Efficient Management of Environmental Resources through Sustainable Crop Production Intensification

Abstract

Agriculture is crucial to the survival and well-being of the populations of most nations. It is the single most important means of livelihood and foreign exchange earnings for many nations globally. Crop Production is the bedrock of agriculture on which most other agricultural activities depend, because of the ability of plants to manufacture their food via photosynthesis, which is an essential phenomenon for the sustenance of the natural system. Thus, most other agricultural activities depend directly or indirectly on crop production. As a result of the exponential increase in world population, leading to a significant reduction in agricultural land due to urbanization; deforestation, air pollution, erosion, climate change, and consequently, food insecurity; measures must be put in place to ensure crop production intensification via sustainable and environmentally safe methods that guarantee food security. The principles of sustainable crop production intensification discussed in this Chapter include optimum tillage method, land and water resources management practices, suitable choice of agricultural system, precise crop management techniques, and bioremediation, in an already contaminate environment.

1. Introduction

Agriculture is the global largest industry. It provides employment for more than a billion people and generates in excess of $1.3 trillion dollars’ worth of food annually [1]. Pasture and cropland occupy about half of the Earth’s habitable land and provide habitat and food for a good number of organisms [2]. Most agricultural activities are dependent on environmental resources which must be properly managed to ensure food security. When agricultural operations are sustainably managed, they can preserve and restore delicate habitats, protect water resources, and improve soil health and water quality. Conversely, poor management practices have potentially grave negative impacts on the environment and the ecosystem.

This fact is even truer for crop production. Crops occupy the primary producers’ level of the food chain. Thus, they manufacture their food using environmental resources, i.e., soil nutrients and sunlight. As a result, all other life forms depend directly or indirectly on plants for food and survival. Crop production is therefore considered the bedrock of agriculture [3].

Among others, factors which are social, economic and biological in nature; environmental factors, especially edaphic and climatic factors are of utmost importance in crop production. The soil provides anchorage, and a growth medium for plants. It supplies the necessary nourishment needed for crop growth and also houses essential organisms and micro-organisms which are responsible for the recycling of nutrients necessary for crop growth [4].

The rate of partitioning of photosynthetic assimilates for dry matter production also depends in no small measures, on the amount of nutrient and moisture in the soil, as well as favorable climatic conditions including humidity, temperature, and most importantly solar radiation [5]. Unfortunately, there are several modern socio-economic and environmental challenges to overcome in our bid to optimize agricultural productivity especially in the area of crop production. Such challenges include, industrialization leading to increased environmental pollution, urbanization causing reduced access to fertile land for agricultural activities, fast declining soil fertility from continuous cultivation of the same area of land as a result of urbanization, poor management practices on the limited land, indiscriminate use of agricultural input to compensate for the aforementioned problems leading to more dangerous environmental and hydrological pollutions, deforestation interacting with environmental pollution to force excessive warming of the environment and consequently, climate change, among a number of other challenges [6].

It is a fact that the world’s population is increasing. The rate of increase is projected to intensify in the coming decades [7]. As a result, the level of food production must increase to meet the need of the teaming population despite the significant decrease in available land resources which is expected to further decline as the population increases. Production intensification on the available environmental resources is therefore of critical importance in order to ensure optimum crop growth. This involves social, cultural and environmental modifications which must be carefully done in ways that are environmentally and ecologically safe in order to preserve the delicate ecosystem.

This Chapter highlights the principles that should be considered to ensure sustainable and ecological intensification to guarantee optimum food production in a safe and friendly environment in light of the myriad of contemporary challenges facing agricultural, especially crop production.

2. Crop production intensification and sustainable/ecological intensification

2.1 Crop production intensification

These are the method employed to increase crop yield output per unit area of land in time and space.

2.2 Sustainable/ecological intensification

This is production intensification carried out using methods that ensure environmental health and safety. This involves increased production without leaving any harmful effect on the biotic and abiotic factors of the environment including land and water resources. It also ensures continued or sustainable production.

