Search

Tomatoes are delicate and prone to damage quickly, which ultimately leads to lower quality and increased post-harvest losses. Hence, an ideal storage environment is very important to maintain the quality of tomato fruits after harvest. Therefore, this study was conducted to determine the effect of storage conditions on the quality parameters of tomato fruits. Experiments were de-signed for six storage periods (4, 8, 12, 16, 20, and 24 days) and two temperatures (12 °C and room air temperature "22 °C"). Three tomato fruit quality parameters (Brix, color, and firmness) have been selected and measured for three tomato varieties (Ghandowra-F1, Forester-F1, and Feisty-Red) grown hydroponically at three salinity levels (2.5, 6.0, and 9.5 dS m−1) of the nutrient solution. Results showed that the highest mean Brix values, for all varieties, were recorded at the highest salinity (9.5 dS m−1), and were significantly (Pr < 0.0001) higher than those at medium (6.0 dS m−1) and low (2.5 dS m−1) salinity levels. In addition, the highest fruit firmness was recorded at high salinity level (9.5 dS m−1), but there was no significant difference to that recorded at medium salinity (6.0 dS m−1). Regarding tomato fruit color, the highest average values were recorded for the Ghandowra-F1 (2.51) and Forester-F1 (2.69) varieties at medium salinity (6.0 dS m−1), while the highest average color value for the Feisty-Red variety (1.54) was obtained at high salinity (9.5 dS m−1). On the other hand, the Brix, color, and firmness of tomato fruits were significantly affected by the storage temperature. Moreover, the mean Brix values (7.66%) were slightly higher at 12 °C storage temperature compared to those at 22 °C (7.38%). In general, the fruit color values gradually increased with the storage period, especially under 22 °C storage temperature, with peak color values of 2.73, 2.70, and 1.66 recorded on the 12th day of the storage period for Ghandowra-F1, Forester-F1, and Feisty-Red, respectively. Tomato fruit firmness decreased faster with the storage period at 22 °C compared to the storage temperature of 12 °C. However, the highest average values of fruit firmness for Ghandowra-F1 (9.37 N cm−1) and Forester-F1 (9.41 N cm−1) recorded at control condition were not significantly different those recorded on the 8th day of storage at 12 °C storage temperature. By contrast, the highest average value of fruit firmness for Feisty-Red (8.85 N cm−1) recorded at control condition was not significant than that recorded on the 4th day of the storage period at 12 °C storage temperature (8.82 N cm−1). Overall, tomato fruits can be stored at 12 °C temperature for up to 20–24 days, without negative effects on fruit quality. [ABSTRACT FROM AUTHOR]

To overcome the scarcity of fresh water, researchers have turned to investigating different techniques that enable using saline water to irrigate crops, aiming to increase the efficiency of using available water resources. A glasshouse experiment was conducted to investigate the yield responses of grafted and non-grafted (self-rooted) tomato plants grown hydroponically under three levels of water salinity (2.5, 6.0, and 9.5 dS m−1). Three tomato varieties (Ghandowra-F1, Forester-F1, and Feisty-Red) were grafted onto five rootstocks (Maxifort, Unifort, Dynafort, Vivifort, and Beaufort). The implemented treatments were studied in terms of tomato fruit yield and quality parameters. Although increasing the concentration of salts in the nutrient solution led to a decrease in fruit yield, the moderate salinity level (S-2: 6.0 dS m−1) showed its superiority over both low salinity (S-1: 2.5 dS m−1) and high salinity (S-3: 9.5 dS m−1) in terms of tomato yield parameters. The studied rootstocks did not significantly improve the tomato fruit yield, but the interaction between the grafting combinations and salinity was significant for both production and quality. More specifically, tomato plants grafted onto the rootstocks "Vivifort and Beaufort" rendered the highest yield at a low salinity level (S-1: 2.5 dS m−1) and a moderate salinity level (S-2: 6.0 dS m−1), respectively, while at high salinity (S-3: 9.5 dS m−1), grafting did not improve tomato productivity, irrespective of the rootstock. These results confirm that tomatoes can be successfully grown under hydroponic systems using salinity levels of up to 6.0 dS m−1 without sacrificing fruit yield and quality. Among the studied tomato varieties, Feisty-Red was found to be appropriate for hydroponic production. The results also demonstrated that Vivifort and Beaufort rootstocks are suitable for grafting hydroponic tomatoes under low and moderate salinity levels, respectively. [ABSTRACT FROM AUTHOR]

