Maize Monocrop Research Articles

Night-time light-traps and push–pull integrated system enhanced the control of different life stages of fall armyworm, Spodoptera frugiperda, (Lepidoptera: Noctuidae)

BackgroundMaize, Zea mays L (Cyperales: Poaceae), is one of the major cereal crops grown in Ethiopia for its food and feed values. Recently, the fall armyworm (FAW) (Spodoptera frugiperda) has become a major challenge of maize production threatening smallholder farmers in the country. Developing effective and smallholder farmers-friendly integrated pest management for FAW is vital. Therefore, a study was conducted to evaluate the effect of night-time light-traps and push–pull integrated system on controlling different life stages (adult, larvae and eggs) of FAW.MethodsThe study was conducted in Northern Ethiopia included four treatments; maize monocrop, maize plots with night-time light-trap, a push–pull system, and night-time light-trap and push–pull integrated system. Each treatment was replicated five times. The study was carried out twice involving a rain feed (from July to October 2018) and irrigated (from April to June 2019) experiments.ResultsA significantly greater number of FAW moths were captured on traps placed outside maize field plots treated with light-trap and push–pull integrated system than traps placed outside the maize monocrop, light-trap alone and push–pull alone treated plots during the 2018 and 2019 experiment seasons. As a result, a significantly lower number of moths was found inside maize field plots treated with light-trap and push–pull integrated system than the other treatments. The levels of FAW eggs and larval infestation were significantly lower in maize plots treated with the light-trap and push–pull integrated system than the maize monocrops, push–pull alone, and light-trap alone treated plots. The proportion of plants damaged by FAW larvae was significantly lower in maize plots treated with the light-trap and push–pull integrated system relative to maize plots treated with the other treatments.ConclusionThis study proved that a system integrating night-time light-traps and push–pull results in better and more effective control of different stages of FAW than a push–pull system or night-time light-traps alone.

Effects of Green Manure Cover Crops on Weed Suppression at Mashare and Liselo, Namibia

Small-scale farming communities in northern Namibia often encounter poor soil fertility and financial constraints. They don’t afford buying mineral fertilizers and herbicides, thus highlighting the need for cost-effective cropping systems that enhance productivity. While green manure cover crops (GMCCs) have been extensively studied elsewhere and shown to boost productivity, information on their use remains limited in Namibia. Experiments were conducted over two seasons (2016/2017-2017/2018) at Mashare Irrigation Training Center (MITC) and Liselo Research Station (LRS), which have different soil types, to explore the effects of rotating Pearl millet and maize with various GMCCs on crop weed populations. The experiments compared the effects of rotating nine different GMCCs with Pearl millet and maize separately against monocropping of Pearl millet and maize. Results showed that weed density varied across treatments and locations, with the highest densities observed in certain rotations, such as Pearl millet-pigeon pea and maize-pigeon pea, while the lowest densities were found in rotations involving lablab and velvet bean. This is indicative that lablab and velvet bean suppressed weeds better than all other GMCCs, while pigeon pea was vulnerable to weed infestation. Lablab exhibited the highest biomass yields. Overall, rotating Pearl millet and maize with cover crops demonstrated greater benefits compared to monocropping, emphasizing the need to identify suitable cover crops for specific niches to optimize productivity.

Deciphering Nitrogen Stress Responses in Maize Rhizospheres: Comparative Transcriptomics of Monocropping and Intercropping Systems

