Search Results (77)

Integrating organic soil amendments such as vermicompost (VC) and vermicompost tea (VCT) in agriculture has received increasing attention as a sustainable strategy to improve soil fertility, enhance plant growth, and suppress pest infestations. This study aimed to evaluate the effects of varying concentrations of VCT (10%, 20%, and 40%), alone and in combination with VC (2.47 ton/ha), on the development and yield of corn (Zea mays), and suppression of fall armyworm (FAW, Spodoptera frugiperda) infestation. The experiment was conducted in seven raised beds with seven treatments: V0 (control), VCT10, VCT20, VCT40, VC1 + VCT10, VC1 + VCT20, and VC1 + VCT40. Six weekly applications of VCT were applied starting at the V2 stage, and soil and plant nutrient contents were determined post-harvest. Additionally, relative chlorophyll content, height, cob yield, dry biomass, and FAW infestations were assessed. Results show that both VC and VCT significantly enhanced soil nutrient content compared to the control treatment (V0). VCT20 and VC1 + VCT10 improved plant N, K, and micronutrient uptake. Corn treated with VCT10 and VC1 + VCT10 had the highest biomass (6.52 and 6.57 tons/ha, respectively), while VCT20 produced the highest cob yield (6.0 tons/ha), which was more than eight times that of V0. SPAD values and corn height were significantly high across all treatments, with VCT20 achieving the highest SPAD readings while the control achieved the lowest. For FAW infestation, the control treatment experienced moderate infestation. At the same time, there was complete suppression in VCT20 and VCT40 treatments and a reduction in VC + VCT treatments, likely due to the bioactive compounds and beneficial microbes in VC and VCT that strengthened plant immunity. The results suggest that VCT20 is a cost-effective, eco-friendly amendment for improving corn performance and FAW resistance. This study contributes to sustainable agriculture by demonstrating how organic amendments can enhance crop resilience while supporting environmentally friendly farming practices. Full article

This study presents the MSPAT (Multispectral Soil Plant Analysis Tool), a device designed for assessing leaf nitrogen concentrations in maize crops under field conditions. The MSPAT includes the AS7265x sensor, which has 18 bands and covers the spectrum from 410 to 940 nm. This device was designed to be portable, using the ESP32 microcontroller and incorporating such functionalities as data storage on a MicroSD card, communication with a smartphone via Wi-Fi, and geolocation of acquired data. The MSPAT was evaluated in an experiment conducted at the Federal University of Ceará (UFC), where maize was subjected to different doses of nitrogen fertiliser (0, 60, 90, 120, 150, and 180 kg·ha⁻¹ N). Spectral readings were taken at three phenological stages (V5, V10, and R2) using the MSPAT, an SPAD-502 chlorophyll meter, and a FieldSpec PRO FR3 spectroradiometer. After the optical measurements were taken, the nitrogen concentrations in the leaves were determined in a laboratory by using the Kjeldahl method. The data analysis included the calculation of normalised ratio indices (NRIs) using linear regression and the application of multivariate statistical methods (PLSR and PCR) for predicting leaf nitrogen concentrations (LNCs). The best performance for the MSPAT index (NRI) was obtained using the 900 nm and the 560 nm bands (R² = 0.64) at stage V10. In the validation analysis, the MSPAT presented an R² of 0.79, showing performance superior to that of SPAD-502, which achieved an R² of 0.70. This confirms the greater potential of the MSPAT compared to commercial equipment and makes it possible to obtain results similar to those obtained using the reference spectroradiometer. The PLSR model with data from the FieldSpec 3 provided important validation metrics when using reflectance data with first-derivative transformation (R² = 0.88, RMSE = 1.94 and MAE = 1.28). When using the MSPAT, PLSR (R² = 0.75, RMSE = 2.77 and MAE = 2.26) exhibited values of metrics similar to those for PCR (R² = 0.75, RMSE = 2.78 and MAE = 2.26). This study validates the use of MSPAT as an effective tool for monitoring the nutritional status of maize to optimize the use of nitrogen fertilisers. Full article

