Abstract

                                Field experiments were conducted to study the effect of biochar with/without FYM and inorganic fertilizers on soil productivity of cotton – maize – cowpea based cropping system and to examine the direct, cumulative and residual effects of biochar on soil properties at field No.36 B, Eastern block, TNAU, Coimbatore, on an Inceptisol belongs to Periyanaickenpalayam series and Vertic Ustropept in USDA classification. The study reveals that application of biochar irrespective of levels, increased the available N, P and K of the post harvest clay loam soil of cotton. The effect was increased with corresponding increase in the rate of application. Significant improvement was found when biochar was applied in conjunction with fertilizers and FYM. Among the treatments, the trend of results were significantly higher in biochar @ 10 t + 100 % NPK + FYM followed by biochar @ 10 t + 75% NPK + FYM treatment which was statistically on par with biochar @ 7.5 t + 100 % NPK + FYM treatment. Similar trend of direct effect was registered in the post harvest soil of maize grown under both cumulative (continuous application) and residual (one time application) studies. However, the effect was higher under cumulative study than the residual study. Similar trend of results were also registered in the post harvest soil of cowpea under both the cumulative residual (residual effect of continuous application) and second residual (second residual effect of one time application) studies. A significant improvement in the soil properties of post harvest soil of cowpea under second residual study was also recorded. Thus, proving the biochar’s ability to sustain the soil fertility over long run. .

Key words : : Biochar, Soil health, Residual and cumulative effect.