Sustainable Maize Production and Carbon Footprint in Arid Land Context: Challenges and Perspectives

Abstract

Maize is a versatile crop that serves as a staple food for millions of people and provides various raw materials. Its adaptability to different climates and potential makes it economically valuable. However, the ongoing emissions of greenhouse gases pose significant challenges to sustain maize production. Sustainable agricultural practices are crucial to mitigate greenhouse gas emissions and reduce carbon footprints. Conservation tillage practices based on no-till promote carbon sequestration, and reduce carbon footprints compared to conventional tillage. These practices potentially improve soil health and water productivity. This chapter explores various aspects to sustain maize production, with a focus on conventional and conservation tillage systems, engineering technologies, carbon footprint reduction. It discusses also the challenges and perspectives in achieving sustainable maize production. It begins with an overview of conventional maize farming, highlighting its practices and challenges. The second section explores the advantages of conservation tillage in maize production. The third part focuses on engineering technologies and precision agriculture tools, as well as remote sensing. In the fourth section, strategies for reducing carbon emissions and adopting clean energy in maize farming are considered. The final part addresses the challenges and perspectives for sustaining maize production, discussing barriers, opportunities, and potential solutions.

1. Introduction

Maize (Zea mays L.) holds immense importance as a major cereal crop, serving as a staple food for over 900 million people in developing countries. Maize earns its esteemed title as the “Queen of Cereals” due to its remarkable demand and impressive adaptability. Maize holds the distinction of being the most abundantly produced cereal worldwide, with a staggering production of 1148 million metric tons. Not only does maize boast the highest average productivity of 5.9 tons per hectare, but its growth rate is also among the most rapid in comparison to other crops [1]. It holds the distinction of being the most significant cereal crop globally in terms of both acreage and production [2]. Additionally, it serves as a valuable raw material for the production of food sweeteners, protein, oil, starch, and even as a fuel source. This versatility is supported by its ability to thrive and adapt to a wide range of climatic conditions worldwide [3]. It is not only a vital food crop but also a significant source of income for many farmers, particularly in developing countries.

Its unique characteristic of being able to be cultivated twice in a year further enhances its economic value. In regions with favorable climatic conditions and appropriate agricultural practices, farmers can harness the potential of double cropping, allowing them to maximize their yields and income from maize cultivation [4].

According to the most recent assessment report by the Intergovernmental Panel on Climate Change, the ongoing emission of greenhouse gases is projected to result in continuous warming and persistent alterations in all aspects of the climate system. This, in turn, increases the probability of experiencing severe, widespread, and irreversible impacts on both human societies and ecosystems. The report highlights the urgent need to address greenhouse gas emissions to mitigate the potential consequences of climate change. Thus, in light of the projected severe and irreversible impacts of climate change, there is an urgent and critical need for sustainable food production systems. Agricultural practices, in conjunction with the combustion of fossil fuels within domestic settings, exert a significant influence on the global carbon (C) and nitrogen (N) cycles. This combined impact has been identified as a potential contributor to the observed global temperature rise [5].

There is a strong recommendation for crop producers to implement efficient management practices in order to reduce GHG emissions and minimize the carbon footprints associated with agricultural products at the farm level [6, 7]. Research has consistently shown that implementing improved agronomic practices can contribute significantly to reducing GHG emissions associated with crop production. These practices not only enhance crop yield but also result in higher inputs of carbon-rich residues, which can contribute to increased carbon storage in the soil [6]. Examples of these effective practices include the use of high-yielding crop varieties, timely management of crop diseases, crop rotation with species that allocate more carbon below ground, and careful nutrient management [7].

Conservation tillage, which encompasses practices such as no-till or reduced tillage along with residue retention, has been widely implemented to enhance soil quality and promote sustainable agriculture. The adoption of no-till (NT) and subsoiling (ST) practices has been proposed as a means to decrease soil organic carbon (SOC) mineralization and promote the accumulation of SOC. These practices involve minimal soil disturbance, leading to enhanced SOC sequestration and reduced carbon dioxide (CO₂) emissions, consequently lowering carbon footprints (CFs). In contrast, conventional tillage methods contribute to higher CO₂ emissions through increased diesel consumption, whereas NT practices result in reduced carbon emissions due to decreased diesel usage. Furthermore, tillage practices influence soil physicochemical properties and have implications for grain and biological yields [8].

There have been very limited studies exploring the C footprint of maize production under variable agronomic practices such as conventional and no-tillage farming systems, especially in the context of Morocco. In this literature review, our objective is to examine maize production within two farming systems: conventional and no-till. We will analyze and compare the carbon footprints associated with these two approaches and aim to draw conclusions regarding the potential carbon footprint reduction achievable through the adoption of no-till farming. By assessing the available literature and research on these farming systems, we will explore the environmental implications of each method and evaluate the carbon footprint gains that can be achieved by transitioning from conventional to no-till maize production. Ultimately, our review aims to provide insights and recommendations on how adopting no-till practices can contribute to sustainable maize production with reduced carbon footprints.

