with no significant yield loss.