Intercropping System Research Articles

Effect of fertility levels and stress mitigating chemicals on nutrient content, uptake, intercropping advantage and competition effect in cowpea-baby corn intercropping

The primary goal of this study was to analyze how various row ratios of intercrops, in conjunction with different fertilizer levels with spray of two stress mitigating chemical, affect nutrient content, land productivity, and economic viability during Summer season. Furthermore, we aimed to explore the competitive dynamics within legume/cereal intercropping systems. Hence, A field experiment at Agriculture University, Kota, during the summers of 2019 and 2020, investigated different cowpea + baby corn intercropping system's intercropping indices, nutrient dynamics, uptake, and post-harvest soil nutrient balance under varying recommended fertilizer levels and foliar spray of stress mitigating chemicals. Using a split-split plot design replicated four times, the experiment involved thirty treatment combinations, including five intercropping techniques viz. Sole cowpea, sole baby corn, cowpea + baby corn 2:1, cowpea + baby corn 3:1, cowpea + baby corn 4:1 in the main plot, three fertility levels viz. 100 %, 125 % and 150 % recommended dose of fertilizer (RDF) in subplots, and two stress mitigation chemicals; CaCl2 0.5 % and KNO3 1% in sub-subplots. The findings revealed notable trends, including nitrogen (N) and (P) content in cowpea seeds and straw, baby corn cobs and fodder, as well as enhanced land-equivalent ratio (LER) and monetary advantage index (MAI) within the cowpea + baby corn 2:1 row ratio. However, despite these advantages, total N and P uptake were markedly higher in sole crops. Notably, sole cowpea demonstrated the highest actual N and P balance and lowest was under sole baby corn. Among the fertility levels, the 150 % RDF level exhibited the most favorable outcomes across various parameters, including LER, MAI, NP content, and uptake in both crops. Additionally, higher fertility levels correlated with increased apparent and actual soil nutrient balances. While, among stress mitigation chemicals, CaCl2 0.5 % resulted in significantly heightened N and P uptake. Hence, to optimize intercropping dynamics and maintain soil nutrient balance, it is advisable to intensify cowpea cultivation along with baby corn in a 2:1 row ratio, utilizing 150 % RDF is beneficial. Additionally, alleviating higher temperature stress during the summer season can be achieved by applying a 0.5 % solution CaCl2 through spraying at the flowering and pod development stages of cowpea.

Nutrients Dynamics and uptake Patterns in Groundnut (Arachis hypogaea L.)- Sweet corn (Zea mays var. Saccarata) Intercropping Systems

A field experiment was conducted in the summer season during 2020-21 and 2021-22 on clayey soil at Regional Rice Research Station, NAU, Vyara (Gujarat), India to evaluate the nutrients dynamics and uptake patterns of groundnut-sweet corn intercropping systems. The experiment comprised of ten treatments which was laid out in randomized block design with three replications. The results showed that the productivity of these systems in terms of groundnut pod equivalent yield 3221 kg/ha was significantly higher with intercropping of groundnut + sweet corn (2:1) with paired row (30-60-30 cm) (T10) followed by groundnut + sweet corn (3:1) in additive series (3073 kg/ha) (T8). Maximum N and K balance was recorded in case of treatment T10 (+107.18 and +144.52 kg/ha, respectively) which was followed by groundnut + sweet corn (2:1) in replacement series (T4) (+71.14 and +108.78 kg/ha, respectively) and (3:1) in additive series (T8) (+56.35 and +107.44 kg/ha, respectively). Phosphorus balance was negative under all treatments of intercropping system.

Rice Varieties Intercropping Induced Soil Metabolic and Microbial Recruiting to Enhance the Rice Blast (Magnaporthe Oryzae) Resistance.