2. Conventional maize production and drawbacks

The overuse of synthetic fertilizers and pesticides leads to soil degradation, nutrient runoff and greenhouse gas emissions. It also disrupts ecosystems, fosters resistance, and poses health and environmental risks. Unsustainable irrigation depletes water resources, causes salinization, and contributes to energy consumption. Solutions include integrated nutrient management, integrated pest management, efficient irrigation techniques, education, policy support, and research.

Tillage plays a crucial role in creating favorable conditions for seedling emergence, development, and root growth by preparing an ideal seedbed. It is considered a critical component of soil management systems. However, it is important to select appropriate tillage practices to ensure optimal crop growth and yield. Inappropriate tillage practices can have detrimental effects on crop performance. Tillage management, as well as the application of chemicals and manure, are important factors that have a significant impact on soil physical properties. Tillage is a practice used to loosen the soil and create a suitable seedbed for plant growth. It plays a crucial role in crop production, contributing up to 20% of the overall factors influencing crop performance [9].

The choice of tillage method has implications for the sustainable utilization of soil resources, as it directly influences soil properties. Deep tillage, in particular, has several benefits. It helps break up compacted soil layers, facilitating improved water infiltration and movement within the soil. This enhanced water penetration allows for better root growth and development, ultimately increasing the potential for crop production [10]. Studies have shown that deep tillage practices, reaching depths of up to 90 cm, have led to increased corn yield [11].

In his study case, Memon et al. [9] compared the effects of different tillage practices, Deep Tillage (DT), Conventional Tillage (CT), and Zero Tillage (ZT), on maize production at the experimental site of National Agriculture Research Center (NARC), Islamabad, Pakistan. The study revealed significant differences among the tillage treatments in terms of seedling emergence, plant height, number of leaves per plant, and grain and dry matter yields. Deep Tillage (DT) exhibited notable advantages over the other treatments. It resulted in a higher seedling emergence percentage, taller plants with more leaves, and the highest grain and dry matter yields. Conventional Tillage (CT) followed suit, demonstrating favorable outcomes in terms of seedling emergence, plant height, leaf number, and yield. Considering the specific soil (loamy soil) and weather conditions (spring season) of the experiment, the findings indicate that Deep Tillage (DT) proved to be the most effective tillage practice for maize production.

Zero Tillage (ZT), although offering potential benefits in certain contexts, was less favorable in this study. These results emphasize the importance of selecting appropriate tillage practices based on specific conditions to optimize maize production outcomes. It is important to note that balancing the benefits and potential drawbacks of tillage management and chemical/manure applications is crucial. While tillage can improve soil conditions and crop productivity, it may also lead to increased soil erosion and loss of organic matter. Likewise, the use of chemicals should be carefully managed to minimize environmental impacts and promote sustainable agricultural practices.

In another study conducted by Orfanou et al. [12] in USA Georgia, they found that Conventional tillage had slightly better yield results but was not statistically different from conservation-tilled plots that lead to the conclusion that conservation tillage could be a good solution for farmers, not only for preserving water but also for achieving acceptable yield results.

Conventional tillage in maize production, while commonly practiced, comes with several drawbacks. It demands significant time, fuel, labor, and water resources, leading to higher production costs. These increased costs can ultimately reduce profits for farmers. Additionally, conventional tillage methods may contribute to higher greenhouse gas emissions compared to alternative options [13]. The constraints and nonsustainability issues mentioned earlier have specific implications. Maize farming often involves intensive tillage practices, which can lead to soil erosion, reduced soil organic matter content, and soil compaction, ultimately impacting the long-term productivity of the land. Additionally, the removal of crop residues and the practice of monocropping in maize cultivation further contribute to the nonsustainable aspects of conventional agricultural systems [14]. To ensure sustainable maize production, it is crucial to address these challenges and adopt alternative farming practices such as conservation tillage.

In a study conducted in South Korea under intensive conventional cultivation, [15] concluded that the carbon footprint (CF) of maize production is largely influenced by nitrogen (N) in chemical fertilizers and the use of organic fertilizers. Both types of fertilizers significantly contribute to CF and carbon efficiency. Sustainable practices that prioritize high yields and low GHG emissions are associated with greater sustainability. South Korea’s maize production demonstrates relatively low CF and GHG emissions on a global scale. The study highlights the positive correlation between nitrogen use, chemical and organic fertilizers, and the carbon footprint of agriculture (CFA) and carbon footprint intensity (CFI). This emphasizes the importance of proper management and selecting suitable land management systems, especially in the context of climate change. By implementing effective strategies and informed decision-making, it is possible to reduce GHG emissions and promote sustainable development in maize farming.

3. Maize-based conservation tillage and benefits

Conservation tillage plays a significant role in sustainable maize production by promoting soil health, reducing erosion, improving water retention, and minimizing the environmental impact of farming practices.

