Orchard Sites Research Articles

Viral Diversity in Mixed Tree Fruit Production Systems Determined through Bee-Mediated Pollen Collection

Commercially cultivated Prunus species are commonly grown in adjacent or mixed orchards and can be infected with unique or commonly shared viruses. Apple (Malus domestica), another member of the Rosacea and distantly related to Prunus, can share the same growing regions and common pathogens. Pollen can be a major route for virus transmission, and analysis of the pollen virome in tree fruit orchards can provide insights into these virus pathogen complexes from mixed production sites. Commercial honey bee (Apis mellifera) pollination is essential for improved fruit sets and yields in tree fruit production systems. To better understand the pollen-associated virome in tree fruits, metagenomics-based detection of plant viruses was employed on bee and pollen samples collected at four time points during the peak bloom period of apricot, cherry, peach, and apple trees at one orchard site. Twenty-one unique viruses were detected in samples collected during tree fruit blooms, including prune dwarf virus (PDV) and prunus necrotic ringspot virus (PNRSV) (Genus Ilarvirus, family Bromoviridae), Secoviridae family members tomato necrotic ringspot virus (genus Nepovirus), tobacco necrotic ringspot virus (genus Nepovirus), prunus virus F (genus Fabavirus), and Betaflexiviridae family member cherry virus A (CVA; genus Capillovirus). Viruses were also identified in composite leaf and flower samples to compare the pollen virome with the virome associated with vegetative tissues. At all four time points, a greater diversity of viruses was detected in the bee and pollen samples. Finally, the nucleotide sequence diversity of the coat protein regions of CVA, PDV, and PNRSV was profiled from this site, demonstrating a wide range of sequence diversity in pollen samples from this site. These results demonstrate the benefits of area-wide monitoring through bee pollination activities and provide new insights into the diversity of viruses in tree fruit pollination ecosystems.

Pre-Plant Soil Treatments Influence Tree Performance and Nematode Dynamics in Replanted Cherry Orchards.

In this two-year field study, the impacts of pre-plant soil management strategies, including soil fumigation, nematicide application, and organic amendments, on the growth and nematode community dynamics on cherry cultivars 'Emperor Francis' and 'Ulster' grafted to 'Mahaleb' rootstock were investigated in a replanted orchard site. In the first year, fumigation with 1,3-dichloropropene - chloropicrin mixture (Telone C-35) led to significantly increased trunk cross-sectional area and canopy height in both cultivars. Pratylenchus penetrans population densities were suppressed only short-term. Plots treated with the fungicide/nematicide fluopyram (Velum® Prime) had P. penetrans reproduction factors below one throughout both years independent of the scion. Additionally, the combined application of Seed Starter 101®, Dairy Doo® compost, and straw mulch reduced the reproduction factor of P. penetrans to below one in the first year. In the same time period, this combinatory treatment had the highest reproduction factor for bacterivore and fungivore nematodes. Based on results of this study, fumigation with Telone® C-35 resulted in improvement of tree establishment and provided effective short-term suppression of P. penetrans. Velum® Prime exhibited longer-term efficacy for the suppression of P. penetrans.

The Root-Lesion Nematode, Pratylenchus penetrans, Affects Early Growth and Physiology of Grafted M.9, G.41, and G.935 Apple Rootstocks Similarly Under Field Microplot Conditions.

The root-lesion nematode, Pratylenchus penetrans, is a ubiquitous parasite of roots of temperate fruit trees. It affects early growth of trees replanted into former orchard sites where populations have built up and may contribute to decline complexes of older trees. Most British Columbia, Canada, apple acreage is planted with M.9 rootstock, but growers are increasingly considering Geneva-series rootstocks such as G.41 and G.935. Among these rootstocks, responses to P. penetrans, specifically, are poorly known. To compare the resistance and tolerance to P. penetrans of G.41, G.935, and M.9 rootstocks ('Ambrosia' scion), a field microplot experiment was established in spring of 2020 at the Summerland Research and Development Centre. The experimental design was a two by three factorial combination of: P. penetrans inoculation (+/-) and rootstock (G.41, G.935, and M.9), with 20 replicate microplots of each of the six treatment combinations arranged in a randomized complete block design. The P. penetrans inoculum was 5,400 nematodes per microplot (54 P. penetrans liter-1 soil), which is below commonly accepted damage thresholds. Though P. penetrans population densities were lower for the G.41 rootstock by the end of the 2021 growing season, the effects of P. penetrans were similar among rootstocks. In the establishment year (2020), P. penetrans caused significant reductions in aboveground growth. In 2021, shoot growth and root weight were reduced by P. penetrans. The nematode also reduced rates of leaf gas exchange and stem water potential. These data suggest that while G.41 and G.935 may have other horticultural benefits over M.9, they are equally susceptible to P. penetrans at the early stages of tree growth.

