A study on soil fertility management in the Highlands has found that natural fallow is still a best option for nutrient supply and productivity of kaukau or sweet potato. Findings from the three-year collaborative research have established that natural fallow of more than half a year old provided sufficient supply of crop nutrients for succeeding sweet potato cropping systems.
This biomass can efficiently provide nutrients when incorporated into the soil as organic material in compost mounds. However, this can be highly dependent on quality and quantity of the fallow biomass.
This was revealed during the final review of the project, Soil fertility management in the PNG Highlands for sweet potato based cropping systems, funded by the Australian Centre for International Agricultural Research (ACIAR). The review meeting was held in Goroka last month and was attended by project partners – ACIAR, NARI, Queensland University, Ramu Agri-Industries, Community Development Agency – Simbu, DPI Anglimp-South Waghi, and farmer representatives. The focus of the review was on soil fertility trials and training and extension activities.
The project was aimed at improving nutrient management options in sweet potato based cropping systems in the PNG Highlands. As such, the large Engan compost mound was exploited as an alternative nutrient management option.
Farmers engaged in the project acquired practical skills and knowledge by participating in the research. They also became good trainers for other farmers. Joseph Kuru, an innovative farmer from Eastern Highlands has coordinated well training and extension services on improved soil fertility practices. His training has extended to over 2500 farmers in Western Highlands, Jiwaka, Simbu and Eastern Highlands Provinces since 2008.
Trained farmers have taken the initiative to train others, through a multiplier effect, and more farmers are still expressing interest in hands-on training.
Farmers adopting the improved practices have made improved harvests. This has encouraged the incorporation of training in sweet potato processing for both human and livestock consumption to utilise surplus yield. This has been momentous in the Jiwaka Province.
During the review, a trip was organised to Keafu, Okapa to see what farmers are doing after receiving training in soil fertility management. The reviewing team were impressed to see the impact of utilizing improved management practices and to receive feedback from the farmers.