[Background] Intercropping is considered an effective approach to defending rice disease. [Objectives/Methods] This study aimed to explore the resistance mechanism of rice intraspecific intercropping by investigating soil metabolites and their regulation on the rhizosphere soil microbial community using metabolomic and microbiome analyses. [Results] The results showed that the panicle blast disease occurrence of the resistant variety Shanyou63 (SY63) and the susceptible variety Huangkenuo (HKN) were both decreased in the intercropping compared to monoculture. Notably, HKN in the intercropping system exhibited significantly decreased disease incidence and increased disease resistance-related enzyme protease activity. KEGG annotation from soil metabolomics analysis revealed that phenylalanine metabolic pathway, phenylalanine, tyrosine, and tryptophan biosynthesis pathway, and fructose and mannose metabolic pathway were the key pathways related to rice disease resistance. Soil microbiome analysis indicated that the bacterial genera Nocardioides, Marmoricola, Luedemannella, and Desulfomonile were significantly enriched in HKN after intercropping, while SY63 experienced a substantial accumulation of Ruminiclostridium and Cellulomonas. Omics-based correlation analysis highlighted that the community assembly of Cellulomonas and Desulfomonile significantly affected the content of the metabolites D-sorbitol, D-mannitol, quinic acid, which further proved that quinic acid had a significantly inhibitory effect on the mycelium growth of Magnaporthe oryzae, and these three metabolites had a significant blast control effect. The optimal rice blast-control efficiency on HKN was 51.72%, and Lijiangxintuanheigu (LTH) was 64.57%. [Conclusions] These findings provide a theoretical basis for rice varieties intercropping and sustainable rice production, emphasizing the novelty of the study in elucidating the underlying mechanisms of intercropping-mediated disease resistance.

Microbiological mechanism of hydrogen fertilizer effect in soil.

For a long time, intercropping and rotation of leguminous with non-leguminous crops is widely used to reduce the application of nitrogen fertilizer and increase yield in agroecosystems. At present, most researchers considered that this management measure is helpful for reducing fertilizer consumption and increasing its efficiency, as it can improve nutrient supply of legumestonon-legumes, the spatial nutrient utilization efficiency by enhancing soil spatial heterogeneity, and improve soil structure and disease resistance. However, current theories cannot fully explain the positive effect of crop rotation and inter-cropping systems involving legumes. A large amount of hydrogen (H2) can be produced as an obligatory by-product of nitrogenase responsible for nitrogen (N2) fixation in the root nodules of leguminous plants. Despite of substantial amounts of H2 enriched in the rhizosphere of legumes, only a minor proportion of H2 is found to leak to soil surface. Increasing evidence showed that most H2 released in soil is immediately depleted in the surrounding of N2-fixing nodules by H2-oxidizing bacteria (HOB) thriving in soil. HOB can use H2 as an electron donor to assimilate and fix CO2 through redox reactions to synthesize cellular substances and consequently promote plant growth. To date, however, little is known about the biological mechanism and ecological process behind the "hydrogen fertilizer effect". Therefore, we review the H2-induced plant growth-promoting effects and its microbiological mechanisms. Our aims were to explore a new way for enhancing agroecosystem production, and to provide scientific basis for future utilization of H2 in agricultural production practices.

Effect of peanut straw mulching on the soil nitrogen change and functional genes in the Camellia oleifera intercropping system

Effect of peanut straw mulching on the soil nitrogen change and functional genes in the Camellia oleifera intercropping system

Weeding force saving to improve profitability of cassava-legumes cropping systems in eastern Democratic Republic of the Congo