This study addresses the critical need for effective data fusion strategies in pest prediction for pitahaya (dragon fruit) cultivation in the Ecuadorian Amazon, where heterogeneous data sources—such as environmental sensors and chlorophyll measurements—offer complementary but fragmented insights. Current agricultural monitoring systems often fail to integrate these data streams, limiting early pest detection accuracy. To overcome this, we compared early and late fusion approaches using comprehensive experiments. Multidimensionality is a central challenge: the datasets span temporal (hourly sensor readings), spatial (plot-level chlorophyll samples), and spectral (chlorophyll reflectance) dimensions. We applied dimensionality reduction techniques—PCA, KPCA (linear, polynomial, RBF), t-SNE, and UMAP—to preserve relevant structure and enhance interpretability. Evaluation metrics included the proportion of information retained (score) and cluster separability (silhouette score). Our results demonstrate that early fusion yields superior integrated representations, with PCA and KPCA-linear achieving the highest scores (0.96 vs. 0.94), and KPCA-poly achieving the best cluster definition (silhouette: 0.32 vs. 0.31). Statistical validation using the Friedman test (${\chi }^2$ = 12.00, p = 0.02) and Nemenyi post hoc comparisons (p < 0.05) confirmed significant performance differences. KPCA-RBF performed poorly (score: 0.83; silhouette: 0.05), and although t-SNE and UMAP offered visual insights, they underperformed in clustering (silhouette < 0.12). These findings make three key contributions. First, early fusion better captures cross-domain interactions before dimensionality reduction, improving prediction robustness. Second, KPCA-poly offers an effective non-linear mapping suitable for tropical agroecosystem complexity. Third, our framework, when deployed in Joya de los Sachas, improved pest prediction accuracy by 12.60% over manual inspection, leading to more targeted pesticide use. This contributes to precision agriculture by providing low-cost, scalable strategies for smallholder farmers. Future work will explore hybrid fusion pipelines and sensor-agnostic models to extend generalizability. Full article

The development of critical levels for sap nitrate and chlorophyll meter reading (SPAD test) in the case of various crops is of great importance for growers in characterizing a plant’s N status. A field experiment with spring oat (Avena sativa L.) was carried out on loamy soil in Debrecen, Hungary, using a small-plot design. Ammonium nitrate was broadcast at rates of 0, 30, 60, and 90 kg N/ha in three replicates. The total N content of the plant, sap nitrate content, and SPAD values were measured at jointing when the first node appeared above the soil surface (Feekes 6) and at boot stage (Feekes 10). Regression analysis between total N content and sap nitrate showed cubic and linear relationships with r² = 0.7982 (Feekes 6, whole plant) and 0.9625 (Feekes 10, upper developed leaves), respectively. Optimal grain yield was obtained when sap nitrate exceeded 650 mg/L and 540 mg/L at Feekes 6 and Feekes 10, respectively. There were linear and logarithmic relationships between total N content and SPAD values with r² = 0.8058 and 0.6258 at Feekes 6 and 10. Optimal grain yield occurred over SPAD values of 43 and 48 at Feekes 6 and 10, respectively. Optimal N rate was 60 kg N/ha on the experimental site. Full article

