N and K fertilizer application rate under drip-fertigation for greenhouse grown sweet pepper

Drip fertigation is an effective way to apply water soluble fertilizer in a split doses to meet water and nutrient demands of sweet pepper (Capsicum annuum L.). The application rates of N and K through urea and muriate of potash (MOP) were evaluated for sweet pepper under naturally ventilated greenhouse during two consecutive seasons of 2010–11 and 2011–12. Eleven N and K fertilizer combinations, including nine combinations of urea and MOP, one commercially available ready mix dry liquid (water soluble) fertilizer with a ratio of 20:20:20 and a control, were applied through low head drip irrigation system weekly in 32 equal split doses. Uniform P (through surface) was applied in all the treatments. The two years average maximum yield of 62.2 t ha−1 was achieved at the fertilizer rate of 400 kg N ha−1 and 360 kg K ha−1. This yield was significantly higher than the average yield of 56.1 t ha−1 recorded from the normal recommended dose of 320 kg N ha−1 and 360 kg K ha−1and was at par with 400 kg N ha−1 and 450 kg K ha−1 (59.4 t ha−1). The average yield obtain from the fertilizer rate of 400 kg N ha−1and 360 kg K ha−1 was 11, 26 and 104% higher than the fertilizer application of normal dose, ready mix dry liquid fertilizer and the control, respectively. These results were obtained after enhancing the rate of application of N fertilizer by 25% while keeping the normal dose of application of K fertilizer.