3. Tillage operations

The necessary conditions for optimum seedling emergence and proper growth after sowing include adequate moisture availability in the growth medium, favorable temperature, proper soil aeration, favorable soil structure, and for some crops, light availability. To provide the necessary conditions for seed germination and emergence, appropriate seedbed must be prepared according to the requirements of each crop. This is achieved through tillage. The purpose of the seedbed is to provide optimum conditions for seed germination, seedling emergence and growth [8]. Tillage also eliminates competition from weeds; and could increase soil nutrient availability to the seed/seedling. Tillage is the act of land preparation prior to planting. It involves a series of activities carried out in sequence to get the agricultural land ready for crop cultivation. The type and level of tillage depends on a number of factors including soil and the crop intended for cultivation. For any given location, the choice of tillage will depend on any of the following (Table 1) [9].

Soil factor; Relief/slope; Erodibility; Erosivity; Rooting depth; Texture and structure; Organic matter content; Minerology	Climatic factor; Rainfall amount and distribution; Water balance; Length of growing season; Air and soil temperature; Length of raining/rainless period
Crop factor; Duration of growth; Root characteristics; Water requirement; Seed	Socio-economic factors; Farm size; Availability of power; Family structure and composition; Labour situation; Access to cash and credit
Other government policies	Objectives and priorities

Table 1.

Factors affecting choice of tillage [9].

Thus the right tillage for specific crop must be done to ensure optimum performance. There are three broad tillage methods used for seedbed preparation. They are conventional, minimum, and conservation tillage [10]. The goal here is to carry out tillage operations in a manner that helps conserve the precious soil resources and prevents damage to the structure of the soil or open up the soil to erosion and other forms of disturbances [11]. In conventional tillage, heavy machineries like the tractor are used to open up the land and get it to the desired seedbed conditions. The compaction that often results from the movement of these machines is capable of causing a potentially dangerous alteration to the soils structure via compaction which reduces aeration and affects the soil microorganisms and eventually disrupts the addition of organic matter to the soil. It is therefore very important to minimize the exposure of agricultural land to such heavy equipment where possible. Different crops also require different levels of soil preparation. For instance, maize (Zea mays L.) performs well irrespective of the tillage method used as long as important crop management practices are deployed. Cowpea [Vigna unguiculate L. (Walp)] often requires a well pulverized soil to do appreciably well. Vegetables such as green amaranth (Amaranthus sp.), African jute mallow (Corchorus olitorus L.) and Celocia agentea require a high level of soil pulverization to ensure optimum seedling emergence and growth. The tuber crops like potato (Ipomoea batatas (L) Poir), yam (Dioscorea sp.) and cassava [Manihot esculenta L. (Crantz)] require hips and ridges for optimum tuber production. It is generally recommended that Conservation tillage be done or tillage be kept to the minimum level that supports proper growth of specific crops [10, 12]. This reduces the disposition of the cultivated land to soil compaction from excessive use of heavy machineries, soil erosion, and excessive nutrient leaching beyond crop root-zone, nutrient volatilization, and excessive loss of soil moisture due to evaporation. It also conserves energy expended in land preparation [11] and reduces carbon emission, thereby, in part, mitigating climate change in the process. According to Li et al. [13] conservation tillage can improve soil physical structure and water storage, protect moisture, and increase crop yield. However, the long-term adoption of a single tillage method may have some adverse effects on soil and ecological environment, even though it favors increased crop yield. They therefore recommended integrating conservative tillage methods with other methods to ensure long term sustainability (Table 2).

Crop	No-till (t/ha)	Conventional till (t/ha)	Soil type
Maize	3.64	2.58	Clay loam
Soybean	2.36	1.97	Clay loam
Sorghum	3.30	3.42	Sandy clay loam
Groundnut	4.66	4.61	Sandy clay loam

Table 2.

Yield of some arable crops under two tillage methods [14].

Result of the study by Thiagalingam et al. [14] revealed that yield for all crops were higher under the no-till condition than in conventional tillage over a four year period of maize-cowpea and sorghum-groundnut rotations.

