Efficacy of Potassium Humate and Chemical Fertilizers on Yield and Nutrient Availability Patterns in Soil at Different Growth Stages of Rice

ABSTRACT

Potassium humate (PH) is a promising natural resource to be utilized as an alternative for increasing crop production. A pot experiment was conducted during 2009 and 2010 to assess the efficacy of application of potassium humate (0, 5, and 10 mg kg⁻¹ soil) alone and in combination with chemical fertilizers (75% and 100% recommended dose of nitrogen–phosphorus–potassium) on yield and nutrient availability patterns in soil at different growth stages of rice. Two doses of zinc, viz. 0 and 12.5 mg kg⁻¹, were also applied. Sole and combined application of potassium humate with nitrogen–phosphorus–potassium (NPK) and zinc significantly (p < 0.05) improved the yield and availability of nitrogen, phosphorus, potassium, sulfur, zinc, and dehydrogenase activity in soil. Application of 10 mg kg⁻¹ potassium humate along with 100% NPK and 12.5 mg kg⁻¹ zinc sulfate proved significantly superior when compared to 75% and 100% of NPK alone.

KEYWORDS:

• Chemical fertilizers
• dehydrogenase and soil health
• potassium humate
• rice grain yield

Acknowledgments

The authors thank the Head of the Department of Soil Science and Agricultural Chemistry, Institute of Agricultural Sciences, Banaras Hindu University, Varanasi, India, for providing necessary facilities during the course of investigation.