According to Food and Agriculture Organisation (FAO) the long-term health of soils, and water is fundamental to accessing sustainable food, guaranteeing nature-positive production. As Nigeria join in marking this year’s World Soil Day, John Oba, in this write up call attention to the need for protection of Soil and Water as a way of achieving President Tinubu’s target on food sufficiency.
World Soil Day (WSD) is held annually on 5 December as a means to focus attention on the importance of healthy soil and advocating for the sustainable management of soil resources.
With the Federal Government declaration of a State of Emergency on food security, the place and need to invest properly on healthy soil and clean water cannot be overemphasized.
Though, Nigeria is blessed with abundance water resource and huge arable land, the country is still faced with several challenges, firstly, in improving access to portable water, despite the rapidly increasing demand driven by high population growth, urbanization, and rising living standards resulting from economic growth, while Nigeria land is threatening, with degradation, among many other challenges.
Soil and water are basic, vital and essential resources for sustainable agriculture. Sustainability implies utilizing these resources in ways that ensure little or no damage whilst guaranteeing their continuous usage. It involves a system of management through wise use of resources while still providing food and fibre for the teeming population. It seeks to control cost and improve farm profitability.
According to FAO report, a sustainable soil management could produce up to 58% more food, hence a healthy soil and clean water is a major step for any country to increase its food production. This year’s World Water Day theme, “Soil and Water: A Source of Life,” captions this succinctly.
Soil and Water
Soil and water are essential resources for sustaining life on Earth. They both provide the foundation for food production, ecosystems, and human well-being. Recognizing their invaluable roles, we can take proactive measures to safeguard these resources for future generations.
Soil erosion and compaction disrupt the capacity of soil to store, drain and filter water, and exacerbates the risk of flood, landslides and sand/dust storms. Soil and water are the medium in which plants grow and obtain essential nutrients. Healthy soil plays a crucial role as a natural filter, purifying and storing water as it infiltrates into the ground.
The health of the soil and the quality and availability of water are interconnected. Implementing sustainable soil management practices enhances water availability for agriculture.
Water Pollution
The decrease of freshwater resources worldwide is the result of its severe pollution, as a consequence of waste discharging, the massive generation and the inadequate treatment of wastewater, and the lack of the sanitary systems that favour the contamination of the water resources. Pollution can be permanent, systematic, periodic, or accidental, when the period of time the pollutant acts is considered. Groundwater, surface water, and oceans are subjects of continuous pollution from point sources, non-point sources, or transboundary pollution.
Soil Resource
Soil is one of the most valuable resources on Earth, essential for food security on a global level. However, as the climate changes, the pressure on both soil and water resources intensifies, which is why the need for sustainable management becomes more and more demanding. One strategy recommended as being potentially effective and lasting for mitigating climate change is the safe storage of atmospheric carbon as a substantial potential sink for greenhouse gases (GHG).
A quality (healthy) soil is characterized by several physical, chemical, and biological properties such as: the content of organic matter in adequate proportion; adequate structure; and suitability as a habitat for various organisms.
Soil and Water Interactions
Water exists in soil as thin films outside of soil particles, and in pore spaces (such as gravitational water and capillary water), determined by the texture, bulk density, and structure of soil. Water-holding capacity represents the soil capacity to store water from rainfalls and available for plants. This is a highly essential soil property for growing plants, especially during dry periods.
Capillary water plays the most important role for plants because it is held by the particles of soil against the force of gravity, as opposed to the gravitational water that moves in the ground as a result of the action of gravity. The two forms of soil water are in competition: as the water seeps into the soil, it fills the pores’ spaces with water, which as the pores fill up, moves through the soil due to gravity and capillary forces, until a balance between the two categories of forces is reached.
Achieving food sufficiency
According the President, Nigeria Institute of Soil Science (NISS) and the Chairman, NISS Council, Professor Ayoade O. Ogunkunle, in his forwarding note on NISS publication recently, meeting Nigeria food and water requirements would be an insurmountable challenge without the presence of healthy soil and clean water.
“The quality and health of soils largely determine agricultural production and sustainability, environmental quality and, as a consequence of both, has bearing on plant, animal and human health. The swift development of the urban and industrial environment observed in the last decades has put significant pressure on the natural resources of the world, with concerns manifested by resource shortages, price growth, and instability and degradation of ecosystems.
“The value of life, the health of humans and ecosystems, and the state of the economy are dependent on how natural resources (water, land, energy, minerals, biomass, fossil fuels, etc.) are sustained. The invaluable roles of soil and water should be recognized and it is very essential for us to take proactive measures to safeguard these resources for future generations.