Maize cultivation can be achieved without the need for primary tillage through a practice known as no-till farming. This approach offers several advantages, including reduced cultivation costs and improved efficiency in resource utilization. To ensure successful crop establishment, it is essential to maintain optimal soil moisture during sowing. Additionally, the proper placement of seeds and fertilizers in bands using a zero-till seed-cum-fertilizer planter with a suitable furrow opener, taking into account the soil texture and field conditions, is crucial [2].

A study conducted in Zimbabwe in a semi-arid climate examined the impact of conservation tillage on maize production. The objective of the study was to assess the maize yield advantage associated with conservation tillage compared to conventional tillage, which represented the farmers’ practice in the region. The researchers aimed to provide insights into the potential benefits of introducing conservation tillage as a technology for maize production in the semi-arid conditions of Zimbabwe and compare the efficacy of conventional tillage and conservation tillage methods in terms of maize yield. When comparing the performance of various tillage methods, it is important to acknowledge that for any alternative system to be considered viable, its yield should be equal to or higher than that of conventional tillage in the short term. Additionally, it is crucial to consider the resource constraints faced by smallholder farmers during the adoption of alternative tillage practices. They evaluated eight tillage experiments conducted between 1984 and 2008. Nyakudya et al. [16] found results that showed Conservation tillage methods demonstrated slight but noteworthy yield advantages in regions with less than 500 mm of rainfall. In cases where grain yields reached 2.5 tons per hectare and the rainfall was below 500 mm, the adoption of 1.0 m tied ridging resulted in an additional 144 kg per hectare, while mulch ripping contributed an extra 344 kg per hectare compared to conventional tillage practices. These findings highlight the potential of conservation tillage methods to enhance maize yields in areas with limited rainfall, albeit with modest improvements.

In another research in Western Colorado Research Center in USA, Keshavarz et Dekamin 2022 evaluated the sustainability of maize production by comparing four different tillage systems: conventional tillage with moldboard plow (MP), conventional tillage with chisel plow (CP), strip-tillage (ST), and no-till (NT). The assessment was conducted using life cycle assessment (LCA) and Material Flow Cost Accounting (MFCA) methods. By considering the entire production process, including energy and material wastage, a more comprehensive understanding of the hidden costs of production was obtained. The results showed that the total annual energy input varied among the tillage systems, with NT having the lowest energy demand. NT also exhibited improved energy efficiency and yield increase. The economic analysis revealed that eliminating negative products in corn production could significantly increase farmers’ net benefit. Environmental impact assessments indicated that NT and MP performed better than CP and ST in most categories, with NT showing the best performance in terms of global warming potential, acidification, and eutrophication. Overall, NT proved to be the most sustainable option for corn production, followed by the MP system, considering energy, economic, and environmental indicators.

4. Practices and engineering technologies for sustainable maize production

Sustainable maize production is of utmost importance in ensuring food security, environmental preservation, and the well-being of farming communities. To achieve sustainability, it is crucial to adopt the best practices and technologies that optimize resource utilization, reduce environmental impact, and enhance the resilience of maize farming systems. During the last decades, several farming innovations have been tested on cereal crops to improve water and energy use efficiencies and increase yields of biomass and grains. Dokyi et al. [17] stated that the adoption of Improved Seed and Management Technologies (ISMT) has a significant positive impact on technical efficiency. The ISMT adoption resulted in a notable increase of the efficiency to show an actual improvement of 16%. Consequently, the maize productivity showed a substantial boost, rising by 33.8% as a result of ISMT adoption. This study recommends the widespread dissemination of improved maize seeds to farmers. The transformation of corn farming over the past two decades has been fueled by the rapid adoption of new technologies and advancements in seed breeding. A comprehensive analysis (ARMS survey conducted from 1996 to 2016) reveals the significant impact of these innovations on yield changes in intensive corn production.

Otherwise, the advancements in genetically engineered seeds allowed farmers to optimize their practices and achieve higher yields. With the ability to plant corn seeds more densely and at an earlier stage in the growing season, farmers maximized the crop’s growth potential. Additionally, the improved pest resistance and drought tolerance provided by genetically engineered seeds opened up profitable production opportunities in different pedo-climatic contexts. These changes were not limited to planting practices alone, as the increased adoption of drought-tolerant and insect-resistant seeds prompted adjustments in irrigation and chemical applications. Over the course of two decades, the percentage of corn acres planted with single-pest-resistant varieties containing proteins from Bacillus thuringiensis (Bt) increased from 2% in 1996 to 78% by 2016. Similarly, herbicide-tolerant varieties, enabling efficient weed management, saw a remarkable area increase from 3% in 1996 to 84% in 2016 [18]. However, adoption of genetically engineered seed varieties improved substantially productivity of conventional farming but the sustainability of this production system cannot maintained as different problems of soil health, soil physic, pest resistance; herbicide tolerance and chemical pollution kept unsolved in a sustainable way.