From economic and nutritional points of view, tomato is, historically, considered one of the most important crops. Without significant yield reduction, most commercial cultivars of tomato crops are sensitive to moderate levels of salinity. However, high levels of salt stress can negatively affect the yield and quality of tomato fruits. Therefore, this study was conducted to evaluate the yield and fruit quality of three tomato cultivars (Forester, Ghandowra-F1, and Feisty-Red) cultivated hydroponically, under three different levels of nutrient solution salinity. Evaluation of tomato fruits was performed based on quantity (number and weight of fruits, and total fruit yield), physical quality (color and firmness), and chemical quality (refractometric index "Brix", pH, EC, K+, Na+, and NO3-). Experiments were conducted using three salinity levels of the nutrient solution with electrical conductivity values (dSm-1) of 2.5 (control), 6.0, and 9.5. Results showed that the studied tomato cultivars were significantly influenced by high salinity (9.5 dSm-1) in comparison to the low (2.5 dSm-1) and medium (6.0 dSm-1) levels of salinity. On average, the highest fruit weight per plant of 1944.84 g and total fruit yield of 4.42 kgm-2 were observed at the low salinity level; however, no significant differences were obtained in the two yield factors (single fruit weight and total fruit yield) for the low and medium salinity levels. On the other hand, a significant reduction in tomato yield (31%) was associated with the high salinity level compared to the yield at low and medium salinity levels. Results of physical quality parameters showed highly significant differences among all salinity levels. On average, the maximum value of color change (1.72) was associated with the medium salinity level, and the maximum value of firmness (9.61 Ncm-1) was recorded at the high salinity level. Salinity levels and tomato cultivars introduced significant differences in chemical quality parameters; however, no significant differences in these parameters were attributed to the low and medium salinity levels. The maximum value of pH was recorded for the combination of medium salinity and Forester cultivar. Moreover, the maximum values of Brix, EC, K+, Na+, and NO3- were recorded for the Ghandowra-F1 cultivar at the high salinity level. Unlike the Feisty-Red, the performance of the Forester and Ghandowra-F1 cultivars was found to be acceptable at the tested medium salinity level (6.0 dSm-1). [ABSTRACT FROM AUTHOR]

Remotely sensed images provide effective sources for monitoring crop growth and the early prediction of crop productivity. To monitor carrot crop growth and yield estimation, three 27 ha center-pivot irrigated fields were studied to develop yield prediction models using crop biophysical parameters and vegetation indices (VIs) extracted from Sentinel-2A (S2) multi-temporal satellite data. A machine learning (ML)-based image classification technique, the random forest (RF) algorithm, was used for carrot crop monitoring and yield analysis. The VIs (NDVI, RDVI, GNDVI, SIPI, and GLI), extracted from S2 satellite data for the crop ages of 30, 45, 60, 75, 90, 105, and 120 days after plantation (DAP), and the chlorophyll content, SPAD (Soil Plant Analysis Development) meter readings, were incorporated as predictors for the RF algorithm. The RMSE of the five RF scenarios studied ranged from 7.8 t ha−1 (R2 ≥ 0.82 with Scenario 5) to 26.2 t ha−1 (R2 ≤ 0.46 with Scenario 1). The optimal window for monitoring the carrot crop for yield prediction with the use of S2 images could be achieved between the 60 DAP and 75 DAP with an RMSE of 8.6 t ha−1 (i.e., 12.4%) and 11.4 t ha−1 (16.2%), respectively. The developed RF algorithm can be utilized in carrot crop yield monitoring and decision-making processes for the self-sustainability of carrot production. [ABSTRACT FROM AUTHOR]

Tomato (Solanum lycopersicum L.) is an important vegetable crop that grows easily under controlled conditions, such as in greenhouses and hydroponics. To overcome freshwater scarcity, researchers are searching for alternatives to groundwater sources such as desalinated water (saline water) for irrigation. High salinity in irrigation water alters physiological functions and crop development, thereby reducing the yield. Best management practices and the use of grafted tomato plants on salt-tolerant rootstocks can alleviate salinity stress. The present study was conducted to address the impact of salinity stress on leaf transpiration (Tr), stomatal conductance (gs), photosynthesis (Pn), leaf chlorophyll content, proline content, and yield of hydroponically cultivated tomato plants. Saline (NaCl) water was used for the preparation of nutrient solution with three salinity levels, electrical conductivity (EC, dS m−1) of 2.5 (control), 6.0, and 9.5. Three commercial tomato cultivars (Valouro-RZ, Ghandora-F1, and Feisty-Red) were used. Both self-rooted plants and plants grafted onto Maxifort rootstocks were transplanted onto a perlite substrate. The recorded data revealed that all studied cultivars were critically affected by higher salinity (≈ 9.5 dS m-1) compared to low (≈ 2.5 dS m-1) and medium (≈ 6.0 dS m-1) salinity levels. The Variations in Tr, Pn, gs, chlorophyll content of leaf, and yield between medium and high salinity trials were reported at 3%, 5%, 9%, 5%, and 7.1%, respectively, whereas no significant differences were observed between low and medium salinities. However, at medium salinity levels, grafted plants performed better in photosynthesis than non-grafted plants. This is due to the accumulation of leaf proline, which maintains osmotic regulation and photosynthetic activity by preventing cell damage at medium salinities. Hence, this study confirmed the use of saline water for growing tomatoes under hydroponic conditions up to an EC of 6.0 dS m-1 including the EC of nutrient fertilizers. [ABSTRACT FROM AUTHOR]