Nitrogen (N) deficiency in soil limits the development of forage grasses, while its application can significantly increase productivity. This study aimed to evaluate the effects of increasing N doses and cutting intervals on structural and productive traits, biomass allocation, leaf chlorophyll index, and specific leaf area in Megathyrsus maximus cv. MG12 Paredão. The experiment was conducted with a randomized block design in the field, using a 5 × 2 factorial scheme, with five N fertilization levels (0, 100, 200, 300, and 400 kg N ha⁻¹ year⁻¹) and two cutting intervals (either 28 or 56 days). Our measurements included plant height, number of tillers, dry mass production, fresh shoot weight, root dry mass, leaf and stem biomass, SPAD readings, and specific leaf area. The results indicated a significant increase in SPAD values associated with higher N fertilization levels, so that the 300 kg N ha⁻¹ year⁻¹ dose resulted in the most significant changes compared to the control, with SPAD values increasing from 38.2 in the control group to 54.7. Dry mass production (DMP) was higher at the 28-day cutting interval compared to 56 days, particularly with 400 kg N ha⁻¹. The 400 kg N ha⁻¹ year⁻¹ dose resulted in a 68% increase in DMP compared to the control at 28-day intervals. Additionally, fertilization enhanced the number of tillers, leading to greater biomass accumulation. Significant differences in plant height were observed between cutting intervals, with taller plants recorded at 56 days. N fertilization promoted increased plant height, particularly at doses of 200, 300, and 400 kg ha⁻¹year⁻¹. Therefore, our study suggests the use of 400 kg N ha⁻¹ year⁻¹ dose at 28-day intervals. Thus, cutting frequency directly influenced plant growth. Full article

In this study, the gene ZmPR5, associated with resistance to ear rot, was identified through transcriptome data analysis of the maize inbred line J1259. The gene was subsequently cloned and its function was investigated. The ZmPR5 gene comprises an open reading frame of 525 base pairs, encoding a protein of 175 amino acids. ZmPR5 was overexpressed in Arabidopsis and the ZmPR5EMS mutant in maize, and they were subjected to q-PCR and measurements of antioxidant enzyme activities (POD, SOD, CAT, MDA), electrical conductivity, and chlorophyll content. The results indicate that the expression of ZmPR5 is up-regulated upon infection by Fusarium verticillioides, with significant differences observed in the activities of POD, SOD, CAT, MDA, electrical conductivity, and chlorophyll content. The study found that ZmPR5 is localized in the nucleus and interacts with Zm00001d020492 (WRKY53) and Zm00001d042140 (glucA). Trypan blue staining revealed that the stained area in the ZmPR5EMS mutant of maize was significantly larger than that in B73. The expression of ZmPR5 is closely associated with resistance to maize ear rot. Full article

Perennials improve soil strength and stabilize the slope. However, they are very prone to drought stress (DS). To identify plant health indicators, this study investigated the responses of five tropical perennials commonly grown in Singapore’s slope to DS and re-watering (RW) in the greenhouse. The durations for mild, intermediate, and severe DS defined as T1, T2, and T3, respectively, before RW were based on the extents of reduced F_v/F_m ratio (maximal quantum efficiency of PSII) and the levels of wilting. After RW, soil water content (SWC) increased until field capacity in all DS soil, although they were significantly lower than in well-watered (WW) soil. Overall, the F_v/F_m ratios and leaf water content (LWC) decreased significantly in all DS plants compared to those of WW plants, but all increased to the similar level as WW plants after RW. Nitrogen deficiency did not occur in any plants during DS. There were clear positive correlations of SWC with F_v/F_m ratios, LWC, effective quantum yield of PSII (∆F/F_m’), electron transport rate (ETR), and photochemical quenching (qP) for all species. To monitor plant health, it would recommend using both non-destructive measurements such as SWC and F_v/F_m ratios and destructive parameters like LWC, ∆F/F_m’, ETR, and qP. Full article

