Spatial variability of available micronutrients in burning and non-burning paddy soils

Abstract

An open burning in paddy field is a conventional way to remove stubbles and prepare for the next crop cycle, yet a controversial issue about available micronutrients in soils remains, in particular, in a long-term burned field. This study aimed to i) compare available concentrations of Cu, Fe, Mn and Zn between burning and non-burning paddy soil, ii) assess the relationship of micronutrient availability and soil properties, iii) map the spatial distribution of soil micronutrients. Two sets of soil samples, a total of 40, were collected from two paddy fields based on minimum consecutive five-year periods of burning versus non-burning practices. Available Cu, Fe, Mn and Zn were obtained by diethylenetriaminepentaacetic acid (DTPA) extraction method. Mean available micronutrients were as follows: Fe>Mn>Cu>Zn. Abundant concentrations of Cu, Fe, and Mn were sufficient for growing rice in both sites; however, they were significantly greater in burning paddy field as compared to non-burning field. Zn deficiency occurred across paddy farming soils. On the basis of results obtained, Strategies to improve Zn availability are required.