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Intercropping

Intercropping is the simultaneous cultivation of two or more crop species, or genotypes, in the same field for at least part of their growth cycle, often planned to optimize resource use and productivity.^[1] This practice has ancient origins, with evidence from traditional systems such as the Indigenous American "Three Sisters" method combining maize, beans, and squash, and similar mixed cropping in ancient civilizations across Africa, Asia, and Europe.^[2]^[3] It contrasts with monoculture by diversifying plant arrangements to enhance ecological interactions, such as complementary nutrient uptake and pest deterrence.^[4] Key types of intercropping include row intercropping, where crops are planted in alternating rows; strip intercropping, involving wider bands of multiple crops; mixed intercropping, with random or patterned mixing of species without distinct rows; and relay intercropping, where a second crop is sown into a maturing first crop before harvest.^[5] Other variations encompass companion planting, interseeding, and temporal intercropping, often integrating cash crops with cover crops to support organic farming systems.^[6] Intercropping offers substantial agronomic advantages, including improved land use efficiency, with meta-analyses of field experiments showing average land equivalent ratios of 1.23 for grain yields, equivalent to 19% land savings over sole cropping.^[4] It boosts protein production by approximately 10% in maize-legume systems and enhances nitrogen use efficiency by 18%, contributing to sustainable intensification.^[4] Additionally, it promotes crop resilience against pests, weeds, and pathogens—reducing pest densities through plant diversity and beneficial insect attraction—while improving soil fertility, organic carbon content, and overall biodiversity.^[7]^[8]^[9] These benefits make intercropping a vital strategy for resilient, environmentally friendly agriculture, particularly in resource-limited settings.^[10]

Introduction

Definition

Intercropping is the simultaneous cultivation of two or more crop species in the same field or growing area, typically in close proximity to facilitate beneficial interactions between the plants.^[11] This practice involves planting the crops within the same growing season or during overlapping periods, allowing them to share resources such as light, water, and nutrients while varying in density and spatial arrangement to optimize growth.^[12] Unlike sequential planting methods, intercropping emphasizes concurrent growth rather than alternating crops over time.^[13] A key metric for evaluating the productivity of intercropping systems is the Land Equivalent Ratio (LER), which compares the combined yield of intercrops to the yields from growing each crop alone on equivalent land areas.^[14] The LER is calculated using the formula:

\text{LER} = \left( \frac{\text{[Yield](/page/Yield) of [crop](/page/Crop) A in intercrop}}{\text{[Yield](/page/Yield) of [crop](/page/Crop) A in sole [crop](/page/Crop)}} \right) + \left( \frac{\text{[Yield](/page/Yield) of [crop](/page/Crop) B in intercrop}}{\text{[Yield](/page/Yield) of [crop](/page/Crop) B in sole [crop](/page/Crop)}} \right)

An LER greater than 1 indicates that the intercropping system is more efficient in land use than sole cropping, signifying a yield advantage.^[14] Intercropping is particularly relevant in sustainable agriculture, where it promotes resource efficiency and agroecosystem resilience by diversifying crop production and reducing reliance on external inputs. This approach aligns with broader goals of ecological intensification, enhancing overall farm productivity without expanding cultivated land.^[15]

Historical Background

Intercropping practices trace their roots to ancient agricultural systems, where farmers integrated multiple crops to enhance productivity and resilience. In Mesoamerica, the milpa system—combining maize, beans, and squash—emerged around 2500–1500 BCE, with archaeological evidence dating back approximately 3,500–4,500 years among indigenous communities in Mexico and Central America.^[16] This polyculture approach allowed beans to fix nitrogen for maize while squash provided ground cover to suppress weeds and retain moisture, forming a symbiotic triad that sustained Mayan and other civilizations for millennia. Similarly, traditional farming in Africa and Asia incorporated intercropping well before 1000 CE; in West Africa, millet and sorghum were interplanted with legumes from 3000 to 1000 BCE, leveraging indigenous knowledge to optimize limited resources in diverse agroecological zones. In Asia, early systems in China and South Asia featured mixed cropping of cereals with legumes and vegetables by the Han dynasty (1st century BCE), as documented in early agricultural texts such as the Fan Shengzhi Shu, reflecting adaptive strategies in intensive rice-wheat rotations.^[17] The adoption of intercropping declined in industrialized regions during the late 19th and early 20th centuries, as mechanization and the push for large-scale monocultures prioritized uniform fields for efficient harvesting and chemical inputs. Research on intercropping, which had been explored since the late 1800s in Europe and North America, largely faded from prominence after 1945 amid the rise of synthetic fertilizers and pesticides that favored single-crop systems. This shift was driven by industrial agriculture's emphasis on yield maximization through specialization, rendering diverse cropping less economically viable in mechanized settings. However, a revival began in the mid-20th century through emerging agroecology movements in the 1970s, which sought to reintegrate ecological principles into farming, including intercropping to mimic natural biodiversity and reduce reliance on external inputs. Key milestones in the modern era include the Food and Agriculture Organization (FAO) of the United Nations promoting intercropping in the 1980s, particularly through integrated pest management programs and farmer field schools in Southeast Asia and sub-Saharan Africa, targeting smallholder farmers to boost yields and sustainability in resource-poor contexts. In the 21st century, intercropping has resurged globally as a cornerstone of sustainable agriculture, driven by concerns over climate change and soil degradation; for instance, the European Union's Common Agricultural Policy (CAP) reforms post-2010, including the 2013 greening measures and 2023-2027 strategic plans, provide incentives for crop diversification—such as intercropping—via eco-schemes and direct payments that reward environmental benefits like enhanced biodiversity and reduced erosion. Intercropping plays a pivotal role in food security for developing countries, where it remains a dominant practice in low-input systems, estimated to be practiced on approximately 12% of global cropland as of the early 2020s, particularly among smallholders in Africa, Asia, and Latin America.^[18] This widespread use supports resilient production on marginal lands, contributing significantly to household nutrition and income stability amid population pressures and limited mechanization.

