Farmer attitudes to and yields of three tropical grasses.

Abstract

Proc. Aust. Soc. Anim. Prod. Vol. I9 FARMER ATTITUDES TO AND YIELDS OF THREE TROPICAL GRASSES W. K. EHRLICHA and W. A. WILLIAMSB *QDPI, Mutdapilly Research Station, M/S 825, Ipswich, Qld 4305. *University of Queensland, Gatton College, Lawes, Qld 4343. Milk production from tropical pastures declines in late autumn, in response to lower temperature and low rainfall (Cowan and Stobbs 1976). This experiment was conducted to compare 3 tropical grasses for production and quality parameters in autumn and to see if the results were similar to farmer perceptions of the performance of those grasses. Sixty dairy farmers supplying Queensco Dairy Co-operative Qld were asked to rank 3 tropical grasses (Table l), from most to least preferred for the autumn period. Pasture yield and quality in autumn were assessed in a plot trial at Gatton College. Grasses were sown in December 1990 in 3 by 1 m* plots in a randomised block design of 4 replicates. They were fertilised with urea at 300 kg N/ha.year. Plots were defoliated on 1 March 199 1, fertilised and then sampled at 42-day intervals to June 12. Total and leaf dry matter yields were recorded and samples analysed for in vitro dry matter digestibility (IVDMD), leaf protein and neutral detergent fibre (NDF) on each occasion. The results from the farmer survey were analysed using a Chi-square test and pasture data by analysis of variance. Forty-six and 42% of farmers rated Rhodes grass and green panic similarly (P > 0.05) as their most preferred grasses. Setaria received first preference from only 12% of farmers (P > 0.05). Dry matter yields increased and leaf protein declined through autumn (Table 1). Green leaf yields for all grasses peaked in May and were lowest in June. IVDMD declined and NDF increased over the sampling period. Rhodes grass was superior to the other grasses in total yield and leaf yield throughout the experiment (P > 0.05) (Table 1). Leaf protein, IVDMD and NDF were similar for all grasses (P > 0.05). These data support farmer perceptions of higher productivity for Rhodes grass in autumn in this environment. Table 1. Yield and quality of 3 tropical grasses in autumn 1991 COWAN, R. T. and STOBBS, T. H. (1976). Aust. J. Exp. Agric. Anim. Husb. 16: 829. 327