Effects of manure-based urea pellets on growth, yield, and nitrate content in coriander, garden cress, and parsley plants

Various organic residues and animal manures represent an excellent matrix material for production of natural-based pellet fertilizers. Fully decomposed cow manure with 50% w/w urea was used for pellet production in densities of 400 or 800 kg/m3, representing low and high compact urea pellets. The growth of coriander (Coriandrum sativum L.), garden cress (Lepidium sativum L.), and parsley (Petroselinum crispum Mill.) were then evaluated under application of these pelleted urea compared to urea alone and unfertilized plants. The total amount of applied nitrogen (N) in the form of urea or pelleted urea was 300 mg/kg soil, wherein pelleted urea treatments, 30% of N was incorporated into the soil as urea alone before planting. The results showed that application of pelleted urea in low and high compactness resulted in different plant responses in the three vegetable crops. Plant growth and biomass production was increased in plants treated with urea or low compact urea pellets. Leaf N concentration and the Soil-Plant Analysis Development (SPAD) index were increased by low but not by high compact urea pellet application. Regardless of compactness, pellet treated plants had less nitrate content compared to urea treated plants. Number of flowering plants in coriander and garden cress was higher with high compact urea pellet and in unfertilized plants, whereas plants treated with urea or with low compact urea pellet showed fewer flowering plants. So, for production of these leafy vegetables low compact pellet is preferred.