Nestling Diet of Two Sympatric Insectivorous Passerines in Different Habitats—A Metabarcoding Study

Increasing landscape transformations and urbanisation affect insectivorous bird populations in various ways such as food availability, breeding phenology, or reproductive success. Especially during the breeding season, many passerine birds rely on the availability of caterpillars as the main prey for their nestlings. Previous studies suggested that similar diet preferences of sympatric species may result in interspecific competition, as demonstrated for Blue and Great Tits in forest habitats. However, nestling diet and prey preferences in other habitats are not fully understood. Prey availability, especially caterpillars, is lower in cities than in forests, thus influencing prey choice and interspecific competition. Here we used faecal DNA metabarcoding to investigate if nestling diet composition of the two sympatric species Blue Cyanistes caeruleus and Great Tits Parus major varied among species and different habitats (forest, traditional orchards, and urban parks). Furthermore, we examined food availability by DNA barcoding of the arboreal arthropod communities among habitats and compared them to the nestling diet to infer parental prey selectivity. The study was carried out in central Germany from 2018 to 2019. Blue and Great Tits showed a diverse diet which was dominated by Lepidoptera in all habitats. Lepidopteran diet components were most similar between forest and orchard sites, as were the components with other arthropods between orchard and urban sites. Both tit species showed selectivity for the lepidopteran families Geometridae and Tortricidae in all habitats, and for Noctuidae (Lepidoptera), Tenthredinidae and Braconidae (Hymenoptera) in forest and orchard sites. As the tits showed preferences for mainly families of Lepidoptera, and Hymenoptera, our approach provides a baseline to support monitoring of these groups.

A CHERRY FRUIT RECOGNITION METHOD FOR CURRENT TASK BASED ON DEEP LEARNING

To improve the accuracy of cherry fruit recognition during picking operations and to enable automated cherry picking by robots, both original and complex sample image sets were collected at the orchard site in two phases. Concurrently, the basic data set, enhanced data set, and task data set were generated, wherein the recognition targets were all mature cherry fruits and the recognition targets were cherry fruits that became within the current operation range. First, the basic and enhanced data sets were used for comparative training on you only look once (YOLO) v3. The test results demonstrated that the ability of YOLO v3 to recognize occluded and overlapping cherry fruits can be greatly enhanced by increasing the quantity and percentage of samples in the training set that have high levels of occlusion and overlap. Second, the enhanced data set was used to train the Faster R-CNN, SSD, YOLO v3, and YOLO v5 networks. The test results indicated that YOLO v5 had the best recognition effect on mature cherries. Next, the enhanced data set and the task data set were used to train YOLO v5. Experiments revealed that YOLO v5 was more successful in identifying cherry fruits that needed to be picked within the current task range, while shielding mature cherries that should not be picked outside of it. 96% of the data was precise, and 99% of the data was recall.

