**2. Carbon oxidation and deposition in the soil**

Organic carbon is an important component of the soil that can stimulate functional compounds and enhances the performance of a microbial community [22, 23]. It provides lubrication and facilitates ease of energy transfer in an ecosystem [6, 8]. Cropping history and management on agricultural land are determining factors for net carbon sink or CO2 availability in the soil [7, 23]. Arable crop production decline carbon stored between 40% - 60% through conventional tillage and planting activities [9, 24]. Though at some point depending on the soil type and climate change crop production may attain an equilibrium carbon [9, 24]. This attainment may vary with different agro-ecological zones or regions [25, 26]. Soil carbon accumulation largely depends on the rate at which biomass decomposes [12, 22]. This includes primary reduction of plant residues above ground; leaves, stems, and other tissues. Likewise, plant exudates and the below ground as well as the roots. The pool of carbon in the soil depends on the rate at which organic carbon is oxidized by microbes and invertebrates [12, 22]. Soil organic carbon can be categories into active, stable, and inert organic carbon pools; active organic carbon is closely related to the nutrient requirement supply into the soil [7, 27]. They are permeable and can efficiently build up organic matter [13]. This category comprises microbial biomass carbon, soluble organic, mineralisable carbon, and carbohydrate, stable organic carbon pools are dominated by carbohydrate and lipid. This pool is made of organic particles and carbohydrates [15, 22]. The release of nutrients in this case is relatively slow. In other words, the inert organic carbon pool deposition is very

*Restoration of Soil Organic Carbon a Reliable Sustenance for a Healthy Ecosystem DOI: http://dx.doi.org/10.5772/intechopen.100188*

slow. It comprises lignin, hummus, polyphenol, and polysaccharide [15, 22]. More carbon will be available in the soil if organic carbon oxidation is low but with high oxidation, soil organic matter is used up than it is replaced by new biomass [2, 5]. A low oxidation rate increases the net sink of CO2. However, in the soil where biomass deposition is stable, the net change in carbon will be stored is continually [2, 5]. The continuous application of biomass at a point attains maximum carbon saturation. Equilibrium change of CO2 uptake into the atmosphere plays a significant role in net carbon sink in the soil [2, 5]. The quality of organic matter is affected by deposition. Microclimate and microorganisms play a major role in steady metabolization processes [20, 22, 27]. This regulates the extent to which chemical constituent is released into the soil. It was recorded that senesced leaves and stems with high carbon-nitrogen and corn stalks as well as the wood decomposes at a very low rate [28, 29]. Nevertheless, legumes and stems decompose more rapidly due to their low carbon-nitrogen and lignin content. The aggregate of oxygen supply to microbes in the soil may be restricted by tillage due to accelerated deposition by breaking apart the soil [15, 30]. This promotes rapid oxidation of carbon into the air. Plowing exposes the soil to direct insolation which may support rapid deposition [3, 31]. In this regard, CO2 emission is remarkably high and profound. This affects the quantity and quality of organic matter in the microenvironment [11, 22]. The net annual flux of soil CO2 year after year represents a change in organic soil carbon where erosion is put to control [14, 32]. Erosion prevents direct oxidation of carbon into CO2 due to surface runoff, particles are washed into waterways to bury existing carbon [14, 32]. It slows its deposition due to accumulation in anaerobic sediments. In other words, a carbon sink may be achieved as a result of slow deposition on an eroded site [14, 32]. It was recorded that the sink capacity of eroded soil amounted to 26% in a finding [3, 14, 15]. Several chemicals used in agricultural land increase CO2 in the air. Its impact on global warming is highly detrimental for instance 2.3 kg CO2 per active ingredient (750 Ngm−1) 4.5 kg CO2 per kg of N methane (CH4) are applied as fossil fuel to meet its temperature and pressure requirement [31, 33]. Also, lime (CaCO3) and dolomite (CaMg (CO3)2) were applied to neutralize the effect of acid cation in the soil [2, 32]. The use of lime may be influential as an agent of weathering. Nitric acid produces nitrifying bacteria [1, 4]. This supports the breakdown of carbon in lime.

