Assessment of soil fertility status in soybean growing soils: A case study from the semi-arid region of central india

462The edible oil needs of an ever increasing population of the country have been greatly supplemented by the yellow revolution, which used to be just 5 m tons at the time of India’s Independence. A significant role has been played by introduction of soybean (Glycine man (L.) Merr.) and sunflower (Helianthusannutrs L.) in late sixties for commercial cultivation. At present, soybean covers an area of nearly 7 m ha in the country and can be placed neck and neck to traditionally cultivated and established crops like groundnut (Arachis hypogaea L.) and rapeseed-mustard group of crops. Hence, the case study of semi arid region of central India has been carried out to know the fertility status with respect to major macro and micronutrients of major soybean growing soils of Latur district in the year 2009–10. For this purpose, 140 representative soil samples (0–15 cm depth) were collected from seven tehsils (20 villages from each tehsil) of Latur district and analyzed for available Phosphorus (P), Sulfur (S) and some micronutrients viz., Iron (Fe), Manganese (Mn), Zinc (Zn) and Copper (Cu) following standard procedures. The available phosphorus in these soils varied from 0.20 to 21.15 kg ha⁻¹ with an average value of 7.42 kg ha⁻¹, out of 140 soil samples 66.43% were low (< 10 kg ha⁻¹) and 33.57% samples were found medium (10 To 25 kg ha⁻¹) in available P content. Available sulfur ranged from 3.62 to 53.52 mg kg⁻¹ with a mean value of 21.47 mg kg⁻¹, about 12.14% samples were low (<5mg kg⁻¹), 32.14% medium (5 to 10 mg kg⁻¹) and 55.72% high (> 10 mg kg⁻¹) in sulfur content. In case of micronutrients, available Zn ranged from 0.12 to 2.96 mg kg⁻¹, the available Fe varied from 0.48 to 17.1 mg kg⁻¹, available Mn content were 0.16 to 21.12 mg kg⁻¹, Cu was very high varying from 0.25 to 12.19 mg kg⁻¹. Renapur and Chakur tehasils were found deficient in available P, all tehsils were depleted in case of Zn, available Fe, Mn, Cu and S were adequate in all tehsils. Soil Nutrient Index values of the soybean growing soils of Latur district were high in S, Fe, Mn and Cu, whereas low in available P and Zn. All the seven tehsils were high in available Mn and Cu, while all the tehsils were low in available Zn. In case of available Fe, Renapur tehsil belonged to medium category while remaining six tehsils were in high category. The soybean growing soils of Latur district were found depleted with respect to available phosphorus, whereas they were adequate in available sulfur.