Effects of rice husk biochar (RHB) with combined inoculation of arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB) on growth of maize (Zea mays)

Abstract

For optimal plant growth and productivity, agricultural activity is dependent on soil quality and nutrient availability. Soil amendment such as rice husk biochar (RHB), which abundantly found in Malaysia, are capable of improving soil fertility due to its longevity and other benefits to soil biota, including beneficial soil fungi and bacteria such as arbuscular mycorrhizal fungi (AMF) and phosphate solubilizing bacteria (PSB). AMF are well-known for their capacity to improve plant nutrient uptake, particularly P, which is essential for plant growth. Similarly, PSB, which is a beneficial bacteria, are able to solubilize phosphate into soluble form thus enhance the P availability for plant. However, the combination effect of AMF and PSB in the presence of RHB is not known. Thus, in order to assess the effects of AMF and PSB in the presence of RHB on soil properties and maize growth, a pot experiment was done. Randomized completely block design (RCBD) arrangement was applied to the following treatments: T1 (control), T2 (RHB), T3 (AMF), T4 (PSB), T5 (+RHB, +AMF), T6 (+AMF, +PSB), T7 (+RHB, +PSB) and T8 (+RHB, +AMF, +PSB). About 10 t/ha RHB was added to the soils for treatments T2, T5, T7, and T8. Ten grams of AMF inoculum and double application of PSB were applied to their respective treatments. Plant growth and soils sampling were done at 45 days after planting (DAP). Results showed that T7 gave 137% root biomass and 123% P uptake higher than control. Our findings were in line with our hypothesis (application of RHB, AMF or PSB or their combination would improve maize growth compared to control, in which T8 gave highest root volume and 150% higher than control. The results suggested that there were positive and synergistic effects of beneficial soil microorganisms (AMF or/and PSB) either with or without RHB. Thus, these combined inoculations and RHB application could be used in biofertilizer formulations to increase the maize growth and yield in sustainable agriculture system.