Selection Criteria for Identification of Turkey Berry (Solanum torvum) Genotypes for Variability, Heritability and Genetic Advance

Background: Breeders can determine the likelihood of passing on advantageous traits to the following generation by using heritability, which calculates the portion of phenotypic variation that can be attributed to genetic factors. Methods: The present study was conducted at College Orchard on clay loam soil in the years 2022-2023 at the Department of Vegetable Science, Horticultural College and Research Institute, TNAU, Coimbatore. The experimental orchard site at HCandRI is located in the tropical plain topography at 11 degrees north latitude, 77 degrees east longitude and 411 metres above mean sea level (MSL). There are 20 genotypes of turkey berry for variability, heritability and genetic advance study. These genotypes are collected from different areas of Tamil Nadu and other Indian states. One season measurements have been taken of the following traits: plant height, internodal length, number of branches per plant, stem girth, number of stem prickles, number of leaves, leaf area cm2, number of leaf prickles per plant, days of first flowering, number of flowers/clusters, number of flowers per plant, number of fruits/clusters, the number of fruit clusters per plant, fruit diameter, the individual fruit weight and the fresh fruit yield (gm/plant). As part of the current study, five randomly chosen plants from each genotype in each replication were tagged to record the observations. Result: The results from this study revealed that higher values of PCV, GCV, heritability and GAM are indicative of a greater influence of environmental factors, according to variability studies. These data demonstrated that there was a high level of variability for these traits in the germplasm and that selection for these traits might be successful. These data were combined with high estimates of genetic advance for traits like the number of leaf prickles per plant, number of flowers per cluster, fruit diameter, number of fruits per cluster, leaf area, stem girth, number of stem prickles per plant and internodal length. The promising accessions discovered in this study could be applied to projects aimed at improving crops, such as pre-breeding for turkey berries.

Halyomorpha halys (Hemiptera: Pentatomidae) trap captures at orchard and nonorchard sites and the influence of uncultivated woody host plants in adjoining woodlots.

The invasive Halyomorpha halys (Hemiptera: Pentatomidae) has threatened Mid-Atlantic tree fruit since 2010. To identify factors underlying observed differences in H. halys pest pressure among individual orchards within a geographically proximate area, a 3-yr study was conducted across 10 apple orchard and 8 nonorchard sites bordered by unmanaged woodlots. At each site, 3 pheromone traps were monitored weekly for H. halys captures from late April to mid-October. Apple injury was assessed at harvest at orchard sites annually, and a survey of woody plants found in woodlots adjacent to all sites was conducted. There were no significant differences in captures between orchard and nonorchard site types, but captures were significantly different among individual orchard sites and among individual nonorchard sites. A significant positive relationship between the amount of stink bug injury on apple at harvest and late season captures was detected at orchard sites in 2018 and 2019. Among woodlots adjacent to all sites, a significant positive relationship between the proportion of Lonicera spp. and mid- and late-season nymphal captures was identified. Season-long nymphal captures were positively related to the proportion of Lonicera and Elaeagnus and negatively with Sassafras. For adults, captures were negatively related to the proportion of Ailanthus and positively related to the proportion of Fraxinus in the early and mid-season, respectively. Our results indicate that orchard presence was not driving the relative abundance of localized H. halys populations and that differences in relative densities among sites point to other factors, such as abundance of specific uncultivated woody hosts in unmanaged areas.

Population dynamics of fruit flies and correlation matrix with weather and host variables in mango (Mangifera indica) orchards

The present study was carried out in the Mango orchards at Indian Agricultural Research Institute, New Delhi during 2020–2021 and 2021–2022 and aimed at analysing the population dynamics of fruit fly (Bactrocera dorsalis) species after putting the requisite number of methyl eugenol traps (@6 per acre). Weekly monitoring of fruit fly populations was performed and correlated with various weather parameters. Among the fruit fly species, the oriental fruit fly was found to be the most prevalent and abundant, followed by B. zonata, B. correcta, and B. cucurbitae. Fruit fly populations peaked in mango plantations between June and July, coinciding with the ripening time and the occurrence of humid conditions and rainfall. Multiple factors, including weather conditions, the presence of preferred host plants, and alternative hosts, fruits characteristics were found to influence the dynamics of fruit fly populations. The seasonal trap captures of male fruit flies showed a moderately significant negative correlation (-0.612*) with maximum but significant positive correlation with the minimum temperature (0.701**). However, a positive correlation was observed between relative humidity (r = 0.924**) and rainfall (r = 0.721**) with the fluctuations of fruit fly populations across all the monitored orchard sites.

