SPECIES COMPOSITION AND SOIL CHARACTERISTICS BETWEEN GRAZING FORAGE SYSTEMS AND CUT AND REMOVED FORAGE SYSTEMS IN WALAWE REGION

Abstract

Botanical composition and soil parameters of grazing and cut and removed forage systemsin five villages (Barawakumbuka, Manadala, Nonagama, Bolana, Ambalantotoa) Walaweregion were studied to observe the impact of different management systems on theproductivity of plant and soil characteristics. Herbage and soil samples were collectedrandomly using a quadrate (50*50cm2) from five grazing and five cut and removed sites.Samples (3 replicates) were collected three times from each locations during the followingperiods. Herbage from grazing lands consisted 85% grasses and 15% other species.Prostrate grass species such as Efeusine indica and Chrysopgon aciculatus, were dominantand improved groundcover. Moisture (20.04%) retention in the grazed soil wassignificantly increased due to the improvement of ground cover with increasing thepotential for soil conservation. Herbage collected from cut and removed sites consisted70% grasses and 30% other species.

Dominant plants were tufted species such as Pennisetum polystachyon, Grewiacorpinifolia and Leucaena leucocepha. Moisture (6.13%) retention in these sites wassignificantly lower as compared with grazed sites.

Soil collected from grazing sites had higher pH (7.88) as compared to the cut and removedsites (6.13). This may be due to recycling of nutrients via dung and urine. Threading byanimals, which may cause a packing of the soil particles and loss of the large pores in thesoil mass increased the bulk density (1.34 g/crrr') of the grazing sites as compared with thesoil of cut and removed sites (1.16 g/cnr'). This would have been reduced the porosity ofthe soil in grazing sites (24.96%) as compared to the soil in cut and removed sites(46.86%).AIthough the bulk density of the grazing soils was negatively affected bythreading, ground cover, moisture retention and spatial redistribution of mineral nutrientsare influenced by grazing management as compared with cut and removed systems.Therefore, it can be suggested that grazing management is more suitable for low inputoutput subsistence farming systems in the Walawe region.