Understanding the spatial pattern of soil chemical properties along with the topologic indicators is essential for site-specific agriculture management. A study was conducted on a 50 ha field to investigate the effect of selected topographic indicators, including elevation (DEM), slope (SL), flow accumulation (FA) and Topographic Wetness Index (TWI) on forage crop production. The soil samples and yield data were obtained from the field inventory. Topographical parameters of elevation and slope were estimated with the use of a real-time kinematic global positioning system (RTK-GPS), and then the DEM was generated. The collected soil samples were analyzed for pH, EC, nitrogen and soil organic carbon. Sentinel-2 images were for the creation of yield maps of alfalfa and Rhodes grass. Subsequently, on the basis of DEM, the generated elevation, slope and FA model were then compared with the yield and soil chemical properties. Statistical analysis revealed that the SL, FA and TWI, which are associated with water distribution, were significantly related to crop yields. The FA showed a medium-to-non-significant correlation with the productivity of both alfalfa (R2 = 0.586; p = 0.015) and Rhodes grass (R2 = 0.578; p = 0.01). A significant inverse correlation was recorded between the SL and the yield of both crops (R2 = −0.591 to −0.617; p = 0.01). The yield map revealed that the majority of the area (37.56%) of the experimental field was occupied by the medium-yield class, followed by the high-yield class (33.03%). [ABSTRACT FROM AUTHOR]

A study on a 30 hm² field was conducted to assess the variability in soil compaction and to investigate its effect on the engineering properties of potato tubers in terms of tuber shape and key dimensions (length, width and thickness) and resistance to penetration, rupture and shear forces. Three soil compaction levels were spatially correlated with the engineering properties of potato tubers through linear regression and ANOVA test. The three compaction levels included a low level (C1) ranging between 1.2-1.9 MPa, a medium level (C2) with compaction levels between 2.0-2.3 MPa and a high level (C3) ranging between 2.4-2.9 MPa. Results revealed that there were no significant changes in the key tuber dimensions corresponding to the variability in soil compaction. However, inverse linear relationships were observed between soil compaction and the key tuber dimensions with R² values of 77%, 97% and 96% for length, width and thickness, respectively. Similarly, the soil compaction was shown to have no effect on the tuber resistance to compression and shear force. In contrast, the tuber resistance to penetration was significantly affected by soil compaction (p>F = 0.0012). [ABSTRACT FROM AUTHOR]

Precision agriculture techniques were employed to study the impact of the spatiotemporal variations of soil compaction on the performance of potato crop during its various growth stages. The study has been conducted on a 30 ha centre pivot irrigated potato field, located in Wadi Al‐Dawasir area in Saudi Arabia. In situ soil compaction measurements were collected, in conjunction with Sentinel‐2A satellite data, and correlated spatiotemporally against potato crop growth and yield parameters. The univariate and bivariate Moran's function (Moran's I), the linear regression and the analysis of variance (ANOVA) techniques were used to analyse the data and examine the interrelationships. The spatial correlations between the measured variables revealed high clustering, producing Moran's I of 0.87, 0.79 and 0.57 for soil compaction, yield and normalized difference vegetation index (NDVI), respectively. Compaction‐yield relationship revealed a relatively high significant negative spatial correlation (Moran's I = 0.68). While, the spatial correlation between the average values of compaction and NDVI has negatively produced a Moran's I value of 0.45 (at 0.001 significance level), when 999 permutations were tested for all relationships. A significant positive correlation was observed between high compaction and high proportion of small size tubers, with R2 and P > F values of 0.65 and.0001, respectively. In contrast, a significant negative correlation has been obtained between high compaction and high proportion of large size tubers, with R2 and P > F values of 0.57 and.0001, respectively. Understanding the causes of disparity in the productivity of agricultural fields will help decision‐makers and farmers to take proactive actions towards better agricultural practices. [ABSTRACT FROM AUTHOR]

The soil organic carbon (SOC) plays a vital role in plant growth and development and therefore, is considered as one of the most important indicators of soil quality. This study was carried out in the central region of Saudi Arabia to explore the potential of spectroscopy in determining the SOC concentration in low-fertility soils. Spectral reflectance data was collected, under the controlled laboratory conditions on 39 air-dried 2.0 mm sieved soil samples, using a handheld spectroradiometer of a wavelength range between 350 nm and 2500 nm in the direct contact probe mode. The concentration of the SOC was determined using the Walkley and Black (W&B) and the UV-VIS spectrophotometric methods. The increase in the concentration of SOC was associated with a decrease in the corresponding spectral reflectance. Regression analysis showed linear relationships with high significant correlation between the spectral reflectance and the SOC measured by both the UV-VIS (Model-1: R²=0.46, p=0.00015 and RMSE=6.6 g/kg) and the W&B (Model-2: R²=0.48, p=8.92E-05 and RMSE=2.8 g/kg) methods. For these models, two wavebands with wavelengths of 2167 nm (Model-1) and 1359 nm (Model-2) were identified as the most sensitive bands to the SOC concentration. The cross-validation confirmed the validity of Model-1 with R², p and RMSE values of 0.50, 0.0099 and 6.6 g/kg, respectively. The validation results of the Model-2 showed values of R², p and RMSE of 0.72, 0.00023 and 4.0 g/kg, respectively. Results of this study revealed the possibility and the potential of using the spectral reflectance technique in predicting the concentration of SOC. [ABSTRACT FROM AUTHOR]