Impact of landscape configuration and composition on pollinator communities across different European biogeographic regions

IntroductionHeterogeneity in composition and spatial configuration of landscape elements support diversity and abundance of flower-visiting insects, but this is likely dependent on taxonomic group, spatial scale, weather and climatic conditions, and is particularly impacted by agricultural intensification. Here, we analyzed the impacts of both aspects of landscape heterogeneity and the role of climatic and weather conditions on pollinating insect communities in two economically important mass-flowering crops across Europe.MethodsUsing a standardized approach, we collected data on the abundance of five insect groups (honey bees, bumble bees, other bees, hover flies and butterflies) in eight oilseed rape and eight apple orchard sites (in crops and adjacent crop margins), across eight European countries (128 sites in total) encompassing four biogeographic regions, and quantified habitat heterogeneity by calculating relevant landscape metrics for composition (proportion and diversity of land-use types) and configuration (the aggregation and isolation of land-use patches).ResultsWe found that flower-visiting insects responded to landscape and climate parameters in taxon- and crop-specific ways. For example, landscape diversity was positively correlated with honey bee and solitary bee abundance in oilseed rape fields, and hover fly abundance in apple orchards. In apple sites, the total abundance of all pollinators, and particularly bumble bees and solitary bees, decreased with an increasing proportion of orchards in the surrounding landscape. In oilseed rape sites, less-intensively managed habitats (i.e., woodland, grassland, meadows, and hedgerows) positively influenced all pollinators, particularly bumble bees and butterflies. Additionally, our data showed that daily and annual temperature, as well as annual precipitation and precipitation seasonality, affects the abundance of flower-visiting insects, although, again, these impacts appeared to be taxon- or crop-specific.DiscussionThus, in the context of global change, our findings emphasize the importance of understanding the role of taxon-specific responses to both changes in land use and climate, to ensure continued delivery of pollination services to pollinator-dependent crops.

Effect of orchard site and climatic conditions on plant nematode density levels

Phytoparasitic nematodes are commonly found in the soil and their presence can lead to plant diseases, weaker growth, reduced yields and lower fruit quality. A study conducted in 2006–2009, involving the monitoring of climatic conditions, identified the influence of precipitation and temperature on the number of nematodes, in 7 sites within a cherry orchard. Soil samples to assess nematode populations were taken from 7 sites that differed in terms of cultivation and age: 5 cherry orchards established in different years. Not all nematode taxa responded in the same way to temperature increase. Members of the families Belonolaimidae, Trichodoridae and the genus Aphelenchus increased in number with rising temperatures. The negative water balance limited the number of nematodes in the soil in the layer up to 30 cm, whereas the increase in soil moisture had a positive effect on the development of Paratylenchus spp., and mebers of the family Hoplolaimidae and Heterodera. The largest total number of nematodes was found on the strip cultivated with agricultural crops after orchard liquidation. However, parasitic nematodes accounted for were at low levels (17%). The size of fruits from trees growing on sites with a large number of nematodes decreased with a simultaneous increase in total soluble solids and fruit firmness.

Transformative changes in tree breeding for resilient forest restoration

Deciding how to establish woodland in forest restoration is not straightforward as different outcomes may be obtained from different establishment approaches, each with cost implications and degree of success limitations attached. Planning restoration requires knowledge of site conditions, including how sites are likely to respond under climate change. For objectives of production and high timber quality it is likely that ground preparation will be used, and planting with forest reproductive material (FRM) of known traits, such as: high survival and growth in establishment, drought tolerance adequate for climate projections, good resistance to pests and pathogens. For objectives associated with biodiversity, carbon sequestration, water supply protection, soil protection, natural regeneration could be a less costly solution with a limited amount of assisted translocation of selected FRM to improve resilience. If objectives are for rewilding forest areas, a degree of natural colonisation perhaps with translocation of some FRM could be a solution. Ignoring site conditions and suitability of available sources of FRM for forest restoration is likely to provide unexpected results with a mix of open ground, scrub and scattered trees resulting from climate, herbivore, and browsing impacts. The recent B4EST EU Horizon 2020 project examined progress in novel rapid approaches for testing the quality of FRM from existing genetic trials. Here we review the work of B4EST to show the opportunities from transformative tree breeding in forest restoration schemes, including: new climate projection ensembles at high temporal and spatial resolution to develop norms of reaction and transfer models with genetic components; multi-environment genotype-phenotype associations and multi-locus genotype-environment associations in identifying drivers of local adaptation; techniques for genomic selection using single nucleotide polymorphism (SNP) arrays to derive functional traits from polygenic associations; work on seed orchard site and climate specific FRM and zones for deployment; and work on some of the forest ecosystem service benefits derived at a landscape scale. We conclude that tree-breeding will provide robust forest restoration for planting, and rewilding (assisted natural regeneration), and if not “ignoring” but instead assisting natural colonisation processes – tree breeding may improve long-term forest resilience under environmental change.

