Studies on the transfer of copper from soil to pastures at different sampling periods: a case study of a semiarid region (Sargodha) in Pakistan.

The present investigation was carried out to assess the transfer of copper element from the soil to forage plants consumed by the ruminants in two different pastures at the Livestock Experimental Station at Sargodha, Punjab, Pakistan. Soil and forage samples were collected periodically from two different pastures and analyzed after wet digestion. The survey of copper flow from forage from both pastures in the grazing period exhibited a consistent pattern of decrease from sampling periods 1 to 4 across all the sampling periods. In the legumes and grass pastures, it was decreased regularly and reduced up to 50% to that at the beginning across all the samplings. The copper concentration was higher in the legume pasture than that of grass pasture and sufficient to fulfill the requirement of grazing animals, while in grass pasture, it was higher at the first two sampling periods but dropped to a marginal deficient level at sampling period 3 and reached at the severe deficient level at the fourth sampling period during this investigation. The soil-plant transfer factor for Cu was higher in legume pasture compared to its counterpart. It was found that with the increase of forage maturity, a significant reduction in the forage Cu concentration was observed reaching its minimum level at the last sampling period in the grass pasture. These concentrations were within the marginal and severe deficient levels and provide for only 76% of the ruminant requirements. The naturally upset balance of Cu offers a potential hazard not only to both pastures, but also to the Cu status of grazing ruminants therein. This necessitates the provision of additional amount of Cu mixture in the nutrition of livestock for health and reproduction potential enhancement of the animals being reared at that farm. Supplementing the deficient mineral with locally available Cu feed sources like green fodders, cakes, and brans or providing region-specific mineral supplements would alleviate the deficiency of copper during the late season at the livestock farm.