Diversified Crop Rotation: An Approach for Sustainable Agriculture Production

Institute of Agriculture and Animal Science, Gokuleshwor College, Tribhuvan University, Gokuleshwor, Baitadi, Nepal Central Department of Chemistry, Tribhuvan University, Kathmandu, Nepal Ministry of Forests and Environment, Government of Nepal, Kathmandu, Nepal College of Agriculture, Life, and Physical Sciences, Southern Illinois University of Carbondale, Carbondale, IL 62901, USA Tri-Chandra Multiple Campus, Ghantaghar, Kathmandu, Nepal Paklihawa Campus, Institute of Agriculture and Animal Science, Tribhuvan University, Bhairahawa, Rupandehi, Nepal Nepal Agricultural Research Council, National Plant Breeding and Genetics Research Centre, Khumaltar, Lalitpur, Nepal


Introduction
With insufficient agricultural supplies, meeting the population's ever-increasing food demand is a tremendous challenge on a national and global scale [1,2]. Due to increased food demand and lower crop yields as a result of population growth, the agricultural sector is critical in resolving the productivity crisis. In terms of agricultural efficiency, soil texture or fertility is critical to maintaining a healthy environment. In future, rising food demand and a scarcity of agricultural land will necessitate greater crop yield and soil productivity [3]. An increasing interest in efficient and innovative agricultural practices has sparked a pragmatic strategy for agricultural land management, especially in light of the concerns of soil erosion exacerbated by anthropogenic behavior and unsustainable farming practices. In recent years, experts have become increasingly concerned about soil depletion caused by intensive farming [4,5]. Since the 1950s, almost 60% of soil depletion has been attributed to various degrees of soil ecological processes, with farming practices becoming one of the major contributors [6,7]. Researchers will explore taking a significant position in the global resilience of agricultural purposes by transforming scientific information about soils into actual techniques that increase farmers' understanding of the viability of their farming activities [8]. One of the approaches of sustainable farm management is aimed at growing soil organic matter and reducing soil erosion by crop rotation. Crop rotation disrupts insect and pathogen reproduction and hence their life cycle. Plant nutrients are restored when certain plant species are included in crop rotation, requiring less chemical fertilizer. Crop rotation is a useful technique in the practice of sustainable agriculture [9]. In contrast to monocultures or double farmed rotations, diversified crop rotations (DCR) refer to a set or multiple rotations of three or more crops [10]. Carefully selecting a crop rotation scheme has the potential to reduce trade-offs between crop viability and environmental impacts, maintain long-term soil fertility, and disrupt the weed and disease cycle process through intrinsic nutrient recycling [11]. e benefits of DCR in food security and soil health maintenance are shown in Figure 1. Diverse cropping systems are also used as a promising option for more productive agriculture [12], and this diversified crop rotation method offers many benefits for soil quality by strengthening soil conditions and increasing system production around the world [13]. Doran and Zeiss said, "the soil to serve as a vital life cycle within the ecosystem and land-use limitations for sustaining plant and animal growth, controlling or increasing the quality of water or the environment, and nurturing plant and animal health," [14]. Soil health [15], or the ability of the land to sustain crop production despite soil depletion or environmental degradation, determines the quantity and consistency of soil-based organic meals [16]. Soil health is defined as a soil's ability to function and maintain ecosystem resources [15], or the soil's ability to boost crop development without deteriorating the soil or harming the environment. Soil health determines the quality and performance of soil-based agricultural products [17]. After the rotation, the expanding heterogeneity of the crop production system will sustain or improve soil performance by increasing crop residues and diverse root systems, as well as ramping up and expanding microbial activity [18]. e DCR boosts soil water conservation, wet-soil aggregate equilibrium (WAS), and soil enzymatic activities. Restoration of the physical and chemical quality of soil have been reported in a variety of studies [19][20][21][22]. e DCR helps in soil erosion management and crop production enhancement [23] and significantly improves the soil properties and uses water and nutrients in the soil profile to sustain productivity [24]. Nonetheless, no single piece of literature covers the subject of DCR. Recognizing this, the purpose of this study is to summarize the concept of DCR, its importance, the problems of adapting DCR in various locations, and the reasoning behind adapting DCR for agricultural productivity and sustainability.
is study will give insights into the quality of soil in the agriculture system and provide a clear understanding of how DCR helps to improve soil health through the disruption of the disease cycle by enhancing the physical and chemical properties of soil systems while preserving soil quality and its foundation for the adoption of better agricultural practices. Moreover, the study accentuates the challenges, obstacles, and influences impacting the adaptation and implementation of the DCR in the agricultural production system. ese thematic areas are described briefly in the following subheadings.