3.1 Conservation tillage methods

1. Mulch tillage: this is based on the principle of causing least disturbance to the soil and leaving the maximum of crop residue on the soil surface, while obtaining a quick germination and adequate stand in the process. A chisel plow is often used for this purpose.

2. No tillage: this is a specialized method of tillage where planting is done in the soil with minimal disturbance. The surface residue of such system is important for soil and water conservation. Weed control is generally achieved by the use of herbicides and crop rotation.

3. Strip/zonal tillage: this divides the land into the planting zone and the soil nutrient/water management zones. The planting zone about 10 cm long is tilled while the inter-row spaces are left untilled to conserve resources.

4. Ridge tillage: ridges are cultivated at planting to optimize soil nutrient for seedling growth and reduce erosion.

5. Minimum tillage: Minimum tillage minimizes tillage operation to the lowest level that supports the desired crop.

As earlier mentioned, it is also very important to consider the soil type and physical characteristics before deciding on the tillage method to use to ensure maximum conservation of resources. Different soils have different proportion of silt, sand, clay and organic matter which impact their water and nutrient holding capacity, hence, different levels of tolerance to tillage. Tillage must be minimized on soil with high proportion of silt and sand. Soils with a high proportion of clay and organic matter could tolerate higher level of tillage without a major risk of loss of soil resources through leaching, deep percolation and surface runoff [15]. Where conventional tillage is necessary, tillage must account for land topography and slope. According to Oost et al. [16], in areas with high gradient, there is a high tendency of movement of water downslope. Erosion and nutrient movement is also expected to follow the slope. It is therefore expected in most case, that the lower areas of the field would be more fertile than the higher area. The direction of tillage must therefore be that which ensures the control of erosion i.e., tillage must be done across slope, and not along it [17].

4. Land and water resources management

Land, healthy soils, water and plant genetic resources are key inputs for food production. Their growing scarcity in many parts of the world makes it imperative to use and manage them sustainably. Boosting yields on existing agricultural lands, including restoration of degraded lands, through sustainable agricultural practices would also relieve pressure to clear forests for agricultural production. Wise management of scarce water through improved irrigation and storage technologies, combined with development of new drought-tolerant crop varieties, can contribute to the sustenance of dry land productivity.

Halting and reversing land degradation will also be critical to meeting future food needs. Given the current extent of land degradation globally, the potential benefits from land restoration for food security and for mitigating climate change are enormous. However, there is also recognition that scientific understanding of the drivers of desertification, land degradation and drought is still evolving [18].

4.1 Land management

4.1.1 Agricultural systems

The agricultural systems may seem like an old practice, but the concept is still relevant even in contemporary agriculture. As highlighted above, one of the major limiting factors in the modern day agriculture is access to land amidst the exponential increase in population. As population increases, the demand for food and other social infrastructures increase. These require opening up the precious forest reserves. This is often done without any plan to replace the forest reserves that are being displaced. Deforestation is one of the major causes of the significant increase in the amount of greenhouse gases (GHGs) in the atmosphere [19]. This results in global warming leading eventually to the prevalent and imminent climate change impacts. Trees are major sinks for some GHGs especially CO₂, which is one of the gases easily emitted as a result of anthropogenic activities in the environment. CO₂ has an atmospheric resident time (ART) of upwards of 50 years and will remain in the atmosphere for that period if not removed somehow from the atmosphere. Plants, especially trees, serve as major sinks for CO₂ by using it as a raw material in the synthesis of glucose via photosynthesis. Therefore, when deforestation is done without afforestation, the precious environmental purification tendencies of the heavy vegetation are also nullified thus leading to a harmful concentration of the gases in the atmosphere, hence, global warming and climate change. Therefore, managing the current land resources available for agricultural production without necessarily destroying the forest reserves is expedient for a healthy environment.

Mixed farming, arable farming, crop rotation, Shifting cultivation and bush fallowing are some of the farming systems that have been used in agriculture.

