A phenological stage-based nutrient scheduling approach was developed and validated for tomato cultivation under naturally ventilated polyhouse conditions. Nutrient uptake dynamics revealed a progressive decline in nitrogen and phosphorus concentrations from seedling to ripening, whereas potassium demand increased steadily toward fruiting, with the reproductive phase accounting for the majority of total nutrient requirements. Based on tissue nutrient removal and nutrient use efficiency, an estimated dose of fertilizers framework was derived and translated into stage-wise fertilization schedules using water-soluble fertilizers. Five fertilization levels (75-175% of the estimated dose of fertilizers) were evaluated. Among these, a 125% estimated fertilzer dose consistently resulted in superior plant growth, yield attributes, and fruit yield, while maintaining desirable fruit quality traits. Lower fertilization levels enhanced certain bioactive compounds but at the expense of yield. Overall, the study demonstrates that an estimated dose of fertilizers-based fertilization at 125% provides an effective balance between productivity and quality, offering a physiologically grounded and resource-efficient nutrient management strategy for protected tomato cultivation. These findings highlight a trade-off between yield and nutraceutical quality, suggesting that fertilization strategies should be tailored according to production objectives.
Melon cultivation in various regions of the world is conditioned by water limitations. This study was developed to evaluate the potential damage to the photosynthetic structures of the F1 Caribbean Gold RZ hybrid melon cultivar grown under conditions of saline stress. The experimental carried out in a greenhouse, in the city of Recife, Pernambuco. The experimental design consisted of randomized blocks in a 2 & times; 4 factorial scheme with four replications. The melon plants were subjected to nutrient solutions with electrical conductivity of 2.0 or 3.5 dS m-1 applied by daily irrigation levels to maintain 55, 70, 85 and 100% soil moisture. The parameters were evaluated: dynamics of the photosynthetic surface, content of photosynthetic pigments, and chlorophyll a fluorescence, subjected to analysis of variance, using the F-test, at a probability level of 0.05. It was found that in plants exposed to 70% soil moisture, the effect of using nutrient solutions with 2.0 or 3.5 dS m-1 produced similar photosynthetic results. The proportionality adopted between the depth irrigation and nutrient apport led to characteristics of nutritional deficiency, observed as one of the causes of the reduction of photosynthetic surface and photosynthetic pigments in plants exposed to humidity levels below 70%.
This study assessed the efficacy of calcium polysulfide suspension concentrate (SC) against cucumber powdery mildew (Golovinomyces cichoracearum) under glasshouse conditions in Varamin and Pishva, Tehran Province. A randomized complete block design included eight treatments - calcium polysulfide at 1-5 ml/L, reference fungicides tetraconazole (Domark (R) .4 ml/L) and trifloxystrobin (Flint (R) .2 g/L), and an untreated control - with four replications per treatment. Foliar sprays began at first symptom appearance and continued at 5-10-day intervals. Disease severity was rated using the Horsfall-Barratt scale, Disease Severity (DS), and Area Under the Disease Progress Curve (AUDPC). ANOVA and Duncan's test (p = .01) revealed significant treatment differences at both sites. In Varamin, 3-5 ml/L calcium polysulfide reduced AUDPC by 70-87.5%, matching reference fungicides. In Pishva, reductions ranged from 74-84.5% at these rates. Concentrations of 3-4 ml/L provided reliable control comparable to standards, positioning calcium polysulfide as a low-risk alternative for rotations every 7-14 days.
Cadmium contamination of agricultural soils limits leafy vegetable production and threatens food safety. We investigated cadmium accumulation and mitigation strategies in luhao (Artemisia selengensis), a widely consumed leafy vegetable in the Yangtze River Delta, China. Analysis of 185 paired soil and plant samples from vegetable-dominated farmland in suburban Nanjing revealed mean cadmium concentrations of 0.28 mg kg(-1) in soils and 66.1 mu g kg(-1) in edible tissues. Using crop-category-specific limits in GB2762-2022, 3.8% of crop samples exceeded the applicable Cd limit; for leafy vegetables, including luhao, the limit is 0.2 mg kg(-1). Field experiments evaluated soil amendments combining lime, sulfide, and organic wastes. In acidic soils, these treatments reduced extractable cadmium by 22.1 to 25.0% and decreased cadmium in luhao shoots by 31.6 to 33.2%. Soil acidity and total soil cadmium were the primary drivers of uptake. Green and Kunming luhao accumulated less cadmium than red luhao in acidic soils, whereas differences diminished in neutral soils. Largescale field validation across 200 hectares showed that lime and organic fertilizer reduced cadmium in luhao by 50.5% and increased yield by 51.5%. Integrating soil amendments with low-cadmium cultivars is an effective strategy for safe luhao production.