Factors Affecting Adoption of Diversified Crop Rotation
Different studies [25][26][27][28][29] showed that land fragmentation is also seen as the major factor that affects the adoption of diversified crop rotation attributed to inadequate allocation of resources, which is correlated with production costs; suboptimal use of factor inputs that minimize total returns to land due to extra travel time losses, wasted space across boundaries, insufficient surveillance, and reluctance to use predefined types of machinery; and hindering agricultural development and restructuring schemes to adjust adverse implications, among others. e incentive to improve the productivity of smallholders' farmland through area expansion is confined, and farmers are hesitant to diversify crops due to modest outputs from diverse specified crops, given the expanding population versus the subsequent fragmentation of land size and depletion of natural resources [30]. According to [31], farmers with more and smaller plots prefer employing fewer current technologies, monocropping, and decreasing the average distance between plots, while an increase in farm size improves the farmer's interest in picking diverse crops with rotation, lowering the overall cost of production per unit. e factors influencing the adoption of these technologies and practices (i.e., DCR), the diffusion of information (cultivation knowledge and adoption technique), and the impact of the interventions that facilitate them (improved production and benefit to farmers) have all been highlighted, although there are substantial gaps in knowledge (training and outreach programs). In low-income nations, there are numerous dramatic market swings in outputs, production variables, and awareness; as a result, the mechanisms of diffusion, adoption potential, and profitability are likely to be diverse across a wide range of technologies, which have been the primary barrier to agricultural practice acceptance [32,33]. Risks and uncertainty are widespread in agriculture, as there is disconnection between decision-making and profit realization. Many factors influence DCR adoption, including crop insurance limits, experience adopting new technology, economic level, and decision-maker age, all of which must be taken into account while developing strategies and procedures.

Examples of Crop Rotation
Crop rotation increases yield and profit and allows for sustained production. Crop rotation with legumes not only increases the cropping intensity but also increases the total food availability and the net return from selling it. e use of a legume cover in crop rotation can provide a substantial amount of nitrogen (N) to a succeeding crop. e Nepalese agriculture system and the cropping pattern are highly dominated by geography. e common crop rotation prevalent in Nepal is given in Table 1.

Soil Health Improvement.
Researchers and farmers have been the forerunners in developing and maintaining soil health methods. Agricultural producers and academicians play an important role in preventing inadvertent soil depletion by focusing on long-term sustainability. Soil health and quality are influenced by agricultural production methods such as diverse crop cultivation, crop rotation, and associated intercropping from a variety of spatial and temporal perspectives [35]. Diversified crop rotation is essential not only for crop production optimization, but also for enhancing soil health by increasing soil fertility, nutrient efficiency, and preventing the spread of soil-borne diseases [36,37]. e broad topic themes involved in increasing soil health are explored further down.

