Effect of applied calcium-boron ratio on the accumulation of nutrient-elements by radish (Raphanus sativus L.)

The present study was based on the hypothesis whether applied Ca/B ratio has an association with other plant nutrients. A green house study was carried out in sandy heath land soil, growing radish (cv. French breakfast) as a test crop. The experiment was laid out in a randomized complete block design and replicated three times. Different Ca/B ratios were applied 2000:1, 1000:1, 500:1, 250:1, 125:1 and 25:1, corresponding to soil solution ratios 7959:1, 4369:1, 1035:1, 851:1, 486:1 and 45:1 along with a basal dose of all essential nutrients. Significant treatment effects were observed in the growth response of radish and maximum dry matter yield of tops and roots were recorded at Ca/B ratio of 1035:1 in soil solution or applied 500:1. Results further revealed that B deficiency and toxicity symptoms were clearly apparent on plant leaves when the radish plants received higher and lower Ca/B ratios, respectively. However, no visible symptoms of other nutrients were found on plants during growth. The concentrations of P, K, Ca, Mg, Na, Mn and B in plants were significantly affected, while the total uptake of all nutrients were significantly changed due to Ca/B ratios in soil, in terms of applied or in soil solution, and showed close similarity to growth response. Correlation between Ca/B ratios and the concentrations of P, Ca, Mg, Na, Cu, Fe, Mo and B attained statistical significance, while in case of total uptake only N, P and Na showed significance, suggesting Ca/B ratios have some association with the other plant nutrients. It appears from the present study that no single or narrow range of Ca/B ratios in soil, whether applied or in soil solution is best for the concentration and total uptake of plant nutrients studied. However, considering the test soil from sandy heath land and the radish crop it seems that the best Ca/B ratios for the concentration and total uptake of nutrients ranged from 1000:1 to 500:1, corresponding to soil solution ratios ranged from 4369:1 to 1035:1. However, the role of Ca/B ratio on the behavior of plant nutrients is still not well defined, and further experimentations are desirable in this field.