Comparative effects of organic and inorganic soil amendments on the growth of cashew nut (Anacardium occidentale l.) seedlings

Abstract

Amendment of nursery soil with nutrient-containing compounds could promote seedling development. The utility of coffee husk and the optimum quantity needed in sole or combination with NPK for enhanced cashew seedling development was investigated. Medium size cashew nuts were raised for 20 weeks in six nutritional treatments. There were three coffee husk application rates (0.0021 g-1 Kg, 0.0041 g-1 Kg and 0.0062 g-1 Kg), CH and NPK (0.00208 g-1 Kg CH and 0.00016 g-1 Kg NPK), 0.00016 g-1 Kg NPK and a control in 3 Kg of soil. Leaf count (LC), stem girth (SG), plant height (PH) and leaf area (LA) were measured five times. Amended nursery soil significantly (P < 0.05) and positively affected the performance of cashew seedling. Potted nursery soil amended with higher (≥ 0.0041 g-1 Kg) CH concentration and CH/NPK significantly (P < 0.05) increased LC, SG, PH and LA at every periodic intervals of measurement. The five sequential intervals of measuring LC, LA, SG and PH showed different trend patterns: linear, quadratic and cubic with respect to each treatment. Post-experiment soil and plant nutritional test revealed that the N, P, K, Ca, Mg, soil pH, soil organic carbon (SOC), and soil organic matter (SOM) were significantly (P < 0.05) higher compared to the control. CH with 0.00625 g-1 Kg concentration increased soil pH, SOC, SOM, N, K, C, Mg and leaf N by 10.20%, 10.50%, 19.20%, 8.33%, 42.38%, 25.00%, 50.00% and 93.20% respectively. Post experiment evaluation revealed that the five nutritional treatments significantly aided higher biomass. However, addition of 18.75 g coffee husk to 3 Kg of soil was most effective for improved cashew seedling growth and development.