Gas exchanges and photosynthetic pigments of ‘Tommy Atkins’ mango as a function of fenpropimorph

ABSTRACT The objective of the present study was to evaluate the influence of the application of fenpropimorph and paclobutrazol on gas exchanges and photosynthetic pigments of ‘Tommy Atkins’ mango grown in the semi-arid region in different evaluation periods. Two experiments were carried out in ‘Tommy Atkins’ mango orchards in the first production cycle between September and December 2018 (first experiment) and between September and December 2019 (second experiment) in Petrolina, PE, Brazil. The experimental design adopted was randomized blocks in split plots in time, 4 × 4 + 1, with four replicates. The plots corresponded to the concentrations of fenpropimorph: 0, 0.7, 1.0, and 1.3 g per linear meter of plant canopy diameter plus the additional paclobutrazol treatment (1 g per linear meter of plant canopy diameter), and the subplots corresponded to the evaluation dates (0, 30, 60, and 90 days after the first application of treatments). The following traits were evaluated: CO2 assimilation rate, stomatal conductance, internal CO2 concentration, transpiration, water use efficiency, chlorophyll a, chlorophyll b, total chlorophyll, and carotenoids. The fenpropimorph dose of 1.3 g per linear meter of plant canopy promotes a higher rate of CO2 assimilation; however, paclobutrazol was more effective in the accumulation of chlorophyll a and total chlorophyll, and the use of fenpropimorph did not interfere in the concentration of photosynthetic pigments.

Plant canopy may promote seed dispersal by wind

Seed dispersal has received much research attention. The plant canopy can intercept diaspores, but the effect of the plant canopy (the aboveground portion of a plant consisting of branches and leaves) on dispersal distance has not been explored empirically. To determine the effect of plant canopy on seed dispersal distance, a comparison of diaspores falling through open air and through plant canopy was made in a wind tunnel using three wind speeds and diaspores with various traits. Compared with diaspores falling through open air, the dispersal distance of diaspores falling through plant canopy was decreased or increased, depending on wind speed and diaspore traits. When falling through a plant canopy, dispersal distance of diaspores with thorns or those without appendages was promoted at low wind speed (2 m s−1), while that of diaspores with low wing loading (0.5 mg mm−2) and terminal velocity (2.5 m s−1) was promoted by relatively high (6 m s−1) wind speed. A plant canopy could increase seed dispersal distance, which may be due to the complicated updraft generated by canopy. The effect of maternal plants on seed dispersal regulates the distribution pattern and the species composition of the community.

Estimating Leaf Area Index in Row Crops Using Wheel-Based and Airborne Discrete Return Light Detection and Ranging Data

Leaf area index (LAI) is an important variable for characterizing plant canopy in crop models. It is traditionally defined as the total one-sided leaf area per unit ground area and is estimated by both direct and indirect methods. This paper explores the effectiveness of using light detection and ranging (LiDAR) data to estimate LAI for sorghum and maize with different treatments at multiple times during the growing season from both a wheeled vehicle and Unmanned Aerial Vehicles. Linear and nonlinear regression models are investigated for prediction utilizing statistical and plant structure-based features extracted from the LiDAR point cloud data with ground reference obtained from an in-field plant canopy analyzer (indirect method). Results based on the value of the coefficient of determination (R2) and root mean squared error for predictive models ranged from ∼0.4 in the early season to ∼0.6 for sorghum and ∼0.5 to 0.80 for maize from 40 Days after Sowing to harvest.

Analysis of the role of plant canopy on hydrological systems

High rainfall intensity causing high erosion rates in Indonesia. Land cover conditions greatly determine water degradation in the hydrological cycle. The shape and type of plants canopy have significant effect on soil structure and water absorption. This study aimed to examine the role of plant canopy on the value of rainwater canopy escape as a supporter of hydrological cycle. Tree species were determined based on the level of dominance at study site using transect method. The dominant trees are Sea Sengon Tree (Paraserianthes falcataria), Teak Tree (Tectona grandis), Suren Tree (Toona sinensis) and Durian Tree (Durio zibethinus). The results showed that high rainfall intensity with a long rain period affected the amount of canopy escape. Durian Tree has highest canopy density with value of 0.301, and Sengon Laut is the lowest with value of 0.240. The value of passing the canopy of the Suren Tree is lower than the other tree species. The shape of canopy of Suren tree, which is round and oval, also affects the lower pass value of canopy compared to other tree species. The higher the value of canopy density can reduce the value of canopy escape to support the hydrological cycle.

