Legume crops have been considered as suitable crops for the intercropping systems. Legume crops are used with the aim of improving soil fertility through root nitrogen fixation and mulching of crop residues (Ashokan et al., 1985). Binh et al. (1997) and Dung et al. (2003) reported that intercropping leguminous tree can improve soil fertility.
Tropical Kudzu (Pueraria phaseoloides) is a leguminous plant that appears naturally throughout humid-tropics, which is used as a part of a mixture or a sole cover crop to prevent soil erosion as well as enrich the soil of tree crop such as coconuts, oil-palm and rubber throughout South East Asia and the Pacific islands. The most important role of Kudzu cover crop in the beneficial contribution to the parent tree crops through the deposition of leaf litter and nitrogen fixation in the soil (Soong and Yap, 1976; Tajuddin et al., 1990).
In Vietnam, Kudzu was used mostly in interplant with rubber. According to the report of Vietnam General Rubber Corporation (GERUCO)(2005), in the Southeast region of the country the total new established or replanted rubber areas was 17,251 ha, in which 6,292 ha were inter-planted with Tropical Kudzu or Mucuna (Mucuna pruriens). The interplant area made up more than 36% of the new established area. The biomass production of Kudzu in the rainy seasons was 36.7, 57.1 and 39.2 fresh matter tons/ha at first, second and third years, respectively according to the report of Dongnai Rubber Company (DARUCO)(2005). Only one cutting per year was done at the end of rainy season and the whole biomass of the cover-crops was used as a green manure to the rubber field.
Up to the present time, some of the experiment reports evaluated the production potential of Kudzu foliage for animal by pure planting or grass mixture (Manh et al., 2003; Trong, 1981; Quang, 1979; Nghia, 1978) and non published report have focused on the nutrition value of Kudzu foliage production when planted as cover-crop in perennial tree farm, particularly in the rubber plantation.
The overall objective of the study was to identify and evaluate forage production and conservation methods of Kudzu legumes as feed for cattle in Vietnam.
The specific objectives were:
· To evaluate the effect of cutting interval on biomass yield and chemical composition of Tropical Kudzu foliage, which has been inter-planted in the rubber plantation in the second planting year.
· To determine the influence of different amounts of sugarcane molasses in making Tropical Kudzu silage and to evaluate the feed intake and digestibility of Kudzu silage and Kudzu hay by crossbred Sindhi heifers.