Maize Plants Research Articles

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.

Prospecting for fine scale establishment of exotic stem borer pupal parasitoid (Xanthopimpla stemmator Thunberg) in Kenya

Lepidopteran stem borers are an important constraint to cereal production in Sub- Saharan Africa. The exotic Chilo partellus (Swinhoe) is one of the most economically important stem borer pest causing extensive losses on cereal crops in Kenya. This pest has also displaced indigenous species of stem borers while expanding its range in warm, mid and high altitude areas. In order to exert control on various developmental stages of this pest, both Cotesia flavipes Cameron (larval endoparasitoid) and Xanthopimpla stemmator Thunberg (pupal endoparasitoid) were imported and released in 2002 in the Eastern region of Kenya. This study was conducted to assess the establishment status, spread and impact of X. stemmator on C. partellus following its release in Kenya. Stem borer sampling was done on farms where the biocontrol agents had been released and on transects radiating outwards from them every 15km to assess spread. A total of 100 maize plants were inspected for stem borer infestation and destructive sampling done on 10 maize stems per farm to collect immature stem borer stages. Emerging parasitoids and adult moths were identified, counted and recorded. Results of this study showed that C. partellus was the most dominant stem borer species (constituted 71.2%) followed by Sesemia calamistis and Busseola fusca (26.0 and 2.8% respectively). A decrease in overall stem borer infestation (22.47±7.42%) with no significant difference across distances from parasitoid release points (F=0.4; df=3, 51; p>0.05) was also recorded. Seven parasitoid species were recovered, the most abundant being C. flavipes and this coupled with a significant increase in parasitism (25.27±3.27%) (V=1213, p˂0.05) from pre-release levels. The parasitoid of interest, X. stemmator was not recovered. This suggests a failure to establish though there is need to sample alternative hosts before this is declared. Key words: Classical biological control, lepidoptera, pupal parasitoid, post release survey, Xanthopimpla stemmator, Eastern Kenya

Monitoring of fall armyworm infestation status and current attack on maize plants in southern Egypt

Monitoring of fall armyworm infestation status and current attack on maize plants in southern Egypt

BIOLOGIE ET NUTRITION DE LA CHENILLE LEGIONNAIRE DAUTOMNE, SPODOPTERAFRUGIPERDA(J.E. SMITH) (LEPIDOPTERA : NOCTUIDAE) SUR CINQ PLANTES HOTESAU BURKINA FASO

The fall armyworm, Spodoptera frugiperda, is an insect pest that feeds on over 300 species of host plants, causing significant damage. In order to control this pest, it is essential to know its life cycle on its host plants. The aim of this study was to contribute to a better understanding of the biology and feeding preferences of S. frugiperda in choice and non-choice situations on five host plants (maize, millet, sorghum, cowpea and ricin) encountered in Burkina Faso. The results of the biology study showed that S. frugiperda larval development passes through six larval stages on maize and ricin and seven on millet, sorghum and cowpea. The duration of S. frugiperda larval development time was shortest on maize (10.43 ± 0.16 days) and longest on sorghum (19.59 ± 0.50 days). In general, females lived longer than males, between 7.58 and 8.44 days. S. frugiperda fecundity varied significantly according to food substrate, with hatching rates ranging from 97.39 to 99.20%. Results on food preference showed that in both choice and no-choice situations, maize, followed by ricin, were the preferred substrates for stage 1 and 3 larvae.These results can be used for sustainable and effective management of S. frugiperda in Burkina Faso.

A robust segmentation method combined with classification algorithms for field-based diagnosis of maize plant phytosanitary state

Abstract Early diagnosis of maize-plant phytosanitary state in the field is crucial to prevent crop damage and optimize yield. However, this field diagnosis presents a challenge due to the variable background of the field environment, which can hinder the performance of classification algorithms. In this article, we introduced a novel segmentation technique using a combined normalized difference vegetation index that effectively isolates the features of interest, such as the leaves, from the surrounding image, which includes the diverse field background. To assess the effectiveness of our segmentation approach, we conducted early diagnosis of maize plants in the field using supervised classification algorithms. We generated a dataset that incorporated four essential texture features: energy, entropy, contrast, and inverse. These features were extracted from each of the segmented images using grayscale co-occurrence matrices. We employed four different classification methods, namely Adaboost, Random Forest, K-Nearest Neighbors, and support vector machine. When combined with the proposed segmentation technique, the support vector machine outperformed the other models, achieving an accuracy rate of 97%.