Coupled archaeological and ecological analyses reveal ancient cultivation and land use in Nuchatlaht (Nuu-chah-nulth) territories, Pacific Northwest

Indigenous peoples’ legacies of plant cultivation and management can have profound effects on contemporary forest structure and species composition long after cultivation has ceased. Despite rich ethnographic accounts of practices like orcharding and fruit tree management in the Pacific Northwest, archaeological and ecological research documenting these practises have been lacking. To investigate ancient and historical land-use and cultivation in Nuchatlaht (Nuu-chah-nulth) territory, we undertook a multidisciplinary study combining archaeological surveys on Nootka Island and ecological analyses of seven anomalous plant communities found adjacent to former village sites. Fifty-seven archaeological sites were inventoried, and 16 previously recorded sites were updated, including six notable village sites. Intensive botanical surveys were subject to indicator species analysis, NMDS, and ANOSIM analysis, which suggest that three putative orchard sites were highly enriched for culturally important and edible fruit and root plants, such as Pacific crabapple (Malus fusca), saskatoon berry (Amelanchier alnifolia), salmonberry (Rubus spectabilis), and wild rice root (Fritillaria camschatcensis), and are highly distinctive compared to nearby sites and regional floristic patterns. Four shell midden sites were characterized by plant communities distinct from both orchard sites and control sites. Our archaeological and ecological analyses, alongside ethnohistorical data, strongly suggest a pattern of ancient and/or historical cultural landscape modification by Nuchatlaht peoples to produce food-bearing plant communities in their territories. This compliments findings in other literature, and what Indigenous peoples have long told researchers, that plant resources were routinely encouraged and harvested across their inhabited landscapes.

Divergent pattern of soil CO2, CH4 and N2O emissions in 18-year citrus orchard and Camellia oleifera plantations converted from natural shrub forests

A large number of natural shrub forests were converted to oil plants and orchards in the subtropical area of China for economic reasons, but the ecological consequences such as greenhouse gas (GHG) flux, remains unclear. The objectives were to explore how environmental factors, including seasonal and inter-annual variations, and management factors are affecting the GHG fluxes. The study was performed in 18-years-old plantations in a subtropical hilly region in south China. Methane (CH4), nitrous oxide (N2O), and carbon dioxide (CO2) fluxes were continuously measured using a manual static chamber technology at a citrus orchard and Camellia oleifera plantation. Results showed that fluxes of CH4, N2O, and CO2 fluxes were strongly affected by the two plantations, and CH4 uptake and CO2 emission rate at the C.oleifera plantation were higher than those in the citrus orchard site mainly due to the high soil temperature and soil organic carbon contents in C.oleifera systems. The citrus orchard had higher annual N2O emission than the C.oleifera plantation. One of the reasons was N fertilizers were applied to the orchard, as indicated by increase in NO3−-N content and the positive correlation between N2O emissions and soil NO3−-N. Overall, the global warming potential (GWP) was significantly higher in C.oleifera plantation than that in the citrus orchard (579.11 ± 17.06 vs. 418.13 ± 17.19 kg CO2eq ha−1 yr−1). The range of annual cumulative fluxes measured from the citrus orchard and C.oleifera ecosystems were – (78.88–92.42) g CH4–C ha−1 yr−1, 89.3–124.75 g N2O-N ha−1 yr−1, and 389.58–563.56 kg CO2-C ha−1 yr−1. The amount of GHG emitted in summer was 1.5–6.6 times higher than the sum of the other three seasons, indicating that CO2 may be emitted from soil in cool seasons when temperature continues to increase due to global warming. Notably, the continuous increase in the use of fertilizers in economic forests in subtropical hilly regions might increase N2O emissions, which may offset the net climate benefits of increasing carbon sequestration by plants.

