Response of cassava (Manihot esculenta Crantz) to calcium and potassium in a humid tropical upland loamy sand soil

Calcium (Ca) and potassium (K) are essential nutrients for plant growth but the antagonistic effect between these nutrients may reduce crop yield. A two-year field trial was carried out in a loamy sand soil to evaluate cassava response to Ca (0, 50,100, and 200 kg ha-1, as ground limestone, GL) and K (0, 50,100, and 200 kg K2O ha-1, as potassium chloride, KCl). Calcium addition, especially 200 kg Ca ha-1, adversely affected soil K availability with more pronounced on water-soluble K than on exchangeable and non-exchangeable K from day-7 onwards. Both Ca and K had no antagonistic impact on cassava. However, growth and yield responded positively to K more promptly than to Ca. Combined rates, except 100 kg Ca ha-1 with no K fertilizer, significantly increased fresh tuber yield by 7.6-41.1 % over the control. To gain the highest fresh tuber yield by adding 200 kg Ca ha-1, 200 kg K2O ha-1 must be implemented. This light-textured soil was physically preferable for cassava tuberization, and the optimum yield can be achieved by proper Ca and K fertilization.(c) 2022 Published by Elsevier Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Calcium and potassium are essential nutrients for plant growth, but their antagonistic effect may reduce crop yield. A two-year field trial showed that increased calcium negatively affected soil potassium availability, with a more pronounced effect on water-soluble potassium. However, calcium and potassium had no antagonistic impact on cassava, and cassava responded more promptly to potassium compared to calcium. Combined application of calcium and potassium significantly increased fresh tuber yield, with the highest yield achieved by adding 200 kg Ca ha-1 and 200 kg K2O ha-1.