4.1.1.1 Bush fallowing versus shifting cultivation

Bush fallowing and shifting cultivation have a subtle difference between them. The basis of both systems is to give enough time for a depleted agricultural land to recover while continuing crop cultivation on a different, more fertile piece of land. Shifting cultivation is becoming less friendly because it involves the opening up of fresh land area, as a result of the continuous reduction in agricultural land due to urbanization [20]. This destroys forests and opens the environment up to adverse effects including climate change. Bush fallowing, on the other hand does not open up a new land or destroy forest. It only rotates on the existing agricultural land, such that a depleted area is given enough time to fallow and recover its resources. While it is necessary to stress that the destruction of forest reserved is not encouraged as explained above, it is important to note that a fallow period is necessary where alternative agricultural land exists where production intensification could be safely done while the depleted agricultural land is allowed time to recover through bush fallowing [21].

4.1.1.2 Mixed farming, arable farming and crop rotation

Mixed farming is simply a system where crop production is coupled with animal husbandry. This is a complementary system where crop and animal bye-products each support the other and plays a major role in the conservation of the precious environmental resources; and such is crucial for sustainable intensification and therefore, highly encouraged.

Arable farming which involves production of short duration crops alone, either on a subsistence or commercial level must be accompanied with crop rotation where crops that supplement the soil nutrient e.g., legumes and pulses are rotated with crops that deplete soil nutrients such as the cereals. By so doing the level of soil nutrient and overall soil health could be maintained.

4.1.2 Fertilization

This involves every measure taken to supplement the natural nutrient present in the soil. This is done by the addition of compounds to the soil which are capable of increasing the levels of essential nutrients in the soil needed for crop growth. Such compounds added to the soil for the aforementioned purpose are known as fertilizers. Fertilizers could either be organic or inorganic (synthetic) in nature. Both organic and inorganic fertilizers have their pros and cons. For instance, inorganic fertilizers are formulated to contain special blend of nutrients for specific crop growth and developmental requirements and for unique soil requirements. They are also highly soluble and nutrients are readily available for crop growth [22].

For this reasons, inorganic fertilizers become an easy choice for most farmers especially as pressure increases on agricultural produce from rising population. Unfortunately, application of inorganic fertilizers for an extended period significantly alters soil physical and chemical properties and often leads to extensive soil degradation [23]. The high solubility of this group of fertilizers also means that their nutrients are easily leached beyond the root zone in the event of a heavy rainfall for instance. They also pose a risk to the environment as they are easily eroded to non-intended targets such as nearby water bodies where they often cause water pollution and endanger aquatic species. Organic fertilizers or manures on the other hand are usually too bulky and messy compared to their inorganic relatives and the release of nutrients usually takes a while sequel to the breakdown and release of organic matter by natural processes which also depend on other environmental factors both biotic (soil micro-organisms) and abiotic or climatic (e.g., temperature) factors. These make inorganic manures immediately unattractive to many stakeholders. Yet, organic fertilizers are highly environmentally friendly and ensure soil health and conservation, and are therefore highly recommended for sustainable crop production intensification [23]. Organic manures are also cheaply available especially as the costs of inorganic fertilizers continue to increase globally. The benefits of organic fertilizers therefore outweigh their disadvantages and should be the main source of soil nutrient supplement. Inorganic fertilizers should be used only when absolutely necessary, and as precisely as possible (i.e., the exact quantity needed per unit area of land should be applied and not more [24].

4.2 Water resources management

Water is a critical input for agricultural production and plays an important role in food security. Irrigated agriculture represents 20 percent of the total cultivated land and contributes 40 percent of the total food produced worldwide. Irrigated agriculture is, on average, at least twice as productive per unit of land as rain-fed agriculture, thereby allowing for more production intensification and crop diversification [25].

Due to population growth, urbanization, and climate change, competition for water resources is expected to increase, with particular impact on agriculture. Population is expected to increase to over 10 billion by 2050 [7], and whether urban or rural, populations will need food and fiber to meet their basic needs. Combined with the increased consumption of calories and more complex foods, which accompany income growth in the developing world, it is estimated that agricultural production will need to expand by approximately 70% by 2050.

Agriculture accounts (on average) for 70 percent of all freshwater use globally, and an even higher share of “consumptive water use” due to the evapotranspiration from crops [26]. Therefore ensuring efficient use of water in agriculture would go a long way to ensure conservation of the precious environmental resource.