$$\text{CaCO}\_3 + 2\text{HNO}\_3 \rightarrow \text{Ca}^+ + 2\text{HNO}\_3^- + \text{H}\_2\text{O} + \text{CO}\_2$$

But a weak carbonic acid from the root acid and microbial respiration transform lime into bicarbonate [1, 4].

$$\text{CaCO}\_3 + \text{H}\_2\text{O} + \text{CO}\_2 \rightarrow \text{Ca} + 2\text{HNO}\_3^-$$

Dissolution of lime by strong acid generates a large amount of CO2 into the air but weak acid support carbon sinks into the soil [15, 34]. It was revealed in research that sequestration of lime carbon depends on nitric or carbonic acid [24, 35]. CO2 may largely be neutralized for agricultural lime [3, 36]. The growth of biomass both above and below ground represents CO2 sink as carbon is captured in perennial vegetative growth [2, 37]. Perennial crops increase carbon sequestration due to persistent land cover [2, 37]. In this case, soil carbon is continually stored in the soil [37]. Perennial crop accumulates more carbon than annual crops [31]. Land cover prolong carbon stored in the soil. However, soil biomass is often accomplished by

reducing the soil deposition rate. It increases soil organic carbon [38, 39]. Carbon sequestration is high with crops that have abundant residue [6, 11]. Soil carbon can be enhanced through corn rotation. The use of corn-soybean rotation was found to be effective than corn rotation [12, 16]. The biochemical complexity of carbon residue input in the soil is a result of land cover. This helps build soil carbon [12, 16]. The no-till practice performs the function of deepening carbon into the soil. It increases the storage at the surface layer. Soil carbon content is ample evidence for no-till gain [8, 9]. More so, agricultural CO2 could be derived from energy input and soil amendment [25, 35]. Most cropping systems are not effective at retaining carbon as exogenous input such as manure, biochar, or sewage sludge [11, 33]. In other words, the native ecosystem is preferred at storing carbon to the use of the organic supplement [2, 25]. It is better concluded that permanent no-till mitigation is by far sustainable at retaining carbon in the soil [20, 40].

### **3. Climate change and its influence on environmental balance**

Climate change is an environmental behavior that characterizes the amount of water availability or dryness in a particular area. It is proportionate to land utility and nutrient availability [24, 25]. A land cover with the forest is significant to accumulating carbon and nitrogen in the soil [16, 27]. In other words, land use and evacuation of forests for buildings are inversely proportional to the balance of greenhouse gas emissions for the atmosphere [24, 26, 35]. This involves activities such as tractor pass on the land, burning of trees, and continuous harvest. This change is substantial to agricultural development and food availability [6, 7, 19]. In recent findings, it was hypothesized that soil depth of 30 cm is rich in carbon than the entire atmosphere. The carbon sink in the ocean is though relatively higher than the amount in the soil [1, 8]. However, soil and forest vegetation play a major role in carbon storage [2, 36, 38]. The global average temperature has risen nearly twice as much as high as the land surface air temperature [34]. Climate change has been noted to harm food security and the terrestrial ecosystem since the pre-industrial revolution [6, 7, 19]. This change was observed between 1850 and 1900 and 2006– 2015. The land surface air temperature was found to have increased by 1.53°C and the global mean surface temperature (GMST) by 0.87°C '[34]. This frequent rise in temperature was recorded in the Mediterranean, West Asia, South America, Africa, and North-East Asia [34]. This global change has resulted in vegetation browning than greening in many regions [2, 6, 7]. This is associated with dust storms, evapotranspiration, and decrease precipitation coupled with human activities [14, 28, 29]. This has drastically affected sustainability and development [24, 25]. In the last two decades, it was discovered that continuous rise in average temperature and reduction in the amount of rainfall might create a need for irrigation and poor agricultural output [8, 41]. More so, the success of agricultural output depends on the plant and animal cycle [12, 35]. Global warming may cause a polar shift in the climatic zone in the middle of the equator [1, 2]. The global warmth may result in high latitude. The regions with high latitude suffer drought, wildfire, and pest outbreaks [1, 2]. These regions have been depicted with global warmth of 1.5°C – 3.0°C. This warmth can be ascribed to permafrost degradation, poor agricultural output, and minimal carbon sink [2, 17]. This resulted in soil compaction and dryness [9]. It destabilizes the structural relevance of the soil, poor water retention, and plant growth [24, 40]. The nutritional quality of crops is lowered with increased atmospheric CO2 [5, 9]. Presently, over 7.6% rise in global crop and economic model of cereal due to climate change predict higher food price, food insecurity, and hunger in 2050 [25, 26]. In this case, food stability is disrupted due to extreme weather