Weeding is a common farming practice for optimal emergence, growth and maturity of crops. Smallholders in Central Africa use a traditional hoe for weed control. This is a hard and time-consuming activity. To address this bottleneck, a study was conducted at three sites, namely Walungu, Uvira, and Mulungu in South-Kivu in the Democratic Republic of the Congo (DRC), over two growing seasons (September 2020 and February 2021). The purpose was to minimize the workload involved in weed control and boosting cassava yields via time-, labour, and energy-saving through adjusted weeding. Experiments were carried out as a split-plot design with three randomized blocks at multiple locations. Weed control was assessed for hand hoe, herbicide, and single-wheeled hoe (a weeding tool that combines manpower with improved weeding precision) in a cassava-legume intercropping system. Results show that the use of herbicide translated into about 6 times less energy use than a hand hoe, accounting for a ca. 4 times reduced weeding workload, and a reduction in weeding time up to 84%. The single-wheeled hoe use accounted for almost 61% reduction in weeding energy consumed, a reduction of 40% of the weeding time, and for about 38% of the weeding load saving. Although the three weeding methods gave statistically similar yields, it nevertheless turned out that herbicide treatment achieved the lowest cost-benefit ratio (CBR) (0.2), evoking its superiority in terms of profitability over both the hand hoe and the single-wheeled hoe. The study asserted that weed control is ‘moderately heavy’ and ‘light’ when involving the single-wheeled hoe and herbicide, respectively.

A Holistic Approach to the Selection of Soybean (Glycine max) Cultivars for Shade Environments Based on Morphological, Yield and Genetic Traits

ABSTRACTThe reduction of photosynthetically active radiation impacts the growth and productivity of soybean in agroforestry and intercropping systems. Thus, this report explored the responses of 16 soybean cultivars submitted to shade levels in field conditions. Multi‐faceted and relative importance analyses revealed that the steam diameter and plant height are fundamental morphological markers for selecting shade‐resilient cultivars, both were high and positively correlated to yield components. Moreover, the responses to shade varied among soybean cultivars, with certain genotypes demonstrating distinct tolerance levels, which allowed also the estimative of genetic variance that revealed strong participation of genetic components in responses to shade. Multivariate and clustering analysis using steam diameter and plant height in combination with two yield components resulted in the identification of four soybean cultivars more tolerant to shade environments and two sensible. Therefore, this report provides insights into soybean cultivation under varying light conditions, provides a robust foundation for the integration of morphological and yield markers in breeding programmes focused on shade tolerance and guides future endeavours in crop improvement for optimal and sustainable yield and resilience in the climate change context.

Effects of Maize–Lablab Intercropping and Lactic Acid Bacteria Additives on Forage Yield, Fermentation Quality and Profitability

Intercropping systems and exogenous microorganism additives are recognized for their potential to influence silage fermentation and quality. This study aims to evaluate the impacts of maize–lablab bean intercropping and lactic acid bacteria (LAB) additives on silage yield, nutritional quality, and economic profitability. A randomized block design was employed with two cropping patterns—maize monocrop (M) and maize–lablab intercrop (ML)—and five additive treatments: No additives (CK), and varying ratios of Lactobacillus Plantarum (LP) and Lactobacillus Buchneri (LB), T1 (100% LP), T2 (9LP:LB), T3 (8LP:2LB), and T4 (100% LB). The silage was analyzed and evaluated for its nutritional quality, fermentation quality, and fermentation effect after 90 days of fermentation. ML intercropping significantly enhanced the fresh matter yields by 8.59% and crude protein content by 8.73% compared to M. From the point of view of inoculation with different lactobacilli, the pH, AA, and NH3-N/TN were lower in the T2 and T3 treatments than in the other treatments, while LA was significantly higher. The V-score, which reflects the overall fermentation quality, was excellent across all treatments, with scores exceeding 80 points; the T2 treatment in ML silage achieved the highest score of 99.58. In addition, intercropping can increase the net income of farmers by 21.67%. In conclusion, maize–lablab intercropping combined with LAB inoculation, particularly with the T2 and T3 treatments, significantly enhances the silage quality and economic returns by reducing pH, increasing the LA content, and improving the CP levels. This study is the first to comprehensively analyze the synergistic effects of altering cropping systems and adding functional microorganisms on forage yield and fermentation quality, offering strategic insights for farms, especially mixed farms, to produce high-quality feed. We recommend adopting these methods to improve feed quality and maximize the profitability of silage production systems.