A well-developed rhizospheric system is crucial for maize to adapt to environmental stresses, thereby enhancing yield and quality. However, nitrogen (N) stress significantly impedes rhizospheric development and growth in maize. The genetic responses of maize’s rhizosphere to N stress under monocropping systems with exogenous inorganic N fertilization and intercropping systems reliant on biological N fixation are not well understood, especially regarding common and specific response genes. Therefore, through transcriptomic analysis, this study systematically investigated the gene expression and molecular responses of maize’s rhizosphere under two N supply regimes to N stress. The results showed that N stress generated 196 common and 3350 specific differentially expressed genes across the two systems, with the intercropping system exhibiting a stronger specific response. KEGG analysis revealed that the common genes, though few, are involved in key pathways essential for crop growth. Maize monocropping specific differentially expressed genes (MM) were enriched in pathways related to membrane lipids, cell wall formation, and intracellular signaling, while maize/alfalfa intercropping specific differentially expressed genes (MA) were linked to stress resistance through the glutathione metabolic pathway. WGCNA analysis identified five co-expression modules (CM). MA significantly increased the transcription factor families and structural domains directly targeting rhizospheric growth and development genes, including AP2, GRAS, Cys2His2 Zinc Finger, and LBD in CM blue. Conversely, MM significantly increased the transcription factor families and NAC structural domain targeting the promoters of N transporter protein genes in CM pink. This study emphasizes the importance of both common and specific genes in maintaining maize growth under suboptimal N supply in monocropping and intercropping systems.

Maize crop performance on different Agricultural Production Systems and co-inoculation with A. brasilense and T. asperellum

Considering the increasing global population and demand for food, it is crucial to adopt agricultural practices that ensure both food security and environmental preservation. In this context, plant growth-promoting microorganisms (PGPM) and integrated crop-livestock-forestry systems (ICLF) have emerged as promising strategies for sustainable productive intensification. This research aimed to determine the effects of inoculating Azospirillum brasilense and Trichoderma asperellum on maize crops (Zea mays L.) grown in monocropping and ICLF systems. A complete randomized block design was performed in a 4 × 2 factorial arrangement with three replications. The crop systems included maize monocrop (C), crop-livestock (CL), crop-forest (CF), and crop-livestock-forest (CLF). Concomitantly, the co-inoculation (A. brasilense + T. asperellum) was compared to the control management (with no PGPM). CL and C systems with co-inoculation showed the highest yields, while the CF and CLF systems, which include the arboreal component, showed lower yields because of tree shading. CL + co-inoculation treatment was the most significant with increases of 17.14% in shoot dry mass, 43% in 1000-grain weight, and 9.56% in yield (t ha-1) compared to the C + control treatment. Additionally, the CL + co-inoculation treatment overcame the CLF + control by 136.63% in yield. Results indicate that the PGPM co-inoculation in maize within the CL system is an effective strategy for optimizing crop production.

Long‐Term Effects of Arable and Tree Cropping Systems on Soil Organic Carbon and Nitrogen Dynamics in a Tropical Agroecological Transition Zone

ABSTRACTContinuous cropping can affect soil carbon and nitrogen stocks and litter decomposition, but research on smallholder farms in Africa is limited. This study, conducted from 2020 to 2023 in Ghana's forest‐savanna transition zone, examined four cropping systems: continuous maize monocrop (M), maize rotated with legumes (ML), young cashew intercropped with maize or legumes (YCM/L), and mature cashew (MC). The objective was to assess the long‐term impact of the cropping systems on soil organic carbon (SOC), nitrogen (N) stocks, and soil organic matter (SOM) decomposition rates using the tea bag protocol. Results showed significant variability in SOC and N stocks across the systems. At a 0–15 cm depth, SOC in the MC and M systems was 160% and 149% higher than in the YCM/L system. At 15–30 cm, SOC in the M and MC systems was 86% and 132% higher than in YCM/L. Soil nitrogen stocks followed a similar trend, with MC and M systems showing 94%–199% higher values than YCM/L at both depths. SOM decomposition rates for green and rooibos tea in the MC and ML systems were statistically similar after 90 days of incubation (p > 0.05). This study, the first to use the tea bag protocol in Ghanaian soils, revealed that mature cashew and sustainable practices, such as adding maize stover, can enhance SOC and N stocks in highly weathered tropical soils. These findings underscore the potential for specific cropping systems to improve soil health on smallholder farms.

