DSpace Collection:

Soil Compaction in Montado Mediterranean Ecosystem: Dolomitic Limestone Application, Sheep Grazing Management and Tree Effects

Tue, 31 Mar 2026 23:00:00 GMT

Title: Soil Compaction in Montado Mediterranean Ecosystem: Dolomitic Limestone Application, Sheep Grazing Management and Tree Effects Authors: Serrano, João; Shahidian, Shakib; Carreira, Emanuel; Moral, F.; Paniagua, L.; Charneca, R.; Pereira, A. Editors: Rusu, Teodor Abstract: Extensive animal production systems based on dryland pastures in Mediterranean regions have low profit margins. Improvements in soil fertility or grazing management and stocking rates are recognized strategies for reversing this situation and to ensure long term agricultural sustainability. This article aims to assess whether this strategy of possible intensification of sheep production has a significant impact on soil compaction, which is a manifestation of soil functionality degradation resulting from trampling. An experimental design with four treatments was implemented (with and without dolomitic limestone application; continuous grazing with low stocking rates, CG-LSR, and deferred grazing with high stocking rates, DG-HSR). The study involved cone index (CI, in kPa) measurements (48 sampling areas, 12 in each treatment) on eight dates during two annual pasture/grazing cycles (2023/2024 and 2024/2025). Other soil parameters, the presence of trees and grazing preferences were also monitored and correlated with CI. The main results showed: (i) significantly higher soil compaction under CG-LSR than under DG-HSR; (ii) a negative and significant effect of soil moisture content (SMC) on CI (r = −0.381; p < 0.05); (iii) a significant CI increase in preferential grazing areas, but only in the topsoil layer (0–10 cm) and with a very weak correlation coefficient (r = 0.172; p < 0.05); and (iv) no significant differences in CI under and outside tree canopy areas (UTC and OTC, respectively) for the depth range of 0–30 cm. These results are good indicators of the desired and sustainable intensification of extensive livestock grazing systems.

Diagnosing Early Establishment of Hybrid Sorghum in Response to Seeding Rates Using UAV-Based Remote Sensing and Soil ECa Analysis

Sun, 01 Mar 2026 00:00:00 GMT

Title: Diagnosing Early Establishment of Hybrid Sorghum in Response to Seeding Rates Using UAV-Based Remote Sensing and Soil ECa Analysis Authors: Póvoa, G.; Silva, L.; Dias, S.; D'Antonio, P.; Lidon, F.; Serrano, J.; Conceição, L.A. Editors: Escobar Gutiérrez, Abraham J. Abstract: Sorghum is a resilient crop important for sustainable intensification in semi-arid regions, yet the impact of variable seeding rates on its early development remains under-researched. This research investigated the early establishment of hybrid sorghum under three seeding strategies, "Uniformise" (medium density across all zones), "Optimise" (increased density in low-soil apparent Electrical Conductivity (ECa)), and "Maximise" (increased density in high-soil ECa), at the Herdade da Comenda (Innovation Center - Elvas, Portugal). Crop performance was monitored over 33 days, the established window for safe direct grazing, using Unmanned Aerial Vehicle (UAV) multispectral imagery to derive the Normalised Difference Vegetation Index (NDVI) and Canopy Cover (Cveg), alongside physical sampling of plant height and biomass. Statistical analysis revealed that both the seeding strategy and soil variability significantly affected early growth. The "Uniformise" strategy recorded the highest plant height, NDVI, and Cveg values, whereas the "Optimise" strategy performed the poorest. Additionally, an accumulation of 407.5 Growing Degree-Days (GDDs; ºC) accelerated the phenological cycle by five days relative to the climatological normal. Despite differences in vegetative vigour, no statistically significant variations were observed in final biomass across the strategies. These results indicate that while the "Uniformise" approach provided a more balanced environment for early establishment under these specific Mediterranean conditions, the lack of biomass differentiation highlights the potential for resource optimisation. The study demonstrates that UAV-based remote sensing is a useful diagnostic tool to identify these spatial limitations, providing the data to refine variable-rate seeding (VRS) algorithms and improve the economic efficiency of precision sowing.