High temperatures are considered the most important limiting factor for the productivity of beans, and the ongoing increase in global temperature is estimated to have a strong negative impact on its yield. With the aim of mitigating the effects of high temperatures that usually prevail during growing seasons, the efficacy of two novel biostimulants (not yet commercially available) based on amino acids supplemented with sulfur or silicon was tested in two consecutive growing seasons (early and late). During the early season (May 7-June 30), conditions of intense heat stress prevailed, and in combination with the cultivation of a relatively sensitive genotype, the marketable yield was reduced by 51%, compared to the yield in the late season (7,323 kg ha(-1)). The exogenous application of amino acid-based biostimulants supplemented with sulfur or silicon did not significantly mitigate yield reduction (7,143-7,693 kg ha(-1)). On the other hand, during the late season (August 5-October 19), conditions of milder heat stress prevailed, and in combination with the cultivation of a relatively resistant genotype, the marketable yield was high (14,915 kg ha(-1)). The exogenous application of amino acid-based biostimulants supplemented with sulfur or silicon did not significantly affect chlorophyll fluorescence parameters or yield (13,908-15,833 kg ha(-1)).
Heavy metal contamination of soils poses a significant risk to food safety by accumulating toxic metals in edible crops, such as leafy vegetables. This study tested whether melatonin seed priming reduces chromium accumulation while maintaining plant performance in Spinacia oleracea cultivar Arka Anupama under controlled and polyhouse conditions. Melatonin priming improved seedling growth under chromium stress, with 50-micromolar melatonin treated plants showing better performance. Under polyhouse conditions, 50 micromolar melatonin increased leaf number to 5.25 +/- 0.55 compared with 3.75 +/- 0.29 in chromium-stressed plants (40% increase), and improved leaf area to 3.70 +/- 0.35 cm(2) in 100 micromolar melatonin-treated plants compared with 2.27 +/- 0.03 cm(2) in chromium-stressed plants (63% increase). The chlorophyll normalized difference vegetation index increased from 0.15 +/- 0.04 in chromium-stressed plants to 0.26 +/- 0.01 in 50 micromolar melatonin-primed plants, representing approximately 78% improvement (significant p < .05). Atomic absorption spectroscopy analysis showed a 42.9% reduction in leaf chromium content following 50-micromolar treatment. Spectral analysis revealed stress-associated variations, including a 512-515 cm(-1) band under chromium stress. These findings indicate that melatonin priming improves plant growth and reduces chromium accumulation in spinach, with 50 micromolar showing the most consistent response.
Bank savings are closely linked to access to credit, farm investment, and agricultural productivity, yet many smallholder farmers in Ghana do not use formal banking services due to low incomes and long distances to financial institutions. Empirical evidence on the role of bank savings in tomato farming remains limited. Using cross-sectional data from 311 tomato farmers, we examine the relationships among farm productivity, credit access, and bank savings. We apply three-stage least squares, propensity score matching, inverse probability weighting, and augmented inverse probability weighting for robust analysis. The results show that productivity, bank savings, and borrowing capacity among tomato farmers are generally low. These outcomes are influenced by factors such as land ownership, labor sources, distance to district capitals, farm and non-farm diversification, leadership roles, nativity, and farm size. Access to credit significantly improves productivity, while bank savings enhance both access to credit and the amount received. These findings highlight the importance of promoting formal savings and the effective use of credit through targeted training and support from governments, financial institutions, and private organizations.
