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• Intercropping intercepted more light than sole peanut but less than sole maize.• Maize light use efficiency (LUE) increased with plant density in the intercropping.• Intercropping did not affect LUE of maize but increased peanut LUE.Intercropping increases crop yields by optimizing light interception and/or use efficiency. Although intercropping combinations and metrics have been reported, the effects of plant density on light use are not well documented. Here, we examined the light interception and use efficiency in maize-peanut intercropping with different maize plant densities in two row configurations in semiarid dryland agriculture over a two-year period. The field experiment comprised four cropping systems, i.e. monocropped maize, monocropped peanut, maize-peanut intercropping with two rows of maize and four rows of peanut, intercropping with four rows of maize and four rows of peanut, and three maize plant densities (3.0, 4.5 and 6.0 plants m−1 row) in both monocropped and intercropping maize. The mean total light interception in intercropping across years and densities was 779 MJ·m−2, 5.5% higher than in monocropped peanut (737 MJ·m−2) and 7.6% lower than in monocropped maize (843 MJ·m−2). Increasing maize density increased light interception in monocropped maize but did not affect the total light interception in the intercrops. Across years the LUE of maize was 2.9 g·MJ−1 and was not affected by cropping system but increased with maize plant density. The LUE of peanut was enhanced in intercropping, especially in a wetter year. The yield advantage of maize-peanut intercropping resulted mainly from the LUE of peanut. These results will help to optimize agronomic management and system design and provide evidence for system level light use efficiency in intercropping.

Aims The objective of this study was to propose a maize–peanut intercropping system for traditional sole maize to increase economic benefits and decrease environmental pollution for dryland farming. Methods The treatments comprised sole maize, sole peanut, maize–peanut intercropping, maize–peanut intercropping–rotation (rotation of the maize and peanut planting strips every year), and maize–peanut intercropping–rotation with 20% and 40% N reduction in maize planting strip. Soil water and total N stock, photosynthetic traits, yield, greenhouse gas emissions, economic income, and interspecific relationships were evaluated. Results Intercropped maize absorbed more moisture but lost more N than sole maize. Maize–peanut intercropping had higher economic benefits and less N 2 O emissions than sole maize, but had no intercropped advantage on land equivalent ratio. In addition, intercropping increased the continuous cropping barriers of peanuts than a sole peanut. Rotation of the planting strips in intercropping increased the peanut yield and economic benefits compared with not rotating the planting strips, and the economic benefits reached the highest level in the third planting year. A 20% N reduction in maize planting strips can decrease the global warming potential without affecting economic benefits. A 40% N reduction in maize planting strips could reduce soil N stock, maize yield, water use efficiency, N use efficiency, land equivalent ratio, and income. Conclusions A maize–peanut intercropping–rotation system is recommended for dryland farming since it promoted efficient use of N and economic benefits and decreased N 2 O emission. The proper N reduction in maize planting does not lead to N stress but decreased global warming potential.

Border row effects impact the ecosystem functions of intercropping systems, with high direct interactions between neighboring row crops in light, water, and nutrients. However, previous studies have mostly focused on aboveground, whereas the effects of intercropping on the spatial distribution of the root system are poorly understood. Field experiments and planting box experiments were combined to explore the yield, dry matter accumulation, and spatial distribution of root morphological indexes, such as root length density (RLD), root surface area density (RSAD), specific root length (SRL), and root diameter (RD), of maize and peanut and interspecific interactions at different soil depths in an intercropping system. In the field experiments, the yield of intercropped maize significantly increased by 33.45%; however, the yield of intercropped peanut significantly decreased by 13.40%. The land equivalent ratio (LER) of the maize-peanut intercropping system was greater than 1, and the advantage of intercropping was significant. Maize was highly competitive ( = 0.94, CR=1.54), and the yield advantage is mainly attributed to maize. Intercropped maize had higher RLD, RSAD, and SRL than sole maize, and intercropped peanut had lower RLD, RSAD, and SRL than sole peanut. In the interspecific interaction zone, the increase in RLD, RSAD, SRL, and RD of intercropped maize was greater than that of intercropped peanut, and maize showed greater root morphological plasticity than peanut. A random forest model determined that RSAD significantly impacted yield at 15-60 cm, while SRL had a significant impact at 30-60 cm. Structural equation modeling revealed that root morphology indicators had a greater effect on yield at 30-45 cm, with interactions between indicators being more pronounced at this depth. These results show that border-row effects mediate the plasticity of root morphology, which could enhance resource use and increase productivity. Therefore, selecting optimal intercropping species and developing sustainable intercropping production systems is of great significance.