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 outweighs straw incorporation driving community and functional diversity of microarthropods after 5 years of tillage practices

Crop-leguminous intercropping and straw incorporation are considerable approaches to sustainable agriculture and have been widely used as a coping strategy to mitigate the negative effects caused by intensive agriculture. Yet, as a sustainable agriculture requires a deeper understanding of the impacts of conservation tillage practices on soil fauna, such as collembolans and acarid mites. These organisms are considered the most abundant and functionally critical soil fauna in many terrestrial natural, agricultural, and urban systems. In the present study, we assessed the responses of the community and functional diversity of collembolan and acarid mite assemblages to long-term intercropping and straw incorporation practices in a temperate farming land, in China. The experimental site was established with a full-factorial design of conservation managements (maize monocropping, maize-peanut intercropping, without maize straw addition, and with maize straw addition) over five consecutive years. Results showed that intercropping doubled collembolan and acarid density. Most of the enriched species in the intercropping field were euedaphic collembolans and cleptoparasitic mites. Nonetheless, the density of most phoretic species decreased, resulting in a negative effect of intercropping on acarid diversity. Despite straw incorporation additionally boosting the intercropping-induced increases in biomass, richness, and density of the collembolan community, the effects of straw incorporation on the community structure of collembolans and acarid mites were negligible. Similarly, intercropping affected the functional composition of collembolans and mites differently. Intercropping favored euedaphic collembolans characterized by less-developed furca, ocelli and sexual reproduction, but fungivorous, and benefited the cleptoparasitic mites that might be transported by their provisional hosts during pollinating peanut flowers. Moreover, intercropping decreased the functional dispersion of acarid mites, resulting in an acarid community with a homogenized ecological niche of acarid mites. In contrast, the ecological niche was more differentiated. Similar to intercropping, the ecological niche of collembolans in the field with straw was relatively higher, as well as the functional divergence, suggesting more intense resource competition between collembolans. In conclusion, intercropping has species-specific effects on the community and functional diversity of collembolans and mites and is relatively beneficial to collembolans, whereas straw incorporation has a marginal advantage on collembolans and acarid mites.

Conversion of monocropping to intercropping promotes rhizosphere microbiome functionality and soil nitrogen cycling

Intercropping can increase soil nutrient availability and provide greater crop yields for intensive agroecosystems. Despite its multiple benefits, how intercropping influences rhizosphere microbiome assemblages, functionality, and complex soil nitrogen cycling is not fully understood. Here, a three-year field experiment was carried out on different cropping system with five fertilization treatments at the main soybean production regions. We found that soybean yields in intercropped systems were on average 17 % greater than in monocropping system, regardless of fertilization treatments. We also found that intercropping systems significant increased network modularity (by 46 %) and functional diversity (by 11 %) than monocropping systems. Metagenomics analyses further indicated intercropping promotes microbiome functional adaptation, particularly enriching core functions related to nitrogen metabolism. Cropping patterns had a stronger influence on the functional genes associated with soil nitrogen cycling (R2 = 0.499). Monocropping systems increased the abundance of functional genes related to organic nitrogen ammonification, nitrogen fixation, and denitrification, while functional guilds of nitrate assimilation (by 28 %), nitrification (by 31 %), and dissimilatory nitrate reduction (by 10.1 %) genes were enriched in intercropping systems. Furthermore, we found that abiotic factors (i.e. AP, pH, and Moisture) are important drivers in shaping soil microbial community assemblage and nitrogen cycling. The functional genes include hzsB, and nrfA, and nxrA that affected by these biotic and abiotic variables were strongly related to crop yield (R2 = 0.076 ~ R2 = 0.249), suggesting a key role for maintaining crop production. We demonstrated that land use conversion from maize monocropping to maize-soybean intercropping diversify rhizosphere microbiome and functionality signatures, and intercropping increased key gene abundance related to soil nitrogen cycling to maintain the advantage of crop yield. The results of this study significantly facilitate our understanding of the complex soil nitrogen cycling processes and lay the foundation for manipulating desired specific functional taxa for improved crop productivity under sustainable intensification.

A 4-year field study monitoring the evolution of Trp574Leu-resistant plants in an Echinochloa crus-galli population under different crop rotation and herbicide programs in maize.