Studies linking credit and tomato commercialization in Ghana are rare. Thus, the exact effects of credit on tomato commercialization remain unexplored. We used primary data from 311 Ghanaian tomato farmers to investigate credit accessibility and its relationship with commercialization. Cragg hurdle and three-stage least-squares models were used. About one-third of tomato farmers accessed credit, with a mean loan amount of US$93, implying low credit access. Credit is disbursed in cash from formal and informal sources. The proportion of tomatoes sold is significantly high, averaging over 90%. This infers a strong market-oriented tomato production system. The key drivers of credit accessibility and commercialization are extension visits, group membership, land ownership, and farm size. Our three-stage least-squares estimates suggest a positive and statistically significant association between credit and commercialization. Hence, the quantity of tomatoes sold boosts access to credit, while credit also boosts the quantity of tomatoes sold. Tomato producers should collectively secure credit in groups, and lenders should target farmer groups to extend credit to farmers, thereby reducing default rates.
The availability of zinc is critical for promoting tomato growth and achieving superior fruit quality under deficient conditions. This study evaluated 12 zinc fertilization treatments across two growing seasons 2022-23 and 2023-24 to determine the most effective strategies for improving tomato performance in the field. The combined application of ZnSO4.7 H2O via seed priming, soil, and foliar spray consistently enhanced vegetative growth with plant height of 112.86 cm and canopy width (49.15 cm2), while accelerating flowering by 13.5 days as compared to the control. T10 increased total and marketable yield by 11.6% and 25.6%, respectively. It is important to note that foliar application alone (T4) was as beneficial as a combined application in terms of benefit-cost ratio, demonstrating its practical efficiency. Zinc treatments also improved fruit quality, increasing ascorbic acid content to 31.90 mg 100 g-1, TSS to 6.09 degrees Brix, and titratable acidity to 0.96%. Multivariate analysis rebealed that fruit weight, size, and number were important determinants of yield, whereas excessive vegetative growth negatively impacted productivity. These findings provide economically viable suggestions for zinc fertilization for sustainable tomato production and quality improvement.
Optimizing supplemental Light-Emitting Diode lighting in tropical greenhouse production requires understanding on how photoperiod duration and timing affect crop growth and quality. Two greenhouse experiments investigated Light-Emitting Diode supplementation duration (0, 2, 4, and 6 hours per night) and timing schedules (18:00-22:00, 22:00-02:00, and 02:00-06:00 at fixed 4-hour duration) on lettuce (Lactuca sativa L.) over 42 days using white Light-Emitting Diode modules (4,500K, 85 mu mol m-2 s-1). Four-hour supplementation maximized total fresh weight (175.3% increase), biomass across all plant organs, and nutritional quality (67.8% and 75.0% increases in protein and vitamin C), while 6-hour duration yielded no further improvement. Timing-based management produced contrasting organ-specific responses, pre-dawn supplementation favored vertical growth while evening supplementation enhanced leaf proliferation and root biomass accumulation, with midnight supplementation achieving the highest root biomass partitioning (19.13% vs. 14.61% in control). All timing treatments reduced leaf width by 6.3-6.9% despite improving other parameters, confirming trait-specific growth responses. Treatment effects emerged from 28 days after sowing, indicating growth-stage-dependent light sensitivity. These findings establish that integrating duration and timing provides a practical framework for optimizing yield and quality in greenhouse lettuce production.
Optimizing the timing of supplemental lighting is a key strategy for improving crop performance in controlled-environment hydroponics. This study evaluated the effects of light-emitting diode lighting timing on mustard greens grown in a recirculating hydroponic system. Four treatments were compared: a control (no supplemental light) and three 4-hour lighting periods (18:00-22:00, 22:00-02:00, and 02:00-06:00). The 02:00-06:00 treatment significantly increased soil plant analysis development values, leaf number, plant height, and leaf width, resulting in 44% higher fresh weight (79.78 g) and 52% higher dry biomass (1.25 g) than the control, with the highest leaf-to-total ratio (90.88%) and lowest stem ratio (4.60%). Multiple regression showed that leaf number and width were strong positive predictors of productivity, while height was negatively correlated. Principal component analysis identified the 02:00-06:00 treatment as optimal based on the first principal component score (2.69), whereas the 22:00-02:00 treatment showed the strongest etiolation based on the second principal component score (-1.58); the first two principal components together explained 72.68% of the total variance. These results demonstrate that late-night or early-morning lighting best supports leaf development and yield. Future research should combine lighting-time optimization with spectral and energy-efficiency analyses to refine smart-lighting strategies for commercial hydroponics.