Improving cropping systems together with suitable agronomic management practices can maintain dry farming productivity and reduce water competition with low N inputs. The objective of the study was to determine the photosynthetic and yield responses of maize and peanut under six treatments: sole maize, sole peanut, maize–peanut intercropping, maize–peanut rotation–intercropping, 20% and 40% N reductions for maize in the maize–peanut rotation–intercropping. Maize–peanut intercropping had no land-use advantage. Intercropped peanut is limited in carboxylation rates and electron transport rate (ETR), leading to a decrease in hundred-grain weight (HGW) and an increase in blighted pods number per plant (N BP ). Intercropped peanut adapts to light stress by decreasing light saturation point (I sat ) and light compensation point (I comp ) and increasing the electron transport efficiency. Intercropped maize showed an increase in maximum photosynthetic rate (Pn max ) and I comp due to a combination of improved intercellular CO 2 concentration, carboxylation rates, PSII photochemical quantum efficiency, and ETR. Compare to maize–peanut intercropping, maize–peanut rotation–intercropping alleviated the continuous crop barriers of intercropped border row peanut by improving carboxylation rates, electron transport efficiency and decreasing I sat , thereby increasing its HGW and N BP . More importantly, the land equivalent ratio of maize–peanut rotation–intercropping in the second and third planting years were 1.05 and 1.07, respectively, showing obvious land use advantages. A 20% N reduction for maize in maize–peanut rotation–intercropping does not affect photosynthetic character and yield for intercropped crops. However, a 40% N reduction decreased significantly the carboxylation rates, ETR, I comp and Pn max of intercropped maize, thereby reducing in a 14.83% HGW and 5.75% lower grain number per spike, and making land-use efficiency negative.

The spatiotemporal dynamics of soil nutrients in the crop row zone are critical determinants of crop yield, necessitating precision fertilization for optimal plant growth. However, previous studies have predominantly focused on plant-available nutrient status at the scale of entire cropping systems, yet a granular understanding of their distribution patterns across precise temporal and spatial dimensions remains limited. Therefore, this study investigated maize–legume intercropping systems to quantify the dynamics of soil alkaline-hydrolyzable nitrogen (AN), available phosphorus (AP), and available potassium (AK) across distinct growth stages, soil depths, and row positions. The experiment comprised five treatments: maize–soybean intercropping, maize–peanut intercropping, and monocultures of maize, soybean, and peanut. Throughout the two-year study, maize–soybean intercropping significantly enhanced the plant height of both maize and soybean relative to their respective monocultures (p < 0.05). In contrast, within the maize–peanut system, intercropping significantly promoted peanut plant height but suppressed stem diameter in both species (p < 0.05); these effects were consistent across both study years. Both systems exhibited a “benefit-sacrifice” pattern, where dry matter was preferentially allocated to maize, thereby increasing total system productivity despite suppressing legume growth. Furthermore, during the mid-to-late growth stages, intercropped maize showed an enhanced capacity for nitrogen uptake from deeper soil layers. In contrast, the alkaline-hydrolyzable nitrogen content in intercropped soybean and peanut remained lower than in their respective monocultures throughout the growth period, with reductions ranging from 8.49% to 34.79%. Intercropping significantly increased the soil available phosphorus content in the root zones of maize, soybean, and peanut compared to their respective monocultures. The available phosphorus content in the 0–20 cm soil layer was consistently higher than in monoculture systems, with a maximum increase of 41.70%. Moreover, intercropping effectively mitigated soil potassium depletion, resulting in a smaller decline in available potassium. This effect was most pronounced in the maize–peanut intercropping pattern within the 20–40 cm soil layer. The distribution of soil available nutrients (N, P, K) was also influenced by drip tape placement. The levels of these nutrients for soybean and peanut were higher at 50 cm from the drip tape than at 30 cm, while for maize, levels were higher at 80 cm than at 40 cm. Intercropping increased the thousand-kernel weight of maize and soybean but decreased that of peanut. Overall, the strategic row configuration optimized the yield performance of both intercropping systems, resulting in land equivalent ratios greater than 1, which indicates distinct yield advantages for both intercropping patterns.

