Soil conservation basically refers to the prevention of soil loss as a result of erosion or even a loss of fertility as a result of salinization, acidification, over-usage, and other contamination of soil by chemicals. Soil conservation also results from unsustainable subsistence farming including slash and burn techniques, which may cause massive erosion, soil nutrient loss, deforestation, and desertification (Ramos et al., 2015). Generally, soil erosion, which is the main consequence of poor soil conservation, removes top soil that is required for micro-organism, nutrients, and organic matter needed for the growth of crops. Healthy soil is essential for the flourishing and growth of plants, which necessitates soil conservation to maintain and enhance soil and crop productivity. The ability to supply food in an environment of continuous population growth is dependent on the soil carrying capacity, which in turn depends on soil quality that is harmed by soil erosion and lack of soil conservation (Blaikie, 2016). Indeed, provision of food for the world’s population is an environmental factor which determines the carrying capacity of specific species. This paper strives to determine the extent to which soil conservation measures influence the carrying capacity for human populations.
There are several methods of soil conservation that may be used to enhance soil carrying capacity for human populations. The first method is the use of cover crops, which entails the use of specific crops like radishes and turnips that are used to blanket the soil across the entire year while also providing green manure to replenish critical soil nutrients like nitrogen, managing soil erosion, and suppressing weeds (Pimentel & Burgess, 2013). This method has several advantages including improvement of soil quality, increasing soil organic matter, supplying nitrogen, reducing soil compaction, and reducing soil erosion. Further, cover crops also enhance water infiltration, reduces leeching of nitrates, increase crop yield, and decreases water runoff. However, cover crops also have several disadvantages such as increased cost related to planting the crop and tilling it back, reducing soil moisture effects, and difficulties in using tillage (Pimentel & Burgess, 2013).
A second method of soil conservation is terracing, which entails the replacement of slopes using horizontal terraces. Terraces are used in the cultivation of sloped land similar to steps on the sloping sides of hilly farmland, with the main aim being to reduce water runoff velocity and reduce soil erosion by reducing the slope length across which the water flows (Borrelli et al., 2016). This technique has several advantages including prevention of erosion by reducing runoff water velocity and interrupting fast-flowing rain water, as well as allowing farmers to plant crops on steep slopes. Further, terracing also prevents flooding by slowing down the rate at which water reaches plain surface and enabling more gradual water absorption by the ground, while also allowing for the planting of more crop varieties which may not flourish in plain lands. However, terracing also has several disadvantages for soil carrying capacity including saturation of the ground by rainwater, increased need for manpower thus increasing cost, and high maintenance cost of terracing (Borrelli et al., 2016).
A third technique for soil conservation is plowing, which is an old farming method that produces loosened soil and a straw-free surface on which farmers can create seedbeds and establish new crops. The advantages of this method include increased efficiency by achieving desired depth that allows for planting of seeds with more accuracy, while also enhancing the drainage properties of the soil (Morgan, 2013). In addition, plowing increases weed control by burying weeds into the ground thus inhibiting weed growth during the next planting season, as well as enhancing soil fertility by providing green manure. Further, plowing also improves pest control by churning the soil thus increasing crop productivity and carrying capacity. Nevertheless, plowing increases the risk of soil erosion by loosening the soil and making it easier for runoff water to carry away mineral-rich top soil. Moreover, by eradicating soil organisms, plowing also reduces the aeration levels of soil and may harm carrying capacity (Morgan, 2013).
Contour farming is another method of soil conservation that entails the plowing of grooves on the farmland, which is the followed by plating the crop furrows into the contours and grooves to prevent runoff and enhance carrying capacity (Dymond et al., 2013). Advantages of this technique are increased water conservation and improved irrigation systems, conservation of the top soil layer and prevention of erosion, slowing down the rate of water runoff after heavy rains, and prevention of gully and rill formation on the farmland. In addition, contour farming also eases harvesting and reduces labor requirements. However, this technique also has several disadvantages including its unsuitability for farmlands with high levels of overland flows, impracticability on steep hills and irregular topographic land, and the impracticability of using some types of farm machinery on curved rows (Dymond et al., 2013).
Finally, crop rotation is also used for soil conservation and entails the growing of different or dissimilar crops in one area across sequenced planting seasons with the aim of preventing deletion of nutrients used by specific crops. This method of soil conservation has several advantages such as reduction of water runoff and soil erosion by improving microbial communities and soil tilt, thus enhancing water infiltration and enhancing soil structure (Held & Clawson, 2013). Crop rotation also enhances soil conditions through the planting of crops with fibrous or tap rots, which enhance the physical, biological, and chemical soil structure. Thirdly, crop rotation also reduces weed and pest buildup by taking away their host organisms and replacing them with others. On the other hand, however, crop rotation needs additional machinery which increases initial costs, while this method may also have fluctuating crop yields and financial returns during specific seasons or years when less valuable crops are planted (Held & Clawson, 2013).
- Blaikie, P. (2016). The political economy of soil erosion in developing countries. Abingdon: Routledge
- Borrelli, P., Paustian, K., Panagos, P., Jones, A., Schütt, B., & Lugato, E. (2016). Effect of good agricultural and environmental conditions on erosion and soil organic carbon balance: a national case study. Land Use Policy, 50, 408-421
- Dymond, J. R., Ausseil, A. G., Parfitt, R. L., Herzig, A., & McDowell, R. W. (2013). Nitrate and phosphorus leaching in New Zealand: a national perspective. New Zealand Journal of Agricultural Research, 56(1), 49-59
- Held, R. B., & Clawson, M. (2013). Soil conservation in perspective. Abingdon: Routledge
- Morgan, R. J. (2013). Governing Soil Conservation: Thirty Years of the New Decentralization. Routledge
- Pimentel, D., & Burgess, M. (2013). Soil erosion threatens food production. Agriculture, 3(3), 443-463
- Ramos, M. C., Benito, C., & Martínez-Casasnovas, J. A. (2015). Simulating soil conservation measures to control soil and nutrient losses in a small, vineyard dominated, basin. Agriculture, Ecosystems & Environment, 213, 194-208