A 4-year experiment evaluated the effects of different integrated weed management (IWM) programs on the evolution of a Echinochloa crus-galli population resistant to acetolactate synthase (ALS) inhibitors in a maize cropping system. The programs included the continued use of ALS inhibitors, mixing them with alternative herbicides, or without ALS-inhibitors, in all cases under maize monocrop or a biennial crop rotation. IWM programs that relied solely on non-ALS-inhibitors usually achieved high control levels across years (> 90%). Additionally, Trp574Leu-resistant plants became prevalent (> 90%) in programs only using ALS inhibitors, while in the rest the frequency of susceptible plants did not substantially decrease below 40%. Regarding the other monitored grass weeds, Digitaria sanguinalis and Panicum dichotomiflorum were effectively controlled in programs using ALS-inhibitors without soybean rotation or in programs without ALS-inhibitors altogether, excepting the program relying on an 4-hydroxyphenylpyruvate dioxygenase (HPPD)-inhibitor under maize monocrop for the latter species (0%). At the end of the experiment, the only IWM programs that reduced infestation levels were the one without ALS-inhibitors under soybean rotation, and the one with standard pre-emergence treatments. These findings highlight the effectiveness of crop rotation and alternative herbicides both pre- or post-emergence in controlling E. crus-galli. ALS-inhibitors, while challenged by resistance in E. crus-galli, remain valuable tools for managing other grass weed species in maize. It is crucial to adapt IWM strategies for herbicide-resistant E. crus-galli and other grass weed populations to mitigate the further evolution of resistance. © 2024 Corteva Agriscience. Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Differential regulation of belowground rhizospheric ecosystem by biological and chemical nitrogen supplies: implications for maize yield enhancement mechanisms.

Nitrogen (N) content affects aboveground maize growth and nutrient absorption by altering the belowground rhizospheric ecosystem, impacting both yield and quality. However, the mechanisms through which different N supply methods (chemical and biological N supplies) regulate the belowground rhizospheric ecosystem to enhance maize yield remain unclear. To address this issue, we conducted a field experiment in northeast China, comprising three treatments: maize monocropping without N fertilizer application (MM), maize/alfalfa intercropping without N fertilizer application (BNF), and maize monocropping with N fertilizer application (CNS). The MM treatment represents the control, while the BNF treatment represents the biological N supply form, and CNS treatment represents the chemical N supply form. In the autumn of 2019, samples of maize and rhizospheric soil were collected to assess parameters including yield, rhizospheric soil characteristics, and microbial indicators. Both BNF and MM significantly increased maize yield and different yield components compared with MM, with no statistically significant difference in total yield between BNF and CNS. Furthermore, BNF significantly improved N by 12.61% and available N (AN) by 13.20% compared with MM. Furthermore, BNF treatment also significantly increased the Shannon index by 1.90%, while the CNS treatment significantly increased the Chao1 index by 28.1% and ACE index by 29.49%, with no significant difference between CNS and BNF. However, CNS had a more pronounced impact on structure of the rhizosphere soil bacterial community compared to BNF, inducing more significant fluctuations within the microbial network (modularity index and negative cohesion index). Regarding N transformation pathways predicted by bacterial functions, BNF significantly increased the N fixation pathway, while CNS significantly increased assimilatory nitrate reduction. In CNS, AN, NO3-N, NH4-N, assimilatory nitrate reduction, and community structure contributed significantly to maize yield, whereas in BNF, N fixation, community structure, community stability, NO3-N, and NH4-N played significant roles in enhancing maize yield. While CNS and BNF can achieve comparable maize yields in practical agricultural production, they have significantly different impacts on the belowground rhizosphere ecosystem, leading to different mechanisms of yield enhancement.

Mixed particle swarm optimization algorithm-based approach to optimize spatial distribution of virtual maize

Increasing crop yields is one potential way to solve the problem of food shortage and limited field resources. Optimization of crop spatial distribution is an efficient method to increase yield. However, extensive field experiments are costly and time consuming, which renders conventional optimization studies difficult if not prohibitive. In this study, a new optimization strategy was proposed, integrating a Functional-Structural Plant Model (FSPM) of maize with a workflow based on a Mixed Particle Swarm Optimization (MPSO) algorithm. The maize FSPM applies a dynamic interactive feedback method between plant morphology and plant growth dynamics on the one hand, and simultaneously between plant spatial distribution and plant growth, and furthermore can respond to different environmental factors. MPSO is a new mixed particle swarm optimization algorithm with multistage disturbance, which enhances the ability of traversing the solution space and jumping out of local extrema. This study performs a plant spatial distribution optimization of monocropping maize to maximize light interception. Simulation results indicate that the optimized row spacing can increase maize light interception comparing to the random row spacing within the spacing range (with maximum of 36.44% increment), and that the optimization results satisfy the optimal interval provided by previous field experiments.