Resistance to Diseases.
In varied crop rotation, the ability to break the disease cycle in a soil profile is extremely beneficial. Pathogen buildup is aided by monoculture on the same farmland. In the absence of rotation, such infections can proliferate in the soil and outrun spreads, causing plant disease outbreaks to become more severe. e monoculture farming method could serve as a host plant for diseases to thrive. e pathogen cycle is disrupted by rotations that result in the growth of a plant belonging to a different family, as the pathogen cannot infect a plant belonging to a different family. As a result, the pathogen population in the soil rapidly declines. Consider the seven-year diverse crop rotation period, which includes three years of alfalfa, two years of chile pepper, and two years of cotton before returning to alfalfa. Alfalfa, chile, and cotton are three plants that correspond to a variety of crops. ese three plants-alfalfa, chile, and cotton-belong to different crop families, so they can help break the disease cycle and boost productivity [38,39]. By breaking the pest cycle, lowering weeds and illnesses, improving soil quality, and safeguarding the ecosystem, the DCR aids in pest management [40].
By shortening the life cycles of soil-borne pathogens aligned with a species plant or crop genotype, the DCR offers a good chance for the development of certain soil-functional microorganisms [41]. For example, different genotypes of chickpeas (cultivars) or rotating vegetative crops (such as pea and chickpea) can affect the microbial functionality of the soil as well as the performance of pulse crops and subsequent wheat crops [42]. Various plant species, in particular, can produce residues and root exudates that improve the diversity and efficiency of the soil's microbial population as well as soil C and N cycling [17,36,43]. e goal of DCR implementation is to increase the microbial population and soil heterogeneity [35]. Different microbes interact with different plant roots, promoting soil quality with a wider spectrum of soil microbiomes [44].

Improvement in Physical and Chemical Properties of Soil.
Diversified crop rotation approaches as cover crops sown between both forms of cash crops integrate root exudates and biomass to maintain the physicochemical composition of soil erosion.
rough the creation and secretion or emergence of rhizosphere, root and associated hyphal interaction or degradation stabilizing and destabilizing components, and the creation of resilient biopores, the root and remnants of these plant parts may impact numerous elements in preserving soil quality. e study in [45] reported small and inconsistent differences in soil watertable and bulk aggregates accompanying the use of crops like wheat or lupin in South Australia. Similarly, the work in [46] found that following canola and lupin cropping; the soil was more permeable and had decreased soil hardness. After harvesting diversified crop peas and barley and after their roots were accounted for the accumulation of soils and the production of macropore, the soil has solid and more permanent particles. It is worth noting that the non-AMF (arbuscular mycorrhizal fungi) hosts are both lupin and canola, which makes it difficult to interpret changes in cumulative stabilization supporting glomalin development by the matching AMF [47] regarding the recent history of other crops. Furthermore, certain nonmycorrhizal plant species, such as canola and mustard, may be unable to form symbiotic relationships with a specific rhizobacterial characteristic as more chemical fertilizer is required, thus altering the physiological soil structure and fertility in the near future [48].

Soil Quality Maintenance.
It is self-evident that soil with perfect physical, chemical, and biological features improves soil quality in the farming system. For example, a wheatpulse crop rotation can improve soil conditions and increase system productivity [49][50][51].
e authors of [52][53][54][55] found that a four-year wheat-fallow field pea (Pisum sativum) rotation provided enough cover to prevent soil deterioration by conserving the land's physical structure. According to certain recorded studies [56]; diversifying cropping systems with plus crop rotation is beneficial to increase soil water conservation and boost the supply of soil nitrogen. e study in [55] discovered that cover crops like rye and phacelia (Phacelia tanacetifolia L.) were successful in absorbing nitrogen and water, reducing nitrate leaching in irrigated broccoli (Brassica oleracea var. italica) by 70%, and reducing fertilizer consumption in the soil. e diversified cropping system has a number of substantial advantages that have been documented around the world. Diversified cropping schemes, for example, improve water use efficiency and grain production by combining cereals with broadleaf crops [57]. According to two global studies conducted by [24,56,58], crop rotation diversification or better crop rotation has been linked to higher soil organic carbon (SOC) levels than monoculture [59,60]. In general, the crop rotation system's different abundance, uniformity, and dispersion of crop residues contribute to higher soil enzyme activity than the crop rotation system [61].
High soil component quality has been shown to have a positive impact on crop productivity [62]. Farmers can improve management of weed, insect, and disease , reduce soil depletion, and promote SOC and nitrogen fixation in agricultural production processes by farming different crops in the same location (crop rotation). For example, in two current long-term rotational tests of consistent corn, consistent soybean, corn-soybean, and corn-soybean-wheat rotation, the most diversified rotation of corn-soybeanwheat rotation increased the organic carbon capacity of the Advances in Agriculture soil by 7% compared to consistent soybean, and rotational and tilling interactions with soil organic carbon were 7% greater than standard farming [22]. e mutual retention or enhancement of these plants' output capacities can provide an extra benefit [32,63]. By adopting a wider variety of crops, SOC sequestration, soil composition, and texture can be enhanced while production is enhanced, reducing soil and environmental damage [49,56,64].

