Application of Organic Fertilizers and Biofertilizers on Growth, Yield, and Spodoptera exigua Infestation in Shallot (Alium ascalonicum L.)

Abstract

Shallot (Allium ascalonicum L.) is an important horticultural commodity in Indonesia, and demand is increasing as the population grows. However, its productivity remains low, owing to land degradation caused by the extensive and continual use of inorganic fertilizers and pesticides. Organic fertilizers and biofertilizers have been offered as a long-term solution for increasing soil fertility and agricultural yield. The purpose of this study was to assess the effects of organic and biofertilizers on plant growth, yield, and Spodoptera exigua infestation in shallots. The experiment used a randomized block design with five treatments. These included 100% inorganic fertilizer and mixes of organic fertilizer (15−30 t ha⁻¹) and biofertilizer (6 mL plant⁻¹). The results showed that using organic fertilizers in conjunction with biofertilizers had no significant changes in plant growth and yield when compared to using only inorganic fertilizers. The highest bulb weight was attained by applying 30 t ha⁻¹ organic fertilizer coupled with biofertilizer. In contrast, the incidence of S. exigua infestation was considerably reduced in organic and biofertilizer treatments compared to inorganic fertilizer treatments. These findings suggest that combining organic and biofertilizers can reduce reliance on inorganic fertilizers while preserving yields and controlling pest infestation. Keywords: biofertilizer, organic fertilizer, shallot production, Spodoptera exigua