Quality and seasonal yields of promising forage species in the red soils region of southern China

摘要

Following increasing interest in the use of special purpose forages to provide quality feed for small holder beef farmers in the red soil region of inland southern China, 14 of the most promising accessions were evaluated over 2 years to measure their seasonal yield of leaf and stem. Seven grasses (six perennials and one annual) and two non-leguminous broadleaf herbs were fertilised with both 200 and 400 kg of nitrogen (N)/ha.year. Two herbs were fertilised with only 200 kg N/ha and three legumes were fertilised with 60 kg of N/ha. The accessions were evaluated under cutting, as cut-and-carry of improved forages is, and is likely to remain, more widely used than grazing in this region. The highest yielding accessions were an elephant grass hybrid Guimu-1 [(Pennisetum purpureum x P. americanum) x P. purpureum cv. Mott] closely followed by elephant grass (P. purpureum) with total annual yields of 18-24 000 kg/ha in 2002, depending on accession and N rate, and 13-22 000 kg/ha in 2003. Their yields of leaf were 9-17 000 kg/ha in both years. Dwarf elephant grass cv. Mott gave similar yields of leaf but only half the yields of stem. Average leaf yields of the three elephant grass accessions were 24% higher at the higher rate of N in the first year and 40% higher in the second year. With the exception of the herbs Cichorium intybus and Silphium perfoliatum, there was negligible growth in the cooler months (November-March) and the periods of peak growth were in July and August. C. intybus was the most promising of the legumes and herbs, but is damaged by waterlogging and disease. Averaging over both years and all harvests, there was very little variation in the protein percentage of the different perennial grasses with levels of 12.4% at 200 kg N/ha and 13.7% at 400 kg N/ha. The corresponding protein percentage of the annual Mexican forage corn was higher (13.5 and 15.0%) but the legumes and herbs had a higher protein percentage (16-23%). The most promising accession was dwarf elephant grass as it gives a high yield of leaf, but a relatively low percentage of stem. As such, it is well suited to a cut-and-carry system of feeding, especially as the time of cutting is less critical than with other forms of elephant grass, which can rapidly develop a high percentage of stem. However, given good management, higher yields of leaf can be obtained from the elephant grass hybrid..