Nitrogen fertilization greatly affects the development of sugar beet leaf and photosynthetic activity. This study aimed to evaluate the dynamics of leaf SPAD index, chlorophyll a (Chl a), chlorophyll b (Chl b), carotenoids (Caro), and the macronutrient status (N, P, K, Na, Mg) in different N fertilization rates in sugar beet production. This study set up a two-year field experiment in Eastern Croatia. The N fertilization rate was applied as: N0—control, N1—only presowing fertilization (45 kg/ha), and N2—presowing with topdressing (99 kg/ha in 2014 and 85.5 kg/ha in 2015). In general, N fertilization has a significant (p ≤ 0.05) influence on leaf pigments, except for Chl b. With the highest N dose (N2), the Chl content in the leaves increased by 12% compared to the control treatment (0.75 mg/g FW). The Caro dynamics in the leaves of vegetative growth were significantly different (p ≤ 0.05); leaves in the younger growth stage at the end of May had the highest Caro content (0.011 mg/g FW). In general, the SPAD index was significantly different (p ≤ 0.05), among N fertilization, whereas the lowest SPAD was found at the control treatment (38.7) and the highest at the N2 treatment (40.8). In general, regarding nitrogen fertilization, the lowest SPAD readings had sugar beet leaves at the control treatment (38.7), whereas the highest was determined at the N2 treatment (40.8). A strong positive relationship (p ≤ 0.01) was determined for Chl a, Chl b, Chl a + b, and Chl a + b/Caro with the SPAD index, whereas an inverse relationship with the SPAD index was determined for Caro and Chl a/b. The results demonstrate that nitrogen application, particularly at higher rates, positively influences chlorophyll and carotenoid content, as well as overall plant health, which can inform agricultural practices for more sustainable and efficient sugar beet cultivation. Full article

Drought is one of the key challenges of climate change. The basic global problem related to the increasing water deficit is that the vast majority of crops are species and varieties that are the result of breeding work that did not anticipate such a rapid decrease in water availability in the soil. The main objective of the conducted research was to compare the physiological and biochemical response to water deficit of plants of the species Fragaria vesca—two cultivated varieties, and one collected from the natural environment. A two-year pot experiment was conducted in a polyethylene tunnel. The substrate moisture level was monitored using tensiometer readings. Measurements of gas exchange parameters, chlorophyll “a” fluorescence, content of photosynthetic pigments in leaves, index of relative water content in leaves, total fruit yield, single fruit mass and content of K, Ca, Mg, Na, Cu, Zn, Mn, Mo and the ratio of mono- to divalent cations in leaves, roots and plant crowns were taken three times each year during the experiments. Based on one-way and two-way analysis of variance, statistically significant differences were observed between wild-growing plants and cultivated varieties under control conditions, particularly in terms of chlorophyll fluorescence values and the content of photosynthetic pigments. A significant main effect of the soil moisture level was identified for most measured parameters across the majority of assessment time points. However, a significant interaction effect between soil moisture level and genotype was less frequently observed. Significant changes in response to water deficit varied depending on the parameter and genotype, ranging from 2.5% to 106.1%. For the content of chemical elements, the changes reached up to 157.1%. The results suggest that plants obtained from natural environments exhibit better adaptation to water deficit conditions, making them suitable for use in breeding programs aimed at developing varieties resistant to soil water deficits. However, the study’s limitations, particularly the absence of molecular analyses regarding the plants’ adaptive mechanisms, should be taken into consideration. Full article

Balanced nitrogen (N) supply is essential for high root yield in sweet potatoes (Ipomoea potatoes [L.] Lam.). A portable chlorophyll meter can support N fertilization management. Here, we determined the appropriate N sufficiency index (NSI) for sweet potato leaves to achieve the best leaf N status, plant growth, N uptake and removal, and storage root yield and quality. Experiments were conducted at three sites (Braúna, São Manuel, and Regente Feijó) in São Paulo, Brazil, using a randomized block design with four replicates. Treatments included a control (without N application), conventional N fertilization (50 kg ha⁻¹), reference N fertilization (150 kg ha⁻¹), and NSI-based N fertilization (NSI: 90% or 95%, based on the chlorophyll meter readings). Plant response to N fertilization was low, with no N deficiency observed in the conventional and chlorophyll meter-managed treatments. NSI < 90% was better than NSI < 95% for N top-dressing management, reducing N application rates by 44–66%, depending on the site. In contrast, NSI < 95% increased the N application rate without any yield benefit. Thus, monitoring N fertilization using a portable chlorophyll meter with 90% NSI can reduce N fertilization rates without negatively impacting the sweet potato root yield. Full article

