Optimizing the application of biochar to improve irrigation efficiency and enhance the growth of chili plants in loam soil

Drought significantly threatens crop production by causing groundwater deficits, which hinder plant growth and development. Biochar has demonstrated its potential to improve soil water and nutrient retention. The study aimed to determine the optimal biochar dosage to promote the best growth of chili pepper plants under drip and conventional irrigation systems, calculating plant water needs and watering scenarios. Conducted in Dusun Bawang, Tunggulwulung Village, Malang, the study collected soil samples from Sumbergondo Village, Bumiaji District, Batu City. The experimental design employed a nested structure with eight irrigation treatments (drip and conventional) and four biochar doses (0%, 2%, 4%, and 6% of soil weight, each polybag containing 6 kg of soil). Each treatment was repeated four times, consisting of five units for each treatment, resulting in 160 experimental units. The chili pepper variety Ori 212 was planted in polybags pre-treated with chicken manure as a base fertilizer. NPK pearl fertilizer was applied at half the recommended dose. This study concluded that applying biochar at an optimal dosage of 4% can significantly promote the growth of chili plants. Integrating biochar with drip irrigation systems has proven effective in enhancing growth, especially in loam soils. The average potential evapotranspiration rate was measured at 3.91 mm/day. A water surplus was recorded from the third week of October to April, while a water deficit was noted from May until the third week of October, highlighting the necessity for efficient irrigation management. The water needs of chili plants varied across their growth stages. In the early phase, the requirement was 173 ml/day, which increased to 341 ml/day during the growth phase, peaked at 606 ml/day during fruit formation, and decreased to 598 ml/day during maturation. This rise in water demand reflects the plants’ development.