“The pressures on land and water ecosystems are now intense, and many are stressed to a critical point. Against this background, it is clear our future food security will depend on safeguarding our land, soil and water resources. Taking care of land, water and particularly the long term health of soils is key in accessing food in an ever demanding food.”
NISS publication states that soil and water are interconnected resources that need integrated management. Healthy soils, enriched with organic matter, play a crucial role in regulating water retention and availability.
“Efficient use of quality water, promoting the sustainable use of fertilizers and pesticides, employing appropriate irrigation methods, improving drainage systems, controlling pumping, and monitoring soil and groundwater salinity levels are essential to maintaining sustainable agricultural practices.
Water in Soil
Water is a renewable, vulnerable natural resource, being a determining factor in maintaining the ecological balance. Water existing in soil is a vital resource which cannot be overstated, for both plants, since water is a key element for plant growth and development, consumed in relatively large quantities and for various types of ecosystems.
The water content of soil is particularly vital, as it influences its moisture, the amount of nutrients available to plants, and the aeration state of the soil. Soil water refers to water that exists naturally in soil as gravitational water, capillary water, and hygroscopic water, depending on the functions of the soil.
The extent to which water is stored or redistributed in soil depends on the size of the soil pores and their dimensional distribution, which, in turn, depend on soil texture and structure (Ball, 2021; Rogers et al. 2021). Whereas irrigation water use represents almost 70% of Total human ‘blue water use (water withdrawn from water bodies such as river, lakes, and aquifers) global agricultural blue water consumption that is the amount of water that transpires productively through crops or evaporates unproductively from soils, water bodies and vegetation canopies is estimated to be even higher.
Threat to soil and water management
NISS report assert that sustainable soil management is key to improve water productivity in irrigated systems. Improper soil and water management practices affect soil erosion, soil biodiversity, soil fertility, and water quality and quantity.
“Water scarcity leads to the loss of soil biodiversity, while leaching and eutrophication from agriculture practices lead to the loss of biodiversity in water bodies.
“The mismanagement of pesticides and fertilizers not only threatens soil and water quality but also poses significant risks to human health and ecosystems. Poor irrigation and drainage practices are some of the main drivers of soil salinization. Rising sea levels contribute to land loss, increasing the risk of soil salinization and sodification, which can negatively impact agricultural productivity,” the report revealed.
The publication also states that soil and water conservation contribute to climate change mitigation and adaptation. Improved soil and water management improves the land’s capacity to withstand extreme climate events such as droughts, floods and sand/dust storms.
As integrated soil and water management practices provide essential ecosystem services, supporting life on earth and enhancing ecosystem resilience, while healthy soils act as a carbon sink, by sequestering carbon from the atmosphere, thus contributing to both climate change adaptation and mitigation efforts.
NISS counsel that strategies aimed at achieving food security should be based on soil health, which is both a prerequisite and the ultimate goal. “Soils rich in biota and organic matter are the foundation of increased crop productivity. The best yields are achieved when nutrients come from a mix of mineral fertilizers and natural sources, such as manure and nitrogen-fixing crops and trees.
“Judicious use of mineral fertilizers saves money and ensures that nutrients reach the plant and do not pollute air, soil and waterways. Policies to promote soil health should encourage conservation agriculture and mixed crop-livestock and agro-forestry systems that enhance soil fertility. They should remove incentives that encourage mechanical tillage and the wasteful use of fertilizers, and transfer to farmers’ precision approaches such as urea deep placement and site-specific nutrient management.”
Sustainable intensification requires smarter, precision technologies for irrigation and farming practices that use ecosystem approaches to conserve water. Cities and industries are competing intensely with agriculture for the use of water.
Despite its high productivity, irrigation is under growing pressure to reduce its environmental impact, including soil salinization and nitrate contamination of aquifers. Knowledge-based precision irrigation that provides reliable and flexible water application, along with deficit irrigation and wastewater-reuse, will be a major platform for sustainable intensification. Policies will need to eliminate perverse subsidies that encourage farmers to waste water.
In rainfed areas, climate change threatens millions of small farms. Increasing rainfed productivity will depend on the use of improved, drought tolerant varieties and management practices that save water.
Effect of soil organic matter
As the world marks the 2023 World Soil Day, it is time the government give soil and water management a priority. Healthy soils with a high organic matter content have the capacity to store large amounts of water. This is beneficial not only during droughts when soil moisture is crucial to plant growth, but also during heavy rainfall because the soil reduces flooding and run-off by slowing the release of water into streams.
Healthy soils are therefore crucial for maintaining food production and clean groundwater supply, while also contributing to resilience and disaster risk reduction.