Classification and Methods

Spatial Intercropping

Spatial intercropping refers to the simultaneous cultivation of two or more crop species within the same field, arranged in specific spatial patterns to optimize resource use and minimize competition. This approach contrasts with temporal methods by focusing on concurrent growth without staggered planting times. Key subtypes include mixed intercropping, row intercropping, and strip intercropping, each defined by the arrangement of crops relative to one another.^[19]^[20] Mixed intercropping involves the random or patterned mixing of crops without distinct rows, such as cereals with legumes sown together across the field. This subtype allows for flexible integration but can complicate mechanical harvesting. Row intercropping features alternating rows of different crops, often in ratios like 2:1 for maize and soybean, where two rows of maize are paired with one row of soybean to balance light and nutrient access. Strip intercropping uses wider bands of 4-6 rows per crop, enabling mechanized operations while permitting inter-crop interactions, particularly suited for large-scale fields.^[21]^[22]^[20]^[23]^[24]^[25] Design principles for spatial intercropping emphasize complementarity between species to enhance overall productivity. In additive series designs, the total plant density remains fixed by adding intercrops to the main crop's standard density, promoting higher biomass without reducing the primary crop's population. Replacement series designs, conversely, substitute proportions of the main crop with intercrops, maintaining constant total density to study competitive dynamics. Selection of crop pairs considers factors like differing heights for vertical light partitioning—taller crops intercept upper canopy light while allowing shorter ones access to lower levels—and root depth variations for horizontal soil resource separation, such as deep-rooted legumes paired with shallow-rooted cereals.^[26]^[27]^[28]^[29] Representative examples illustrate these principles in practice. In sub-Saharan Africa, maize-bean intercropping often employs row arrangements where maize's height facilitates light interception for the understory beans, improving nitrogen fixation through legume roots. In Asia, rice-fish systems integrate fish into flooded rice paddies as a form of mixed or strip intercropping, where fish utilize the spatial niches below the rice canopy for foraging, enhancing aquatic resource complementarity.^[20]^[30]^[31] Implementation of spatial intercropping requires precise seeding patterns and spacing to ensure compatibility. Crops are typically sown simultaneously using broadcast for mixed systems or precision planters for row and strip configurations, with row widths of 50-100 cm allowing adequate machinery passage and light penetration. For instance, in row intercropping, maize may be spaced at 75 cm between rows with soybeans in adjacent 25 cm interspaces, while strip systems maintain 4-6 row bands at 60-90 cm widths to support mechanization without excessive shading. These guidelines promote uniform establishment and reduce early competition.^[23]^[32]^[33]^[34]

Temporal Intercropping

Temporal intercropping refers to the practice of cultivating two or more crops in the same field during the same growing season, but with deliberate differences in planting and harvesting times to allow for sequential or overlapping growth periods. This approach intensifies land use by exploiting temporal niches, where crops occupy the field at different stages of their life cycles, minimizing idle periods and enhancing overall productivity. Unlike purely spatial arrangements, temporal intercropping emphasizes the timing of sowing and reaping rather than physical layout, though the two can be combined for optimized resource use.^[35] Key subtypes include relay intercropping and sequential intercropping. In relay intercropping, the second crop is sown into the standing first crop before the latter reaches full maturity, creating an overlap in their growth phases; a classic example is the relay planting of cotton into maturing wheat fields in China's Yellow River region, where cotton seeds are sown 40-50 days before wheat harvest to capture early-season heat resources. Sequential intercropping, by contrast, involves harvesting the first crop shortly before or with minimal overlap to the planting of the second, bordering on crop rotation but confined to a single season; this is seen in systems where early-maturing varieties enable tight succession without prolonged fallow. Overlap periods in temporal systems typically range from 20-50% of the combined growth cycles, allowing the second crop to establish while the first still provides soil cover and nutrient cycling benefits.^[36]^[37] Practical advantages of temporal intercropping stem from its ability to extend effective land utilization and reduce fallow durations, often achieving land equivalent ratios exceeding 1.2 compared to sole cropping. For instance, relay intercropping of soybean into maize in southwest China prolongs the productive window, boosting total yields by 15-30% through better synchronization of maturity differences, particularly when using early-maturing maize varieties to avoid shading the emerging soybean. Similarly, sorghum-cowpea relay systems in India's semi-arid zones leverage cowpea's shorter cycle to follow sorghum establishment, enhancing forage and grain output while minimizing soil exposure. Management considerations include selecting varieties with staggered maturities to prevent excessive competition during overlaps and adjusting planting densities to accommodate growth trajectories. This temporal focus distinguishes it from spatial intercropping, which prioritizes simultaneous arrangement over sequence, enabling temporal methods to integrate with spatial designs for multifaceted efficiency.^[38]^[39]