Intercropping with Robinia pseudoacacia reduces soft rot incidence in konjac by modulating the root bacterial community.

Soft rot (Pectobacterium aroidearum and Dickeya) is a devastating soil-borne bacterial disease that threatens konjac production. Intercropping with false acacia has been shown to significantly reduce soft rot incidence in konjac by shifting the microbial community. However, how intercropping shapes the root bacterial community and affects soft rot incidence remains unclear. To address this, we investigated three konjac intercropping systems (false acacia, paulownia, and maize) to explore the relationships among intercropping, soft rot incidence, root bacterial community, soil enzyme activity, and soil properties. Konjac intercropped with false acacia exhibited the lowest soft rot incidence and the lowest abundance of pathogenic taxa. Soft rot incidence was negatively correlated with total soil nitrogen and potassium but positively correlated with total and available soil phosphorus. The bacterial community structure and function in konjac roots differed among intercropping types, mainly driven by available soil phosphorus. Beneficial microorganisms such as Bradyrhizobium and Variovorax were enriched under a false acacia intercropping system and were negatively correlated with soil-available phosphorus. Additionally, the stable bacterial community in healthy konjac roots under false acacia may make konjac less susceptible to pathogen invasion. The study showed that intercropping reduced the soft rot incidence by regulating the structure and stability of the konjac root bacterial community, and soil-available phosphorus was the main factor affecting the difference in the konjac root bacterial community, which provided a basis for the management of soil fertilization in konjac cultivation. © 2024 Society of Chemical Industry.

Soybean performance under the biomass of Quênia guinea grass cover crops after intercropping with maize

Soil cover biomass in integrated systems can improve agronomic characteristics and impact in soybean productivity. Thus, the objective is to evaluate the desiccation efficiency, biomass production, nutrient accumulation, and soybean productivity in Quênia guinea grass (Panicum maximum cv. BRS Quênia) biomass after with an intercropped with maize in different forms of seeding, in compare the conventional soybean. The experimental design was a randomized block with four replicates. The treatments consisted of cover crop biomass: maize monoculture; Quênia guinea grass monoculture; maize intercropped with Quênia guinea grass within rows; maize intercropped with Quênia guinea grass between rows and an additional soybean treatment without cover biomass. The results showed that the Quênia guinea grass in the different cropping systems presented high desiccation efficiency, showing potential as a cover plant in integrated systems. The intercropping system of maize with Quênia guinea grass between rows is more recommended than seeding in the same rows as maize, because it promotes greater biomass production and nutrient cycling, reflecting in higher soybean productivity. The integrated production systems is a promising and efficient technology for production systems compared to the system of monoculture maize and soybeans without soil cover biomass, which ensures greater sustainability of agricultural systems.

Intercropping in Coconut Plantations Regulate Soil Characteristics by Microbial Communities

Intercropping is a commonly employed agricultural technique that offers numerous advantages, such as increasing land productivity, enhancing soil health, and controlling soil-borne pathogens. In this study, Artemisia argyi, Dioscorea esculenta, and Arachis pintoi were intercropped with coconuts and compared with naturally growing weeds (Bidens pilosa), respectively. The regulatory mechanism of intercropping was examined by analyzing the variability in soil properties and microbial community structure across different intercropping modes and soil depths (0–20 cm, 20–40 cm, and 40–60 cm). The results indicate that intercropping can increase the diversity of soil bacteria and fungi. Moreover, as soil depth increases, the changes in microbial communities weaken. Intercropping reduced soil SOM and increased pH, which is directly related to the changes in the abundance of Acidobacteria in the soil. In various intercropping systems, the disparities resulting from intercropping with A. pintoi are particularly pronounced. Specifically, intercropping with A. pintoi leads to an increase in soil potassium and phosphorus levels, as well as an enhancement in the abundance of Bacillus sp., which plays a crucial role in the suppression of plant pathogenic fungi within the soil ecosystem. The results of the correlation analysis and structural equation modeling (SEM) suggest that the impacts of three intercropping systems on microbial composition and soil indicators exhibit considerable variation. However, a common critical factor influencing these effects is the soil phosphorus content. Furthermore, our findings indicate that intercropping resulted in lower soil nitrogen levels, exacerbating nitrogen deficiency and masking its impact on the microbial community composition.

