Vol. 10, Issue 10 (2021)

Author(s):
Shivani Yadav, Vinay Bachkaiya, Alok Tiwari, Mukesh Kumar Mandal and Dilesh Ray

Abstract:
The present investigation entitled “Assessment of soil enzyme activity as influenced by nutrient management practices in a Vertisol under rice-wheat cropping system” was conducted during Kharif 2020 in a Vertisol at Long Term Fertilizer Experiment, Research cum instructional Farm, IGKV, Raipur (Chhattisgarh). The treatments of this long-term experiment comprised of control, 50% NPK, 100% NPK, 150% NPK, 100% NPK + ZnSO₄@ 10 kg/ha, “100% NP, 100% N, 100% NPK + FYM @ 5t/ha, 50% NPK + BGA @ 10 kg/ha, 50% NPK + Green Manure” (Sunhemp). The treatments were laid out in Randomized Block Design (RBD) with four replications. Soil bio-chemical characteristics were recorded to be improved with continuous addition of chemical fertilizers in conjunction with organic over only chemical fertilizers. The soil pH and EC doesnot shows to have any significant effect of application of inorganic fertilizers either alone or in combination with organic manure. The organic carbon was recorded to be highest (6.84 g kg^-1) in treatment T₈ (100% NPK + FYM @ 5 tonnes/ha) and the lowest value (4.14 g kg^-1) is observed in treatment T₁ (control). The result indicated that application of 150% NPK and conjoint application of organic and inorganic nutrient sources tends to improve the available N, P, K status of soil. The soil enzyme activity, viz. dehydrogenase (55.39 TPF µg 24 hr^-1g^-1), urease (44.08 μg NH4⁺ - N g^-1 soil hr^-1)“acid phosphatase”(76.30“µg p-nitrophenol g^-1 hr^-1) and “alkaline phosphatase” (52.23“µg p-nitrophenol g^-1 hr^-1”) were significantly influenced due to addition of 100% NPK + FYM @ 5 tonnes/ha. The results also showed that application 150% NPK and 100% NPK + FYM @ 5 tonnes/ha recorded higher grain (6930 kg/h and 6850 kg/ha respectively) and straw yield (7785 kg ha^-1 and 7415 kg ha^-1 respectively) as compared to 100% N alone and control. The findings of experiment clearly indicated that continuous balanced use of fertilizers with organic manures, either alone or in combination is vital for enhancing nutrient status, enzyme activity, and yield in a rice-wheat cropping system on Vertisols.