4.1 Practices for better maize crop establishment under no-till

Several practices were proved to improve maize crop establishment for more sustainability under no-till cropping system. For a successful introduction of no-till farming method, farmers cannot sense an initial benefit without starting by fixing problem of soil compaction as a common issue of intensive agriculture. Compaction can be attributed to various field operations related to soil-machine interactions due to use of heavy machinery and equipment and to animal trampling. These activities can result in damage to the soil structure, which is crucial for the soil’s ability to retain and drain water, nutrients, and air necessary for plant root functions. Compacted soil restricts root growth and can lead to reduced water infiltration, poor nutrient availability, and inadequate oxygen levels for plant roots. Several researches showed that compaction constitutes a systematic problem of irrigated cropping systems due to difficulty of traffic management with reference to soil practicability and soil plasticity. Olubanjo et al. [12] conducted a study in Nigeria to show the response of maize crop to compacted soil under relatively stable environmental conditions. They find that high soil strength resulting from compaction lead to reduced yield production. However, the negative impact of compaction on yield seems to be mitigated when there is an abundant water supply, although certain treatments with lower soil strengths experienced further reduction in yield due to water stress. Additionally, increased soil compaction was found to have a negative influence on plant nutrient uptake. According to this study, maize plants should not be cultivated in soils with a penetration resistance more than 2.0 MPa.

Methods of chiseling and tillage of deep soil layers are of great importance to break hardpans and to alleviate soil compaction prior to cultivation of maize under conventional tillage. Such methods are also primordial for a successful start of producing maize under conservation tillage. In fact, it is essential to address soil compaction through proper management practices such as chiseling before no-tillage and use of adapted no-till seeders for a better maize crop establishment. The conservative best practices help farmers to guarantee a sustainable maize production when the maize crop establishment is good to show consistent biomass and grains yields during the start years of the conservative practices (Figure 1).

Figure 1.

Factors affecting no-till production system sustainability [19].

To enhance maize crop productivity and improve farmers’ profitability, there is a significant focus on implementing alternative methods and technologies to promote conservative practices. These efforts aim to mitigate the negative impact of traditional cropping systems and have resulted in the development of various resource conservation technologies. Considering the importance of conserving natural resources, it is crucial to prioritize the widespread adoption of cost-effective and environmentally friendly crop management practices. These include techniques such as ridge and furrow, conventional flatbed, and raised-bed planting [20].

The ridge and furrow planting method involves creation of raised ridges and sunken furrows for a better crop establishment. This method offers several benefits for crop growth. The ridges provide better drainage and aeration for the plants, reducing the risk of waterlogging. The furrows help to channel water and prevent excessive runoff, improving water distribution and conservation.

The conventional flatbed planting method can be prepared by leveling the soil surface to create a flat and even bed for planting. In this method, the entire field is tilled and smoothed to achieve a uniform surface for easier planting, cultivation, and harvesting operations.

The zero tillage raised-bed planting method involves creation of elevated planting beds above the ground level. The raised beds are typically formed by mounding soil or using specialized equipment to shape them.

Saad et al. [21] conducted a study in India to find that energy use in tillage is influenced by different tillage and crop establishment methods, as well as residue management practices. The zero tillage with raised-bed establishment (ZTB) consumed approximately 8% less energy compared to conventional tillage based on flatbed planting (CTF) in a maize-wheat cropping system. This reduction in energy consumption in ZTB was due to energy savings in land preparation, sowing, and irrigation activities.

Pooja et al. [20] also examined the impact of different planting methods on weed population, yield improvement, water management, and weed control in maize production. The results indicate that raised beds have lower weed populations and offer advantages such as better water management and higher yields compared to flat beds. Stale seedbed practices also prove effective in reducing weed density. Bed planting methods, particularly raised beds, demonstrate higher soil microbial biomass carbon and have a significant positive effect on crop growth and yields. Studies conducted by Jat et al. and Singh et al. show that raised-bed systems outperform conventional and zero tillage systems in terms of maize yield. Overall, the research suggests that raised-bed planting is the most effective method for minimizing weed population and enhancing crop performance [20].

4.2 Digital monitoring of crop performance for sustainable maize production

There are several technologies that contribute to sustainable maize production. For example, Soil–Plant Analysis Development (SPAD) meter technology. It has emerged as a valuable tool in the field of agriculture. This technology has gained significant attention, particularly in the context of optimizing nitrogen fertilizer applications in corn (Zea mays L.) production. The SPAD meter is a handheld device that measures the chlorophyll content of plant leaves, providing an indication of their nitrogen status. The use of SPAD meter technology offers several advantages for corn producers. By providing a quick and nondestructive assessment of leaf chlorophyll levels, it enables farmers to monitor the nitrogen status of their crops in real-time. This information is crucial for making informed decisions about nitrogen fertilizer applications, ensuring that the crops receive adequate nutrients for optimal growth and yield.

Farmers often opt for high nitrogen (N) rates to maximize corn yield, highlighting the need to determine optimal N quantities for promoting efficient farming practices that increase yield and crop profitability while minimizing resource wastage. Striking the right balance is crucial, as excessive N application poses a challenge for both farmers and environmentalists in safeguarding groundwater against nitrate contamination. By adopting appropriate N management strategies, farmers can mitigate the potential negative impacts of excessive N use, reduce environmental risks, and contribute to sustainable maize production.