Conservation of water resources starts from the tillage method used in crop production. Employing conservation tillage ensures as much soil moisture is conserved as possible. Mulching, planting of cover crops, irrigation especially smart irrigation, water harvesting and storage are measures that could conserver water resources.

4.2.1 Mulching

Mulching involves the use of plant materials from weeding; or other materials such as plastic or polythene to achieve different agronomic purposes including conservation of soil water, reduction of soil surface temperature to favor optimum growth, addition of nutrient to the soil and sometimes weed control and crop protection from harmful pests and environmental conditions. This process is relevant both for soil and soil water resources conservation [27].

4.2.2 Cover crops

According to Delgado et al. [28], cover crops are key tools that could contribute to increased yields, conservation of surface and ground water quality, reduced erosion potential, sequestration of atmospheric carbon and improved soil quality and health. Cover crops are usually leguminous plants which form branches and twine over and essentially cover and screen the land from direct atmospheric impact from sunlight or rainfall. The leguminous plants used as cover crop add precious nutrients like nitrogen to the soil in addition to the protection of soil from erosion and excessive water loss from evaporation.

4.2.3 Irrigation

This should be done to supplement the natural soil moisture. Some environments receive very little amount of annual rainfall as a result of which irrigation is the main source of water to the soil. Other environments receive significant amount of rainfall and only need irrigation as a supplement where there is either cessation of rainfall or during dry spells. It is crucial for irrigation to be as precise as possible. That is, the exact amount of water needed for the soil and crop requirement should be applied. Addition of too much amount of water amounts to wastage of the precious water resources and could lead to undesirable conditions such as surface flooding, lodging, nutrient leaching or worse still contamination of non-target areas in the case of washing of agricultural chemicals to location where they are not intended. There have been advents of technologies that monitor soil and crop water requirements and trigger the release of the precise amount of water to the area based on the specific requirements of the crop in modern day agriculture. This process is termed Precision Irrigation which is a component of a group of modern and more efficient techniques of agriculture and crop production known as Precision Agriculture (PA) [29]. The use of remote sensing technologies and Internet of Things (IoT) sensors is becoming widespread in this regard [30]. Where there is no access to sophisticated facilities, irrigation technologies such as the drip setup should be promoted to ensure more efficient supply of water to crops.

In addition to drip irrigation mentioned above, subsurface soil irrigation where pipes are installed beneath the soil, thereby supplying water to the root zone of the crop is also highly efficient. This ensures that the crop receives the needed amount of water while protecting soil moisture from excessive surface heat, thereby significantly reducing water loss through evaporation. The soil surface is also freed up for other agronomic/crop management activities.

The benefits of the old gated pipe irrigation method could also be harnessed in the modern day agriculture to conserve water. This process spread water into unlined ditches and allowed it to saturate the soil, while preventing waste by limiting its flow into those ditches. It’s a very simple technique that can easily be upgraded by incorporating IoT sensors in the soil and remote or autonomous gates in each of the pipes.

4.2.4 Reservoir for water

Where there is good amount of annual rainfall, and even in environments with low rainfall, efforts must be made to develop storage facilities to collect and store water from every rainfall which could then be processed and applied accordingly, for different agricultural operations [31, 32, 33].

4.2.5 Importance of level field for resource conservation

Fields with higher gradient are likely to experience higher water loss via runoff and higher nutrient erosion [34]. One of the biggest sources of water waste is runoff because the fields or gardens where planting is done aren’t perfectly level, so any water that does not soak into the soil immediately flows away. Crop production site must be carefully selected such that it is on a level plane free of major slope, and where there are slopes, effort should be made at leveling the land out before planting operations. Laser land leveling reduces or even eliminates the problem of runoff by using lasers and other tools to make the field perfectly level before crops are planted, reducing runoff and, by proxy, preventing waste and promoting conservation.

