A HEALTHY SOIL IS IMPORTANT
Keeping it healthy is just like taking care of our health, with enough nutrients and medication for specific diseases, writes
SINCE the dawn of human civilisation, soil has been indispensable in supplying the food, water, and air for our survival, yet its importance has been largely taken for granted. Despite the fact that some vegetables can be cultivated with a “soilless” hydroponic method, the majority of food and commodity crops that feed and fuel the world rely on earthy soil.
Based on the latest World Bank statistics of 210 countries, Malaysia is ranked number 76 with 7.8 million hectares of agricultural land in 2015, compared with the largest agricultural country, China, with 527.8 million hectares.
The world’s total of 4.9 billion hectares of agricultural land in 2015 has been on a declining trend since 2008. To raise awareness of soil health, year 2015 has been coined as the year of soils (IYS2015) and Dec 5 as World Soil Day by the United Nations Food and Agriculture Organisation.
Land is a limited natural resource. Only around three per cent of land is suitable for agriculture; the thin layer on top represents the soil on which we grow crops.
The gradual weathering of rocks takes hundreds of years to form one centimetre of soil, and in the case of fertile soil with enough organic matter, it will take thousands of years. Furthermore, soil is constantly threatened by intensive farming, which leads to nutrient depletion, accumulation of agrochemicals, soil erosion and compaction.
Soil is regarded as a non-renewable resource: it is lost forever once destroyed. Therefore, it is imperative for us to take good care of our ever-shrinking arable land by considering soil health.
Soil health goes beyond soil quality in that it covers the concept of continued capacity and vital living system to sustain a diverse community of soil organisms known as biota.
Healthy soil also contributes to climate change mitigation through carbon assimilation. Sustainable farming such as intercropping or crop rotation promotes healthy soils by keeping the soil nutrient balanced and reducing pests. This is particularly pertinent to small-scale farmers in Malaysia; not only can the manure from livestock serve as organic fertiliser or feed for aquaculture, but also multiple cropping can diversify income from different produce.
For larger-scale farmers in oil palm or rubber plantations, maintaining soil health will often heavily rely on chemical fertilisers which serve as an easy solution. However, this could result in excessive use of agrochemicals that can be harmful to soil biota.
Chemical fertilisers can be described as medicine in treating acute nutrient deficiency in plants; organic fertilisers are akin to natural herbal remedies; while biofertilisers with beneficial microbial enrichment are like health supplements or prebiotic drinks.
To maintain a healthy soil is like maintaining human health, which will require balanced intake of nutrients or proper medication for specific diseases. There is no shortcut or “one prescription for all” solution to soil health, which requires integrated management of fertiliser application accordingly.
This ingenious concept has been applied as a solution to basal stem rot (BSR) disease that is threatening our oil palm industry. BSR is caused by a fungus known as Ganoderma boninenses which invades through the roots and degrades the trunk of oil palm inside out. By the time farmers detect the fruiting bodies that are shaped like a Lingzhi mushroom, it is too late to save the tree. The tell-tale signs of infected trees include spearing young leaves and skirting of yellowing older leaves.
Based on the concept of plant nutrient supplement, trees surrounding the infected tree can be prevented from getting BSR by providing biofertilisers with special formulation to promote plant lignin formation. Lignin is a class of organic polymers that make wood hard by reinforcing the plant cell wall. When the pathogenic fungus cannot invade trees with impenetrable roots, disease spreading is prevented. To put it simply, a strong healthy person is less likely to get infected by another flu patient.
Therefore, it is important to maintain healthy soils with all the micronutrients necessary for a healthy plant to grow than just supplying macronutrients from chemical fertilisers alone.
In short, maintaining soil health is not only important for preventing plant diseases and sustaining crop yield to ensure food security, but also to maintain a balanced ecosystem of soil biota for biodiversity.
Furthermore, there is a new concept of regenerative agriculture to reclaim loss of infertile soils through organic farming practices, such as conservation tillage, cover crops, composting, biochar, and pasture cropping.
The recent Malaysia International Agriculture Technology Exhibition has provided a great opportunity for all the stakeholders in agro-industry to meet and showcase the latest technology in promoting soil health and educating farmers on its importance.
Before farmers can dream of a bumper crop, they must first take good care of the soil!
The writer is a leader of Plant Functional Genomics Research Group at the Institute of Systems Biology, Universiti Kebangsaan Malaysia