Ecological and Agronomic Benefits

Resource Partitioning and Efficiency

Intercropping optimizes resource partitioning by enabling complementary use of environmental resources among component crops, thereby minimizing competition and maximizing overall system productivity. In spatial arrangements, such as row or strip intercropping, crops with differing root architectures can access distinct soil zones; for instance, deep-rooted legumes like pigeon pea (Cajanus cajan) extract nitrogen from subsoil layers, while shallow-rooted cereals like maize (Zea mays) primarily utilize surface water and nutrients.^[1] Similarly, vertical light partitioning occurs in mixed systems where tall crops, such as maize, intercept sunlight in the upper canopy, allowing shorter companions like beans (Phaseolus vulgaris) to capture diffuse light below.^[40] These mechanisms reduce overlap in resource capture, enhancing efficiency compared to monocultures.^[41] Quantitative benefits from resource partitioning are evident in improved yields and input efficiencies. Meta-analyses indicate that intercropping systems often achieve land equivalent ratios (LER) greater than 1, with average values of 1.23 for grain production, equivalent to 19-23% higher land productivity than sole crops.^[4] This translates to total output equivalent to 19% higher land productivity than sole crops, driven by better capture of light, water, and nutrients.^[11] For nutrients, legume components fix atmospheric nitrogen, reducing synthetic fertilizer needs; in maize-legume systems, this can save 50-100 kg N ha⁻¹ while maintaining or boosting yields, as legumes supply 30-50% of the cereal's nitrogen demand through transfer and residual effects.^[42] In dryland environments, intercropping enhances water use efficiency by approximately 29% via temporal and spatial niche differentiation, where early-maturing crops conserve soil moisture for later ones, reducing evaporation losses.^[43] Intercropping also promotes soil health through enhanced organic matter inputs and microbial activity. Decomposed residues from diverse crops increase soil organic carbon by 10-20% over monocultures, fostering beneficial microbial communities that improve nutrient cycling.^[44] In maize-legume systems, legumes facilitate phosphorus recycling by acidifying the rhizosphere and mobilizing insoluble forms, increasing phosphorus uptake efficiency by approximately 24% and supporting sustained fertility without additional inputs.^[45] The primary metric for assessing resource partitioning efficiency is the land equivalent ratio (LER), which quantifies total productivity relative to sole crops. To derive LER for a two-crop system, calculate the partial LER for each component as the ratio of its intercrop yield to its sole-crop yield under equivalent management:

\text{LER}_A = \frac{Y_{A,\text{inter}}}{Y_{A,\text{sole}}}, \quad \text{LER}_B = \frac{Y_{B,\text{inter}}}{Y_{B,\text{sole}}}

where Y_{A,\text{inter}} is the yield of crop A in the intercrop, Y_{A,\text{sole}} is the yield of A grown alone, and similarly for B. The total LER is the sum:

\text{LER} = \text{LER}_A + \text{LER}_B

An LER > 1 indicates an advantage, as the intercrop produces more total output than the land area would yield in monoculture; for example, if \text{LER}_A = 0.7 and \text{LER}_B = 0.6, then LER = 1.3, meaning 30% more land would be needed in sole cropping to match intercrop yields.^[46] Interpretation must account for edge effects in small experimental plots, where boundary rows receive disproportionate resources like light, inflating LER by 10-20%; larger field-scale assessments mitigate this by averaging over the plot area or using strip designs.^[11]

Biological Interactions and Mutualism

Intercropping fosters mutualistic interactions among plants and associated microorganisms, enhancing nutrient availability through symbiotic relationships. In legume-cereal systems, such as those pairing soybeans with maize or wheat, Rhizobia bacteria in legume root nodules fix atmospheric nitrogen, which is subsequently transferred to the cereal companion via root exudates, mycorrhizal networks, or decomposition, benefiting both crops by reducing fertilizer needs.^[47] Nitrogen fixation rates in these agricultural legumes typically range from 50 to 200 kg N ha⁻¹ yr⁻¹, with transfer efficiencies varying from 0 to 73% depending on species and environmental conditions.^[48] Companion planting further exemplifies mutualism by deterring pests; for instance, intercropping tomatoes with marigolds (Tagetes patula) releases alpha-terthienyl from marigold roots, suppressing root-knot nematodes (Meloidogyne spp.) by up to 46%, thereby protecting the primary crop without significantly impacting yields.^[49] These interactions extend to biodiversity enhancement, where intercropped flowering species provide nectar and pollen resources, attracting pollinators and increasing overall insect diversity. Strip intercropping of insect-pollinated crops like faba beans and turnip rape supports a characteristic pollinator assemblage, elevating species richness compared to monocultures.^[50] Multispecies mixtures can boost pollinator abundance and diversity, with studies reporting substantial increases in beneficial insect visits per hectare (up to 1.5 million in some mixtures), fostering pollination services for the main crops.^[51] Additionally, diverse intercrops create microhabitats that harbor beneficial organisms, such as predatory insects like ladybugs and parasitic wasps, which prey on herbivores and sustain ecological balance within the system.^[52] Specific examples illustrate these mutualisms in practice. Trap cropping employs sacrificial plants, such as mustard intercropped with brassicas, to lure pests like aphids away from cash crops, concentrating herbivore pressure on the trap and enabling targeted management while preserving the primary yield.^[53] Nurse crops, like rye sown with potatoes, offer physical protection by acting as windbreaks and stabilizing soil, reducing erosion losses by up to 50% in vulnerable fields and allowing the main crop to establish more robustly.^[54] Over multiple seasons, intercropping promotes long-term soil health through diversified microbiomes. Maize-Desmodium systems, for example, significantly increase fungal diversity (e.g., Shannon index p=0.047), enriching beneficial taxa like Trichoderma that suppress pathogens such as Aspergillus flavus, thereby lowering disease incidence and pathogen buildup compared to monocultures.^[55] This microbial shift enhances overall ecosystem resilience, supporting sustained mutualistic networks.^[56]