Camellia (Camellia japonica) is a semi-shaded plant that is highly vulnerable to heat stress. To investigate the mechanisms underlying heat stress in C. japonica, two C. japonica cultivars, “Xiaotaohong” and “Zhuapolian”, which exhibit significant differences in heat tolerance, were selected from four common cultivars. The selection methods included phenotypic observations and physiological index detection, including relative electric conductivity (REC), malondialdehyde (MDA) content, superoxide dismutase (SOD) enzyme activity, relative water content (RWC), and chlorophyll content. RNA-seq analysis yielded 980 million reads and identified 68,455 differentially expressed genes (DEGs) in the two C. japonica cultivars during heat stress compared to the control samples. Totals of 12,565 and 16,046 DEGs were differentially expressed at 16 h and 32 h, respectively, in “Xiaotaohong” during heat stress. In “Zhuapolian”, 40,280 and 37,539 DEGs were found at 16 h and 32 h, respectively. KEGG enrichment analysis revealed that both cultivars were enriched in the “plant hormone signal transduction” and “circadian rhythm” pathways at two stages, indicating the critical role these pathways play in the heat stress response. The differences in the tolerance between the two cultivars are likely linked to pathways such as “plant hormone signal transduction”, “photosynthesis”, and “circadian rhythm”. Some members of heat shock proteins (HSPs) are associated with the heat stress response. It is speculated that transcription factor families contributing to the tolerance differences include AP2/ERF, C3H, bHLH, bZIP, and MYB-related with a small number of heat shock factors (HSFs) also induced by the stress. In conclusion, these results reveal the changes in the physiological indices and molecular networks of two C. japonica cultivars under heat stress. This study lays the foundation for the breeding of superior heat-resistant C. japonica cultivars and for further molecular research. Full article

Given the global importance of sweet potatoes as a nutrient-rich staple food, this research aimed to find the optimal cultivation practices to improve both yield and carotenoid content, with a particular focus on enhancing β-carotene content. In this study, the effects of different cultivation methods and plant densities on the agronomic parameters, physiological characteristics and carotenoid content of the ‘Beauregard’ variety were investigated across two consecutive growing seasons. Besides storage root yield, the key physiological parameters, including SPAD and chlorophyll fluorescence (Fv/Fm), were monitored to assess plant health and photosynthetic performance. Carotenoid content, including trans-β-carotene, cis-β-carotene, and ζ-carotene, was quantified using high-performance liquid chromatography (HPLC). Results indicated that the ridge cultivation method, particularly when combined with twin-row planting, consistently produced the highest yields, reaching the maximum of 40.87 t ha⁻¹ in 2020. The flat cultivation method, especially in simple rows, showed the lowest yield. The analysis revealed that plant density had a more pronounced effect on yield and carotenoid content than the ridge or flat cultivation method alone. The maximum β-carotene content was achieved in the simple row (17,500 plants/ha) treatment planted on ridges with 247 µg/g. Significant correlations between both SPAD readings and Fv/Fm and yield were revealed, but no correlations with storage root carotenoid content were found. This suggests that, while these leaf physiological traits can be used to estimate the yield, they are not directly associated with the carotene content of the storage root. The study highlights the ridge cultivation and 35,000 plants/ha method as a stable and high-yielding option for ‘Beauregard’ in terms of improving and balancing the yield and carotenoid content; however, reducing the plant density resulted in elevated carotenoid content with significant yield reductions. The findings contribute to the understanding of how agronomic practices influence the nutritional and physiological traits of sweet potatoes, with implications for improving food security and nutritional outcomes in sweet potato cultivation. Full article

