Arable lands are the major source of food production worldwide. Increasing crop cultivation in the response to population pressure and the use of synthetic fertilizers and chemicals are the main reasons for the conversion of arable lands into problematic soils. Increasing food demand requires to increase the per acre yield of agricultural crops resulting in over exploitation of soil resources. This is a major contributor to soil degradation which is the major threat to the food security of the world. Climate change and poor-quality irrigation are the other problems are also affecting crop productivity and the conversion of arable lands into problematic lands. Deforestation and urbanization are the main reasons behind the conversion of agricultural land into infrastructure. Adopting precision agriculture, vertical farming and good agricultural practices are the only ways to conserve arable lands. This chapter provides a keen overview of world arable land issues with the focus on threats to arable land and possible solutions to overcome this issue.
TopIntroduction
In May 2020 there have been under 7.8 billion people living on Planet Earth. It took less than 220 years to increase the world’s population by almost eightfold. The increasing population is exerting tremendous pressure on renewable as well as non-renewable natural resources such as soil and water, two major requirements for food production. Also, climate change is making existing challenges more severe (Koubi & Spilker, 2017; Weber, 2011, 2012, 2014). In the current scenario of food insecurity existing resources need to be managed in a sustainable way to meet existing needs without compromising the needs of future generations. To live up to these challenges the world’s existing soils must be managed to allow higher crop yields. Degraded soils must be reclaimed/ restored and added to the areas under crop production (Lal, 2016). Globally, one billion hectares of land is arable and 10% of this area is salt-affected costing US$441/ ha amounting to a total global loss of US$ 27.3 billion per year (Abiala et al., 2018). Arable lands are lands with having the capacity to e used as productive lands and these are cumulative of all the soils which can be used as agricultural soils but are being wasted. An increasing percentage of these soils are degraded due to soil salinity, erosion, deforestation, and different types of soil pollution (Blanco et al., 2017; Costantini et al., 2018; Oldeman et al., 2017). Salt accumulation in arable land is one of the major reasons behind degradation. Salts accumulating in soils reduce the nutrients available to plants and limit plant growth and yield. Common salts that cause soil salinity are sodium (Na+), potassium (K+), calcium (Ca2+), magnesium (Mg2+), and chlorides (Cl−) (Blanco et al., 2017). Land degradation, which is a form of soil structure, and texture deterioration also occurs through extensive tillage and soil erosion. Both operations cause soil structure deterioration which leads to the exposure of soil organic matter to heat which increases its decomposition (León et al., 2017). Deforestation accelerates soil erosion and soil degradation (Marichal et al., 2017). Extensive deforestation and other forms of vegetation loss are additional causes that can lead to desertification and loss of fertility (Bouma et al., 2017). Different forms of pollution such as heavy metals pollution, excessive fertilizer, and pesticide use, application of brackish water for irrigation and natural release of salts from soil sediments are also responsible for soil degradation (Cachada et al., 2018; Romero-Baena et al., 2018).
For restoration and rehabilitation of these soils, to be able to use them as productive soils, there are numerous methods. Some of these methods are e.g. the use of recommended agricultural practices which optimizes crop growth and soil requirements of nutrients and water (Emran et al., 2020), use of organic and inorganic amendments for soil fertility rehabilitation and structure (Emran et al., 2020), and treatment of salt-affected soils through chemicals like gypsum, sulfuric and nitric acids (Al-Saedi et al., 2018).
In addition to the soil reclamation and their improvement for crop production, different alternatives of soil as a growth medium for crops have been studied. Scientists have found various technologies where water and air are suitable media for food crop cultivation. Aeroponics, hydroponics, vertical farming, kitchen gardening, and modifying desserts for crop cultivation have been tested. The methods provided good results during trials (Ayipio et al., 2019; Rubio-Asensio et al., 2020). In addition to these innovative technologies, improvements in existing agronomic practices are employed coupled with existing agronomical practices to improve crop yields. Precision agriculture, site-specific practices, and zero tillage are the techniques that give a considerable amount of crop yield increase (Pedersen & Lind, 2017).
This chapter provides the following: (1) it gives a systematic overview of challenges to the soils of arable land, especially from the perspective of how these challenges compromise global food security in an era of climate change. (2) methods are introduced which support efforts to restore/reclaim/rehabilitate these problematic lands, and (3) the importance of modern technologies is discussed, which can help in alleviating challenges to soils of arable land problems and enhance global food security (Crosson, 2017; Lal, 2016; Kopittke et al., 2019).