Stable pollinator communities in different white clover populations suggest potential win-win scenarios for crop yield and biodiversity

Compared to monocultures, intercropping systems offer many agronomic benefits, including higher yield stability. In this study, we assessed whether cropping systems that are beneficial for yield stability are also beneficial for pollinator communities and whether the effect is modulated by the landscape type. Using a replicated block design in one heterogeneous and one homogeneous agricultural landscape, we studied the pollinator communities in eight populations (i.e., genotypes) of white clover (Trifolium repens) grown as a monoculture or as a two-species mixture (together with perennial ryegrass, Lolium perenne) or three-species mixture (together with perennial ryegrass and chicory, Cichorium intybus). We recorded 1486 honey bees and 1254 wild pollinators belonging to 46 species. Bumble bees were the most abundant wild pollinators (49.6 %), followed by hover flies (23.4 %), and non-Bombus wild bees (21.5 %). Lepidoptera accounted for only 5.4 % of the wild pollinators. We found a higher species richness and abundance of wild pollinators in monocultures than in two-species mixtures, but white clover population did not influence pollinators. Moreover, species richness and abundance were also higher in the homogeneous landscape than in the heterogenous one. Most species were foraging on white clover. However, 18 species (39.1 %, n = 18/46) were recorded foraging on chicory and/or weeds, and ten of these wild pollinator species were never recorded on white clover. Our study highlights that diverse pollinator communities require both abundant floral resources and diverse plant communities, that their needs are not in conflict with the goal of achieving yield stability, and that the landscape type can modulate the effect of the cropping system. Moreover, the lack of pollinator preference for different white clover populations suggests that farmers can select mixtures that enhance yield stability without negatively affecting pollinator communities. Overall, these results highlight that intercropping systems comprising several plant species and plant genotypes can guarantee yield stability without compromising the pollinator community, showing that win-win situations for farmers and biodiversity are possible.

How Cropping System Influences Robusta Coffee Leaf Gas Exchange Efficiency via Stomatal Regulation

Background: Robusta coffee leaves regulate gas exchange in response to climatic factors like full sun and shaded conditions. To fully understand the reasons behind the variations in photosynthetic rates and water-use efficiency, exploring the underlying mechanisms of stomatal regulation in the maximum photosynthetic efficiency of Robusta coffee trees, especially in a shade condition is necessary. Methods: This study aimed to evaluate how stomatal regulation in Robusta coffee leaves affects gas exchange under different cropping systems. The Robusta coffee trees were grown in four different cropping systems: monoculture (full-sun condition) (S1), intercropped (single row) with rubber trees (S2), intercropped (double spacing) with rubber trees (S3), and intercropped in a mixed orchard (S4). Result: The results revealed that Robusta coffee trees grown between rubber tree rows with closer spacing (S2) exhibited the largest stomata sizes. These stomata sizes had a statistically significant increase in width, length, and area (ranging from 12.04 to 14.74 µm, 19.22 to 25.55 µm, and 202.37 to 296.05 µm², respectively) compared to Robusta coffee grown in S1, S3, and S4 systems. On the other hand, Robusta coffee grown in S1 system displayed the highest stomatal density, ranging from 310 to 540 stomata/mm². Interestingly, coffee trees grown between rubber rows (S3) and in the mixed orchard (S4) exhibited both high rates of photosynthesis (9.18 and 9.35 µmol/m²/s) and photosynthetic water-use efficiency (3.78 and 5.15 mmol/mol). Notably, these values were statistically different from those observed in other planting conditions. Additionally, Robusta coffee grown in S1 system exhibited the highest canopy temperature (ranging from 30.8 to 47.4°C). It also had the lowest Fv/Fm value (ranging from 0.706 to 0.759) compared to other planting conditions. This study indicates that Robusta coffee leaves exhibited varying stomatal responses to changes in light and temperature depending on the cropping system. By understanding how these leaf traits influence adaptation, we could potentially optimize Robusta coffee trees to thrive in full sun and shaded conditions, particularly within intercropping systems.