Exploring the dynamics of ISR signaling in maize upon seed priming with plant growth promoting actinobacteria isolated from tea rhizosphere of Darjeeling.

Plant growth-promoting rhizobacteria (PGPR) offer an eco-friendly alternative to agrochemicals for better plant growth and development. Here, we evaluated the plant growth promotion abilities of actinobacteria isolated from the tea (Camellia sinensis) rhizosphere of Darjeeling, India. 16S rRNA gene ribotyping of 28 isolates demonstrated the presence of nine different culturable actinobacterial genera. Assessment of the in vitro PGP traits revealed that Micrococcus sp. AB420 exhibited the highest level of phosphate solubilization (i.e., 445 ± 2.1µg/ml), whereas Kocuria sp. AB429 and Brachybacterium sp. AB440 showed the highest level of siderophore (25.8 ± 0.1%) and IAA production (101.4 ± 0.5µg/ml), respectively. Biopriming of maize seeds with the individual actinobacterial isolate revealed statistically significant growth in the treated plants compared to controls. Among them, treatment with Paenarthrobacter sp. AB416 and Brachybacterium sp. AB439 exhibited the highest shoot and root length. Biopriming has also triggered significant enzymatic and non-enzymatic antioxidative defense reactions in maize seedlings both locally and systematically, providing a critical insight into their possible role in the reduction of reactive oxygen species (ROS) burden. To better understand the role of actinobacterial isolates in the modulation of plant defense, three selected actinobacterial isolates, AB426 (Brevibacterium sp.), AB427 (Streptomyces sp.), and AB440 (Brachybacterium sp.) were employed to evaluate the dynamics of induced systemic resistance (ISR) in maize. The expression profile of five key genes involved in SA and JA pathways revealed that bio-priming with actinobacteria (Brevibacterium sp. AB426 and Brachybacterium sp. AB440) preferably modulates the JA pathway rather than the SA pathway. The infection studies in bio-primed maize plants resulted in a delay in disease progression by the biotrophic pathogen Ustilago maydis in infected maize plants, suggesting the positive efficacy of bio-priming in aiding plants to cope with biotic stress. Conclusively, this study unravels the intrinsic mechanisms of PGPR-mediated ISR dynamics in bio-primed plants, offering a futuristic application of these microorganisms in the agricultural fields as an eco-friendly alternative.

Characterisation and Expression Analysis of LdSERK1, a Somatic Embryogenesis Gene in Lilium davidii var. unicolor.

The Lanzhou lily (Lilium davidii var. unicolor) is a variant of the Sichuan lily of the lily family and is a unique Chinese 'medicinal and food' sweet lily. Somatic cell embryogenesis of Lilium has played an important role in providing technical support for germplasm conservation, bulb propagation and improvement of genetic traits. Somatic embryogenesis receptor-like kinases (SERKs) are widely distributed in plants and have been shown to play multiple roles in plant life, including growth and development, somatic embryogenesis and hormone induction. Integrating the results of KEGG enrichment, GO annotation and gene expression analysis, a lily LdSERK1 gene was cloned. The full-length open reading frame of LdSERK1 was 1875 bp, encoding 624 amino acids. The results of the phylogenetic tree analysis showed that LdSERK1 was highly similar to rice, maize and other plant SERKs. The results of the subcellular localisation in the onion epidermis suggested that the LdSERK1 protein was localised at the cell membrane. Secondly, we established the virus-induced gene-silencing (VIGS) system in lily scales, and the results of LdSERK1 silencing by Tobacco rattle virus (TRV) showed that, with the down-regulation of LdSERK1 expression, the occurrence of somatic embryogenesis and callus tissue induction in scales was significantly reduced. Finally, molecular assays from overexpression of the LdSERK1 gene in Arabidopsis showed that LdSERK1 expression was significantly enhanced in the three transgenic lines compared to the wild type, and that the probability of inducing callus tissue in seed was significantly higher than that of the wild type at a concentration of 2 mg/L 2,4-D, which was manifested by an increase in the granularity of the callus tissue.

