Effect of Gypsum, Nitrogen and Phosphorus on Growth, Yield and Quality of Spring Groundnut

Background: Groundnut kernels contain 48-50% edible oil, 25-34% protein, 10-20% carbohydrates and are a rich source of vitamins (E, K and B complex). Groundnut is a legume-oilseed crop, its requirement of phosphorus, calcium and sulphur is quite high. Gypsum is commonly used as a source of calcium and sulphur for groundnut all over the world. Keeping all these points in view the present study was undertaken to find out the optimum mineral nutrition of spring groundnut Methods: A field experiment was conducted for 2 years at the Students’ Research Farm, Department of Agronomy, Punjab Agricultural University, Ludhiana during spring season of 2018 and 2019. The experiment was laid out in a split plot design replicated three times with four levels of gypsum (0, 125, 175 and 225 kg ha-1) in combination with two gypsum application stages (Full at sowing and 50% at sowing + 50% at flower initiation stage) in the main plot and three levels of nitrogen and phosphorus (15 kg N ha-1 + 20 kg P2O5 ha-1, 25 kg N ha-1 + 30 kg P2O5 ha-1 and 35 kg N ha-1 + 40 kg P2O5 ha-1) in the sub-plot. Result: Application of 225 kg ha-1 gypsum resulted significantly higher growth parameters, pod yield, haulm yield, kernel yield over other gypsum levels. Growth parameters, pod yield, haulm yield and kernel yield were significantly higher with the split application as compared to basal application of gypsum. Growth parameters viz., emergence count, plant height, number of branches plant-1 and dry matter accumulation were increased with increase in the levels of nitrogen and phosphorus up to 25 kg N ha-1 + 30 kg P2O5 ha-1. However, 35 kg N ha-1 + 40 kg P2O5 ha-1 resulted significantly higher protein and oil content of kernels over other levels of nitrogen and phosphorus, while pod yield, haulm yield and kernel yield were at par with 25 kg N ha-1 + 30 kg P2O5 ha-1 during both the years.