Impact of a High-PAR-Transmittance Plastic Cover on Photosynthetic Activity and Production of Cucumber (Cucumis sativus L.) Crops in aMediterranean Solar Greenhouse

Thu, 01 Jan 2026 00:00:00 GMT

Title: Impact of a High-PAR-Transmittance Plastic Cover on Photosynthetic Activity and Production of Cucumber (Cucumis sativus L.) Crops in aMediterranean Solar Greenhouse Authors: Moreno-Teruel, M.A.; Molina-Aiz, F.D.; López-Martínez, A.; Valera-Martínez, D.L.; Peña-Fernández, A.; Baptista, F.J. Abstract: The optical properties of greenhouse cover materials play a critical role in controlling the internal light environment, directly affecting photosynthetic performance and crop productivity. This study evaluates the impact of a high photosynthetically active radiation (PAR) transmittance and high-light-diffusivity polyethylene film on the microclimate, photosynthetic activity, yield, and disease incidence of cucumber (Cucumis sativus L.) crops grown in a Mediterranean passive solar greenhouse. Trials were conducted over two consecutive autumn–winter seasons using a multi-span greenhouse divided into two sectors: one covered with an experimental high-transmittance film and the other with a standard commercial plastic. The experimental cover increased PAR transmission by 8.7% and 11.6% at canopy level in the first and second seasons, respectively, leading to improvements in leaf-level net photosynthesis of 9.3% and 17.9%. These effects contributed to yield increases of 5.0% and 17.3% in the respective seasons. The internal air temperature rose by up to 1.3 ◦C without exceeding critical thresholds, and no significant differences were observed in plant morphology or fruit quality between treatments. Additionally, the experimental film reduced the incidence of major fungal diseases, particularly under higher disease pressure conditions. The use of high-PAR-transmittance films enhances radiation use efficiency and crop performance in resource-limited environments without increasing energy inputs. This approach offers a sustainable, low-cost strategy to improve yield and disease resilience in protected cropping systems under passive climate control.

Influence of the Use of Double Roof with Increased Ventilation on the Development of Fungal Diseases in a Mediterranean Greenhouse

Thu, 01 Jan 2026 00:00:00 GMT

Title: Influence of the Use of Double Roof with Increased Ventilation on the Development of Fungal Diseases in a Mediterranean Greenhouse Authors: Moreno-Teruel, M.A.; López-Martínez, A.; Ávalos-Sánchez, E.; Molina-Aiz, F.D.; Valera-Martínez, D.L.; Proost, K.; Peilleron, F.; Baptista, F.J. Abstract: Mediterranean greenhouses commonly rely on passive climate control techniques to re-duce dependence on energy-intensive systems. This study was conducted in Almería (Spain) in a multi-span greenhouse divided into two sectors: a West sector equipped with a double-roof system using a pink sunlight spectrum photoconverter film combined with an increased natural ventilation surface, and an East control sector with standard ventila-tion and a calcium carbonate-whitened roof. The effects of this integrated passive climate management configuration on the development of naturally occurring fungal diseases were evaluated in tomato (Solanum lycopersicum L.), pepper (Capsicum annuum L.), and cucumber (Cucumis sativus L.). Powdery mildew (Leveillula taurica) and early blight (Alter-naria linariae) were observed in tomato; powdery mildew in pepper; and downy mildew (Pseudoperonospora cubensis), powdery mildew (Podosphaera xanthii), and gummy stem blight (Stagonosporopsis spp.) in cucumber. Across crop cycles, the sector combining dou-ble roofing and enhanced ventilation consistently exhibited lower disease severity for powdery mildew, downy mildew, and gummy stem blight compared with the control sector. In contrast, early blight did not show a clear or consistent response to the green-house configuration. Overall, the results indicate that the combined use of a double-roof system with a sunlight spectrum photoconverter film and increased natural ventilation can contribute to improved microclimate regulation and reduced fungal disease pressure under Mediterranean greenhouse conditions. This integrated passive approach may therefore represent a useful complementary component of sustainable disease manage-ment strategies in protected horticulture.