Assessing the Influence of Planting Dates on Sustainable Maize Production under Drought Stress Conditions

Water is one of the most precious resources and is essential to agricultural output; the biggest user of water is the agricultural sector. Several societal sectors are impacted by the problem of climate change, including agriculture, water resources, and irrigation water demand. A key element in determining sustainable crop production potential is choosing the right cultivars at the right time of year to plant. The dates on which maize is sown are greatly impacted by high summer temperatures and low spring temperatures. Water stress and the timing of sowing can have a significant impact on maize crop yield and water use efficiency. As a result, figuring out the ideal irrigation volume and sowing dates depending on local conditions is essential. A split plot layout was used to create a randomized complete block design for an experiment with five sowing dates (A, B, C, D, and E) and six hybrids (KWS3376, Xinyu 65, KWS9384, Huamei No. 1, Xinyu 102, and Heyu 187). All sowing dates and hybrids had a significant impact on the yield and yield-contributing features (leaf length, ear diameter, grain number per spike, grain breadth, hundred-grain weight, etc.) of maize crops according to the data analysis. A higher grain yield with yield features, such as ear length, number of grains per ear, and hundred-grain weight, was obtained with early-season sowing. Delayed seeding resulted in a lower crop yield. The seasonally delayed seeding of maize reduces yield and yield characteristics. Xinyu 65 produced the highest yield and yield component values of any hybrid. For improved yield and yield traits in the examined area, the study recommended planting maize hybrid Xinyu 65 early in the growing season.

Effects of polyurethane microplastics combined with cadmium on maize growth and cadmium accumulation under different long-term fertilisation histories

Agricultural production uses different types of fertilisation treatments, typically employing the combined application of organic fertiliser (OF) or organic–inorganic fertiliser (OIF) to improve soil quality. When coupled with cadmium (Cd), microplastics (MPs) affect plant growth and Cd accumulation in soils treated with different fertilisers. This study systematically examined the effects of polyurethane (PU) MPs coupled with Cd on the growth characteristics, root metabolite characteristics, rhizosphere bacterial community structure, and Cd bioavailability of maize under different long-term fertilisation treatments and soil types (red/cinnamon soil). The combined effects of PU MPs and Cd on maize growth differed across fertilisation treatments. Under OF, maize plants accumulated more Cd than under OIF. The accumulation of Cd in maize plants in red soil was twice that in cinnamon soil. Under OF, PU MPs promoted Cd activation by decreasing the soil pH, while root metabolites promoted Cd adsorption sites by synthesising specific amino acids, degrading aromatic compounds, and synthesising pantothenic acid and coenzyme A. Under OF, PU MPs can lower the soil pH to promote the activation of cadmium, while root metabolites promote root growth and increase cadmium adsorption sites by synthesizing specific amino acids, degrading aromatic compounds, and synthesizing pantothenic acid and coenzyme A, hereby promoting root Cd absorption. Under OIF, PU MPs act by influencing the biosynthesis of amino acids in root metabolites, enriching energy metabolism pathways, promoting the transport and translocation of mineral nutrients, thereby amplifying the "toxic effects" of Cd. This study provides new insights into the risk assessment of PU MPs and Cd coupling under different fertilisation treatments, and suggests that the prevention and control of combined PU MPs and Cd pollution in red soil under OF treatment should receive more attention in the future.

