Research Frontiers: Trends in Crop & Environment

Protein Hydrolyzate-Based Biostimulants in Fruit Crops: Mechanisms, Agronomic Effects, and Practical Applications

Tue, 12 May 2026 00:00:00 +0000

This review summarizes current scientific knowledge on the use of protein hydrolyzate-based biostimulants in fruit production through evidence mapping, cross-species comparison, and evaluation of protocol-dependent responses within an agronomic framework, centered on foliar applications and their role in sustainable production systems. Research across a broad range of fruit species reports that protein hydrolyzates can significantly enhance yield, improve fruit quality, and mitigate the adverse effects of abiotic stresses such as drought and high temperatures. Treated plants often exhibit improved nutrient uptake, increased photosynthetic efficiency, and enhanced morphological traits, including better root development and vegetative growth. However, the effectiveness of these biostimulants varies depending on the fruit species, developmental stage, and application frequency, indicating the need for more tailored and crop-specific protocols. In conclusion, the literature confirms the functional role of protein hydrolyzates in enhancing resilience and productivity in fruit crops, while highlighting the need for further research to optimize their use under diverse agroecological conditions. Protocol harmonization and robust field validation will be essential for improving the reliability, interpretability, and practical relevance of future research on protein hydrolyzates in fruit production.

Mechanical Damage in Soybeans by Pneumatic Seeder

Wed, 26 Aug 2026 00:00:00 +0000

Research has advanced in the development of precision seed metering devices to ensure proper seed distribution at high speeds. However, little is known about the effect of increasing seeding speed, as well as seeding at different inclinations of the tractor-seeder unit, on the integrity and physiological quality of soybean seeds. This study aimed to identify the effect of travel speeds (5, 7, 9, 11, and 13 km h⁻¹) combined with three longitudinal inclinations of a pneumatic seed metering device (−11^◦, 0^◦, and 11^◦), simulating field conditions, on the distribution and integrity of soybean seeds. We used a 5 × 3 factorial design was used with an additional control treatment in which the seeds did not pass through the metering device. The variables evaluated included the percentage of spacing between individual seeds, germination, mechanical damage (tetrazolium test), and seedling emergence. The results demonstrated that increasing the speed did not prevent the spacing between individual seeds from falling below the minimum limit of 90% for pneumatic seed metering devices. The treatments did not affect germination compared to the control. Sowing on a slope caused the greatest mechanical damage to soybean seeds. All treatments significantly reduced plant emergence, except when the pneumatic metering device operated at an incline of 0^◦ at 9 km h⁻¹.

The Role of Leaf Morphology and Sustainable Management Practices on Optimizing Nitrogen Use Efficiency of Upland Rice: A Review

Faith S. Olanlokun, Oyeyemi A. Dada, Khayelihle Ncama — Mon, 24 Aug 2026 00:00:00 +0000

Nitrogen is an essential macronutrient for plant growth, photosynthesis, and grain yield. However, the nitrogen use efficiency (NUE) of crops remains relatively low, leading to nitrogen losses and environmental concerns. This is particularly important in upland rice because it is a high nitrogen user, but research of its NUE is limited. This literature review explored the contributions of leaf morphology, specifically leaf size and leaf angle, to nitrogen utilization efficiency in upland rice under varying rates of nitrogen fertilization. It also evaluated sustainable nitrogen management practices across diverse cropping systems. Findings reveal that nitrogen fertilization significantly influences leaf development, canopy structure, and nitrogen remobilization, all of which directly affect photosynthetic efficiency and yield. Breeding strategies focusing on moderate leaf size and erect leaf angles improve the nitrogen uptake and use by rice. In addition, sustainable farming practices, including precision nitrogen management, conservation agriculture, and intercropping with legumes, are effective in enhancing NUE and reducing nitrogen losses across various rice production systems. Future research should focus on identifying the thresholds of nitrogen rates that optimize leaf morphology across diverse upland rice genotypes and unravel the genetic and physiological mechanisms linking nitrogen application to leaf development.

Morphophysiological Responses of Lettuce to Irrigation Depths and Wastewater Sources with a Machine Learning Approach

Wed, 26 Aug 2026 00:00:00 +0000

The increasing pressure on water resources has stimulated the use of treated wastewater in agricultural irrigation, although its effects on plant development remain uncertain. This study evaluated the effects of wastewater treatments and irrigation depths on the morphophysiological development of lettuce (Lactuca sativa L.). A split-plot experiment was conducted with crop cycles in the main plots and a factorial arrangement in the subplots, consisting of five water sources and five irrigation depths (50% to 150% ETc), with three replications. Seven variables were evaluated, including growth traits and water productivity. Irrigation depth significantly affected all variables (p ≤ 0.01) and was the main driver of vegetative growth, increasing shoot fresh mass, stem diameter, and plant height. In contrast, water sources showed smaller effects. Water productivity decreased with increasing irrigation depth and showed weak correlations with other variables (r ≤ 0.468). Machine learning models achieved moderate accuracy for irrigation depth prediction (≈55%), with confusion among adjacent classes, indicating detection of a gradient rather than precise classification. Prediction of water sources was low (<30%), confirming limited morphological differentiation. Plant height and stem diameter were the most informative variables. These results indicate that irrigation management has a stronger influence on lettuce growth than water source.

Vermicompost-Based Substrates and a PGPR Consortium Improve the Nutraceutical Quality of Greenhouse Tomato (Solanum lycopersicum L.) in a Semi-Hydroponic System

Wed, 26 Aug 2026 00:00:00 +0000

Tomato (Solanum lycopersicum L.) is a globally important vegetable, prized for its nutritional value and antioxidant content. Given the increasing demand for foods withhealth-promoting properties and the need for sustainable production practices, this study evaluated the impact of different growth substrates combined with plant growth-promoting rhizobacteria (PGPR) inoculation on the yield and nutraceutical quality of greenhouse tomatoes grown in a semi-hydroponic system. ‘Nereida’ variety saladette tomato plants were either inoculated with a single PGPR consortium (1 × 10⁸ CFU mL⁻¹) or uninoculated. Three substrates were used: a chemical fertilization control and a sand-vermicompost mixture with two inherent levels of phosphorus (253 and 442 ppm). The chemically fertilized substrate without inoculation served as the control treatment. The results indicated that the chemically fertilized substrate presented a significantly higher yield per square meter (p < 0.05), reaching values of 5.20 ± 0.70 kg m⁻² and 4.83 ± 0.35 kg m⁻² in the control treatment. However, fruits grown in the vermicompost-based substrate with higher phosphorus content (442 ppm) and PGPR inoculation exhibited significantly greater antioxidant capacity (54.16 μmol TE g⁻¹ FW) and higher concentrations of vitamin C (14.03 mg·100 g⁻¹ FW), lycopene (47.68 mg·100 g⁻¹ FW), flavonoids, carotenoids, and glutathione. This represented an increase of 28–45% in bioactive compounds including lycopene, vitamin C, flavonoids, carotenoids, and glutathione compared to the chemical control. While the interaction between substrate and inoculation was significant only for soluble solids, both factors independently and additively contributed to the enhancement of nutraceutical parameters. These findings suggest that the use of vermicompost-based substrates, particularly those with higher phosphorus content, in combination with PGPR inoculation, is a promising strategy to enhance the accumulation of health-promoting bioactive compounds in tomato fruits, despite a trade-off in total yield.