Maize/peanut intercropping may improve soil health through reducing nitrogen (N) fertilization. However, the effects of maize/peanut intercropping combined with reduced N fertilization on the soil fungal community structure have not been well reported. Using a long-term localized micro-zone experiment, we investigated the combined effects of intercropping and N fertilizer application on soil fungal community diversity and composition. Three cropping patterns (maize/peanut intercropping, maize monoculture, and peanut monoculture) and three N application levels (0 kg·hm−2, 150 kg·hm−2, and 300 kg·hm−2) were assessed. The results showed that the total numbers of fungal species and unique species (operational taxonomic units, OTUs) in both maize and peanut soils tended to first increase and then decrease with increasing N application. Compared with monoculture, the numbers of total OTUs and unique OTUs in intercropped maize soil decreased by 4.14% and 12.79%, respectively, but the total numbers of OTUs and unique OTUs in peanut soil increased by 1.08% and 3.78%, respectively. With increasing N application, the soil fungal Ace and Chao indices of maize soil first increased and then decreased, while the fungal Shannon, Ace, and Chao indices of peanut soil decreased. Compared with the monoculture system, intercropping significantly reduced the maize soil fungal Ace and Chao indices but increased the peanut soil fungal Shannon, Ace, and Chao indices. Nitrogen application and intercropping significantly altered the fungal community structure of maize soil, while N application had no significant effect on the fungal community structure of peanut soil, though intercropping significantly changed the fungal community structure of peanut soil. At the phylum level, Ascomycota, Basidiomycota, Mortierellomycota, unclassified_k_Fungi, and Chytridiomycota were the dominant taxa. Redundancy analysis (RDA) showed that soil nitrate (NO3−) content was the main environmental factor shaping the soil fungal community. In conclusion, excessive N fertilization (300 kg·hm−2) can reduce soil fungal community diversity; maize/peanut intercropping reversed the negative effect of N application on fungal community of peanut soil, but not that of maize soil. Soil NO3− content is the primary environmental driver of soil fungal communities.

Maize’s nitrogen (N) uptake can be improved through maize-legume intercropping. N uptake mechanisms require further study to better understand how legumes affect root growth and to determine maize’s absorptive capacity in maize-legume intercropping. We conducted a two-year field experiment with two N treatments (zero N (N0) and conventional N (N1)) and three planting patterns (monoculture maize ( Zea mays L.) (MM), maize-soybean ( Glycine max L. Merr .) strip intercropping (IMS), and maize-peanut ( Arachis hypogaea L.) strip intercropping (IMP)). We sought to understand maize’s N uptake mechanisms by investigating root growth and distribution, root uptake capacity, antioxidant enzyme activity, and the antioxidant content in different maize-legume strip intercropping systems. Our results showed that on average, the N uptake of maize was significantly greater by 52.5% in IMS and by 62.4% in IMP than that in MM. The average agronomic efficiency (AE) of maize was increased by 110.5 % in IMS and by 163.4 % in IMP, compared to MM. The apparent recovery efficiency (RE) of maize was increased by 22.3% in IMS. The roots of intercropped maize were extended into soybean and peanut stands underneath the space and even between the inter-rows of legume, resulting in significantly increased root surface area density (RSAD) and total root biomass. The root-bleeding sap intensity of maize was significantly increased by 22.7–49.3% in IMS and 37.9–66.7% in IMP, compared with the MM. The nitrate-N content of maize bleeding sap was significantly greater in IMS and IMP than in MM during the 2018 crop season. The glutathione (GSH) content, superoxide dismutase (SOD), and catalase (CAT) activities in the root significantly increased in IMS and IMP compared to MM. Strip intercropping using legumes increases maize’s aboveground N uptake by promoting root growth and spatial distribution, delaying root senescence, and strengthening root uptake capacity.

Maize/peanut intercropping is increasingly promoted as a climate-smart strategy for enhancing resource use efficiency and reducing environmental impacts in dryland cropping systems. However, its effects on multi-gas greenhouse emissions and yield-scaled climate performance remain insufficiently understood in semi-arid regions with sandy soil. Here, a two-year field experiment was conducted in western Liaoning, Northeast China, to quantify soil CO2, CH4, and N2O fluxes, cumulative emissions, crop yield, global warming potential (GWP), and greenhouse gas intensity (GHGI) under sole maize (SM), sole peanut (SP), and two maize/peanut intercropping systems. SM produced the highest cumulative CO2 emissions, whereas SP generated the highest CH4 uptake and the highest N2O emissions. Compared with peanut monoculture, maize/peanut intercropping significantly reduced soil N2O emissions, indicating that the introduction of maize in the intercropping system provided an effective regulatory pathway for reducing N2O emissions. Peanut yields declined by approximately 47.29–49.41%, leading to total land equivalent ratio (LER) values of 0.83–0.99. Although no significant land use advantage was observed for maize/peanut intercropping at the field scale, when crop yields were taken into account for assessment, the global warming potential (GWP) and greenhouse gas emission intensity (GHGI) were lower than those of monoculture uniformity. CO2, CH4 and N2O fluxes were strongly correlated with soil temperature and moisture, underscoring the dominant role of microclimate rather than soil structure in regulating greenhouse gas (GHG) fluxes in monoculture, while in the intercropping system, the microclimate and the soil stucture together regulate the GHG fluxes. Overall, maize/peanut intercropping has the potential of reducing the climate cost per unit of production and represents a promising strategy for enhancing GHG mitigation potential in semi-arid agroecosystems.

