The Role of Microorganisms in the Application of Various Types of Animal Manure Solutions with Various Concentrations in the Cultivation of Lettuce (Lactusa sativa L.)

¹ Department of Agribusiness, Faculty of Agriculture, Universitas Islam Malang, Indonesia
² Department of Biology, Faculty of Mathematics and Natural Sciences, Jember State University, Indonesia
³ Department of Agrotechnology, Faculty of Agriculture, Universitas Islam Malang, Indonesia
⁴ Department of Biology, Faculty of Mathematics and Natural Sciences, Universitas Islam Malang, Indonesia
⁵ Department of Agrotechnology, Faculty of Agriculture, Wisnuwardhana University Malang, Indonesia

¹ Corresponding author: This email address is being protected from spambots. You need JavaScript enabled to view it.

Abstract

This study examined the interaction between manure type and concentration on the growth and yield of curly lettuce in a greenhouse, employing a factorial randomized block design. Four manure solutions were tested: goat (M1), cow (M2), chicken (M3), and rabbit (M4), applied at concentrations of 30%, 3%, and 0.3% (v/v). Results showed that microbial content differed by species, with rabbit and cow manures containing higher total fungal and bacterial counts than goat and chicken manures. The application of manure concentrates significantly influenced lettuce performance, improving vegetative growth (leaf number and area) and yield, with an average harvest index of greater than 0.95, which is higher than that of the control. These findings demonstrate that the effectiveness of liquid organic fertilizers depends not only on microbial abundance but also on community composition and proper dosage. Practical implications suggest that goat manure is most effective at a high concentration (30%), cow manure at a medium concentration (≈3%), rabbit manure at a low concentration (0.3%), while chicken manure remains relatively stable across concentrations. Selecting the right manure type and dosage enables farmers to harness microbial bioactivity, thereby increasing productivity and reducing their reliance on inorganic fertilizers sustainably. Overall, the study emphasizes the significance of manure type and application level in maximizing curly lettuce yield while promoting sustainable horticultural practices.