Rhezali et al. [22] conducted a study in 2014 and 2015 to show that it is possible to explore the relationship between absolute SPAD values and leaf nitrogen concentration, focusing on early corn growth stages such as V6, V8, V10, and V12. Three experiments were conducted to examine the effects of six nitrogen (N) treatments applied at early growth stages of corn. The results indicated a significant linear relationship between corn leaf N concentrations and absolute SPAD values, with an R2 value of 0.80 (p < 0.05). Interestingly, the average optimal corn leaf N concentration decreased as the corn progressed through its growth stages.

Ensuring accessibility of the absolute SPAD method is crucial for its practical application by farmers. The absolute SPAD method, which has shown a significant linear relationship between corn leaf nitrogen concentrations and SPAD values, holds promise for aiding farmers in making informed decisions about nitrogen applications.

Otherwise, satellite imagery and remote sensing techniques have revolutionized the monitoring of maize crops, providing indispensable tools for farmers. Through the development of innovative algorithms and models, researchers have harnessed satellite data to extract valuable information for crop management. These insights include crop yield prediction, disease detection, and analysis of nutrient deficiencies [15, 23]. By leveraging satellite-based monitoring systems, farmers can make data-driven decisions to enhance their crop management practices. Furthermore, satellite and drone technologies have also facilitated the implementation of variable rate application of inputs in maize production. By mapping field variability, these technologies optimize the application of fertilizers, herbicides, and pesticides, resulting in reduced costs and environmental impacts while maximizing yields. The implementation of variable rate application ensures efficient resource utilization and promotes sustainable maize production [24, 25].

Satellite and drone have also been used for crop imaging to provide farmers with detailed information on the health and vigor of their maize crops. By employing multispectral and thermal sensors, farmers can assess crop stress, monitor water use efficiency, detect nutrient deficiencies, and quantify vegetation indices such as NDVI (Normalized Difference Vegetation Index). These assessments enable farmers to take proactive measures to mitigate potential risks and optimize maize production [26, 27].

In addition to satellites, drones equipped with sensors and cameras have emerged as valuable tools for precise data collection in maize fields. Drones capture high-resolution images that enable the measurement of plant height, identification of nutrient deficiencies, and detection of pests and diseases. These images also contribute to the creation of yield maps, providing farmers with detailed information for optimizing fertilization, irrigation, and pest control strategies [28, 29]. The integration of these data-driven insights empowers farmers to make informed decisions, resulting in improved maize production.

The combination of satellite and drone data with crop modeling and decision support systems has further enhanced the accuracy of maize growth prediction and management. Researchers are actively developing models that incorporate climatic data, satellite imagery, soil characteristics, and management practices. These integrated systems optimize irrigation scheduling, planting dates, and fertilizer application, ultimately enabling farmers to achieve better yields [30, 31, 32]. By leveraging these tools, farmers can confidently make decisions based on accurate predictions and optimize their maize production.

Sharifi [33] implemented a model using Near-Infrared Reflectance (NIR) and Red-edge bands in vegetation indices to precisely predict maize nitrogen uptake in three different sites and various conditions. He stated that maize growers can have a good opportunity to map nitrogen uptake for improving nitrogen use efficiency in their field. Use of spectral information of Sentinel-2 satellite data for estimating maize nitrogen uptake served as an efficient tool to optimize fertilizer management in irrigation-based intensive cropping systems.