Pest, Disease, and Weed Management

Intercropping provides natural mechanisms to manage pests by limiting their host availability and disrupting their behavior. The dilution effect occurs when non-host plants in the intercrop reduce the proportion of suitable hosts, thereby decreasing pest infestation rates; for instance, a meta-analysis has shown that intercropping reduces arthropod pest abundance by 38% and density by 41%. Barrier effects arise from the physical structure of diverse canopies, which hinder pest movement and oviposition, while allelopathy involves chemical compounds from one crop inhibiting pest development, though this is less common for insects than for weeds.^[57] In disease management, intercropping breaks pathogen life cycles by incorporating non-host crops that prevent transmission and spore dispersal. For example, intercropping cereals like barley or wheat with faba beans reduces rust severity by interrupting the pathogen's host dependency, achieving an average disease incidence reduction of 45% across various studies. Similarly, legume-grain intercrops lower overall pathogen incidence by 34%, as non-susceptible companions dilute vector landing on infected hosts and limit airborne spread.^[7] In potato systems, intercropping with non-host crops like onions mitigates late blight (Phytophthora infestans) by reducing humidity microclimates and vector activity, avoiding shared susceptibilities seen in monocultures.^[58] Weed suppression in intercropping relies on competitive exclusion, where faster-growing companion crops rapidly occupy space, light, and nutrients, outcompeting invasives and achieving 40-50% reductions in weed density.^[59] Dense canopies create barrier effects through shading, limiting weed germination by up to 49% in diversified rotations.^[59] Allelopathy enhances this, as seen in cereal rye intercrops where root exudates and residues release inhibitory chemicals, suppressing weed biomass by 41-77% in succeeding crops.^[60] Integration with cover crops like rye further amplifies suppression by combining physical mulching with chemical inhibition during establishment.^[61] Empirical evidence indicates intercropping can lower pesticide requirements through these biotic controls, as pest and disease pressures drop significantly in diverse systems.^[62] For instance, broad meta-analyses confirm 40% reductions in nematode damage and 55% in disease incidence, offsetting the need for chemical interventions.^[63] However, limitations exist, particularly during the initial establishment phase when weed pressure may be higher due to slower canopy closure, necessitating supplemental management in early growth stages.^[64]

Challenges and Limitations

Crop Competition and Management Issues

In intercropping systems, crops engage in intra- and interspecific competition for essential resources such as light and nutrients, often leading to asymmetric outcomes where dominant species suppress subordinates. For instance, taller crops like maize or barley can shade shorter companions such as soybean or pea, reducing the photosynthetically active radiation (PAR) available to the understory by 5-18% and thereby limiting their photosynthetic rates and biomass accumulation.^[65] This shading effect is particularly pronounced in vertical strata arrangements, where initial growth advantages allow the dominant crop to capture a disproportionate share of light, resulting in yield reductions for the subordinate crop ranging from 12-22% in cases like soybean under apple trees or maize.^[65] Similarly, competition for soil nutrients, especially nitrogen, favors species with extensive root systems or higher uptake efficiency; barley, for example, suppresses pea nitrogen acquisition in mixed stands, leading to biomass proportions for pea dropping to as low as 43% under high nitrogen conditions.^[66] Management of intercropping systems presents operational challenges, particularly in seeding and harvesting due to the differing requirements of component crops. Seeding precision is complicated by variations in optimal planting depths and seed sizes—for example, chickpeas require 1-4 inches while flax needs only 0.75-1.5 inches—often necessitating separate passes or modified equipment to ensure uniform emergence and minimize early competition.^[67] Harvesting is further hindered by uneven maturity times and physical entanglement; in systems like field pea-canola, mismatched ripening can lead to seed shattering or require desiccation, while intertwined roots or stems in dense mixtures may demand manual labor for separation, increasing time and costs compared to monocultures.^[67]^[68] Unbalanced intercropping can pose soil and environmental risks, including nutrient depletion and increased erosion potential under poor management. When crop pairings lack complementary root architectures, aggressive uptake by one species—such as maize drawing heavily on available nitrogen—can deplete soil reserves, necessitating 10-30% higher fertilizer applications to sustain both crops and risking long-term fertility decline if not monitored via soil tests.^[68] Poor timing in planting or harvesting may exacerbate erosion on sloping fields by leaving soil exposed during critical periods, though this is less common than in monocultures; for example, vines like squash in traditional systems can overwhelm partners if not spatially controlled, smothering growth and altering soil cover unevenly.^[69]^[70] To mitigate these competition and management issues, selecting compatible varieties is essential, focusing on traits like differing maturities, heights, or root depths to reduce rivalry without delving into economic evaluations. For instance, pairing early-maturing canola with late-maturing peas allows staggered resource demands, minimizing shading and nutrient overlap, while choosing soybean varieties with shade tolerance can limit yield losses in maize-soybean systems.^[67]^[65] Spatial adjustments, such as alternating rows, further aid in balancing light interception and root competition, promoting more equitable resource use among partners.^[68]

Economic and Practical Constraints

Intercropping often involves higher initial labor costs compared to monoculture systems, with studies showing that labor requirements for planting and harvesting can nearly double due to the need for more precise and time-intensive operations in mixed fields.^[71] Machinery ownership costs can also increase substantially, by up to 90%, as standard equipment designed for uniform monocrops is less efficient in diverse row arrangements, leading to greater wear and the need for smaller, specialized implements.^[71] These elevated costs contribute to variable markets for mixed harvests, where separating and selling multiple crop types requires additional logistics and may result in lower premiums or inconsistent pricing for secondary crops.^[72] Breakeven analyses indicate that intercropping can achieve profitability on small-scale farms through diversified income streams and reduced input needs, but it carries higher risks on large-scale operations due to amplified labor and equipment demands that may not be offset by yield gains.^[73] In low-input tropical systems, intercropping aligns well with manual practices and resource-limited environments, enhancing overall viability, whereas in temperate, mechanized regions, it faces greater challenges from incompatibility with large-scale machinery and higher operational complexity.^[1] Policy biases, such as agricultural subsidies that favor monocrops through crop insurance and price supports, further discourage adoption by prioritizing uniform, high-volume production over diversified systems.^[74] Practical barriers also include significant knowledge gaps among farmers, necessitating extensive training to optimize crop combinations and manage mixed systems effectively.^[75] These factors contribute to low adoption rates of intercropping in developed countries, where mechanized monoculture dominates and systemic incentives limit uptake to under 20% in many regions as of the 2020s.^[76]