4.2.6 Water reclamation from runoff

It is important to reduce water loss from runoff by selecting or leveling the agricultural land as much as possible. However, this may not completely stop runoff especially in places that experience frequent heavy rainfall concentrated in certain periods of the year. Therefore, setting up means of reclaiming water loss from runoff usually referred to as the tail water can be very useful. This is especially useful in farm enterprises that practice organic farming as there will be less likelihood of water pollution from agro-chemicals and the reclaimed water could be used for irrigation and other purposes [35].

5. Crop management/agronomic practices

5.1 Cropping methods

There are different cropping systems to consider prior to cultivation depending on the intended crop(s) and environment.

Sole cropping involves growing only one crop at any particular time. This can take the form of monocropping, growing a single crop of choice on a piece of land at any particular time; or monoculture: Growing a single crop over and over in an area for a long time. In the sole cropping system, crops must be rotated so that the soil nutrient level could be maintained. Crops that deplete environmental resources, maize for example could be rotated with those which are capable of replenishing the soil such as groundnut or soybean. Monoculture should be discourages unless the crop in such system is one that can maintain nutrients in the soil.

Multiple cropping on the other hand involves growing more than one type of crop with different patterns such as inter cropping – planting two or more crop species on a piece of land at the same time with a specific spatial arrangement; mixed cropping – growing two or more crop species randomly on a piece of land at once with no specific arrangement; sequential cropping/crop rotation – growing two or more crop in succession from one planting period to another; and relay cropping – planting another crop “b” before the initial crop “a” is harvested. Multiple cropping, with a smart choice of the right combination of crops based on nutrient requirements, physiology, gross morphology etc., could aid intensification of crop production while preserving soil and other precious environmental resources.

5.2 Planting material

Not all crops may grow and successfully complete their life cycle in an environment. A good knowledge of the suitability and adaptability of the crop to the area is needed prior to cultivation. Subsequently, decision must also be made on the right crop cultivar/variety to be grown with respect to environment and season. Crops must be carefully selected to reflect the capacity of the environment to support such crop without any adverse effect on the environment. Environmental resources efficient crop cultivars that have been improved for drought tolerance, higher yield, increased levels of essential nutrients, short generation time and disease resistance/tolerance should be selected to ensure conservation of environmental resources and sustainable production intensification.

5.3 Timing of planting

Planting at the optimum planting dates (DOP) could optimize environmental resources and ensure optimum crop yield [36].

The study in Figure 1 investigated the effect of planting dates on maize grain yield evaluated over 42 weekly planting dates in 2 years under natural field conditions. Results showed that planting early each year, with the first few rains optimized grain yield. A steady decrease in grain yield was observed as planting was delayed [36]. A good number of investigations and recommendation can be found in the literature on the optimum DOPs for different crops in different environments. Environmental resources that could be optimized include soil resources, solar radiation and soil moisture. Planting at the optimum planting period ensures maximum crop yield and avoidance of crop failure from unpredictable weather condition in case of agricultural production that is dependent on the natural environmental conditions. This is even more important in light of the prevailing and imminent climate change scenarios.

Figure 1.

Mean grain yield (t ha⁻¹) by DOPs of five maize varieties evaluated over 42 different planting dates at the OAU T&R farm in 2016 and 2017.

5.4 Planting density

This is simply the population of cultivated crop per unit area of land. The number of plants per stand (in crops with the possibility of multiple plants per stand e.g., maize) and the spacing between each stand determine the plant population. Planting at the optimum density ensures optimum crop efficiency and performance [24].

Planting at a density too high for the land area could deplete soil resources from excessive competition and cause poor crop performance. Planting at a density lower than the soil capacity also results in low yield per unit area of land and input. For instance with a higher spacing and low plant population, weed could be a bigger problem. Planting at the optimum density ensure optimum supply of nutrient from the soil and maximum interception of solar radiation for photosynthesis while also controlling weeds in part, when canopies touch and shade the soil surface from sunlight thereby starving the weeds of solar radiation and reducing their growth in the process [3].

