Tropical Grasslands (1994) Volume 28, 129138
Grassland improvement in subtropical Guangdong Province, China.
D.L. MICHALK1 and HUANG ZHI-KAI2
1NSW Agriculture, Agricultural Research and Veterinary Centre, Orange, New South Wales, Australia
Tropical and temperate legumes were evaluated for subtropical grasslands (1522 mm annual rainfall) on high aluminium (Al saturation > 87%) Hapludult soils at Lechang in north Guangdong Province, China. The evaluations were of: (1) 82 accessions and cultivars in rows and mini-plots; (2) 31 tropical and temperate legume cultivars sown in spring and autumn on unlimed soil with low fertiliser inputs; and (3) the same legumes compared when spring sown with Setaria sphacelata with and without lime. In Experiment 1, the best of the tropical legumes were: Chamaecrista rotundifolia (CPI 37234), Desmodium cuneatum (CPI 53953), D. heterocarpon (CPI 86277), Glycine sp. (P7874) and Stylosanthes guianensis (Q8442 and CPI 18750a), with the Ornithopus genus showing most potential of the temperate accessions. Wynn cassia was the most productive (>1700 kg/ha DM) in Experiment 2 and is recommended for use as a "pioneer" legume. The best temperate species were Maku lotus, Pitman serradella and woolly pod vetch, all of which yielded > 1000 kg/ha DM. All Trifolium species showed symptoms indicating severe magnesium deficiency. Legumes responded differently to lime application: greenleaf desmodium, siratro, phasey bean and lotononis increased, stylos decreased and cassia was unaffected. In Experiment 3, the temperate legumes failed to establish with setaria, but white clover production in pure stands increased by 2000 kg/ha DM with lime application. The implications of these results with respect to further species selection, liming strategies and fertiliser policy (especially P, Mg and K) for grassland development in south China are discussed.