Agronomic Impact of Crop Rotation
By replacing fallow periods with growing different crops that replenish soil nutrients, crop rotation has helped to increase productivity. Crop rotation also aids in the fight against erosion forces. e agronomic impact of crop rotation is given in Table 2.

Economic Benefits of Diversified Crop Rotation.
Long before the development of the current farming system, its economic and ecological value was recognized. e diverse crop rotation includes weed, disease, insect, and nematode management; soil erosion reduction; soil fertility maintenance and improved efficiency; ecosystem resource preservation; and lower threat and market risks [66][67][68][69][70][71][72].

Reduction of Production Risk.
Crop diversification is one of the most cost-effective solutions to reduce income instability among farmers, especially among impoverished smallholders [73]. To prevent production risks or control limited resources when seeding or harvesting, farmers frequently employ this strategy by picking diversified crops preceded by crop rotation. e latest data of the economic net return from crop rotations in the Midwest United States shows that increasing land efficiency reduces outside investments while increasing crop yields [74]. Farmers can get significant concrete benefits from alfalfa-containing crop rotations while minimizing the risk of herbicide-resistant enormous ragweed pests, according to the results of the stochastic study [75]. DCR is linked to increased production of various agricultural inputs as well as a systemic economic transformation in which farm contracts account for a greater part of GDP [76]. Continued financial crises, quick demand fluctuations, and increased technological breakthroughs provide a clear incentive to diversify crops, lowering risk in the agricultural system.

Increase in Farmers'
Income. Numerous researchers, including [77] in Zimbabwe, [78] in El Salvador and Honduras, and [79] in the Brazilian Amazon, have found a significant beneficial relationship between crop diversification rotations and total agricultural productivity for the full year. According to [77], increased production from a diverse crop rotation system results in higher revenue for farmers throughout the year. Similarly, [78] showed an average increase of 21% in farm income across all samples in the study, while [79] found a generally positive relationship between diversification and income in the Brazilian Amazon. Furthermore, the integration of different crops in the same area could raise farmers' income and stabilize them [80,81].

Increase in Crop Productivity.
In parts of the world where diverse cropping is a common element of agroecosystem management, productivity is usually far more robust and consistent throughout time [66,82]. In comparison to standard double-crop rotations, the DCR field study in the Iowa region between 2003 and 2011 found that crop output has improved, agricultural inputs have dropped, and weeds have decreased. When compared to a single system, using a varied crop rotation strategy can have a synergistic effect, resulting in enhanced rewards [58]. In crop rotation, the availability of nutrients from the soil provides ample nourishment to all plants, ensuring that the yield produced is successful.