4.3 Contribution of precision irrigation technologies for sustainable maize production

Smart Irrigation and Internet of Things (IoT) technologies consistently contributed to improve water and maize crop productivity. The power of the Internet of Things (IoT) can be used with sensors to monitor various factors like soil moisture levels, weather conditions, and plant water requirements. By collecting real-time data, smart irrigation systems can optimize water use during the cropping system to ensure precise irrigation schedules for more water use efficiency and productivity [34, 35]. Several approaches integrating use of IoT and sensor network have been implemented to efficiently collect and analyze data for promoting more sustainability in the irrigated cropping systems. Use of processed data at the edge server and transferred to the main IoT server is a real-time process of great utility to continuously manage the crops water requirements using only an Android smartphone application [36, 37, 38]. By implementing precise irrigation based on soil moisture sensors and IoT, maize producers can achieve higher yields while optimizing the use of resources such as fertilizers, water, and seeds [39, 40]. The comparison between precise irrigation using sensors and traditional flood irrigation showed that it is possible to conserve water by 50% and increase crop yield by 35% [41]. Integration of IoT technology is also of great importance to adapt for monitoring irrigation data for diverse crops. Singh et al. [26] evaluated an automated irrigation system for Maize, Paddy and Wheat crops to monitor soil moisture and soil temperature and transmit data to a cloud system for digital control of pump to efficiently satisfy the irrigation requirements. By considering Maize as the most important cereal crop worldwide [42], emerging sensors technologies can be of great importance to implement powerful tools helping for more sustainability in producing maize silage and grains. It helps farmers to implement decisional tools based on real-time data [43]. Sharifnasab et al. [44] tested smart irrigation for producing maize grain to show possibility of using only 40% of the farm’s moisture discharge capacity. Compared to conventional practice of using meteorological data to guide irrigation decisions, the implementation of a smart irrigation system resulted in accelerated plant growth, earlier harvesting, and reduced water use (from 8839.5 to 5675.67 m³/ha) for more grain yield and water productivity [44]. Kumar et al. [45] evaluated an irrigation method based on IoT to monitor soil moisture monitoring with reference to use of evapotranspiration-based strategy to manage sweet corn irrigation. The first IoT-based method implemented for two irrigation regimes of 43.5% and 34.8% of the soil field capacity (FC) is compared to the evapotranspiration method (ETc 100%) with 80% of FC. They find that the IoT method based on regime of 43.5% resulted in an increase yield of 12% and water savings of 11% compared to the ETc 100% irrigation method. Asiimwe et al. [46] compared and evaluated sweet corn yield, biomass, water productivity, and other morphometric characteristics based on irrigation scheduling using the irrigation amounts estimated from ET (60%, 90%, and 120% of ETc) and SM irrigation regimes (25%, 30%, and 35% of soil moisture) on sweet corn. The results showed that the average soil moisture levels using both treatments soil moisture (SM35%) and evapotranspiration (ET120%) were identic to show that irrigation can be reduced by 8% for the same grain yield and the highest irrigation level can result in an increase of fresh cob weight by 27%. Such smart irrigation innovations can help to elevate productivity levels while also ensuring sustainable agricultural practices [47]. Considered as a key component of precision farming, this advanced technology is becoming affordable to be adopted by small-irrigated farms to optimize water productivity and enhance crop yield through implementation of irrigation best practices (Figure 2) [48].

Figure 2.

Smart irrigation system structures (From www.flaticon.com).

4.4 Crop growth modeling for sustainable maize production

Maize crop as other crops is subjected to effect of the current meteorological conditions of climate change. Which affect negatively the yield of the crop. For this, growth simulation models are used to simulate different scenarios under the actual climate change [49, 50]. The most affected regions by climate change could be China, Africa, European Union and India, with a maximum decrease in maize yield of 86%, 201%, 71% and 45%, respectively [49]. The major factor affecting the rise in maize yield under climate change is the temperature [50]. The use of models to simulate and forecast the response of maize crop to different environmental conditions are used in several regions as an alternative tool to analyze the response to climate change conditions [49]. However, the simulation models are observed to give mixed results depending on the region and the crop. The parametrization, calibration and validation were found to be the source of uncertainties in model predictions [50]. Different situations could be simulated: those related to optimal conditions with restricted effect of climate conditions (T°, radiation and CO₂), those related to resource availability (water and nutrient), and finally, those related to the reel conditions including all environmental, biological and management variables [49].

Actually, the complexity of the biophysical agricultural system is mathematically formulated by models helped to understand them [49]. The models used to simulate maize production are different in terms of information required, and the end user interface [49]. Climate, plant, soil and crop management are the input data needed by mechanistic models, such as AquaCrop, APSIM, DSSAT-CERES, CropSyst and EPIC [49, 50, 51]. Most of the studies revealed that corn yield decreases under climate change projections, due to temperature increase which reduces vegetative period and dry matter production in some regions, while, there are other regions where the conditions of corn crop growth will be favorable (temperate regions) [49]. The use of experiment data is needed to calibrate and validate each model [51]. The calibration of DSSAT-CERES is made for each genotype of maize and estimate the genetic coefficient. In WOFOST model, the calibration is carried out in the different phenological stages [49].

Otherwise, AquaCrop is used as water-driven crop model under varying irrigation and nitrogen level in [51, 52, 53, 54]. Model efficiency (E), coefficient of determination (R2), Root Mean Square error (RMSE) and Mean Absolute Error (MAE) Nash–Sutcliffe Efficiency (NSE) were used to test the model performance [51, 52, 53, 54]. Appropriate levels of irrigation for maize crop were investigated by using AquaCrop model [51, 53, 55]. The prediction error of the model varied from 2.35 to 27.5% for different levels of irrigation and nitrogen [51]. Some extreme conditions may limit the performance of the model mainly, water stress, excess water and high evaporative demand conditions [52], and the accuracy of the model need more evaluation under field conditions of maize crop. AquaCrop model give good accuracy for field-measured trait for instance soil water, canopy cover, grain yield and total biomass [52, 53, 55]. The methods of field assessment to assessing maize crop yield are expensive, laborious and inaccurate. To overcome this, considerable efforts were made in the development and application of maize crop yield models for yield estimation. Such as the development of the use of models with remote sensing tools [56].

5. Potential of reducing carbon and water footprints for sustainable maize production

5.1 Maize production and carbon footprint

Maize cultivation has traditionally relied on conventional tillage methods involving plowing. However, due to factors such as cost, natural conditions, and environmental concerns, there is an increasing adoption of noninversion systems in modern maize production. These noninversion systems typically involve reduced tillage, where no-till seeders are used for substituting plowing and contributing to sequester more soil carbon. By promoting adoption of the no-tillage system, the seeders put seeds directly into uncultivated soil for low disturbance and high reduction of GHG [57].