Growth and yield of maize in response to reduced fertilizer application and its impacts on population dynamics and community biodiversity of insects and soil microbes

In the North China Plain, farmers are using excessive amounts of fertilizer for the production of high-yield crop yield, which indirectly causes pollution in agricultural production. To investigate an optimal rate of fertilizer application for summer maize, the fertilizer reduction experiments with 600 kg/ha NPK (N: P2O5: K2O = 28: 8: 10) as normal fertilizer application (NFA), (i.e., 100F), were conducted successively during 2020 and 2021 to study the effects of reduced fertilizer rates, including 90% (540 kg/ha; i.e., 90F), 80% (480 kg/ha; i.e., 80F), 62.5% (375 kg/ha; i.e., 62.5F) and 50% (300 kg/ha; i.e., 50F) of NFA, on the plant growth of maize, the dynamics of key population abundances and community diversity of insects, and the composition and diversity of microbial community and finally to find out the N-metabolic enzymes’ activity in soil. Our findings revealed that the fertilizer reduction rates by 10% - 20% compared to the current 100% NFA, and it has not significantly affected the plant growth of maize, not only plant growth indexes but also foliar contents of nutrients, secondary metabolites, and N-metabolic enzymes’ activity. Further, there was no significant alteration of the key population dynamics of the Asian corn borer (Ostrinia furnacalis) and the community diversity of insects on maize plants. It is interesting to note that the level of N-metabolic enzymes’ activity and microbial community diversity in soil were also not affected. While the fertilizer reduction rate by 50% unequivocally reduced field corn yield compared to 100% NFA, significantly decreased the yield by 17.10%. The optimal fertilizer application was calculated as 547 kg/ha (i.e., 91.17% NFA) based on the simulation analysis of maize yields among the five fertilizer application treatments, and the fertilizer application reduced down to 486 kg/ha (i.e., 81.00% NFA) with a significant reduction of maize yield. These results indicated that reduced the fertilizer application by 8.83% - 19.00% is safe and feasible to mitigate pollution and promote sustainable production of maize crops in the region.

Agroecological substantiation of meliorative factors for restoration of soils disturbed by military actions

Тhe armed aggression of the Russian Federation has led to the disruption of balance in agroecosystems in Ukraine. The purpose of this study was to investigate the agroecological consequences of soil disturbance in agrocenosis due to explosive ordnance and to justify the use of ameliorative factors for soil fertility restoration. Vegetation studies were conducted at the «Institute of Applied Biotechnology». Soil samples for the experiment were collected from the liberated territories of Kharkiv region affected by military actions. Soil expertise, disrupted by explosive ordnance, revealed changes in agrochemical, biological, and toxicological indicators compared to the control plot of the agrocenosis. The humus content decreased by 39–46%, hydrolyzable nitrogen by 30–38%, mineral nitrogen by 36–48%, while the availability of mobile potassium increased by 115–139%. Significant excess of heavy metals content in the soil was detected: copper content increased by 3 times, lead — by 1.5 times, nickel — by 2.7 times, and cadmium — by 2.5 times. Microbiological processes were characterized by an increase in mineralization-immobilization coefficients, oligotrophy, pedotrophy, and a decrease in organic matter transformation indicator. Based on the observed changes, ameliorative factors were proposed aimed at soil fertility restoration. The application of nitrogen-phosphorus mineral fertilizer, winter wheat straw as organic fertilizer, and the biological preparation EcoStern Detox contributed to the improvement of soil agrochemical properties and optimized the direction of microbiological processes, but had no systemic impact on the change in the quantity of mobile forms of heavy metals. The positive impact of amelioration on the soil environment was confirmed by bioassay. Combining the studied ameliorative factors resulted in a 14.3–18.1% increase in maize plant height at the BBCH 14 stage, an increase in aboveground biomass by 24–46.2%, and root mass by 13.3–14.3% compared to the control. The highest growth in the development of the photosynthetic apparatus and root system was observed with the application of the entire complex of ameliorants. The obtained results are consistent with the soil analysis, as the simultaneous application of the EcoStern Detox biopreparation, mineral fertilizers, and straw led to a significant improvement in both agrochemical and biological soil indicators compared to the control and other research variants.

Participation of miR165a in the Phytochrome Signal Transduction in Maize (Zea mays L.) Leaves under Changing Light Conditions.