LiDAR-sensed tree canopy correction in uneven terrain conditions using a sensor fusion approach for precision sprayers

Precision spraying is one of the most promising techniques to produce healthy and sustainably profitable crops. However, accurate canopy density measurements for precision spraying decisions are still a challenging endeavor, especially in orchards with uneven terrain conditions. A sensor fusion-based canopy point correction system was developed with a 3D light detection and ranging (LiDAR) sensor and an inertial navigation system-global navigation satellite system (INS-GNSS) for accurate tree canopy density measurement. The LiDAR sensor was used to acquire the tree canopy architectures, while the INS-GNSS sensor was to evaluate the terrain slopes and the tree georeferenced locations. A mathematical model was developed to perform the simulation for correction of canopy points based on given changes in the roll, pitch, and yaw angles. A sensor fusion algorithm was developed to process the canopy point corrections for the tree fruit orchards with three different sloping conditions, including longitudinal, lateral, and combination of both slopes. Simulation results reported that the developed model established the correction of tree canopy points with varying roll, pitch, and yaw angles. Field evaluation results suggested that the developed system could be used for correcting canopy points at any sloping conditions in various terrains. The measured tree canopy density from the corrected canopy points reported a possible of off-target chemical reduction up to 13.87%, 5.19%, and 15.45% in orchard sites 1, 2 and 3, respectively. With the accurate tree canopy density measurement, it is anticipated that the developed system could be used to reduce the off-target deposition for precision spraying applications in uneven tree fruit orchards.

Bluebirds Experience Impaired Hatching Success in Conventionally Sprayed Apple Orchard Habitats: A 31-Year Study.

We analyzed the reproductive success of eastern bluebirds (Sialia sialis) nesting in apple orchards and non‐orchard nest‐boxes in southern Ontario, Canada, from 1988 to 2018. Using data from 2397 nest‐boxes monitored at 20 orchard sites and 52 non‐orchard sites, we first modeled phenological parameters typically linked to climate change across both site types. We found that the first egg of each brood was laid significantly earlier in the season each year over our 31‐year study. Clutch initiation occurred 4 days earlier in the spring in 2018 compared to 1988. Average clutch size in the first or second brood did not change significantly during our 31‐year study; however, clutches were significantly smaller in orchards compared to non‐orchards (0.10 ± 0.03 fewer eggs between sites). Nests built in orchards were also at 6.1‐fold greater risk of parasitism and 2.1‐fold greater risk of depredation than nests in non‐orchards. After accounting for depredation and nest parasitism, hatching success was still significantly lower in orchards than in non‐orchards. Overall, hatching success was 4%–5% lower in orchards. The probability of successfully fledging did not differ significantly between site types. In 2012, a ban on use of the organophosphate insecticide azinphos‐methyl in orchards was enacted in Canada. We did not find a difference in hatching or fledging success in orchards after the ban. In our assessment of available data, we conclude that any pesticide effect on hatching success of eastern bluebirds in sprayed orchards is most likely the consequence of long‐term exposure to dichlorodiphenyltrichloroethane (DDT) compounds in orchard soils and bioaccumulation in eggs rather than pesticides in use since regulation of DDT in the 1970s. Environ Toxicol Chem 2021;40:3369–3378. © 2021 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC. Reproduced with the permission of the Minister of Environment and Climate Change Canada.