Calibration and validation of the AquaCrop model for forage cactus production systems under different management interventions in the semi-arid region of Brazil

Simulation models are useful tools for estimating plant response and contributing to the development of management strategies and yield predictions in crops. This study aimed to calibrate and evaluate the AquaCrop-FAO model for the forage cactus imposed on different cropping systems in the semi-arid region of Brazil. Four experiments were conducted: cactus-sorghum intercropping system with five spacings between plants (0.10, 0.20, 0.30, 0.40 and 0.50 m); cactus-sorghum intercropping system with five spacings between rows (1.00, 1.25, 1.50 and 1.75 m); single cactus with four levels of mulch (0, 5, 10 and 15 Mg ha−1); and single forage cactus with four levels of nitrogen fertilisation (50, 150, 300 and 450 kg of N ha−1). The performance of the model was evaluated using the following parameters: root mean squared error (RMSE); normalised RMSE (NRMSE), coefficients of determination (R2), Nash-Sutcliffe model efficiency coefficient (ME) and the Willmott index of agreement (d). During the calibration stage, the statistical indices pointed to the good performance of the AquaCrop model in estimating dry biomass in most of the cropping systems, with 10 < NRMSE <20; R2 > 0.96 and ME > 0.95. The AquaCrop model showed the best performance simulating systems under different levels of nitrogen fertilisation. Among the intercropping systems, the denser arrangements showed the highest values for simulated biomass.

Intercropping Alters Phytochemical Defenses Against Insect Herbivory.

Given the multiple possible mechanisms for interspecific chemical interaction between adjacent heterospecific plants, phytochemical defenses of pest-susceptible crop species could potentially be enhanced or altered by intercropping with phytochemically diverse neighbors. We assessed the influence of intercropping between phytochemically diverse plants on aerial volatile organic compound (VOC) emission profiles by intercropping Melilotus alba and Triticum aestivum with Silphium integrifolium in AMF-inoculated soil. We also assessed the impact of intercropping on induced plant defenses by conducting an in-situ, no-choice bioassay with Spodoptera frugiperda. Of eight compound classes we identified across the three plant species, prenol lipids (terpenoids) were upregulated in silflower plants when monocropped with wheat and when herbivory was induced. Carboxylic acids and organooxygen compounds were reduced in sweetclover when intercropped with silflower, but increased under herbivory. Uninfested wheat plants emitted more organooxygen compounds and fatty acyls than infested plants when intercropped with silflower, but not when monocropped. This study showed that VOC emissions of plants from three diverse taxa are altered by both intercropping and herbivory in ways that may impact their resistance to insect herbivory. Further research into the role of intercropping on pest resistance in agroecological systems could help farmers to design intercropping systems that optimize natural plant herbivory defenses, thus improving agricultural sustainability.

Decade-long effects of integrated farming systems on soil aggregation and carbon dynamics in sub-tropical Eastern Indo-Gangetic plains

