Effect of potassium fertilization on water productivity, irrigation water use efficiency, and grain quality under direct seeded rice-wheat cropping system

Abstract

A two-year field investigation was conducted to find out the right time, method, rate and source of potassium (K) fertilization for maximizing nutrient and water use efficiency and quality in a basmati rice-wheat cropping system. The split application of a recommended dose of K (RDK = 60 kg K₂O ha⁻¹) as half basal (B) and remaining half at panicle/ear initiation (PI/EI) stages significantly increased the system water productivity (SWP) (0.60 kg ha⁻¹mm⁻¹) and system irrigation water use efficiency (SIWUE) (1.26 kg ha⁻¹mm⁻¹) by 9.1% and 7.1% respectively over basal application of entire RDK. Likewise, in basmati rice, the split application of 100% RDK increased the water productivity (WP) and irrigation water use efficiency (IWUE) by 10.9% and 10.6% respectively over basal dressing of 100% RDK. The split application of RDK and supplementation of K through foliar spray besides basal K application increased the nitrogen, phosphorus and potassium concentration in grain and straw of both the crops. With respect to grain quality, the split application of 100% RDK increased the protein content by 2.3% in basmati rice, and 2.8% in wheat over basal application of 100% RDK. Similarly, the split application of RDK increased the hulling, milling and head rice recovery percentage of basmati rice by 1.3%, 6.6% and 3.3% respectively over basal application of RDK. The root length and dry weight of wheat was increased by 6.9% and 21% by split application of RDK over basal dressing of same dose of K.

Keywords:

• Basmati rice
• dry direct seeding
• agronomic efficiency
• potassium
• wheat
• water productivity
• grain quality

Acknowledgements

This article is part of the PhD thesis submitted to ICAR – Indian Agricultural Research Institute (IARI), New Delhi. The authors acknowledge the financial and laboratory support provided by the ICAR – IARI. Authors also thank faculty, Division of Agronomy, ICAR – IARI, for providing valuable suggestion at the time of framing of experiments.

Disclosure statement

No potential conflict of interest was reported by the authors.