Evaluation of push-pull technology for pest and soil fertility management on maize in north western Ethiopia

Maize (Zea mays L.) production in north western Ethiopia is severely constrained by the parasitic weed striga (Striga hermontica), the stemborer (Busseola fusca) pest, and poor soil fertility due to continuous mono cropping. An intercropping system known as push-pull technology is a novel soil and pest management strategy for improving soil fertility and controlling agricultural pests by using repellent "push" plants (such as desmodium, Desmodiumintortum)and trap "pull" plants (such as napier grass, Pennisetum purpureum). The aims of the study were (i) to evaluate the effectiveness of the push-pull technology against stemborer and striga infestation, (ii) to investigate the impact of the push-pull technology on improving grain yield, and (iii) to assess effect of the push-pull technology on soil fertility. The study was conducted in 2017 and 2018 cropping seasons in 3 districts in north western Ethiopia. Three farmers from each district, who practiced the technology, were randomly selected for the study. Each farmer had a set of two treatments (plots): a push-pull technology (PPT) and maize monocrop (MC) treatments. Data were collected on the percentage of maize plants damaged by stemborers, the number of striga plants that emerged, plant height, grain yield, available phosphorus (P), available potassium (K), total nitrogen (TN), organic carbon (OC), organic matter (OM) and bulk density (BD). There were significant reduction in stemborer damage (2.8 %) and striga count (4.1 Striga plants/m2) in the push-pull treatment compared to the maize monocrop plots (15.4 % and 21.8 striga plants/m2, respectively). Maize plant height (2.34 m) and grain yield (5.3 t ha−1) were significantly higher in the push-pull plots as compared to the sole crop (1.9 m and 3.0 t ha−1, respectively). Similarly, there were significantly higher P (20.06 mg/kg soil), K (406.86 mg/kg soil), TN (2.5 g/kg soil), OC (42.9 g/kg soil), OM (73.8 g/kg soil) levels considered to be moderate to high fertility status in the push-pull as compared to monocrop plots (11.17 mg/kg soil, 347.93 mg/kg soil, 1.6 g/kg soil, 29.8 g/kg soil, and 51.2 g/kg soil, respectively) which is rated from low to moderate soil fertility level. Moreover, bulk density was significantly lower in PPT (0.92 g/cm3) than in MC (0.95 g/cm3) plots. This suggests that push pull technology is effective in reducing striga and stemborer damage and improves soil fertility status which results in better grain yield.

Do rotations and intercrops matter? Opportunities for intensification and diversification of maize-based cropping systems in Zambia

ContextRealizing the double-edged goals of food security and crop diversification require knowledge of crop yield response to different agricultural practices and the extent to which such response is context dependent. This is particularly important in Southern Africa where cropping systems are dominated by maize and smallholders use few external inputs. ObjectiveThe objectives of this study were (1) to evaluate the performance of cropping systems with different levels of legume diversification and intensification on maize productivity across the main agroecological zones and farming systems of Zambia, and (2) to establish the minimum land required to reach maize self-sufficiency at household level with the different cropping systems tested. MethodsSix maize-based cropping systems, comprising maize monocropping, maize-legume rotations and intercrops under ‘conventional’ tillage and conservation agriculture, were evaluated across 40 farms in contrasting agro-ecological zones and farming systems of Zambia. A household survey was conducted in the same communities hosting the on-farm trials to quantify the share of households with enough maize cultivated area to benefit from the tested cropping systems. ResultsMaize yield measured in the on-farm trials ranged, on average, between 3.6 and 5.4 t ha−1, which was greater than mean maize yields reported by farmers not hosting on-farm trials during the same growing seasons and in the same sites. Our results showed a clear positive effect of legume rotation on maize yield in Eastern province only, where cropping systems including groundnut as rotation crop yielded between 1.0 and 2.0 t ha−1 more maize than other cropping systems. Pigeon pea intercrops and Gliricidia hedgerows, crop residue management, and tillage practice had no significant effect on maize yield in any of the provinces. Finally, nearly 35, 50, and 70% of surveyed farms in Northern, Eastern, and Southern province would have enough land to achieve the same level of maize production obtained on their farm with the yields, and associated area requirements, of the maize-legume rotations tested in the on-farm trials. ConclusionLegume rotations can increase maize productivity on land abundant farms in high potential maize production areas of Southern Africa, whereas legume intercrops have benefits at cropping systems level and should be targeted to land constrained farms. SignificanceThe study contributes to better understand the niche for diversified maize-based cropping systems with legume rotations and intercrops in Southern Africa, along with their impacts on maize productivity at the field level and their land requirements at the farm level.