The dual challenges of global climate change and reductions in the amount of arable land represent growing threats to the stability of global human populations. Efforts to further optimize cropping systems to maximize yields while minimizing greenhouse gas emissions in limited land areas have thus emerged as a focus in modern agriculture. Cereal-intercropping management strategies may represent a promising approach to simultaneously addressing both of these challenges in China. We aimed at comprehensively assessing changes in yield, carbon footprint, and net ecosystem economic benefit when transitioning from maize/peanut monoculture to intercropping in a field-scale study in an effort to aid in the development of low-carbon intercropping systems that do not have an adverse impact on Chinese grain yields. Beginning in June of 2018, a randomized complete block design with three treatments was used to initiate this study: (1) peanut monoculture (P), (2) maize monoculture (M), and (3) maize/peanut intercropping (MP). We compared yield, greenhouse gas emissions, carbon footprint and net ecosystem economic benefit. Results over four years showed that the land equivalent ratio associated with MP was greater than 1. All three of these cropping systems were net CO2 and N2O sources as well as net CH4 sinks, with MP generating significantly (p < 0.05) lower N2O and CO2 flux as well as smaller seasonal N2O and CO2 emissions relative to M. MP additionally reduced the carbon footprint associated with this cropping system by 11.11–31.65% and 30.37–43.62% relative to M and P, respectively. Consistently, MP treatment resulted in respective 70.69% and 26.25% net ecosystem economic benefit (NEEB) increases relative to the M and P conditions while simultaneously enhancing energy use efficiency. In summary, MP systems have potential economic benefit with lower environmental risk alternative to traditional peanut or maize monocropping systems. Converting from peanut or maize monocropping systems to MP systems practices contributed to improved farmland use efficiency, clean production and increased farmers’ income in an agricultural system.

Intercropping is a traditional and sustainable planting method that can make rational use of natural resources such as light, temperature, fertilizer, water, and CO2. Due to its efficient resource utilization, intercropping, in particular, maize and legume intercropping, is widespread around the world. However, the molecular details of these pathways remain largely unknown. In this study, physiological, transcriptome, and proteome analyses were compared between maize monocropping and maize–peanut intercropping. The results show that an intercropping system enhanced the ability of carbon fixation and carboxylation of maize leaves. Apparent quantum yield (AQY), the light-saturated net photosynthetic rate (LSPn), the light saturation point (LSP), and the light compensation point (LCP) were increased by 11.6%, 9.4%, 8.9%, and 32.1% in the intercropping system, respectively; carboxylation efficiency (CE), the CO2 saturation point (Cisat), the Rubisco maximum carboxylation rate (Vcmax), the maximum electron transfer rate (Jmax), and the triose phosphate utilization rate (TPU) were increased by 28.5%, 7.3%, 18.7%, 29.2%, and 17.0%, respectively; meanwhile, the CO2 compensation point (Γ) decreased by 22.6%. Moreover, the transcriptome analysis confirmed the presence of 588 differentially expressed genes (DEGs), and the numbers of up-regulated and down-regulated genes were 383 and 205, respectively. The DEGs were primarily concerned with ribosomes, plant hormone signal transduction, and photosynthesis. Furthermore, 549 differentially expressed proteins (DEPs) were identified in the maize leaves in both the maize monocropping and maize–peanut intercropping systems. Bioinformatics analysis revealed that 186 DEPs were related to 37 specific KEGG pathways in each of the two treatment groups. Based on the physiological, transcriptome, and proteome analyses, it was demonstrated that the photosynthetic characteristics in maize leaves can be improved by maize–peanut intercropping. This may be related to PS I, PS II, cytochrome b6f complex, ATP synthase, and photosynthetic CO2 fixation, which is caused by the improved CO2 carboxylation efficiency. Our results provide a more in-depth understanding of the high yield and high-efficiency mechanism in maize and peanut intercropping.