A Step-by-Step Guide for Automated Plant Canopy Delineation Using Deep Learning: An Example in Strawberry Using ArcGIS Pro Software

This publication presents a guide to image analysis for researchers and farm managers who use ArcGIS software. Anyone with basic geographic information system analysis skills may follow along with the demonstration and learn to implement the Mask Region Convolutional Neural Networks model, a widely used model for object detection, to delineate strawberry canopies using ArcGIS Pro Image Analyst Extension in a simple workflow. This process is useful for precision agriculture management.

Critical Level of Manganese in Soil and Leaves: It’s Relationship to Fruit Quality of Mangosteen (Garcinia mangostana L.)

Manganese (Mn) is one of the essential micronutrients that plays a crucial role in plants' growth and development and is also considered a limiting factor for crop production. This study aimed to determine the critical level of Mn in soil and leaves for improving the quality of mangosteen fruit. The research was conducted in 2015 in several mangosteen production centers, including West Sumatra (Simalanggang and Banja Laweh), West Java (Karacak and Barengkok), Bali (Belimbing and Selamadeg). A well-maintained of fifteen to twenty years old mangosteen plants were used with uniform soil fertility. Purposive random sampling is conducted in each location to select ten plants from each site. Soil samples are taken from under the plant canopy around 0-30 cm in depth at the four cardinal directions. The terminal leaves that collected from the middle part of the plant canopy are used as the leaf samples. Physiological ripe fruits are taken after ripening with index 3-4. The parameters observed consist of (1) soil pH of H2O, Ca, Mg, Mn-available, (2) levels of Mn, Ca, Mg, and K in the leaves, (3) fruit quality (fruit weight, fruit diameter, fruit skin thickness, aryl weight, seed weight). The results showed the Mn content in the soil ranged from 18.89 to 33.63 ppm. Available Mn is negatively affected by pH, Ca, and Mg exchangeability. Soil Mn is linearly related to leaf Mn with R2 0.76. The critical values of Mn in leaf and soil for mangosteen plants in Indonesia were 425 ppm and 22 to 24 ppm, respectively.

Energy Minimisation in a Protected Cropping Facility Using Multi-Temperature Acquisition Points and Control of Ventilation Settings

Energy management in protected cropping is critical due to the high cost of energy use in high-tech greenhouse facilities. The main purpose of this research was to investigate the optimal strategy to reduce cooling energy consumption, by regulating the settings (opening/closing) of either vents or curtains during the day, at the protected cropping facility at Western Sydney University. We measured daily changes in air temperature and energy consumption under four treatments (open/closed combinations of vents and shade screens) and developed an optimal cooling strategy for energy management using multi-temperature acquisition points at different heights within a greenhouse compartment. The optimal treatment (vents open/curtains closed) reduced energy load at the rooftop, thereby maintaining a desirable plant canopy temperature profile, and reducing cooling energy. Daily energy consumption was lowest for vents open/curtains closed (70.5 kWh) and highest for vents closed/curtains open (121 kWh). It was also found that delaying the operation of opening and closing of vents and curtains until the plant canopy temperature reached 25 °C reduced cooling energy consumption and decreased heating energy consumption in the morning (e.g., 08:00 to 10:00). The estimated savings of 1.83 kWh per 1 °C cooling between the optimal (vents open/curtains closed) and least optimal (vents closed/curtains open) conditions had the potential for significant energy savings at 494 kWh per °C over a crop cycle of nine months in warm weather conditions. However, selection of the optimal cooling strategy utilising control of vents and curtains must also account for the impact from other greenhouse environmental factors, including light, humidity, and CO2 concentration, which may be crop specific.