*Restoration of Soil Organic Carbon a Reliable Sustenance for a Healthy Ecosystem DOI: http://dx.doi.org/10.5772/intechopen.100188*

conditions [24, 25]. This climate influence on seasonal changes may affect plant blossoming before their pollinators such as insects, birds, etc. are hatched [20, 26]. This may invariably result in flower loss and poor fruit formation [20, 26]. Soil health and agricultural management are hinged on meeting food production for the increasing world population **Figure 1** [16].

Nevertheless, an unprecedented rate of land and freshwater adaptive use for agriculture has been estimated to be 70% [25, 26, 35]. This is a result of global population growth and change in per capita consumption of food, fiber, timbre, and energy release [6, 7, 19]. This global population change has contributed to net GHG emissions, loss of natural ecosystems, and declining biodiversity [2, 7]. Likewise, more than 25 – 30% of food produced is wasted due to climate change [2, 7]. These challenges are aggravated in frost and ice-dominated regions [21, 42]. More so, an area not covered with ice is influenced by human activities [21, 42]. Moreover, due to fossil fuel extinction and greenhouse gas emission, there is an increasing need to replace fossil fuel with biofuel and other plant-based products [40, 41]. Furthermore, erosion is an important determinant of landform and nutrient availability [3, 15]. Intense rainfall, drought, heat loss, heat waves, and a storm cause agricultural land degradation, nutrient loss, plant breakage, stunted growth and total wilting, and perhaps rises in sea level, particularly in the coastal area [3, 43]. Climate change may produce a significant loss in agriculture output by 2050 if measures are not drawn or put in place [25, 26, 35]. Moreover, in some regions of the world climate change is linked to the availability of carbon dioxide and methane in the soil [2, 7]. The permafrost and melt of ice are common in the arboreal region. In this region, an increased temperature causes permafrost to melt [14, 15, 41]. This change over a period trapped organic matter into the frozen which after some time cause a disintegration [3, 43, 44]. Despite the continuous change of climate across the globe, ecosystem and soil quality can be restored by removing carbon dioxide from the atmosphere [1, 38]. According to findings, more than 63 billion tonnes

**Figure 1.** *Global warming and environmental changes sourced from [14].*

of carbon are removed from the soil [1, 38]. The health of the soil is improved by storing carbon underground [2, 37]. The growth of the plant and natural storage of carbon in the soil serves as a defense against climate change [22, 23]. Green space in the cities such as floods and heatwaves is cost-effective protection [25, 26, 35]. They perform the function of flood elimination and storage of excess water [14]. They cool down heat waves due to water accumulation in the soil [14]. They provide a healthy ecosystem during drought through a gradual release of water stored underground [11, 14, 38]. The availability of carbon in the soil can be maintained by converting arable land to grassland [7, 22, 23]. The growth of clover in between harvests and sowing the next crop [8]. This mitigation practice prevents erosion wash. It improves fertility and crop development [12]. Other adaptive measures to fight desertification and land degradation include reduced deforestation, ecosystem conservation, reduced food loss, and waste [3, 15, 30]. The conservation of high carbon ecosystems such as peatland, wetland, rangeland is linked with effective management practice [1, 2]. In addition, carbon sequestration in the soil or vegetation can be maintained by afforestation, reforestation, and agroforestry [12, 29]. The removal of the wood product from the forest restricts carbon in the soil [12, 29]. Peatland is efficient at striking a balance between vegetation and carbon reservoir [22]. This is achieved with the annual removal of CO2 from the atmosphere when the carbon sink declines towards zero [1]. This is the point where saturation measure is reached between vegetation and carbon reservoir [3, 15]. Management practices such as flood, drought, fire, or pest outbreaks may be hindered by mitigation practice if future management plans are considered [8, 40].
