By Onome Amuge
Agricultural waste, also known as agro-waste, has been classified by agronomists as the non-product outputs of production and processing of agricultural products whose economic values are less than the cost of collection, transportation, and processing for beneficial use. It comprises livestock waste (manure, animal carcasses), crop waste, food processing waste, pesticide residues, among others.
The United Nations Food and Agriculture Organisation (FAO), in its State of Food and Agriculture report, pointed out that the global estimate of agricultural waste produced yearly is approximately 998 million tonnes, with over 40 percent of the two billion tonnes of global waste generated annually.
The quest to enhance food production globally has consequently heightened the application of valuable resources such as land area, water, biodiversity, minerals, etc in the agricultural sector characterised by active farming operations and increased production of agricultural commodities.
As positive as this may sound for the agriculture sector, it has resulted in the worrisome accumulation of agricultural waste compounded by residues from the cultivation and processing of raw agricultural products such as fruits, vegetables, meat, poultry, dairy products, and crops. These wastes have also constituted a serious threat to human health through environmental pollution and economic loss, especially in developing economies where there is poor awareness about their potential risks and economic benefits if properly managed. Due to this challenge, agricultural waste management has been considered one of the biggest burdens to agricultural stakeholders in the 21st century.
Rhoda Dia, project manager in charge of food security project at the United Nations Development Programme (UNDP), noted that Nigeria’s palm oil production industry alone generated over 90 million tonnes of effluent (liquid waste) annually, while an estimated 19.5 million cows also generate a large amount of waste.
Dia added that Africa’s largest rice producer generates 4.34 million tonnes of rice straw and 900,000 tonnes of rice husk.
With Nigeria’s increasing population, she projected that the quantity of agricultural waste generated in the country will triple in the coming decades with an adverse implication on the country’s economy if the potential present in converting agricultural wastes to energy as well as other economically viable re-purposed products is not exploited.
Poor awareness regarding waste treatment and the opportunities for converting biodegradable agricultural wastes into valuable resources has oftentimes resulted in many farmers getting rid of farm wastes using environmentally harmful methods such as burning or abandonment to decomposition. This has intensified the magnitude of soil contamination, release of disease-causing organisms and ozone-depleting gases, which have a direct effect on human health and environmental degradation.
On how Nigeria’s agriculture sector can effectively manage waste for both environmental and economic sustenance, Obiageli Umeugochukwu, a lecturer and environmental soil science consultant at the University of Nigeria Nsukka (UNN), said there is an urgent need for the government at all levels to invest in agricultural waste management given the direct and glaring implications of waste on human health, agriculture, the environment, and the economy.
Umeugochukwu also advised the government and players in the agriculture sector to make the move from hydropower and petroleum fuel and tap into the energy and recycling opportunities for using waste to improve the food system.
According to the agriculture expert, there exists the potential of resourcefully reusing agricultural waste materials to reduce environmental harm and boost soil fertility and farm productivity through recycling, using simple science-backed approaches; treating waste water which can be utilised for irrigation and other useful purposes, as well as conversion into bioenergy.
She noted that the country’s rice wastes, estimated at about 4.34 million tonnes of rice straw and 900,000 tonnes of rice husk, can produce around 337.67 megawatts per year of electricity at a conversion rate of 1.7 kilogramme of rice husk/straw/ kilowatt of electricity.
Umeugochukwu further averred that resourcefully reusing wastes to generate biofuels reduces greenhouse gases as well as global warming, increases rural manufacturing jobs and incomes, and improves circulation within the food supply chain.
Oyewole Okewole, founder and team lead at Oakwall Agro-Industrial Consult and Services, said that agro-wastes can be converted into economically viable products through the adoption of Research, Technology and Innovation (RTI).
RTI, he explained, has transformed what could be wastes two to three decades ago into new products and deliverables that foster production of diverse forms of agricultural produce including fruits and vegetables.
Okewole further stated that the rainy season in tropical regions of the country has witnessed great wastage of harvested produce. He pointed out that producers get carried away with the excess in production and do not necessarily bother with the marginal wastes, with most smallholders experiencing insufficient resources to process and store their excess produce for the offpeak seasons.
On how producers and stakeholders in the agriculture sector can gain financial returns in this situation, he said there is a window of opportunity there.
“This is the time to invest in a researched area of focus for agro-commodities that are easily wasted within your area of locality and strategically buy the produce, sell off some, process and store the excess,” he said.
The agro-industrial expert explained that these tied capital investments usually experience increased income in about a few months down the line when the off-peak season emerges. He said that though it may require some costs for inventory, the costs incurred are completely wiped out when their demand becomes evident.
Okewole advocated for more awareness to be created to stakeholders involved in agricultural activities regarding the implications of indiscriminate disposal of agricultural wastes and how it can be properly harnessed for effective purposes. He also called for the formulation of policies to support recycling of agro-wastes, noting that the establishment of a more sustainable agricultural supply chain, infrastructural developments and durable markets will play a significant role in supporting “waste to wealth” initiatives.
Wale Karunwi, managing director, Kalos Agro Homes Integrated Farms, said agricultural waste can be made economically viable through conversion into renewable energy.
Giving an instance of how this can be actualised, Karunwi disclosed that briquette, a form of charcoal, can be produced from rice husk.
Briquette, he explained, does not produce smoke as the injurious gases have been eliminated at the point of processing the rice husk into briquette, making it environmentally safer than ordinary charcoal.
“This technology is known globally, but we are just getting to know it in Nigeria, and it has become imperative because of the hazards inherent using charcoal and firewood.
“It is an emerging market and since I have been using it in my farm, we have been overwhelmed by people coming to us with their rice husks,” he noted.
He also emphasised that rice husk alongside other agro-wastes can be converted to organic fertiliser rather than being discarded.
According to Karunwi, recycling agro-wastes into useful products or harnessing them for value-added products manufacturing would not only increase the economic development of the agriculture sector, but would as well open up job creation opportunities and generate revenues through chains of profitable activities.