Table 3 adapted from a study by Ajayo et al. [24] showed the yield performances of maize varieties under different densities in different agro-climatic zones of Nigeria. In the rainforest/marginal rainforest zones where there was significant difference in yield performance under different densities (i.e., in the 66,666 vs. 88,888 vs. 133,333 plants/ha density contrasts), the density level that guaranteed the highest grain yield should be used i.e., 88, 888 plants/ha. In the savannah where there was no significant difference in yield, the highest density (133,333 plants/ha) is then ideal for intensification purposes.

Agro-climatic zone		Planting density	Grain yield Kg/ha
Rainforest		66,666	2477a
		88,888	2594a
		133,333	2186b
	LSD0.05		138
Marginal rainforest		66,666	2734a
		88,888	2595a
		133,333	2277b
	LSD0.05		176
Southern Guinea Savannah		66,666	3162a
		88,888	3098a
		133,333	3015a
	LSD0.05		236
Northern Guinea Savannah		66,666	3032a
		88,888	3029a
		133,333	3095a
	LSD0.05		311

Table 3.

Means of grain yield and some agronomic traits of extra-early and early hybrids evaluated under varying plant densities in five agroclimatic zones of Nigeria in 2015 [24].

5.5 Fertilization

In addition to the general soil management practices which have been covered earlier in this Chapter starting with tillage, soil fertilization in response to crop demand is an essential crop management/agronomic practice. It is important to supply the needed level of fertilization to each crop when necessary, no more no less! This ensures optimum crop growth and avoids waste of agricultural input and minimizes environmental pollution. Studies have suggested the optimum rate of organic and inorganic fertilizer needed by different crops at separate growth and developmental stages [37].

5.6 Management of Pests and diseases

Diseases and pest management is achieved by several methods that have been described earlier in this Chapter. These include choice of suitable agricultural land, correct tillage operation, suitable crop/crop cultivar selection, right choice of cropping system, and timing of planting operations to avoid specific periods of higher diseases and pest occurrences among other measures. These help manage diseases even before they occur. Carefully observing the aforementioned procedures could reduce the incidences of diseases during the crop growth cycle thereby decreasing the need for special control measures. Consequently, resources for pesticides are conserved and environmental pollution from synthetic pesticides is reduced.

Where application of pesticide is necessary, the choice and concentration must be precise for the specific pest or disease situation, avoiding injury to non-target and even potentially beneficial organisms and the environment must be of utmost consideration. The general methods for pest management and control are mechanical - physical objects such as traps, machines, and devices including manual weeding; Cultural – modification to agricultural practices and techniques, planting pests/diseases resistant/tolerant hybrids etc.; Biological – using natural enemies of pests (prey or diseases), genetics, and natural chemicals such as pheromones; Chemical – applying substances that are poisonous to the pests, such as sprays, dusts, and baits. Cultural and biological methods of pest and diseases control should be amplified as they are more environmentally friendly. Chemical method should be employed only when absolutely necessary and the indiscriminate application of chemicals should be avoided because such often comes at a great danger to the environment by polluting land and water resources and destruction of non-target organisms [38].

5.6.1 Integrated pest management (IPM)

This has been well discussed in the literature to involve an integration or synchronization of all the method of pest control to ensure optimum and efficient pests and diseases management. It involves selecting the control method(s) that are best for the disease/crop. This is important in ensuring ecological/sustainable intensification [38].

5.7 Harvest operation

Harvesting must be timely and done as recommended for each crop. Timely harvesting conserves resources and prevents crop deterioration due to precocious germination and other phenomena. It also frees up the land as quickly as possible to pave way for further cultivation.