The involvement of the microRNA miR165a in the light-dependent mechanisms of regulation of target genes in maize (Zea mays) has been studied. The light-induced change in the content of free miR165a was associated with its binding by the AGO10 protein and not with a change in the rate of its synthesis from the precursor. The use of knockout Arabidopsis plants for the phytochrome A and B genes demonstrated that the presence of an active form of phytochrome B causes an increase in the level of the RNA-induced silencing miR165a complex, which triggers the degradation of target mRNAs. The two fractions of vesicles from maize leaves, P40 and P100 that bind miR165a, were isolated by ultracentrifugation. The P40 fraction consisted of larger vesicles of the size >0.170 µm, while the P100 fraction vesicles were <0.147 µm. Based on the quantitative PCR data, the predominant location of miR165a on the surface of extracellular vesicles of both fractions was established. The formation of the active form of phytochrome upon the irradiation of maize plants with red light led to a redistribution of miR165a, resulting in an increase in its proportion inside P40 vesicles and a decrease in P100 vesicles.

Training YOLOv5s under field-survey conditions to detect the ‎infections of maize plants in real-time

Training YOLOv5s under field-survey conditions to detect the ‎infections of maize plants in real-time

Different effects of polyethylene microplastics on bioaccumulation of three fungicides in maize (Zea mays L.)

Despite the ubiquity of microplastics (MPs) and pesticides in agricultural soils, the effects of MPs on the behavior and bioavailability of pesticides in soil–plant systems remain largely unknown. This study comparatively investigated the adsorption and dissipation of three commonly used fungicides (metalaxyl, azoxystrobin and tebuconazole) in soil as well as their accumulation and distribution in maize Zea mays L. with and without the amendment of polyethylene MPs (PE-MPs). The results showed that the adsorption of the fungicides to both MPs and soil was strongly dependent on their octanol/water partition coefficients (logKow). The addition of 5% PE-MPs significantly increased the adsorption of the hydrophobic fungicides azoxystrobin and tebuconazole to soil due to their greater adsorption affinity to PE-MPs than to soil, while the effect was negligible in the case of the hydrophilic fungicide metalaxyl. The enhanced adsorption of azoxystrobin and tebuconazole to soil with the amendment of PE-MPs decreased their bioavailable fractions in soil, especially the concentration in in situ pore water, resulting in prolonged persistence in soil and reduced accumulation in maize plants. PE-MPs caused a greater reduction in the dissipation and bioaccumulation of tebuconazole than azoxystrobin, presumably because PE-MPs were more effective in promoting the adsorption of tebuconazole (with a higher logKow) in soil. Comparatively, PE-MPs had little effect on the dissipation and bioaccumulation of metalaxyl since its bioavailability was almost unaffected. Our work provides effective information for the risk assessment of co-contamination of MPs and pesticides.

Impacts of Farming Activities on Nitrogen Degradability under a Temperate Continental Monsoon Climate

Nutrient fertilizer application to agricultural land has led to greenhouse gas emissions and has altered soil nitrogen (N) deposition. In soil, N can be degraded in four ways: entering surface water through water flow, absorption by plants and microorganisms, decomposition into gas, and deposition as minerals. This study proposes the concept of N degradability and aims to clarify how farming activities affect N degradability in soil. Over 260 soil profiles were excavated, and the effective soil depth, coordinates, soil types, and vegetation were recorded at each measurement point. The following characteristics were determined in the soil samples: pH, organic matter, total N, total phosphorus, total potassium, total soluble N, available phosphorus, and available potassium. The sample characteristics were subjected to Pearson correlation analysis, principal component analysis, and one-way analysis of variance. The 260 samples included four soil types: dark brown soil, black soil, albic black soil, and meadow soil. Black soil exhibited more stable N levels compared with the other three soil types, showing a tendency towards N accumulation. Ground vegetation was categorized into seven types: forest, rice, maize, red adzuki bean, grassland, soybean, and others. Forests contributed the most to N deposition. Conversely, planting maize led to a tendency for N loss compared with forests. This study can provide a reference for the sustainable development of agriculture and the balance of ecological protection.