Soil fertility and leaf nutrient status of litchi orchard sites

Twelve soil and twelve leaf samples were collected from twelve litchi (Litchi chinensis Sonn.) orchards from different locations of Dinajpur to evaluate some physico-chemical properties and nutrient status of soil, and concentration of nutrients in litchi leaf. The pH of the soil varied from very strong acidic to medium acidic (4.8 - 5.7), organic matter content varied from 0.84 - 1.88%, EC varied from 302.4 - 310.2 μS/cm. The dominant soil textural class was clay loam. The average particle density was 2.49g/cm3. Total N, P, K and S in soils were 0.053 - 0.180%, 0.02 - 0.07%, 0.046 - 0.370 meq/100 g, and 0.015 - 0.028%, respectively. Available N, P, K, S, Zn, Fe, Mn and B in soils 30.40 - 57.8 mg/kg, 10.53 - 14.33 mg/kg, 0.03 - 0.32 meq/100 g, 20.03-34.80 mg/kg, 0.68-1.50 μg/g, 31.8 - 41.5 μg/g, 6.75 - 7.39 μg/g and 0.25-0.51 μg/g, respectively. The concentration of total N, P, K, S, Zn and Mn in the leaf were 1.74 - 2.20%, 0.11 - 0.188%, 0.104- 0.198%, 0.129 - 0.430%, 12 - 14 μg/g and 30 - 74 μg/g, respectively. The overall results indicated that the fertility status of the soils under the litchi plantation in the Dinajpur area are medium fertile. So, farmers could be advised to grow litchi plants after applying amendments to the soils to improve the physico-chemical properties in the Dinajpur area of Bangladesh.
 Dhaka Univ. J. Biol. Sci. 30(2): 141-149, 2021 (July)

Dissipation of tiafenacil in five types of citrus orchard soils using the HPLC-MS coupled with the quick, easy, cheap, effective, rugged, and safe method.

Tiafenacil is a new contact herbicide and its environmental behavior after field application remains poorly understood. In order to understand the dissipation of tiafenacil in the soil, the tiafenacil dissipation experiment was conducted at citrus orchard sites in five provinces of China (Gansu, Shandong, Sichuan, Jiangxi, and Hainan) in 2019 and 2020 (July-August) and the relevant determination methods were optimized. The results showed that the established method showed good linearity in the concentration range of 0.01-0.5mg/kg. The average recoveries of tiafenacil from the five soils were 86.31-101.66%, with coefficients of variation of 0.28-10.79%. The dissipation of tiafenacil at the five experimental sites conformed to the first-order kinetic equation, Ct =C0 exp- kt (R2 =0.8130 - 0.9967). The half-life of tiafenacil ranged from 0.26 to 4.19 days. The dissipation rate of tiafenacil was positively correlated with soil organic matter content and negatively correlated with soil pH, while monthly average temperature and total rainfall were less influential than soil properties. Therefore, the established method was simple and effective for tiafenacil residue analysis in citrus orchard soils. Tiafenacil could readily dissipate in soil and might be a safe alternative to glyphosate for weed control in citrus orchards.

Development of a LiDAR-guided section-based tree canopy density measurement system for precision spray applications

An unmanned ground-based canopy density measurement system to support precision spraying in apple orchards was developed to precisely apply pesticides to orchard canopies. The automated measurement system was comprised of a light detection and ranging (LiDAR) sensor, an interface box for data transmission, and a laptop computer. A data processing and analysis algorithm was developed to measure point cloud indices from the LiDAR sensor to describe the distribution of tree canopy density within four sections according to the position of the trellis wires. Experiments were conducted in two orchard sites, one with GoldRush (larger trees) and the other one with Fuji (smaller trees) apple trees. Tree leaves were counted manually from each section separated by trellis wires. Field evaluation results showed a strong correlation of 0.95 (R2 = 89.30%) between point cloud data and number of leaves for the Fuji block and a correlation of 0.82 (R2 = 67.16%) was obtained for the GoldRush block. A strong correlation of 0.98 (R2 = 95.90%) was achieved in the relationship between canopy volume and number of leaves. Finally, a canopy density map was generated to provide a graphical view of the tree canopy density in different sections. Since accurate canopy density information was computed, it is anticipated that the developed prototype system can guide the sprayer unit for reducing excessive pesticide use in orchards.