6. Precision agriculture (PA)

There are many elements of traditional farmer knowledge that, enriched by the latest scientific knowledge, can support productive food systems through sound and sustainable soil, land, water, nutrient and pest management, and the more extensive and safe use of organic fertilizers. An increase in integrated decision-making processes at the national and regional levels is needed to achieve synergies and adequately strike a balance among agriculture, water, energy, land and climate change. This can be achieved through PA. PA is the science of improving crop yields and assisting management decisions using high technology sensor (Remote Sensors, RS) and analytical tools (Geographic Information System, GIS) [39]. PA is a relatively new concept adopted throughout the world to increase production, reduce labor time, and ensure the effective management of fertilizers and irrigation processes. It uses a large amount of data and information to improve the use of agricultural resources, yields, and the quality of crops [40]. PA is an advanced innovation and optimized field level management strategy used in agriculture that aims to improve the productivity of resources on agriculture fields. Thus PA is a new advanced method in which farmers provide optimized inputs such as water and fertilizer to enhance productivity, quality, and yield. It requires a huge amount of information about the crop condition or crop health in the growing season at high spatial resolution. Independently of the data source, the most crucial objective of PA is to provide support to farmers in managing their business. Such support comes in diverse ways, but the end result is typically a decrease of the necessary resources.

Modern agricultural production relies on monitoring crop status by observing and measuring variables such as soil condition, plant health, fertilizer and pesticide effect, irrigation, and crop yield. Managing all of these factors is a considerable challenge for crop producers. The rapid enhancement of precise monitoring of agricultural growth and its health assessment is important for sensible use of farming resources and as well as in managing crop yields. Such challenges can be addressed by implementing remote sensing (RS) systems such as hyperspectral imaging to produce precise biophysical indicator maps across the various cycles of crop development [40]. Such indicators are analyzed and used for precise crop management. This leads to more efficient use and management of environmental resources thereby enhancing safe and environmentally sound crop production intensification.

6.1 Modeling

Different models have been developed with good levels of accuracy to predict the growth and development of different crops in relation to different environmental conditions such as soil climate and health cum general atmospheric conditions. Such models are used to forecast the performance and yield of crops before planting, given a set of environmental and ecological conditions [41]. This is important in deciding the level of intensification required to reach a desired level of production and at what cost to the environment. This budding area of research is even more valuable with the prevailing climate change scenarios, as crop production could be better adapted to climate change with the development and utilization of models capable of predicting the impact of a plethora of simulated extreme weather scenarios on crop production and devising means of adapting crop production to such scenarios in order to ensure food security while also securing the environment in the process. This would eventually lead in part to climate change mitigation [41].

7. Remediation

This is the term used to describe a group of processes used to consume and break down environmental pollutants, in order to clean up the environment after pollution. Agrochemicals are one of the major sources of pollution to the environment. Other sources of environmental pollution include nuclear and radiological accident and non-nuclear industries, such as petrochemical and mining, as well as harmful wastes generated as a result of a myriad of anthropogenic activities [42].

There are three main categories of remediation. They include soil remediation, ground/surface water remediation and sediment remediation. Remediation in the different categories is usually achieved by different techniques each with its own advantages and disadvantages. These remedial techniques can be physical, chemical, thermal or biological in nature depending on the contaminant that is being dealt with. Biological remediation also known as bioremediation is the use of either naturally occurring or deliberately introduced biological organisms to consume and break down environmental pollutants, in order to clean up an environmental pollution. According to Palansooriya et al. [43], it is a process where biological organisms are used to remove or neutralize an environmental pollutant by metabolic process.

Despite the strengths of physicochemical remediation, bioremediation is fast gaining advantage and wider approval over the physicochemical methods for environmental remediation despite being significantly slower. This is because it cleans up water sources, creates healthier soil, and improves air quality with much less disruption and intrusion; and can facilitate remediation of environmental impacts without damaging the delicate ecosystems. The agrarian environment should be evaluated from time to time for possible pollution from chemicals with the view to bio-remediate the environment where significant pollution is detected.

8. Conclusion

Environmental resource conservation, especially via agriculture is a key area that concerns all nations of the world irrespective of the level of development. Currently, some countries are more conscious and shrewd with the utilization of environmental resources especially for agricultural purpose, while others are not at the same level of consciousness. It is necessary therefore to increase awareness via conferences like the United Nation (UN). Each country should be encouraged to treat this subject with the same manner of seriousness as climate change, and stakeholder should take urgent steps to develop policies and programs to ensure that agricultural production is intensified to ensure food security in an environmentally and ecologically sound manner which preserves precious environmental resources.

Acknowledgments

My profound appreciation goes to The Almighty for the wisdom and strength.