Understanding the interactions of genotype with environment and management (G×E×M) to maize productivity in Conservation Agriculture systems of Malawi.

Climatic variability and soil fertility decline present a fundamental challenge for smallholder farmers to determine the optimum management practices in the production of maize. Optimizing genotype (G) and management (M) of maize under different environmental conditions (E) and their interactions are essential for enhancing maize productivity in the smallholder sector of Malawi where maize is the main staple food. Here, we evaluated over seven seasons, the performance of four commercial maize genotypes [including hybrids and one open pollinated variety (OPV)] managed under different Conservation Agriculture (CA) and conventional practices (CP) across on-farm communities of central and southern Malawi. Our results revealed significant G×E and E×M interactions and showed that hybrids such as DKC 80-53 and PAN 53 outyielded the other hybrid and the OPV in most of the environments while the OPV ZM523 had greater yields in environments with above-average rainfall and shorter in-season dry spells. These environments received a maximum of 1250 mm to 1500 mm of rainfall and yet the long-term averages were 855 mm and 1248 mm, respectively. Despite yielding lower, the OPV ZM523 also exhibited higher yield stability across environments compared to the hybrid MH 30, possibly due to its resilience to drought, heat stress, and low soil fertility conditions which are often prevalent in the target communities. Conservation Agriculture-based practices outyielded CP across the genotypes and environments. However, amongst the CA-based systems, intercropping of maize with pigeonpea [Cajanus cajan (L.) Millsp] and cowpea (Vigna unguiculata Walp.) performed less than monocropping maize and then rotating it with a legume probably due to competition for moisture between the main and the companion crops in the intercrop. The key findings of this study suggest the need to optimize varietal and management options for particular environments to maximize maize productivity in Malawi. This means that smallholder farmers in Malawi should adopt hybrids and CA-based systems for enhanced yields but could also consider OPVs where the climate is highly variable. Further rigorous analysis that includes more abiotic stress factors is recommended for a better understanding of yield response.

Monocropping and Intercropping of Maize with Six Food Legumes at Malkerns in Eswatini: Their Effects on Plant Growth, Grain Yield and N2 Fixation, Measured using the 15N Natural Abundance and Ureide Techniques

Intercropping of legumes and cereals has many benefits to both plant partners. In this study, the effect of legume-maize intercropping on plant growth, grain yield and N2 fixation of six legumes was assessed using the 15N natural abundance and ureide techniques. For this, a field experiment involving six legume species and two cropping systems was established at the Malkerns Research Station, Eswatini during the 2017/2018 cropping season. Based on the 15N isotopic and ureide analysis, the six test legumes respectively obtained 39.06 – 70.19% and 16.46 – 55.79% of their N nutrition from symbiosis. The amounts of N-fixed ranged from 12.66 to 66.57 kg ha−1. In general, high amount of N-fixed by legumes correlated strongly with greater shoot dry matter accumulation (r = 0.7981; p < 0.001) and high grain yield (r = 0.5905; p < 0.001), indicating the importance of N2 fixation in plant growth and reproduction. Legumes grown under monocropping recorded higher plant growth, symbiotic performance and grain yield when compared to those grown in mixed culture with maize. However, shoot %Ndfa was much higher under intercropping than sole cropping due to competition by cereal and legume for soil N. Components of maize yield were similar for the two cropping systems. The %N derived from fixation and %relative ureide-N abundance were significantly correlated (r = 0.4005; p < 0.001), indicating that the 15N natural abundance technique and the ureide method were complementary in measuring N2 fixation in the test legumes. These results have provided some insights on the impact of cropping system on plant growth, symbiotic performance and grain yield of six selected legumes.