Effect of spent engine oil pollution and liquid organic fertilizer application on soil chemical properties and nutrient contents of Maize (Zea Mays)

A trial was conducted to evaluate the effect of spent engine oil (SEO), bio-treated with liquid organic fertilizer, on maize plant growth. The study utilized three concentrations of SEO (0.5 and 10% w/w) and four liquid organic fertilizers (water control, cattle dung, poultry manure and rabbit manure). These factors were arranged in a 3 × 4 factorial setup with three replications in a completely randomized design. Collected data included percentage moisture, dry weight, nutrient content and uptake, heavy metal concentration, and post-harvest soil chemical properties. Soil composite samples on physical and chemical analysis carried out show that the engine oil pollution negatively affected soil pH, total nitrogen, available phosphorus, and exchangeable cations, but it increased total organic carbon before maize cultivation. The percentage moisture and dry weight of the maize plant were not significantly (p &gt; 0.5) influenced by engine oil pollution or liquid organic fertilizer application. N, P and Mg content of maize plant were significantly reduced by the engine oil pollution but significantly boosted by organic fertilizer application. Cr and Pb content of the maize were increased with engine oil concentration but decreased with liquid organic fertilizer. Nutrient uptake was decreased with increase in engine oil content but increased with liquid organic fertilizer application. At the end of the experiment, engine oil pollution significantly depressed pH, total N, available P and exchangeable cations, but increased organic C, total hydrocarbon, exchangeable Al and heavy metal content while it was opposite for liquid organic fertilizer. Our findings suggested that soils polluted with SEO should be corrected with the application of organic fertilizers.

Multitemporal Field-Based Maize Plant Height Information Extraction and Verification Using Solid-State LiDAR

Plant height is regarded as a key indicator that is crucial for assessing the crop growth status and predicting yield. In this study, an advanced method based on solid-state LiDAR technology is proposed, which is specifically designed to accurately capture the phenotypic characteristics of plant height during the maize growth cycle. By segmenting the scanned point cloud of maize, detailed point cloud data of a single maize plant were successfully extracted, from which stem information was accurately measured to obtain accurate plant height information. In this study, we will concentrate on the analysis of individual maize plants. Leveraging the advantages of solid-state LiDAR technology in precisely capturing phenotypic information, the data processing approach for individual maize plants, as compared to an entire maize community, will better restore the maize’s original growth patterns. This will enable the acquisition of more accurate maize plant height information and more clearly demonstrate the potential of solid-state LiDAR in capturing detailed phenotypic information. To enhance the universality of the research findings, this study meticulously selected key growth stages of maize for data validation and comparison, encompassing the tasseling, silking, and maturity phases. At these crucial stages, 20 maize plants at the tasseling stage, 40 at the flowering stage, and 40 at the maturity stage were randomly selected, totaling 100 samples for analysis. Each sample not only included actual measurement values but also included plant height information extracted using point cloud technology. The observation period was set from 20 June to 20 September 2021. This period encompasses the three key growth stages of maize described above, and each growth stage included one round of data collection, with three rounds of data collection each, each spaced about a week apart, for a total of nine data collections. To ensure the accuracy and reliability of the data, all collections were performed at noon when the natural wind speed was controlled within the range of 0 to 1.5 m/s and the weather was clear. The findings demonstrate that the root mean square error (RMSE) of the maize plant height data, procured through LiDAR technology, stands at 1.27 cm, the mean absolute percentage error (MAPE) hovers around 0.77%, and the peak R2 value attained is 0.99. These metrics collectively attest to the method’s ongoing high efficiency and precision in capturing the plant height information. In the comparative study of different stem growth stages, especially at the maturity stage, the MAPE of the plant height was reduced to 0.57%, which is a significant improvement compared to the performance at the nodulation and sprouting stage. These results effectively demonstrate that the maize phenotypic information extraction method based on solid-state LiDAR technology is not only highly accurate and effective but is also effective on individual plants, which provides a reliable reference for applying the technique to a wider range of plant populations and extending it to the whole farmland.

