Soil layers (surface of 30 cm deep) having 6 cm width were collected below drip line to 60cm lateral distance from a vineyard of Thompson seedless (Vitis venifera) cultivar of grapes grafted on Bangalore Dogridge (Vitis champini) rootstock under semi-arid climate of western Maharashtra (India). The soil (vertisol) was black in color, clayey in texture with sub-angular blocky structure, having alkaline in reaction (pH-7.81),non-saline in nature in nature (EC 0.31 dsm-1), low in organic carbon (0.20gm/kg), available N (32mg/kg), P (16mg/kg),K (204 mg/kg),Fe (0.78 mg/kg) and Zn (0.66mg/kg) while sufficient in S (16 mg/kg), Ca (6525 mg/kg), Mg(1056 mg/kg) and high in Na (340mg/kg).There is build up of nutrients and other elements below drip line and their status decrease as the sampling is carried out increasing away from drip line. On application of manures, bio-fertilizers and chemical fertilizers for 4 years, available P has increased from 16 to 277 mg/kg, available K from 204 to 1690 mg/kg, available S from 16 to 357 mg/kg. Fe from 0.78 to 3.58 mg/kg; Mn from 1.38 to 31.56 mg/kg and Zn from 0.66 to 10.73 mg/kg. The moist zone of drip line was found about 30 cm diameter at the surface and about 66 cm at 30 cm depth, indicating zone of maximum root activity.
Considering wide variations in the nutrient status of soil with increasing lateral distance, it is best to locate one distance and soil and nutrient may be developed with reference to the proposed soil sample location.
Thus it is proposed to collect soil layer having 6 cm width and surface to 30 cm deep, at a distance of 30 cm away from drip line on either side. The proposed sampling site has sufficient moisture and is full of active roots for soil nutrient and crop uptake interaction and represent ideal sampling site for fertility evaluation.