Applications and Future Directions

Traditional and Indigenous Systems

Traditional intercropping systems have been integral to indigenous and smallholder agriculture worldwide, relying on locally adapted polycultures to ensure food security and environmental resilience. These practices emphasize the cultivation of complementary crops, animals, and sometimes aquatic species in shared spaces, drawing on generations of community knowledge to optimize limited resources without synthetic inputs. In Mesoamerica, the milpa system exemplifies this approach, involving the intercropping of maize (Zea mays), beans (Phaseolus spp.), and squash (Cucurbita spp.) in a multilayered arrangement where maize provides structural support, beans fix nitrogen, and squash suppresses weeds with its ground cover.^[77]^[78] This triad has sustained Mayan and other indigenous communities by providing diverse, nutritious foods and adapting to variable climates.^[79] In sub-Saharan Africa, the push-pull system integrates cereals like maize with the repellent legume Desmodium (pushed between crop rows) and the trap crop Napier grass (Pennisetum purpureum) planted as borders, effectively managing stem borer pests through natural chemical signaling while enhancing fodder availability for livestock.^[80]^[81] Adopted by smallholder farmers in Kenya and neighboring regions, this method builds on traditional crop associations to reduce pest damage without pesticides, supporting household food production in resource-scarce environments.^[82] Similarly, in Southeast Asia, rice-fish-duck integration combines paddy rice (Oryza sativa) cultivation with ducks and fish such as common carp (Cyprinus carpio), where ducks control weeds and pests, fish consume algae and insects, and their wastes fertilize the rice, yielding multiple products from one field.^[83]^[84] This agroecological model, practiced in countries like Vietnam and Bangladesh, promotes diversified income and nutrient cycling in wetland ecosystems.^[85] These systems hold profound cultural significance, embedding intercropping within indigenous worldviews that prioritize harmony with nature and biodiversity conservation. In Latin America, a significant proportion of indigenous farms—particularly among Mayan groups—employ intercropping like the milpa to maintain agrobiodiversity, with practices fostering resilience against climate variability by preserving heirloom varieties and soil health.^[86]^[87] Such traditions adapt to local conditions, such as seasonal rains or poor soils, ensuring long-term viability through oral transmission of knowledge across communities. Globally, these approaches support millions of smallholders by conserving genetic diversity and cultural heritage amid environmental pressures.^[88] From a sustainability perspective, traditional intercropping minimizes external inputs like fertilizers and chemicals, relying instead on symbiotic plant interactions and animal contributions to sustain soil fertility over generations. Legume components in systems like milpa and push-pull naturally replenish nitrogen, while ground covers prevent erosion, enabling continuous production on marginal lands without depleting resources.^[89] These low-input methods underpin the livelihoods of approximately 500 million smallholder farming households worldwide, many in developing regions, by enhancing system stability and reducing vulnerability to market fluctuations.^[90] Despite pressures from modernization, such as the promotion of monocultures and commercial seeds, traditional intercropping persists through community-led stewardship and the recognition of its ecological value. Indigenous knowledge transmission via elders and local institutions has preserved these systems, allowing adaptation to contemporary challenges while resisting full-scale industrialization.^[91] This endurance highlights their role as living repositories of sustainable agriculture, influencing global efforts to revive resilient farming practices.^[88]

Modern and Research-Driven Practices

Recent advancements in precision agriculture have integrated drone technology for monitoring crop systems, enabling real-time assessment of crop health, nutrient distribution, and growth patterns. These tools facilitate targeted interventions, such as variable-rate fertilization, to optimize resource use in diverse planting configurations.^[92] Complementing this, climate-resilient intercropping combinations, including drought-tolerant maize paired with legumes like lablab or forage species, have demonstrated enhanced soil protection and reduced pest incidence under water-stressed conditions.^[93]^[94] Such pairings improve nitrogen fixation and overall system resilience, with trials in regions like Ethiopia showing legumes suppressing weeds while boosting maize productivity.^[95] Research from 2023 to 2025 highlights yield advantages in European cereal-pulse intercropping, where systems like lentil-cereal mixtures achieved land equivalent ratios greater than 1, indicating higher overall productivity than sole crops, alongside a 16% reduction in grain loss from pests.^[96] Similarly, rapeseed-pea intercrops outperformed wheat-legume combinations in land use efficiency across multiple years, driven by complementary phenologies that mitigate competition.^[97] In agroforestry hybrids, intercropping trees with crops has increased soil organic carbon by an average of 10.7% compared to conventional land uses, enhancing carbon sequestration particularly in arid zones.^[98] Long-term studies further confirm these systems' role in building deep soil carbon pools, supporting climate mitigation efforts.^[99] Innovations in mechanized strip intercropping have addressed labor constraints by employing autonomous machines for planting and harvesting alternating crop strips, significantly lowering labor costs relative to manual methods.^[100] These systems maintain high mechanization compatibility while promoting yield stability. Global trials from 2020 to 2025 underscore intercropping's adaptation to climate change, with multiple cropping practices like maize-legume pairings improving resource efficiency and buffering against variable weather in diverse agroecologies.^[101] Such experiments reveal intercropping's capacity to stabilize yields amid rising temperatures and erratic precipitation.^[102] Looking ahead, policy frameworks align intercropping with the UN Sustainable Development Goals, particularly SDG 2 (zero hunger) and SDG 13 (climate action), through initiatives like the EU's Common Agricultural Policy that incentivize diversified cropping for sustainability.^[101] Scaling efforts involve crop varieties bred for intercropping compatibility to minimize cross-species competition while enhancing biological control interactions.^[103] Intercropping holds promise for urban farming, where space-efficient techniques like strip systems can boost productivity on limited plots, fostering local food security and biodiversity.