Integrated farming system (IFS) aims to diversify the agricultural landscapes by incorporating different components to meet the multifarious needs of the burgeoning population. The present study was undertaken to understand the impact of different cropping systems on soil organic carbon (SOC) stock, aggregate distribution, and aggregate associated organic carbon (AAOC) in 2-IFS models of varying sizes (0.4 and 0.8 ha) established during 2008–2009. After 10 years of the study, the fodder system registered the greatest TOC and carbon stocks across IFS models, with surface soil (0–15 cm) accumulating 17 and 13% higher TOC and C stock, respectively, in 0.4 and 0.8 ha models. In 0–15 cm, macroaggregates (Ma) represented the highest proportion (75–76%) in both models. Among cropping systems, the fodder system recorded the highest large macroaggregates in both IFS models. Within 0–30 cm depth, small macroaggregates are mostly found in the perennial system (fodder, guava+turmeric, and lemon intercropping system), indicating the potential to improve the aggregate stability over the seasonal (shorter duration) system. In general, micro aggregate (Mi) fraction was pre-dominant in sub-surface soil (17.35%). The maximum AAOC was found in Ma compared to Mi fractions, with approximately 67 and 63% of total carbon associated with Ma in 0.4 and 0.8 ha IFS models, respectively. Interestingly, the 0.8 ha IFS model had higher TOC (~11%) and carbon stock (~12%) than the 0.4 ha model, but AAOC did not show a similar result, indicating the influence of cropping systems on AAOC. The study indicated that the fodder-based production system had better performance in terms of soil physical health and increased aggregate stability and content of soil carbon. This is indicative of the advantages of perennial-based systems over seasonal- or annual-based cropping systems for soil sustainability in Eastern Indo-Gangetic Plains.

Maize/soybean intercropping with nitrogen supply levels increases maize yield and nitrogen uptake by influencing the rhizosphere bacterial diversity of soil.

Intercropping practices play a crucial role in enhancing and maintaining the biodiversity and resiliency of agroecosystems, as well as promoting stable and high crop yields. Yet the relationships between soil nitrogen, microbes, and yield in maize cultivated under maize/soybean intercropping systems remain unclear. To fill that knowledge gap, here we collected maize rhizosphere soil at the staminate stage after 6 consecutive years of maize/soybean intercropping, to investigate how intercropping and nitrogen application rates affected nitrogen utilization by crops and soil microbial community composition and function. We also examined correlations of those responses with yields, to clarify the main ways that yield is enhanced via intercropping and by nitrogenous fertilizer gradient changes generated by different nitrogen application rates. The amount of applied fertilizer was 240 kg N ha-1 was best for obtaining a high maize yield and also led to the greatest nitrogen-use efficiency and bacterial diversity. Under the same N application rate, intercropping increased the maize yield by 31.17% and soil nitrogen (total, ammonium and nitrate nitrogen) by 14.53%, on average, in comparison to monocropping. The enrichment of Gemmatimonas and Bradyrhizobium significantly increased the soil nitrogen content, and a greater relative abundance of Sphingomonas and Gemmatimonas increased the maize yield, whereas enrichment of Candidatus_Udaeobacter and Bradyrhizobium decreased it. The benefits of intercropping mainly arise from augmenting the abundance of beneficial microorganisms and enhancing the efficiency of N use by crop plants. This study's findings are of key importance to bolster the stability of agro-ecosystems, to guide the scientific rational use of nitrogen fertilizers, and to provide a sound theoretical basis for achieving the optimalmanagement of intensive crop-planting patterns and green sustainable development.

Growth and water-needs analysis of sweet corn and peanuts in different cropping systems

Maize and peanuts are important food crops in Indonesia and are generally planted in monoculture and intercropping systems. The water required for monoculture and intercropping is believed to be different. However, comparison analysis of water requirements in monoculture and intercropping is rarely conducted. The research aimed to evaluate the growth and production of sweet corn and peanuts in monoculture and intercropping systems concerning water requirement and crop coefficient. The study was conducted at IPB Experimental Station in Leuwikopo, Bogor, Indonesia from September to December 2022. Sweet corn and peanuts were planted in different cropping systems, i.e., monoculture and intercropping. Water consumption of both cropping systems was evaluated in every growing stage. The experiment used a completely randomized block design and was repeated three times. Results showed that sweet corn growth was not significantly different among cropping systems, but yield from intercropping was lower than monoculture. Intercropped peanuts grew lower than monoculture but did not show any significant difference in yield among cropping systems. Water use efficiency in intercropping was higher than monoculture for both crops, indicating intercropping is a suitable cropping system for limiting soil water availability. The land equivalency ratio was 1.80, concluding that intercropping was more efficient than monoculture in land use by 80%. Keywords: climate change; crop coefficient; intercropping; land equivalent ratio; water use efficiency

