Recovery Efficacy of Differentially Applied Nitrogen Regulates the Metabolism Coupled Physiological Phenotyping of Cotton on Leaching Prone Sandy Soil of Desert

Cellular concentration of nitrogen: an essential substrate for vital enzymatic reactions in plants is normally associated with its absorption rate in the diverse range of environments. A little was known about the relationship of nitrogen uptake rate with its metabolism and linked physiological phenotypes of cotton in the desert ambiance, which has been elucidated in this study conducted on the southern edge of Taklamakan desert. The treatments included were urea application in mud (UAM), fertigation with conventional flooding (UFF), fertigation with drip irrigation (UFD), and a control (C) with no nitrogen application. Results showed that cotton plants fertilized with UAM technique recovered almost 6% and 41% higher quantities of applied nitrogen than with UFD and UFF, respectively. This improved nitrogen recovery under UAM upregulated the activity of nitrate reductase by 4.5% over UFD and 15.5% over UFF, while the response of nitrite reductase was improved by 1.5% and 13% over UFD and UFF, respectively. As an outcome, it enhanced the metabolic activities of glutamine synthetase and glutamate synthase, revealing their linear relationship with the amount of nitrogen uptake. Besides, the quantities of free amino acids and chlorophyll molecules also improved linearly with the activities of N-metabolizing enzymes. Eventually, the rate of photosynthesis, soluble sugars, growth, and yielding phenotypes greatly improved with a confirmation of their relationships with N-uptake and its metabolism. Overall, the results suggested that nitrogen metabolism and depending morpho-physiological expressions of cotton can be enhanced on the leaching sensitive sandy soils by improving N-recovery with effective application techniques such as UAM in water adequate and UFD in water limited areas of cultivable deserts.