Empirical evidence of the mediterranean fruit fly movement between orchard types

AbstractUnderstanding species movement in the agroecological system is an important theme in ecology. A mark–release–capture experiment was conducted to study the dispersion behaviour of the Mediterranean fruit fly, Ceratitis capitata (Wied.; Diptera: Tephritidae; Medfly) in northern Israel. Four pairs of pear and citrus orchards were selected for the field experiments. Sterile flies dyed with different colours were released in three seasons during 2015 and 2016, based on the phenological stages of the hosts. The total number of captured marked sterile flies per trap (FT) was approx 300 in both April and August. In November, FT values decreased by about 35% to approximately 200. The wild Medfly that were also captured showed an opposite trend, from an FT of 1.8 and 6.4 in April and August, respectively, to an FT of about 330 in November. Marked sterile flies were captured in both the release and the neighbouring orchard sites. We found that the Medfly migrates from pear to citrus orchards during spring and from citrus to pear during summer, when there are no fruit‐bearing trees in the orchards. However, during November, when the wild Medfly population prevails in the area, a clear pattern of migration is hard to identify, perhaps because of a possible interaction with the wild fly's population.

基于STICS模型的黄土高原苹果园生态系统服务评估

苹果园在确保最大生产力的同时应适当考虑环境和自然资源，如何权衡其生态系统服务是苹果园可持续发展面临的重要问题之一。利用大田试验和STICS模型相结合的方法研究农业管理措施和气候对黄土高原苹果园生态系统服务的影响，并在此基础上对黄土高原南部半湿润区和北部半干旱区土壤氮可利用性、气候调节、水循环调节和果实生产四种苹果园生态系统服务进行了系统的评估。结果表明：（1）STICS模型均能较好模拟白水和子洲试验果园的产量、单果重、土壤含水量和蒸散发等生态系统服务指标；（2）除固碳与产量、单果重及果树相关指标是协同关系以外，其他生态系统服务之间都是权衡关系；（3）对于各管理措施下的果园平均服务标准值，秸秆覆盖（0.67） > 地布覆盖（0.52） > 清耕（0.30），充分灌溉（0.56） > 轻度亏缺灌溉（0.44） > 重度亏缺灌溉（0.30），其中秸秆覆盖和充分灌溉的果园服务概况最佳，地布覆盖和轻度亏缺灌溉的果园服务概况较相似且最平衡；（4）地布覆盖和轻度亏缺灌溉管理措施缓和权衡作用的效果优于其他管理措施。综上所述，STICS模型能够较好的量化果园生态系统服务概况，农业管理措施是果园生态系统服务强有力的驱动因子。;Apple orchards face the major challenge of ensuring maximal productivity with due consideration for the environment and natural resource. How to balance its ecosystem services is one of the important issues facing the sustainable development of apple orchards. The field experiment and the STICS model were used to study the impacts of agricultural management and climate on the ecosystem services of apple orchards in the Loess Plateau of China. And on this basis, four apple orchard ecosystem services including soil nitrogen availability, climate regulation, water circulation regulation,and fruit production were systematically evaluated in the south semi-humid and north semi-arid regions of the Loess Plateau of China. This model was parameterized by using data collected on two experimental apple orchard sites under irrigating and mulching management in the Loess Plateau. The results showed that: (1) the STICS models could well simulate the ecosystem service indicators such as yield, fruit mass, soil water content, and evapotranspiration of the Baishui and Zizhou experimental orchards. (2) Except for the synergies between carbon sequestration and yield, fruit mass and fruit-related indicators, there is a trade-off relationship among other ecosystem services. The contribution of carbon allocaton to fruit in sequestrated carbon was considerable. Nitrogen absorption, impacted by mulch and irrigation, was a major driver of these ecosystem service relationships. (3) For the average service standard value of the orchard under various management measures, straw mulching (0.67) > film mulching (0.52) > clearing cultivation (0.30), comfort irrigation (0.56) > low water stress irrigation (0.44) > high water stress irrigation (0.30). The service profile of the orchard with straw mulching and comfort irrigation were the best. And the service profile of the orchard with film mulching and low water stress irrigation were similar and the most balanced, showing higher yield, fruit mass and soil water content but lower N₂O emission. (4) The effect of mitigating trade-offs of straw mulching and low water stress irrigation are better than other management measures, and these two apple orchards are the most ideal orchards. In summary, the STICS model can quantify orchard ecosystem services profiles well, and agricultural management is a powerful driving factor of orchard ecosystem services.