Land Efficiency and Phosphate Fertilization in Sugarcane-Soybean Intercropping Using Local AMF under Saturated Soil Culture in Tidal Swamps

Tidal swamp land in Indonesia holds great potential for agricultural development but remains underutilized due to soil acidity and low nutrient availability. Integrating arbuscular mycorrhizal fungi (AMF) and efficient intercropping systems may improve land productivity and nutrient use efficiency in such challenging environments. This study evaluated the effects of local AMF inoculation and phosphate fertilization rates on the growth, productivity, and land-use efficiency of sugarcane-soybean intercropping under a saturated soil culture system in tidal swamps. The experiment used a randomized complete block design with two factors: AMF inoculation (with and without AMF) and four P fertilizer doses (0, 36, 72, and 108 kg ha−1 P2O5). AMF inoculation significantly increased sugarcane and soybean productivity in both monoculture and intercropping systems. Sugarcane yield increased by 86.7% in monoculture and 45.5% in intercropping, while soybean yield increased by 17.7% and 17.9%, respectively, compared to uninoculated control. Land equivalent ratio (LER) values ranged from 1.44 to 1.60, indicating more efficient land use under intercropping than monoculture. Phosphate fertilization did not significantly affect LER but moderately improved crop performance. These results highlight the potential of combining local AMF and intercropping systems to enhance crop productivity and support sustainable agricultural intensification in tidal swamp ecosystems.