Sustainability in contrasting farming systems : part 1 - utilisation of herbs and grass in temperate organic (sustainable) farming systems; part 2 - sustainable management of semi-arid ranges in two locations of Pakistan
The aims of the current study were to develop sustainable approaches for contrasting farming systems. Experimental work was started at the beginning of 1995 and completed at the end of the 1997. During that period, besides the development of the model, eleven experiments were conducted at Craibstone, Aberdeen. Out of eleven experiments six experiments ran for a one year period, four experiments for a two year period and an animal feeding trial ran for five weeks. The establishment, persistence and production trials (eight experiments) of chicory and ribwort showed that a perennial ryegrass had negative effect on establishment of roots, shoots leaf size and leaf number of both herbs during the growing phase, which ultimately reduced the percentage contribution and yield of herbs. Nevertheless, it also reduced the infestation of weeds significantly. In contrast, white clover appears to be less competitive to the herbs and with its N fixing ability, it may be an ideal companion in binary mixtures. In tertiary mixtures, timothy appeared to be less competitive than perennial ryegrass and suitable for tertiary mixtures. In the lamb feeding trial, chicory increased markedly the Ca, Mg, Cu and vitamin B12 (Co) status of the lambs and also improved the PO4, Na, and GSH-Px (Se) status as compared to an unsupplemented perennial ryegrass diet. In two separate experiments, the seasonal herbage growth pattern in permanent and temporary swards, were observed under organic farming conditions, which displayed a different herbage growth rate and production than those previously recorded under intensive farming conditions. The mathematical model showed that the existing stocking rates in the Kohistan and Thar rangelands are very high and animals reproductive efficiencies are very low, which make whole system unsustainable in long-term. In order to integrate herbage growth pattern and livestock systems, calving/lambing times have to be moved to match the herbage growth.