The Potential of Burkholderia sp. from Zea mays Roots as Plant Growth Promoting Rhizobacteria

Plant Growth-Promoting Rhizobacteria (PGPR) plays a crucial role in enhancing plant health, while Burkholderia sp. has been identified and has potential as a promising PGPR for maize plants. Recognizing the essential role of PGPR in plant health, this study explores how L-TRP addition might improve PGPR performance for better plant growth. Employing a completely randomized design, the study assesses the effects of Burkholderia sp. as PGPR on maize growth across three treatment groups: PGPR with L-TRP, PGPR without L-TRP, and a control group. The evaluation focuses on plant growth metrics, plant hormone production (auxin and gibberellin), and siderophore activity to gauge plant iron availability. Statistical analysis highlights that L-TRP supplementation notably increases auxin production in the PGPR + L-TRP group, surpassing the PGPR without L-TRP and control groups. Although both PGPR treatments elevate gibberellin levels compared to the control, auxin increase is the most significant outcome, indicating no substantial difference in gibberellin levels between the two PGPR groups. Enhanced siderophore production suggests improved iron assimilation for plants. The findings demonstrate that L-TRP supplementation with PGPR, particularly Burkholderia sp., effectively boosts maize growth, primarily through increased auxin and siderophore production. This combination presents a promising strategy for augmenting agricultural yields, especially for maize productivity, by leveraging the synergistic effects of soil microbes and nutrient supplementation.

Maize (Zea mays L.) Plants Alter the Fate and Accumulate Nonextractable Residues of Sulfamethoxazole in Farmland Soil.

The fate of sulfonamide antibiotics in farmlands is crucial for food and ecological safety, yet it remains unclear. We used [phenyl-U-14C]-labeled sulfamethoxazole (14C-SMX) to quantitatively investigate the fate of SMX in a soil-maize system for 60 days, based on a six-pool fate model. Formation of nonextractable residues (NERs) was the predominant fate for SMX in unplanted soil, accompanied by minor mineralization. Notably, maize plants significantly increased SMX dissipation (kinetic constant kd = 0.30 day-1 vs 0.17 day-1), while substantially reducing the NER formation (92% vs 58% of initially applied SMX) and accumulating SMX (40%, mostly bound to roots). Significant NERs (maximal 29-42%) were formed via physicochemical entrapment (determined using silylation), which could partially be released and taken up by maize plants. The NERs consisted of a considerable amount of SMX formed via entrapment (1-8%) and alkali-hydrolyzable covalent bonds (2-12%, possibly amide linkage). Six and 10 transformation products were quantified in soil extracts and NERs, respectively, including products of hydroxyl substitution, deamination, and N-acylation, among which N-lactylated SMX was found for the first time. Our findings reveal the composition and instability of SMX-derived NERs in the soil-plant system and underscore the need to study the long-term impacts of reversible NERs.

Establishment of a high-yield intercropping system for maize and legumes under rainfed conditions in eastern Bhutan

ABSTRACT Maize-legume intercropping is a sustainable strategy to improve maize production for smallholder farmers. Maize is a staple food crop in Bhutan and integration of legumes with maize has been considered as an alternative option towards enhancing maize production in the country. Here, we conducted two studies in eastern Bhutan: first study (2021) to identify suitable legumes for intercropping with maize and second study (2022) to evaluate the effects of different maize-soybean intercropping patterns on grain yield, land use efficiency, and economic benefits. The maize-soybean intercropping system showed better productivity and economic viability than the kidney bean and groundnut systems in both the sites. Row intercropping and strip intercropping with 2 rows of maize alternating with 2 rows of soybean (2 M:2S) spaced 0.3 × 0.3 m showed stable and consistently higher grain yield at Lingmethang and Wengkhar (LING = 6.05 t ha−1; WENG = 8.37 t ha−1). The land equivalent ratio (LING = 1.78; WENG = 1.73) and net return (0.16 million Nu. ha−1 for LING and 0.21 million Nu. ha−1 for WENG) were notably higher for these intercropping methods. Our results suggest that the integration of legumes between conventional maize planting density, row intercropping and strip intercropping (2 M:2S) spaced at 0.3 × 0.3 m would be beneficial for achieving higher productivity for smallholder farmers in eastern Bhutan.