Comparison of effects of different herbicides on NPK uptake, yield, and quality of Kinnow mandarin plants

The present study was conducted to assess the effect of different herbicides on nutrient uptake, and quality of Kinnow mandarin. Ten year old low-seeded Kinnow plants of uniform size were selected and recommended doses of Glyphosate, Paraquat and Metribuzin herbicides were sprayed under plants canopy three times (during March, July, and November) in a fruiting cycle to eradicate the weeds. The results showed significantly higher N, P, and K contents in the control treatment (2.98% N, 0.395% P, 0.239% K) while these contents were decreased in the treatments of glyphosate (1.68% N, 0.087% P, 0.2% K), paraquat (2.84% N, 0.268% P, 0.249% K) and metribuzin (2.70% N, 0.353% P, 0.205% K). Similarly, morphological parameters such as fruit diameter (6.84cm), fruit weight (156.30 g), number of seeds per fruit (5.06), seed weight (0.47g), peel weight (40.43g), peel thickness (2.13 cm) and average juice weight percentage (53.84% ) were substantially higher in the control treatment as compared to weedicide treatments. However, number of fruits per plant (67.78) and average yield per plant (9.48kg) was higher in the metribuzin treatment while rag weight (31.81g) was higher in fruits of glyphosate treatment compared to other treatments. Total sugars (23.98% ) and non-reducing sugars (20.76% ) were also higher in the control treatment as compared to all weedicide treated plants. However, total soluble solid (10.58 degrees Brix) and titrable acidity (1.02% ) were significantly higher in the metribuzin treatment compared to control and glyphosate treatments and non significantly at par compared to paraquat treatment. The paraquat treatment showed maximum vitamin C (42.93 mg 100g-1) and reducing sugars (5.78% ) among all treatments while TSS (9.38 degrees Brix, TA (0.94%), Vitamin C (40.23 mg/100g), non-reducing sugars (19.32% ) and total sugars (4.09% ) had minimum values in the glyphosate treatment.