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[PDF] Effect of crop spatial arrangement on yield and resource efficiency of ...
There are two types of intercropping systems, namely additive series and replacement series, based on the percentage of plant ... intercrop, is introduced into ...
[24]
[PDF] Field Crops Research - Rothamsted Repository
Apr 12, 2023 · In such circumstances, it may be possible to utilise a third type of intercropping system: one that exploits niche complementarity in space.
[25]
13.2.6: Agriculture around the world - Social Sci LibreTexts
Paddy rice farmers also practice a type of intercropping by introducing fish and other forms of aquaculture into fields. By putting fish that eat bugs into rice ...
[26]
Quantification of the Cumulative Shading Capacity in a Maize ...
Taller crops intercept more photosynthetically active radiation (PAR) [6], but they also prevent direct solar radiation from reaching shorter crops [7]. This ...
[27]
[PDF] optimizing vegetable strip intercropping systems for application in
Apr 12, 2012 · Strip intercropping means simultaneously cultivating two or more crops in different strips, wide enough to allow for independent cultivation, ...
[28]
[PDF] Strip Intercropping Corn and Alfalfa
Strip intercropping is the production of more than one crop simultaneously in different strips that are narrow enough for the crops to interact and wide enough ...
[29]
Intercropping with faba bean under appropriate row configuration ...
Jun 1, 2025 · pilosula intercropping with one row of faba bean (IC2), faba bean was planted with a 50 cm inter-row distance and 25 cm inter-plant distance ( ...Missing: spacing | Show results with:spacing
[30]
The Importance of Multiple Cropping in Increasing World Food ...
Jan 1, 1976 · Multiple cropping for food production is in widespread use by farmers in the warmer parts of the world at all levels of agricultural ...
[31]
Growth, yield and quality of wheat and cotton in relay strip ...
Sep 13, 2007 · More than 65% of cotton is currently cultivated as relay strip intercropping with wheat in this region; in Henan Province, about 95% of cotton ...
[32]
[PDF] Relay Intercropping Brassicas into Chile and Sweet Corn
Relay intercropping is the production of a second crop planted into a field when the first crop has reached its reproductive stage but before physiological.
[33]
Maize–soybean relay cropping increases soybean yield ...
Relay cropping increased the stay-green traits of maize and soybean by 13% and 89%, respectively. Relay cropping prolonged the leaf stay-green duration.Maize--Soybean Relay... · 3. Results · 4. Discussion
[34]
[PDF] Effect of intercropping on growth, yield and profitability of sorghum ...
Aug 12, 2020 · Intercropping of sorghum and cowpea with 2:1 row ratio was found economically viable with higher green fodder yield and net returns. Keywords: ...
[35]
Resource sharing in intercropping models and a case study with ...
We present key intercropping features and processes in seven intercropping models, highlighting strengths and limitations.Missing: seminal | Show results with:seminal
[36]
Mechanisms underlying cereal/legume intercropping as nature ...
Jul 28, 2022 · The principles of the intercropping lie in maximizing the complementary resource use (i.e., canopy and root architecture), facilitation ...Missing: paper | Show results with:paper
[37]
Grain legume-cereal intercropping enhances the use of soil-derived ...
The meta-analysis confirms and highlights that intercropping consistently stimulates complementary N use between legumes and cereals.
[38]
Factors affecting crop water use efficiency: A worldwide meta-analysis
Feb 20, 2020 · Effect of natural factors and management practices on agricultural water use efficiency under drought: A meta-analysis of global drylands.
[39]
Boosting resource use efficiency, soil fertility, food security ... - Frontiers
For example, sorghum + cowpea intercropping decreased runoff by 20–30% compared to sole sorghum and by 45–55% compared to monocropped cowpea, resulting in a 50% ...
[40]
Enhancing Soil Phosphorus Availability in Intercropping Systems
Studies have demonstrated that intercropping significantly improves the bioavailability of soil phosphorus via rhizosphere interactions, thereby promoting crop ...
[41]
The Concept of a 'Land Equivalent Ratio' and Advantages in Yields ...
SUMMARY Criteria for evaluating different intercropping situations are suggested, and the Land Equivalent Ratio (LER) concept is considered for situations ...
[42]
Nitrogen fixation and transfer between legumes and cereals under ...
The estimated amount of N fixation by legumes ranged from 10 to 38 g N m−2 a−1, and the percentage of N transfer to cereal ranged from 0 to 73% (Thilakarathna ...
[43]
Nitrogen transfer and yield effects of legumes intercropped with the ...
Oct 1, 2022 · Intercropping IWG with perennial legumes could reduce N limitation and increase the overall soil N pool for long-term release, while avoiding ...
[44]
Effect of companion plants on tomato greenhouse production
White mustard and marigold as companion crops showed suppressive effect on nematodes. White mustard decreased tomato yield and fruit weight, while marigold did ...
[45]
Intercropping of insect-pollinated crops supports a characteristic ...
Jul 1, 2022 · Intercropping increases pollinator species diversity. According to earlier studies, both crops have characteristic pollinators (Marzinzig et al ...
[46]
Multispecies crop mixtures increase insect biodiversity in an ...
Sep 3, 2023 · Integrating intercropping into agricultural systems could increase flower visits by insects up to 1.5 million per hectare, thus likely also ...
[47]
Intercropping enhances beneficial arthropods and controls pests
Oct 15, 2023 · We found that intercropping, compared to monoculture, significantly increased the overall abundance of beneficial arthropods by 36%, density by 94%, and ...
