Effect of Conservation Agriculture on Vertical Distribution of Organic Carbon and Zinc Transformations under Alluvial soil
Loading...
Date
2017-07
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Department of Soil Science and Agricultural Chemistry, BAU, Sabour
Abstract
Zinc is one of the essential micronutrient elements and is required by the crop plants in very small amounts. Nevertheless, from nutrition point of view, it is indispensable like any other essential element. It plays a fundamental role in various metabolic processes in plants. The present highly intensive cultivation with high yielding varieties which need higher inputs lead to a declining trend in system productivity due to depletion of organic matter and Zinc in the soil. The mobility and leaching of the Zn depends on its concentration in the soil, the soil properties and environmental factors. The downward movement of soluble Zn complexes in soil profiles has received attention because even slow transport through soil may cause an increase in the concentration of Zn at lower depths (Kumar et al.2010). Conservation Agriculture offers an opportunity for arresting and reversing the downward spiral of resource degradation as well as leads to an environmentally sound sustainable agriculture. Organic materials hold a great promise due to their local availability, as a source of multiple nutrients and availability to improve soil characteristics. But it is necessary to quantify the comparative behaviours in the transformation of Zinc and thus, the vertical distribution of Soil Organic Matter for Zn nutrition under rice-based cropping system seems to be important. Keeping these views, the present study “Effect of Conservation Agriculture on Vertical Distribution of Organic carbon and Zinc Transformations under Alluvial soil” was carried out in the post harvest soil (2016) of the ongoing Conservation Agriculture experiment on “Effect of rice establishment techniques on crop yield of different rice based cropping systems” which was initiated in Kharif - 2011 at BAC Farm, Sabour, Bhagalpur. The experiment has been laid out in a split plot design which includes three main plots of different rice establishment techniques viz. Zero tillage (ZT), Permanent bed (PB) and Conventional tillage (ST) and sub-plot treatments comprising of rice crop in three different cropping systems viz. rice-wheat (R-W), rice-maize (R-M) and rice-lentil (R-L). The Rice establishment techniques like Zero tillage and Permanent bed significantly increased the organic carbon, cation exchange capacity and DTPA-Zn, Cu, Fe & Mn of soil as compared to conventional tillage. It was further observed that after 5 years of completion of the experiment, organic carbon build-up up-to 15% (0.61%) and 9% (0.58%) from the initial value (0.53%) due to zero tillage and permanent bed respectively. Among the cropping systems, Rice-Lentil system sustained the soil physico-chemical properties compared to Rice-Wheat and Rice-Maize.
Among the Zinc fractions Water soluble-Zn significantly increased from 1.04 to 1.51 mg/kg due to different treatment combinations. Zero tillage and permanent bed significantly increased the WS, EX, ORG, CRY and AMO-Zn up-to 18, 09, 20, 14 and 15% respectively compared to conventional tillage. Most of the Zn was present in residual form. Only small fractions were present in easily soluble form like WS, EX, complexed and organic fraction. However, Organic carbon and DTPA-Zn decreased with soil depth irrespective of treatments. The soil receiving organic matter had high organic carbon and DTPA-Zn in surface soil than subsurface soil. Conservation agriculture practices significantly affected soil organic carbon (SOC) and Zinc distribution. The retention of crop residues on the soil surface and absence of tillage operations drove SOC dynamics in the top layer of the conservation system, while residues incorporation with ploughing was responsible for SOC accumulation at the subsurface depth in the conventional one (Piccoli et al., 2016)
Description
Keywords
null