Dry matter yield and productivity of forage crops under rotation systems in Longdong loess plateau

Feed source shortage is the main problem that limits livestock production in Longdong loess plateau of China. The object of this experiment was to compare the dry matter yield of forage crops under different rotation sequences to meet livestock demand. The experiments were carried out in 2008 and 2009. Eight forage crops, forage maize (Zea mays), sudan grass (Sorghum sudanense), proso millet (Echinochloa crusgalli var. frumentacea), oats (Avena sativa)，foxtail millet (Setaria italica), common vetch (Vicia sativa), lucerne (Medicago sativa), and one mixed crop (maize, foxtail millet and sorghum sown together, a traditional livestock feed source) were trialed. The forage crops were grown in four rotation treatments: maizevetchoats rotation (MVO), sudan grassvetchoats rotation (SVO), prosovetchoats rotation (PVO) and milletvetchmixed crop rotation (MVM), and the other treatment was perennial lucerne field (Lucerne). The dry matter yield over 2 experimental years averaged 9.5 tha-1a-1 for maize, 5.8 tha-1a-1 for sudan grass, 5.4 tha-1a-1 for oats, and 4.0 tha-1a-1 for proso. The mixed crop had the lowest average yield (2.1 tha-1a-1). The MVO rotation had the highest DM yield (average 7.4 tha-1a-1). Compared to the PVO rotation, the SVO rotation had a higher DM yield (5.6 tha-1a-1). The results showed that maize, proso and oats were productive forage options, especially oats are good summer forage in the region. Introducing annual forage crops into current farming system could reduce feed deficits for livestock producers.