[48]
Application of Trap Cropping as Companion Plants for the ... - MDPI
Trap cropping is one such type of special companion planting strategy that is traditionally used for insect pest management through vegetative diversification.
[49]
Use of Nurse Crops in Potato Production to Protect Soils from Erosion
Planting a fast emerging nurse crop as a short-term cover crop could reduce potential soil erosion. In 2016 and 2017, research was conducted to address nurse ...
[50]
Long-term maize-Desmodium intercropping shifts structure and ...
Aug 14, 2021 · Maize-Desmodium intercropping diversifies fungal microbiomes and favors taxa associated with important ecosystem services including plant health, productivity ...
[51]
Long-term push–pull cropping system shifts soil and maize-root ...
Mar 18, 2024 · This study found that PPT cropping systems led to a higher diversity of soil bacterial communities compared to that of the Mono cropping system ...
[52]
The Potential of Intercropping for Multifunctional Crop Protection in ...
Intercropping can reduce insect pest infestation and crop damage by disrupting visual or olfactory host plant location, reducing host plant quality or ...
[53]
Organic Management of Late Blight of Potato and Tomato ... - eOrganic
Jan 18, 2009 · Intercropping could reduce late blight risk. The BlightMOP project reported that intercropping potatoes with non-host crops (rows planted ...
[54]
Does diversifying crop rotations suppress weeds? A meta-analysis
Jul 18, 2019 · We found diversifying from simple rotations reduced weed density (49%), but did not have a significant effect on weed biomass.
[55]
Allelopathic Effects of Cereal Rye on Weed Suppression and Forage ...
The results of the present study clearly show that cereal rye suppresses weeds and reduces their establishment by up to 77% in the succeeding alfalfa crop.<|control11|><|separator|>
[56]
Mechanisms of weed suppression by cereal rye cover crop: A review
Mar 27, 2023 · Weed suppression is achieved by a combination of competitive and non-competitive interactions between the cereal rye cover and the weeds.
[57]
Crop diversity reduces pesticide use more efficiently with refined ...
Jun 13, 2025 · Studies have demonstrated decreased pest pressure as an effect of crop diversity, but with little or no evidence that the observed decreases in ...
[58]
Associational resistance through intercropping reduces yield losses ...
Intercropping reduces damage from nematodes by 40% and disease incidence by 55%, and nematode control offsets yield reductions.
[59]
Annual intercropping suppresses weeds: A meta-analysis
Dec 1, 2021 · The results confirm that intercropping is generally a useful approach for suppressing weeds in annual crop cultivation.Missing: percentage | Show results with:percentage
[60]
https://www.scirp.org/journal/paperinformation?paperid=83008
[61]
None
Summary of each segment:
[62]
[PDF] Intercropping for Grain Production - North Dakota State University
Weed seeds can make harvested intercropped grain separation difficult, so selecting a field with low weed pressure will facilitate separation and cleaning. ...
[63]
[PDF] Intercropping Principles and Production Practices ~ PDF
Intermill orients his rows east and west to minimize the shading effects of taller crops like corn. The crops are planted in a wheat–corn– soybean pattern ...
[64]
[PDF] Intercrops Impact Soil Loss & Runoff on Sloping Maize Fields
Sep 9, 2024 · Intercropping has emerged as a potential solution to mitigate soil erosion risks in maize cultivation.
[65]
[PDF] The Three Sisters Garden Analogy for Servant Leadership Based ...
To Native Americans of the eastern woodlands, the term “Three Sisters” referred to corn, beans, and squash, which were grown simultaneously in an intercropping ...
[66]
Potential Profitability of Strip Intercropping with Corn and Soybeans
Aug 29, 2013 · We explore differences in labor and machine costs for the 5333 acre corn/soybean operation to implement a 6 row intercropping system. All ...
[67]
Editorial: Intercropping Systems in Sustainable Agriculture - Frontiers
The authors demonstrated the disparity in agroecological practices and socio-economic constraints between farmers, and the FarmDESIGN model was a valuable tool ...
[68]
Profitability of intercropping legumes with cereals: A farm-level ...
An increase in intercrop labor costs by 2.6 times would be required to exclude intercropping from the crop rotation. •. An increase in intercropping labor costs ...
[69]
USDA Squeezes the Food Industry with Outdated Subsidies
May 14, 2018 · Moreover, subsidies incentivize farmers to move away from crop rotation towards monocropping - the practice of planting the same crop year after ...
[70]
Farmers' intention towards intercropping adoption: the role of ...
This paper investigates factors driving the intention to intercrop in Sweden. Factors included in the analysis are participation in private certification ...Missing: post- | Show results with:post-
[71]
Review of agronomic research on the milpa, the traditional ...
The milpa system is the basis of traditional agriculture in Mesoamerica. It is based on a polyculture of maize (Zea mays L.), bean (Phaseolus spp.) and squash ...
[72]
Mexico's Indigenous Farmers Are Practicing the Agriculture of the ...
Aug 11, 2015 · The intercropped milpa system is multilayered, with maize in the upper canopy, beans in the intermediate story, and squash at the bottom. Bean ...
[73]
The importance of the traditional milpa in food security and ...
Feb 19, 2021 · Rural policies in the country have stimulated the production of cash crops to the detriment of the traditional intercropping system, the milpa.Methodology · Results · Population And Food...<|separator|>
[74]
The push–pull intercrop Desmodium does not repel, but intercepts ...
