~ 185 ~ Journal of Pharmacognosy and Phytochemistry 2020; 9(6): 185-187 E-ISSN: 2278-4136 P-ISSN: 2349-8234 www.phytojournal.com JPP 2020; 9(6): 185-187 Received: 12-08-2020 Accepted: 03-10-2020 Gurjinder Singh College of Agriculture, Guru Kashi University, Talwandi Sabo, Punjab, India Balwinder Singh Dhillon College of Agriculture, Guru Kashi University, Talwandi Sabo, Punjab, India Corresponding Author: Gurjinder Singh College of Agriculture, Guru Kashi University, Talwandi Sabo, Punjab, India Effect of crop residue incorporation on physical and chemical properties of soil under rice-wheat, guar-wheat and cotton-wheat cropping systems Gurjinder Singh and Balwinder Singh Dhillon Abstract A field experiment was conducted during May 2018 to April 2020 at agricultural research farm of Guru Kashi University, Talwandi Sabo, Bathinda. The experiment was carried out by incorporating kharif crops viz., rice, guar, cotton and rabi crop viz., wheat residues in combination There were twelve treatments in randomized block design with three replications. Incorporation of crop residues (rice straw and wheat straw) resulted in increase in soil organic carbon, electrical conductivity (EC) and porosity (%) of soil although decrease in bulk density and soil pH was found due to crop residue application. In 2018- 19, the highest organic carbon content was recorded for the treatment T5 (0.54%) where crop residues (both cotton and wheat) were incorporated and the lowest was recorded for T4, T 8 and T 12 (0.42%) and in 2019-20, combine application of both cotton and wheat residues exerted significant positive effect on soil organic carbon content and the highest organic carbon content was recorded for the treatment T5 (0.76%). Keywords: Crop residue, organic carbon, rice, sustainable agriculture and wheat Introduction Rice-wheat cropping system of the Indo-Gangetic Plains has played a significant role in the food security of India. This system spread over a vast area spanning from Punjab in the North- west to East up to West Bengal. Conservation agriculture involving zero or minimum-tillage and innovations in crop residue management (CRM) to avoid straw burning should assist in achieving sustainable productivity and allow farmers to reduce nutrient and water inputs, and reduce risk due to climate change. Crop residues generally left over plant parts of crops after harvest and threshing are important natural resources. The crop residue recycling helps in converting the surplus farm waste into useful products to meet the nutrient requirements of crops apart from improving the ecological balance of crops production system, but burning of rice straw is common in north-western parts of India causing nutrient losses, and serious air quality problems affecting human health and safety. About 82% of rice residue produced is burnt in the field after harvesting rice by combine harvester, resulting in the substantial loss of plant nutrient there in. Straw carbon, nitrogen and sulphur are completely burnt and also lost to the atmosphere in the burning process of rice straw. In addition, the ash lying on the surface of soil after burning absorbs the applied weedicide and decrease the efficiency of herbicides. Residue incorporation legumes have been reported to have greater influence over crop yield and enrichment of soil physicochemical and biological properties by Mandal et al., (2004) [4] . Incorporation of crop residues alters the soil environment, which in turn influences the microbial population and activity in the soil and subsequent nutrient transformations. It is through this chain of events that management of crop residues regulates the efficiency with which fertilizer, water, and other reserves are used in a cropping system. The removal of crop residues leads to low soil fertility and thereby decreased crop production. Organic materials such as crop residues offer sustainable and ecologically sound alternatives for meeting the nutrient requirements of crops. In addition to their role as the primary source of C inputs, crop residues, and the way they are managed, have a significant impact on soil physical properties (Boyle et al., 1989). Materials and Methods The present investigation was carried out in an experimental area of research farm of Guru Kashi University, Talwandi Sabo (Bathinda) during Kharif and Rabi season in the year 2018- 20. Talwandi Sabo is located at 290 57’N latitude and 750 7’E longitude and altitude of 213 meters above the sea levels. This tract is characterized by semi humid climate, where both