High
Resilience at Locality. Multiyear crop rotations, which require fewer commercial fertilizers and additional agricultural inputs including fertilizer and crop nutrient recycling, banded fertilizer application, and chemical pest control inputs, can help reduce reliance on external inputs [83]. Adoption of DCR in a specific sequence, such as corn-soybeanwheat-oats, corn-soybean-wheat, corn-soybean-wheat, cornsoybean-oats, and cover crops, helps to maintain soil health by reducing the use of chemical fertilizers. Crimson clover, annual ryegrass, oats, cereal rye, and oil-seed radishes are examples of cover crops that can improve soil structure, improve soil organic matter, enhance water percolation, suppress weeds, reduce soil erosion, and fix residual nitrogen after grain harvest [84]. ese positive cover crop effects can boost farm profitability by lowering expenses (e.g., by reducing the need for commercial fertilizers) or increasing production (by improving soil quality and fertility). In Michigan, for example, [85] found that using cover crops in a corn-soybean-wheat rotation reduced nitrate leaching while maintaining profitability. As a result, integrating varied crop rotation benefits farmers by reducing their reliance on external inputs, resulting in financial gains. erefore, the implementation of diversified crop rotation enables farmers to reduce the resilience of external inputs, supporting them with economic benefits.

Resources Limitation.
Due to a lack of essential investments in machines, infrastructures, and expertise, as well as research proof, DCR measures are rarely applied [72,[86][87][88][89][90]. One of the most significant challenges to the adoption of this strategy is financial, as integrating extra crops into normal rotations may require farmers to make significant up-front investments, such as in new machinery, and impose an additional short-term cost. Furthermore, most farmers who rent farmland from others have shortterm contracts that do not allow for long-term planning or incentives for soil or production development. Lack of experience, limited financing access for investment, and lack of technological support and knowledge by stakeholders and 4 Advances in Agriculture    [89,91]. Furthermore, the scarcity of markets is widely acknowledged in the form of impediments to extending rotations of varied crops, with some farmers participating in biomass markets, albeit these markets are currently quite regulated [89]. Despite the potential benefits of conservation agriculture, such as diversified crop rotation for enhanced crop yields, soil health through minimizing soil erosion, water-use efficiency, and other factors, its adoption rate is low. Access to information issues and a lack of understanding can stymie broader adoption [68]. Furthermore, due to inadequate budget allocation, the inadequacy of mobility, outmoded knowledge, understaffing, and low staff morale, the basic impediments to the application of new conservation methods are communication skills and technological diffusion [92]. Crop insurance and credit limits are other significant barriers to this approach's adoption, as lenders unfamiliar with the profitability potential of longer cycles with varied cropping systems are sometimes put off by complex rotations and are hesitant to issue loans in this sector. Farmers usually need assurance that new methods are feasible, can be effectively implemented in their locations, and can benefit their bottom line.
Similarly, the DCR adoption is hampered by a lack of reinforcement and institutional coordination that involves both public and private institutions, a lack of investment and apprehension about production risk, and a lack of strategy studies that address dissemination and implementation. Apart from these, climate issues, technological adaptation problems in DCR, model farmer development, exposure and exhibition, and demonstration limitations are the principal roadblocks to DCR adaptation on a larger and broader scale [89,93]. Because the DCR concept is a relatively new system among farming communities, they may be hesitant to adopt it due to concerns about economic loss from the newly chosen rotation compared to their old rotation of fewer crops that they have been familiar with for a long time.

Conclusion
Diversified crop rotations are becoming more popular as a tool for maintaining sustainable crop production as people are becoming more concerned about the need to provide highquality food with minimal environmental impact. DCR encourages beneficial soil microbes and their interactions, breaks the disease cycle, and reduces the number of weeds. DCR improves the physical and chemical properties of soil and increases land-use efficiency and crop productivity. It is a valuable practice for long-term profitability. Farmers require diversified crop rotations that are flexible and economic in order to respond to market demands. Policy and organizational supports are needed to adopt diversified crop rotation practices at the farmer's level. e scientific community should focus their current and future research strategies and efforts on developing better-diversified crop rotation practices that are adaptable to changing climatic conditions.

Data Availability
Data supporting the findings of the study are available upon request from the corresponding author.

Conflicts of Interest
e authors declare that there are no conflicts of interest. (Source: [65]). 6 Advances in Agriculture