Carbon and Zeolite Based Slow Release Fertilizer Formulations Enhances Nutrient Use Efficiency and Yield in Chilli

Aims: To develop slow release fertilizer formulations using humic acid, charcoal and zeolite and to evaluate nutrient availability, nutrient use efficiency and yield in chilli.

Study Design: This experiment was conducted through completely randomized design with 14 treatments and 3 replications.

Place and Duration of Study: The research was appraised at the Department of Soil Science, College of Agriculture, Vellayani between September 2022- December 2022.

Methods: Carbon and zeolite based slow release fertilizer formulations (SRF) containing all the major, secondary and micronutrients were prepared using compatible fertilizer materials (urea, rajphos, muriate of potash, phosphogypsum, magnesium sulphate, zinc sulphate and borax), carrier materials (zeolite, humic acid and charcoal) and the binding agent (carboxy methyl cellulose) in the ratio of 1:1 and 1: 0.5 in the form of pellets. These formulations were applied to chilli and evaluated nutrient use efficiency and yield.

Results: The pellets were highly stable and weight ranged between 4.0 and 4.5 g. The highest fruit yield of chilli observed was 581.2 g/ plant. The available nitrogen (320.86 kg ha-1), phosphorus (87.15 kg ha-1), potassium (214.35 kg ha-1), calcium (351.13 mg kg-1), magnesium (106.54 mg kg-1), sulphur (9.32 mg kg- 1), boron (0.46 mg kg-1) and zinc (4.25 mg kg-1) was found to be highest in treatment receiving 75% recommended dose of fertilizers (RDF) as humic acid based slow release formulation applied in two splits (basal and 1 MAP). The apparent recovery percentage of nitrogen 78.2%, phosphorus 86.33% and potassium 98.70% and partial factor productivity of 25.98 g g-1 were recorded due to the application of pellets.

Conclusion: Carbon and zeolite based slow release fertilizer formulations in the form of pellets are very effective compared to conventional fertilizers due to their gradual pattern of nutrient release which better meets plant demand, minimizes leaching and therefore nutrient use efficiency and ultimately crop yield. Application of slow release formulations significantly increases the nutrient availability in soil, nutrient use efficiency, growth and yield of chilli.