In order to protect the soil and the environment, the use of noninversion tillage techniques and the retention of a minimum of 30% of plant residues on the field, known as conservation tillage, are of particular importance. These practices help preserve soil structure and reduce erosion while promoting the conservation of organic matter.

Enhancing the management of soil cultivation practices to promote the sequestration of organic carbon in the soil is crucial for mitigating greenhouse gas (GHG) emissions in agriculture. Recent research conducted by Holka et Bienkowski [57] in Wielkopolska in Poland, has highlighted that the adoption of no-tillage methods combined with substantial crop residue retention can effectively reduce GHG emissions in maize production. Irrespective of the specific tillage system utilized, the process of mineral fertilization emerged as the key contributor to GHG emissions. Developing low-emission technologies necessitates careful consideration of the associated risks, particularly related to nitrogen fertilizer usage. To minimize emissions from agricultural fields and simultaneously reduce raw material consumption in fertilizer production, optimizing fertilization practices becomes essential, taking into account natural constraints and soil conditions, as well as the desired crop productivity levels.

By considering the sequestration of organic carbon (C) in the calculation of greenhouse gas (GHG) emissions, the net carbon footprint (CF net) of grain maize production was found to be significantly reduced. Compared to the baseline CF value, the CF net values were lowered by 42.9% in the conventional tillage (CT) system, 72.1% in the reduced tillage (RT) system, and 78.3% in the no-tillage (NT) system. When GHG emissions were analyzed per ton of maize produced, the inclusion of C sequestration showed the most substantial impact in reducing total GHG emissions in the NT and RT systems, with reductions of 78.3% and 72.1%, respectively. Effective management of maize crop residues, such as leaving larger amounts of residues in the field, played a significant role in preventing C losses promoting its sequestration, and reducing the carbon footprint in maize production.

5.2 Maize production and water footprint

Water footprint (WF) is an indicator that plays a vital role in promoting sustainable maize production by addressing both water consumption and pollution. Maize is a major global crop, and understanding its water footprint is crucial for ensuring responsible water management practices. It provides a new approach for assessing water resource utilization in agriculture.

The WF of crop production serves as a comprehensive indicator that encompasses the various types of water consumption, quantities utilized, and environmental impacts throughout the entire crop growth period [58]. It provides a holistic understanding of water consumption and its associated implications during the process of crop cultivation. The WF takes into account not only the direct water usage by the crops but also the indirect water footprint related to the production and use of inputs such as fertilizers and pesticides.

The WF considers both the blue water footprint (water from surface or groundwater sources) and the green water footprint (rainwater stored in the soil). Additionally, it accounts for the gray water footprint, which refers to the volume of water that is required to assimilate polluted water [59]. In a study conducted by Sun et al. [58] in Beijing, they found that WF had decreasing trends because of the reduced green WF due to the change in climate and the rising temperature and water scarcity, while the gray WF increased because of chemical fertilizers and pesticides. They concluded that the gray WF should be controlled to achieve a sustainable maize production. In another study conducted in Italy by Borsato et al. [60], they affirm that soil conservation tillage systems can reduce the gray WF by 10%. The study focuses on soil tillage systems and variable rate application as means to reduce the gray WF. It emphasizes that the interaction between soil tillage systems and soil management plays a significant role in reducing the gray WF. They found that minimum Tillage with Precision Farming shows lower gray WF values, both in terms of water usage per ton and per hectare. Soil tillage systems combined with variable rate application exhibit a higher reduction in gray WF. To reduce water pollution, prioritizing the reduction of insecticides and herbicides, using chemicals with a lower gray WF, and implementing sustainable soil management practices are recommended.

6. Challenges and perspectives

Maize yields depend on a range of interconnected factors: genetics influence potential productivity, climate affects growth conditions, agronomy practices impact crop health, policies shape resource access, and political stability enables long-term planning. These elements interact to create a complex impact on yields. Improved genetics can enhance resilience, while effective agronomy optimizes potential.

Challenges in sustainable maize production encompass a range of interconnected factors that need to be addressed collectively. These challenges arise from various dimensions, including environmental, social, economic, and technological aspects. A holistic approach is necessary to tackle these challenges effectively and achieve sustainable maize production. According to [61], the sustainability level of maize farming systems is influenced by various socioeconomic characteristics of farmers and their observed climate change adaptations. Factors such as farmers contact with extension services, membership in agricultural organizations, access to credit, farm size, and their adoption of climate change adaptation measures such as on-farm diversification and land use changes were identified as significant driving forces shaping the sustainability of maize farming systems.

One of the primary challenges is the limited adoption of sustainable practices by farmers. Barriers such as lack of awareness, limited access to resources and information, and resistance to change hinder the widespread implementation of sustainable techniques. Overcoming these barriers requires a multifaceted approach that involves promoting awareness through farmer training programs, providing technical support and guidance.

