Abstract

All the crops require larger amounts of macronutrients for sustainable production. In view of this context, a present investigation was conducted during 2018–2019 at farmer's field, Namakkal, Tamil Nadu, India to study the effect of potassium on growth, yield and nutrient uptake of groundnut in cv. TMV 13. The farm is located at 11006’00’’ N latitude and 78004’11’’ E longitude. The experiment was laid out in randomized block design with three replications and nine treatments. The treatments were Absolute control, RDF (NP alone), RDF (NP alone) + 25 kg K2O/ha, RDF (NP alone) + 50 kg K2O/ha, RDF (NP alone) + 75 kg K2O/ha, RDF (NP alone) + 100 kg K2O/ha, RDF (NP alone) + 125 kg K2O/ha, RDF (NP alone) + 150 kg K2O/ha, RDF (NP alone) + 175 kg K2O/ha. The results of the field experiment revealed that application of potassium significantly increased the growth, yield and nutrient uptake of groundnut. Growth attributes, namely, plant height (18.2, 42.4 and 55.2 cm at FS, PFS and HS, respectively), leaf area index (1.58, 3.31 and 3.03 at FS, PFS and HS respectively), dry matter production (2746, 4449 and 5906 kg/ha at FS, PFS and HS respectively), total chlorophyll content (1.83 and 2.29 mg/ha at FS and PFS, respectively) and yield attributes, namely, pod yield (2558 kg/ha), haulm yield (3348 kg/ha), shelling percentage (75.2%), kernel yield (1923 kg/ha) and test weight (44.5 g) were found to be maximum in application of RDF (NP alone) + 100 kg K2O/ha. The treatment also recorded the maximum of total nitrogen uptake (84. 3 kg/ha), phosphorus uptake (24.7 kg/ha) and potassium uptake (103.6 kg/ha). However, the treatment of RDF (NP alone) + 100 kg K2O/ha was on par with the treatment of RDF (NP alone) + 125 kg K2O/ha. The least values of growth, yield and nutrient uptake were recorded in absolute control. In post-harvest soil, the maximum value of available nitrogen content (179.2 kg/ha) and phosphorus content (26.7 kg/ha) were recorded with application of RDF (NP alone) and the maximum potassium content (275.2 kg/ha) was recorded with application of RDF (NP alone) + 175 kg K2O/ha. From the results, the present experiment concluded that the excess levels of potassium application decreased the growth, yield attributes and nutrient uptake of groundnut. The application of potassium as 100 kg K2O/ha enhanced the better yield and nutrient uptake of groundnut.