~ 2077 ~ Journal of Pharmacognosy and Phytochemistry 2020; 9(5): 2077-2081 E-ISSN: 2278-4136 P-ISSN: 2349-8234 www.phytojournal.com JPP 2020; 9(5): 2077-2081 Received: 16-07-2020 Accepted: 18-08-2020 Vidhi Garg Department of Agronomy Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India Nitish Tiwari Department of Agronomy Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India Omprakash Rajwade Department of Agronomy Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India SK Gupta Department of Agronomy Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India Corresponding Author: Vidhi Garg Department of Agronomy Indira Gandhi Krishi Vishwavidyalaya, Raipur, Chhattisgarh, India Nutrient uptake by direct seeded rice ( Oryza sativa L.) and removal by dominant weeds species in Chhattisgarh plains Vidhi Garg, Nitish Tiwari, Omprakash Rajwade and SK Gupta Abstract The present investigation entitled “Nutrient uptake by direct seeded rice (Oryza sativa L.) and removal by dominant weeds species in Chhattisgarh plains ” was carried out at Research cum Instructional Farm Farm, Indira Gandhi Krishi Vishwavidyalaya (IGKV), Raipur (C.G.) during Kharif season of 2016. Rice variety Rajeshwari was direct seeded on June 27 th 2016 with a spacing of 20 x 10 cm and harvesting was done on November 3 rd, 2016. The results of experiment indicated that maximum uptake of nutrient in grain and straw was recorded in weed free (3 Hand weeding) (T9) 56.14 and 17.52 kg ha -1 of N, 15.26 and 5.07 kg ha -1 of P and 14.16 and 85.03 kg ha -1 of K, respectively. Minimum uptake of 6.70 kg ha -1 of N, 0.91 kg ha -1 of P and 13.32 kg ha -1 of K was observed in control (Mixed flora) (T8) taking the total values of grain and straw. The nutrient removal by weeds was recorded maximum under control (Mixed flora) (T8) at 80 DAS 61.73, 8.72, 169.95 and at harvest 73.79, 10.44, 203.46 N, P, K kg ha -1 . The lowest nutrient removal of N, P and K kg ha -1 was 0.36, 0.12, 0.93 and 0.82, 0.28, 2.13 at 80 DAS and harvest respectively under weed free (3 Hand weeding) (T9). Keywords: Nutrient uptake, rice, Oryza sativa L., dominant weeds Introduction Rice (Oryza sativa L.) is the most important and widely cultivated crop in the world. Asia is the home of rice as more than two billion people are getting 60 70% of their energy requirement from rice and its derived products. About 90% of total rice is grown and consumed in Asia. It occupies an important place in the economy of India. Rice crop is the biggest user of fresh water. Rice as a submerged crop is a prime target for water conservation because it is the most widely grown of all crops under irrigation. Rapidly depleting water resources threaten the sustainability of the irrigated rice and hence the food security and livelihood of rice producers and consumers (Tuong et al., 2005). Due to resource constraints, especially water and labourers, direct seeding under dry condition is now emerging new trend in rice cultivation. Weeds compete for moisture, nutrients, light and space and a consequence, weeds infestation in direct seeded rice results in yield losses in the range of 30 to 90%, reduces grain quality and enhances the cost of production (Singh et al., 2009 [8] The DSR seems to have retained significantly more nitrogen as compared to transplanted rice in straw, more plant population per unit area might have encouraged DSR for more uptake and retention of nitrogen in straw (Dingkuhn et al.1990). Roy and Mishra (1999) experiences that more weeds present in the field suppressed the crop due to nutrient removal and reduced the yield which might be attributed to vigorous growth and development of weeds. Weeds in direct seeded rice systems are mainly managed by using herbicides and manual weeding. Major weeds found in Chhattisgarh plains are Echinochloa colona, Echinochloa crus-galli, Ischaemum rugosum, Oryza sativa (weedy rice), Leptochloa chinensis, Paspalum distichum among the grasses. Cyperus iria, Cyperus difformis, Cyperus rotundus, Fimbristylis miliacea among the sedges and Monochoria veginalis, Eclipta prostrate, Commelina benghalensis, Cynotis axillaris, Ceasulia axillaris, Alternanthera triandra among the broad leaved weeds. Material and method A field experiment was conducted at Research cum instructional farm Indira Gandhi Krishi vishwavidyalay Raipur with objective to find out the Nutrient uptake by direct seeded rice (Oryza sativa L.) and removal by dominant weeds species in Chhattisgarh plains under medium land situation. The experimental field was sandy loam in texture, poor in organic carbon (0.45%), available nitrogen (205.4 kg ha -1 ) and medium in available phosphorus (16.2kgha -1 ) and potash (321 kg ha -1 ).