Phosphorus Availability and Uptake following a Maize-Pigeon Pea Rotation under Conservation Agriculture

Soils on many smallholder farms in Southern Africa are severely depleted in plant nutrients, in particular phosphorus (P), following years of maize monocropping with little or no fertilizer input. Past studies suggest that pigeon pea (Cajanus cajan (L.) Millsp.) may increase plant-available P. Pigeon pea is not a common crop in much of Southern Africa, and the effect of locally grown pigeon pea varieties on plant-available P is unknown. We assessed the changes in plant-available P after growing pigeon pea varieties MPPV-2, MPPV-3, and Babati White in Zambia, viz. Lixisols of Choma and Mkushi, Acrisols of Chipata and Kasama, and Arenosols of Kaoma. The selected soils were not fertilized. Baseline soils (0–20 cm), sampled after long-term maize monocropping and soils from the same fields after growing pigeon pea were collected from field trials in Kaoma, Chipata, Choma, and Mkushi and analyzed for plant-available P. Further, a greenhouse study was conducted with soils from Kasama, Choma, Kaoma, and Chipata, under which soil P was determined before and after growing pigeon pea, soybean (Dina), and maize (SC 419) without fertilizer addition. Pigeon pea under field studies had no significant (p &gt; 0.05) effect on plant-available P in Choma, Kaoma, and Chipata. In Mkushi, pigeon pea cropping resulted in a 47.5% significant decline (p ≤ 0.05) in plant-available P, amounting to a loss of 11.2 kg ha−1. The greenhouse study showed a significant decline (p ≤ 0.001) in plant-available P after seven weeks of maize growth, while there was no significant (p &gt; 0.05) effect on plant-available P after soybean and pigeon pea cropping. The latter was primarily due to the significantly higher P uptake associated with larger biomass production of maize after seven weeks in the greenhouse. During the initial seven weeks, pigeon pea biomass had significantly higher P concentrations than maize. Thus, P deficiency symptoms were exhibited in maize, while pigeon pea appeared healthy. However, mobilized P, calculated as the sum of plant P and soil P after cropping minus soil P before planting, was significantly lower (p ≤ 0.01) in pigeon pea compared to soybean and maize. Synthesizing field and greenhouse experiments suggests that there is a low net decline of plant-available P from soils after pigeon pea cropping. Therefore, rotation with these pigeon pea varieties could be beneficial to resource-poor farmers due to low P removal and its ability to grow in P-deficient soil.

A Modified Climate‐Smart Push‐Pull Technology for the Management of Fall Armyworm (Spodoptera frugiperda) in the Semiarid Lands of Kenya

Successful use of push‐pull technology in the control of fall armyworm (Spodoptera frugiperda Smith) in maize has been limited to areas that receive optimal rainfall as opposed to the semiarid areas. This study sought to determine the viability of a modified push‐pull technology designed for drier areas. The technology involved the use of the drought‐tolerant Brachiaria grass as a potential replacer of Napier grass as a pull crop, alongside drought‐tolerant green‐leaf Desmodium (Desmodium intortum) and edible legumes as push crops. The study was conducted in Mbeere South Subcounty in Embu County, Kenya. The experiments were laid out in split plots arranged in a randomized complete block design with three replications. The main plots contained Napier and Brachiaria grasses as comparative pull crops while the subplots tested the performance of the drought‐tolerant green‐leaf Desmodium and edible legumes (cowpea, pigeon pea, and green gram) as push crops. A maize monocrop was used as the negative control. The pest dynamics were determined using the area under damage/pest curve (AUDPC). The highest pest incidence was observed in the maize monocrop treatments with AUDPC range of 64–65.5 as compared to the intercrop treatments with AUDPC range of 45–56. The AUDPC for damage severity ranged from 24 to 24.5 in the maize monocrop treatments and 15.5 to 18.7 in the intercrop treatments. These findings implied that the drought‐tolerant green‐leaf Desmodium and the edible legumes can be adopted as effective push crops in the modified push‐pull technology. Brachiaria and Napier grasses portrayed similar suitability as pull crops implying that the two can be used interchangeably as pull crops based on farmers’ preference. This study confirmed the viability of the modified climate‐smart push‐pull technology in the management of fall armyworm in dryland areas.