Rhizosphere flavonoids alleviates the inhibition of soybean nodulation caused by shading under maize-soybean strip intercropping

The flavonoids produced by legume roots are signal molecules that induce nod genes for symbiotic rhizobium. Nevertheless, the promoting effects of flavonoids in root exudates in intercropping system on soybean nodulation are still unknown. A two years of field experiments was carried with maize soybean strip intercropping, i.e., the interspecific row spacing of 30 cm (MS30), 45 cm (MS45), 60 cm (MS60), and sole soybean/maize:SS/MM, and root interaction, i.e., root no barrier (NB) and root polythene-plastic barrier (PB), to evaluate relationships between flavonoids in root exudates and nodulation. We found that root-root interaction between soybean and maize enhances the nodules number and fresh weight in intercropped soybean. This enhancement increase gradually with expansion of interspecific distance. Proportion of nodules with diameter greater than 0.4cm was higher in intercropped soybean with NB than with PB. The expressions of nodules-related genes (GmENOD40, GmNIN2b and GmEXPB2) were up-regulated. Furthermore, compared with monocropping, isoflavones secretion of soybean roots reduced, flavonoids and flavonols secretion of maize and soybean roots increased under intercropping. The secretion of differential metabolites of flavonoids in the rhizosphere of maize and soybean declined with root barrier. The expressions of GmCHS8 and GmIFS1 in soybean roots were up-regulated and GmICHG was down-regulated under root interaction. The most of the flavonoids and flavonol compounds were positively correlated with nodule diameter. The nodules number, the nodules fresh weight and the proportion of nodules with a diameter greater than 0.2 cm increased in different genotypes of soybean treated with maize root exudate, which promoted the improvement of nitrogen fixation capacity. Therefore, maize-soybean strip intercropping combined with reasonable spacing to enhance the positive effect of underground root interaction, and improve the nodulation and nitrogen fixation capacity of intercropping soybean.

Soil Mineral Nitrogen and Mobile Organic Carbon as Affected by Winter Wheat Strip Tillage and Forage Legume Intercropping

Diversifying crop rotations by incorporating legumes is recommended to enhance the resilience of agricultural systems against environmental stresses and optimize nitrogen utilization. Nonetheless, ploughing forage legumes or grass-legumes poses a significant risk of nitrate leaching. The study aimed to assess the impact of strip tillage intercropping management on soil mineral nitrogen, water-extractable organic carbon, mobile humic substances content, and winter wheat (Triticum aestivum L.) grain yield compared to forage legume and winter wheat monocropping with conventional tillage. In the intercropping systems, the following bicrops were used: black medick (Medicago lupulina L.) with winter wheat, white clover (Trifolium repens L.) with winter wheat, and Egyptian clover (Trifolium alexandrinum L.) with winter wheat. Research was conducted in two experiments. The results indicated that after implementing strip tillage and winter wheat intercropping, the soil mineral nitrogen content was similar to or lower than that observed in conventional tillage and winter wheat sowing after forage legumes. Winter wheat grain yield in intercrops decreased compared to the legumes monocultures that were ploughed before winter wheat sowing. The highest amount of water- extractable organic carbon was in intercropping growing white clover and winter wheat bicrops or in all fields (except Egyptian clover and winter wheat bicrops) after applying strip tillage. During the research period, the quantities of mobile humic substances and mobile humic acids exhibited similar changes. Their content increased substantially in fields with white clover and Egyptian clover, regardless of whether the legumes were ploughed or grown with winter wheat.