Mar 13, 2024 · The push–pull strategies aim to reduce the abundance of insect pests in crops through repelling the ovipositing herbivores from the crop, while ...
[75]
Push-Pull Technology | icipe - International Centre of Insect ...
The strategy involves intercropping cereals with a repellent plant, such as desmodium, which repels or deters stemborers from the target food crop.<|separator|>
[76]
[PDF] BIOLOGICAL PEST CONTROL: PUSH-PULL IN EAST AFRICA
The push-pull system manages pests through an attract-repel plant chemical strategy that encourages biological control by natural enemies and reduces stem borer ...
[77]
[PDF] Integrated systems of animal production in Asi
Rice-fish-ducks integration gave net returns of US$ 2060/yr while rice monoculture along produced US$ 950/yr. Also, fish production of 185 kg/ha was higher ...
[78]
Using aquatic animals as partners to increase yield and maintain ...
Feb 22, 2022 · Rice-aquatic animal coculture increases food production, increases N-use efficiency, and maintains soil N content by reducing weeds and promoting decomposition.
[79]
Mechanism and capacities of reducing ecological cost through rice ...
The rice–duck intergrowth system effectively prevents rice planthoppers and rice leafhoppers. The control effects can be up to 98.47% and 100% respectively; it ...Missing: sustainability | Show results with:sustainability
[80]
Resilient Roots: Indigenous Agriculture and Climate Change in Latin ...
Jan 1, 2025 · In Guatemala and Mexico, the milpa system is an Indigenous practice that increases soil fertility and crop yields. This system involves ...
[81]
Traditional ecological knowledge and its role in biodiversity ...
The study found that cultural or traditional knowledge plays an important role in valuing species, which further assisted in the conservation and management of ...
[82]
Global trends of local ecological knowledge and future implications
Apr 5, 2018 · Local and indigenous knowledge is being transformed globally, particularly being eroded when pertaining to ecology.
[83]
Intercropping—A Low Input Agricultural Strategy for Food and ...
An intercropping system has enough potential to enable sustainability in agriculture by crop diversification, efficient resource management and soil fertility ...
[84]
[PDF] Working with Smallholders - World Bank Documents & Reports
Poor soil fertility and limited water resources. Most smallholders live in tropical zones with naturally low soil fertility and high acidity. Farmers have ...
[85]
[PDF] Globally Important Agricultural Heritage Systems
By studying traditional systems, scientists can learn more about the dynamics of complex systems, especially about the links between agricultural biodiversity ...
[86]
Drones in Precision Agriculture: A Comprehensive Review of ... - MDPI
Our study examines in detail the technological advancements in drone systems, including innovative aerial platforms, cutting-edge multispectral and ...
[87]
The expanding role of multirotor UAVs in precision agriculture with ...
Sep 16, 2025 · Multirotor drones are transforming farming by enabling fast and precise crop monitoring and management. Smart sensors and AI help detect ...
[88]
Decades of research deliver drought-tolerant maize for a hotter ...
Mar 18, 2025 · These resilient crops, combined with climate-smart farming practices such as reduced tillage and intercropping with legumes, are helping farmers ...
[89]
Intercropping lablab with maize increases grain production and soil ...
Jun 1, 2025 · These results demonstrate the diverse benefits of growing maize with lablab allowing for greater food production, increased soil protection, and reduced pest ...
[90]
Introducing maize-forage legume intercropping in Hawassa Zuria ...
Nov 8, 2024 · These legumes enhance soil fertility through nitrogen fixation, suppress weeds by creating a more diverse environment, and produce high-quality ...
[91]
Lentil–cereal intercropping in a Mediterranean area: Yield, pests ...
Oct 8, 2025 · Both intercrops reduced bruchid grain loss by 16% and showed higher efficiency than single pure stand crops (land equivalent ratio >1).
[92]
Rapeseed-pea intercrop outperforms wheat-legume ones in land ...
Nov 1, 2024 · Rapeseed-pea increased land use efficiency 2 out of 3 years compared to sole crops. Varying species phenology and architecture favour compensation mechanisms.
[93]
Agroforestry increases soil carbon sequestration, especially in arid ...
On average, agroforestry increased SOC by 10.7 %, dissolved organic carbon by 10.2 % and CO 2 emissions by 10.2 % compared to other land uses.Agroforestry Increases Soil... · Introduction · Agroforestry Contributes To...
[94]
Long-term agroforestry enhances soil organic carbon pools and ...
Therefore, this study aims to evaluate SOC pools and C sequestration as affected by long-term agroforestry system and to assess SOC sequestration in deep soil ( ...
[95]
Economics of strip cropping with autonomous machines - ACSESS
Feb 9, 2024 · The autonomous strip cropping had the advantage of reducing labor costs. In total cost percentage shares, the variable costs occupied the ...2 Materials And Methods · 3 Results · 4 Discussion
[96]
The deployment of intercropping and agroforestry as adaptation to ...
Intercropping, the relay or simultaneous cultivation of two or more crops, and agroforestry, the incorporation of trees on at least 10% of agricultural land,
[97]
Impacts of climate change on global agriculture accounting ... - Nature
Jun 18, 2025 · Climate change threatens global food systems, but the extent to which adaptation will reduce losses remains unknown and controversial.
[98]
Harnessing monocrop breeding strategies for intercrops - PMC - NIH
May 10, 2024 · The main idea is to develop compatible variety combinations by improving the monocrop performance in the two breeding pools in parallel and ...