Performance of maize, soybean, and mung bean intercropping systems in East Java, Indonesia

Context Maize ( Zea mays L.)-soybean ( Glycine max L. (Merr.)) intercropping can enhance land and resource use efficiency, but its performance depends on species interactions, environmental conditions, and management. There is little information on intercrop performance under different configurations without major resource deficits in a tropical climate. Objectives We determined the land use efficency of simultaneously sown, flood irrigated maize-soybean intercropping systems comprising maize, soybean and mung bean in the tropical climate of East Java with moderate fertilizer input, and evaluated how narrow-wide row systems and incorporation of mung bean changed the land use efficiency and productivity. Methods Experiments were done during four growing seasons. Two replacement systems used two maize and four soybean rows in alternating strips at local standard spacing or at reduced maize inter-row distances to improve soybean radiation interception (narrow-wide row system). Two additive systems introduced mung bean ( Vigna radiata L.) or additional soybean rows. Results Additive intercrops had higher land use efficiency (average LER ≈ 1.10) than sole crops or replacement systems (LER = 0.93). The narrow-wide row system improved soybean performance and overall LER without significantly affecting maize yield. Soybean outperformed mung bean in additive systems, while mung bean struggled near maize rows. Synthesis and implications Simultaneously sown maize-soybean replacement intercropping systems with recommended fertilizer inputs and sufficient water did not have a land use advantage in East Java. Additive systems provided marginal benefits. These findings align with emerging evidence that yield benefits of intercropping are small under simultaneous sowing and adequate resource inputs.