Proper crop management requires rapid detection methods for abiotic and biotic stresses to ensure plant health and yield. Hemp (Cannabis sativa L.) is an emerging economically and environmentally sustainable crop capable of yielding high biomass. Nitrogen deficiency significantly reduces hemp plant growth, affecting photosynthetic capacity and ultimately decreasing yield. When symptoms of nitrogen deficiency are visible to humans, there is often already lost yield. A real-time, non-destructive detection method, such as Raman spectroscopy, is therefore critical to identify nitrogen deficiency in living hemp plant tissue for fast, precise crop remediation. A two-part experiment was conducted to investigate portable Raman spectroscopy as a viable hemp nitrogen deficiency detection method and to compare the technique’s predictive ability against a handheld SPAD (chlorophyll index) meter. Raman spectra and SPAD readings were used to train separate nitrogen deficiency discrimination models. Raman scans displayed characteristic spectral markers indicative of nitrogen deficiency corresponding to vibrational modes of carotenoids, essential pigments for photosynthesis. The Raman-based model consistently predicted nitrogen deficiency in hemp prior to the onset of visible stress symptoms across both experiments, while SPAD only differentiated nitrogen deficiency in the second experiment when the stress was more pronounced. Our findings add to the repertoire of plant stresses that hand-held Raman spectroscopy can detect by demonstrating the ability to provide assessments of nitrogen deficiency. This method can be implemented at the point of cultivation, allowing for timely interventions and efficient resource use. Full article

Prochlorococcus, a cyanobacteria genus of the smallest and most abundant oceanic phototrophs, encompasses ecotype strains adapted to high-light (HL) and low-light (LL) niches. To elucidate the adaptive evolution of this genus, we analyzed 40 Prochlorococcus marinus ORFeomes, including two cornerstone strains, MED4 and NATL1A. Employing deep learning with robust statistical methods, we detected new protein family distributions in the strains and identified key genes differentiating the HL and LL strains. The HL strains harbor genes (ABC-2 transporters) related to stress resistance, such as DNA repair and RNA processing, while the LL strains exhibit unique chlorophyll adaptations (ion transport proteins, HEAT repeats). Additionally, we report the finding of variable, depth-dependent endogenous viral elements in the 40 strains. To generate biological resources to experimentally study the HL and LL adaptations, we constructed the ORFeomes of two representative strains, MED4 and NATL1A synthetically, covering 99% of the annotated protein-coding sequences of the two species, totaling 3976 cloned, sequence-verified open reading frames (ORFs). These comparative genomic analyses, paired with MED4 and NATL1A ORFeomes, will facilitate future genotype-to-phenotype mappings and the systems biology exploration of Prochlorococcus ecology. Full article

The aim of this study was to determine the nitrogen requirement of maize, the optimal timing and amount of nutrient application, based on long time series data. An additional objective was to examine the response of the relative chlorophyll content of maize to nitrogen fertilisation. The examinations were carried out in a long-term field experiment at the University of Debrecen between 2016 and 2022, using two maize hybrids with different genotypes. Spatial and temporal changes in the N status of maize leaves were monitored using the Soil and Plant Analysis Development (SPAD) instrument. In addition to the non-fertilised (A₀) treatment, six fertiliser treatments were applied (spring basal fertilisation: 60 and 120 kg N ha⁻¹, A₆₀; A₁₂₀). Basal fertilisation was followed by two occasions of top-dressing at phenological stages V6 and V12, at rates of +30–30 kg N ha⁻¹ (V6₉₀ and V6₁₅₀, and V12₁₂₀ and V12₁₈₀). The CMR (Chlorophyll Meter Reading), averaged over the examined years, genotypes and fertiliser treatments, were lowest in the V6 phenological phase (40.23 ± 5.57, p < 0.05) and highest in R1 (49.91 ± 8.41, p < 0.05). A₁₂₀ fertiliser treatment increased the relative chlorophyll content by 5.11 compared to the non-fertilised treatment, 1.67 more than A60 treatment. The basal fertilisation treatment substantially increased the yield (A₆₀: +30.75%; A₁₂₀: +66.68%) compared to the A₀ treatment averaged over years and genotypes. Based on the obtained research results, a basal treatment of 120 kg N ha⁻¹ is recommended and it can be concluded that, under appropriate water supply conditions (rainfall, irrigation), nitrogen top-dressing applied in V6 phenophase results in a significant yield increase compared to basal fertilisation. Full article