Soil Quality Indicators under Different Smallholder Managed Cropping and Landuse Practices in Abuja, Nigeria

There are limited reports about the impacts of smallholder-managed cropping and land-use practices (CLUPs) on soil quality, especially in developing countries. This study investigates the impact of six different Cropping Land Use Practices (CLUPs) on soil quality parameters in Abuja, Nigeria, focusing on sesame mono-cropping (SM), guinea corn mono-cropping (GCM), yam mono-cropping (YM), maize + yam mixed cropping (MYM), maize mono-cropping (MM), and natural forest (NF). The objectives are to determine Soil Organic Carbon (SOC), Total Nitrogen (TN), and pH values in the six CLUPs and assess differences under various CLUPs and soil depths. The study conducted in the University of Abuja Permanent Site, covers 11,000 hectares and analyzes soil samples from three replicate plots per CLUP, considering topsoil (0-15cm) and subsoil (20-30cm). The results indicate slightly acidic soils with low SOC and TN contents. Significant differences in SOC, TN, and C/N ratio are observed among cropping systems, with mixed cropping (MYM) promoting higher SOC. The C/N ratio is consistently low across CLUPs, indicating accelerated decomposition. While intra-plot soil heterogeneity is low, significant declines in soil quality indicators are noted under cropping systems compared to the natural forest. The study recommends site-specific, sustainable land management practices tailored to each cropping system. Encouraging organic matter additions, such as using animal and farmyard manure, is proposed to enhance soil fertility and reverse degradation trends. The findings contribute to understanding how diverse cropping practices impact soil quality, providing valuable insights for sustainable land management in the Abuja region.

Integrative Physiological, Transcriptome, and Proteome Analyses Provide Insights into the Photosynthetic Changes in Maize in a Maize-Peanut Intercropping 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.

Influence of Farmyard Manure Application on Potential Zinc Solubilizing Microbial Species Abundance in a Ferralsol of Western Kenya

Zinc is an important nutrient for plant growth and development. Its availability is influenced by zinc solubilizing microbes (ZSMs). The effects of commonly promoted agronomic practices on the abundance of ZSMs are so far not well understood. In this study, conducted in 2019, we assessed the effects of farmyard manure (FYM) application, either sole or in combination with residue and/or inorganic fertilizer inputs, on ZSM community structure using 11 treatments in a long-term (17 years) integrated soil fertility management experiment located in Western Kenya. Bacterial and fungal community composition were evaluated by amplicon sequencing on an Illumina MiSeq platform. The results showed that putative ZSMs (i.e., the ZSMs generally considered to possess the zinc solubilizing capabilities) were clustered in two major clades based on either the application or no application of FYM. Sole application of FYM significantly (p &lt; 0.05) increased the abundance of several ZSMs under a maize–Tephrosia rotation. In addition, systems with the combined application of FYM with other inputs generally showed significantly increasing trends for some ZSMs under a maize–Tephrosia rotation. Moreover, the combined application of FYM and P rather than only P significantly increased the abundance of some ZSMs under maize monocropping systems. Furthermore, as well as affecting ZSM abundance, soil chemical variables involving soil organic carbon (SOC), total N and Olsen P significantly increased with FYM application. This study indicated that management practices such as the application of FYM that increase SOC, and other soil chemical parameters, also/concomitantly increase ZSM abundance. These results imply enhanced capacities for microbial-linked zinc availability with FYM application.