In a paper review conducted by Cairns et al. [62], they concluded that enhancing the nutritional density of maize within farmers’ fields is a critical goal. Achieving this requires not only increasing yield but also optimizing the nutritional content of the harvested crop. Another challenge involves promoting the wider adoption of new maize varieties and expediting the replacement of older ones. While the use of increased fertilizers holds the potential to elevate maize yields, recent evidence suggests that the low and fluctuating returns on investment can hinder the uptake of this approach. Moreover, the adoption of novel agricultural technologies is marked by uneven patterns, with female farmers exhibiting lower rates of adoption. Ignoring gender-specific barriers to technology adoption undermines the potential impacts of these advancements. To address these issues, it is imperative to implement strategies that encompass an integrative approach, considering the interconnected nature of the challenges.

Climate change poses another significant challenge to maize production. The impacts of climate change, such as increased frequency and intensity of droughts, floods, and heatwaves, affect the productivity and resilience of maize crops. Adapting maize cultivation to changing climatic conditions and developing resilient maize varieties that can withstand extreme weather events are essential strategies. Furthermore, implementing climate-smart practices like conservation agriculture, water management techniques and newer technologies can help mitigate the adverse effects of climate change on maize production.

Therefore, it is imperative to develop strategies for effectively addressing the challenges posed by climate change and mitigating the detrimental impact of water stress on maize production. Several viable approaches exist for adapting to water stress conditions. The initial approach involves harnessing the diverse genetic pool and identifying sources of drought resistance to develop and release new maize cultivars. The second approach centers on leveraging biotechnology advancements, utilizing molecular markers and gene transfer techniques to enhance water stress tolerance in maize plants. The third approach emphasizes the refinement of agricultural practices through the integration of meteorological data, ensuring the alignment of farming techniques with prevailing climate conditions. Additionally, adopting appropriate fertigation programs becomes crucial to counteract the adverse consequences of water stress on maize crops [63].

Soil health and nutrient management present ongoing challenges for sustainable maize production. Issues such as soil erosion, nutrient depletion, and imbalanced fertilizer use can degrade soil fertility and reduce crop productivity. Implementing soil conservation practices, including cover cropping, crop rotation, and precision nutrient management, can help address these challenges and improve soil health over the long term. Efficient water management is crucial for sustainable maize production, especially in regions facing water scarcity such as Morocco in the last decades. Challenges arise from inefficient irrigation practices, water competition, and limited access to water resources. Adopting precision irrigation techniques, promoting water-saving technologies, and implementing sustainable water management practices can optimize water use efficiency and mitigate the risks associated with water scarcity.

It requires collaborative efforts to address these multifaceted challenges that should involve farmers, researchers, policymakers, and other stakeholders. Enhancing knowledge and capacity building is a key component in promoting sustainable maize production. Providing training programs, farmer field schools, and knowledge-sharing platforms can help farmers, extension services, and stakeholders stay updated on best practices, technological innovations, and sustainable farming techniques.

Policy support from governments and policymakers is crucial for creating an enabling environment for sustainable maize production. This can include providing financial incentives, subsidies for sustainable inputs, and creating market opportunities for sustainably produced maize. Policy interventions can play a significant role in driving the adoption of sustainable practices at a larger scale.

Continued investment in research and innovation is essential to advance sustainable maize production. For example, developing improved maize varieties with traits like drought tolerance, disease resistance, and high nutritional value, researchers can enhance productivity and sustainability. Promoting research on sustainable farming techniques, precision agriculture, and climate-smart practices can unlock new approaches and technologies that contribute to sustainable maize production.

Partnerships and collaboration among various stakeholders are vital for driving sustainable maize production. Collaboration among farmers, researchers, government agencies and private sector actors fosters knowledge exchange, technology transfer, and collective action. Working together, stakeholders can address shared challenges, promote sustainable practices, and achieve the common goal of sustainable maize production.

According to the benefits of implementing smart irrigation and IoT technology, certain challenges have been evoqued for promoting a cost-effective digitalization to improve sustainability of irrigated maize cropping systems:

Inefficient fertilizer practices and the demand for irrigation water contribute to environmental impacts, such as increased greenhouse gas (GHG) emissions and poor water quality, which result in business risks in corn production. Efforts are needed to limit GHGs and manage environmental threats by promoting environmentally friendly technologies, practices, and production products, and by encouraging investments in green technologies. Field screening and monitoring are necessary to quickly identify any issues, such as plant emergence problems, nitrogen shortages, insect infestations, epidemics, weed problems, and the effects of water stress.

Utilization of wireless data collection holds promises in enabling farmers to optimize water usage. However, implementing these components underground presents challenges. One such challenge arises when burying antennas that transmit sensor data in soil, as their performance characteristics undergo significant variations based on the moisture content of the soil.

It is also important to consider that farmers typically operate on narrow profit margins, making IoT systems potentially unaffordable for them. Consequently, in order for these systems to have a viable commercial future, there should be a decreasing trend in the cost of IoT devices and overall system implementation.