Nitrogen Uptake Efficiency on Water Spinach in Controlled Planting Medium Using Spent Mushroom Medium Compost and NPK-16 Fertilizer

Ipomoea aquatica (water spinach) is a long and leafy green vegetable with hollow stems that easily grown on the water surface or damp soil. It is a tropical and subtropical perennial herbaceous aquatic or semi-aquatic plant. Water spinach needs more water compared to other vegetable crops, thus suggested to employ slow-release fertilizer for sustain the available nutrients in the soil that being leached off by watering. Nitrogen uptake is the major issue in agriculture to sustain the quality of crops and soil for planting medium. Several studies have been conducted on many types of fertilizer and showed beneficial results on growth of water spinach. This study aimed the research on comparing the nitrogen uptake rate study during the planting period for both organic and inorganic fertilizer. The measurement of plant height, dosage of fertilizer and nitrogen uptake were highlighted in this research activities. Pots has been used and the growth of water spinach was evaluated along 30 days of planting. The spent mushroom medium (SMM) compost and NPK-16 fertilizer were used to evaluate the rate of nitrogen uptake for water spinach based on the Michaelis Menten kinetic study to evaluate the best fertilizer dosage with research design activities. It was showed that a 1 g of NPK16 fertilizer was equivalent to 2 g of SMM in the amount of N. There was a clear correlation between the nitrogen concentration and the water spinach growth. From the result obtained, the application of NPK16 fertilizer provided higher nitrogen value initially. However, SMM compost improved both physical and chemical to help water spinach absorbed sufficient moisture and nitrogen uptake at a steady state rate owing to the higher organic matter in SMM. As a conclusion, SMM compost resulted better nitrogen uptake efficiency by improved the soil fertility and better growth of water spinach.