Influence of Nitrogen Levels and Weed Management Practices on Nutrient Content,
Uptake and Grain Quality of Wetland Rice (Oryza sativa L.)

Nutrients and weeds are two important factors that influence the productivity of the rice.
Azolla and BGA have ability to replace N fertilizers by 25% of the total crop requirement
through biological N fixation. The Azolla covert may significantly inhibit weed infestation
without harming the rice yield. A 2-year field experiment was conducted to study the influence
of nitrogen (N) levels and weed management practices (WMP) on nutrient content, uptake, and
grain quality of wetland rice during Kharif 2018 and 2019. The experiment was laid out in a split
plot design having five nitrogen levels viz. control, 60, 90 &120 kg N ha -1 through inorganic
source and 60 kg N ha -1 as farmyard manure (FYM) in main plots and four weed management
practices viz. Azolla (2 t ha -1 ), blue-green algae (BGA), two-hand weeding (2HW), and weedy in
sub plots replicated thrice. Results indicated that the use of more N (120 kg N ha -1 ) recorded the
highest N content in rice grain and straw while phosphorous (P) & potassium (K) content was
noticed higher with the use of 60 kg N ha -1 as FYM. Higher nitrogen application (120 kg N ha -1 )
improved NPK uptake by grain and straw. Dual cropping of Azolla @ 2 t ha -1 leads to maximum
nutrient (N, P, K) content and uptake by rice grain and straw. Quality parameters viz. kernel
length & breadth before and after cooking were significantly influenced by N levels and
maximum values were noted with the use of 120 kg N ha -1 . The WMP fails to exhibit any
significant effect on the quality parameters of rice viz. kernel length & breadth before and after
cooking. Length: breadth ratio before and after cooking, elongation ratio, and expansion ratio
were also noted unaffected by N levels and WMP during the study period.