INTERVIEW WITH AFUA BONI

 

CSIR-SARI ENHANCES SOIL HEALTH IN NORTHERN GHANA (BIOFERTILIZER-       RHIZOBIUM)

 

•        CSIR-SARI explains the significance and nutrients derived from using Rhizobium Bio-fertilizers.

 

BY MATILDA MENSAH

The Savannah Agricultural Research Institute of Council for Scientific and Industrial Research (CSIR-SARI) has brought to board the use of Bio-fertilizer say Rhizobium Inoculant to enhance crop nutrition, soil and environmental quality thereby contributing to food security. It said that, the bio-fertilizers play important roles in nutrient cycling, promoting plant growth and development and building plant resilience to abiotic and biotic stress. These fertilizers are applied to seed, soil and plants at planting or during plant establishment, and exist in granular, liquid and powdered forms.

CSIR-SARI enhances on the use of  this bio-fertilizer called the Nitrogen-based bio-fertilizer because, it contains nitrogen fixing microbes like Rhizobium sp, Azotobacter and others, that help fix nitrogen(N) for plants uptake.

Again, plant require (16) sixteen essential elements like carbon, hydrogen, nitrogen, oxygen, phosphorus, calcium, potassium, iron, chlorine and others as food for them to grow and develop. Among these elements, phosphorus and nitrogen are the most limiting nutrients in smallholder farming systems in Ghana. Since, such farming systems in Ghana are generally characterized by cereal legume systems with mineral or no use of external inputs like improved varieties pesticides and others leading to crop yields to be low or declined due to poor soil quality.

Additionally, most farmers are poor in resources to purchase these mineral fertilizers especially the mineral N fertilizers to replenish their infertile soils for greater productivity because of high cost and limited access. Hence, the Biological Nitrogen Fixation (BNF) by legumes offers a cheaper alternative to correct the N deficiency in their cropping system than the use of mineral N fertilizer. This is because, BNF is an important process in cereal legume cropping systems.

The process involves the conversion of atmospheric N to form ammonia, usable by plants through soil bacteria called Rhizobia. The leguminous crops such as groundnut, soya bean and cowpea form a symbiotic association with soil Rhizobia to biologically fix N into the soil. The process can contribute a substantial amount of fixed N, up to 80% required by crops in agricultural system.

However, inoculant with Rhizobium bio-fertilizer can significantly enhance the amount of N fixed by legumes. The quantity of  N fixed by Rhizobium varies with the species of legumes and prevailing environmental conditions. Rhizobium can fix about 50-100kgNha  thereby  reducing the use of mineral  N fertilizers. The Rhizobium bio-fertilizers have been reported to increase the yield of leguminous crops by 10-35% in Hungria and others in 2006. The Rhizobium improves soil and environmental quality in terms of water pollution and greenhouse gas emissions, it also increases the biodiversity of the soil, as well as  helps in crop rotation or intercropping systems.

Therefore, using Rhizobium inoculant or bio-fertilizers for grain legume production is economically cheaper and environmentally friendly compared to using mineral N fertilizer for grain legume production. Thus, Rhizobia bio-fertilizer have a minimal negative environmental impacts compared to mineral N fertilizer.