Orchard Cultivation Research Articles

Modeling the impact of long-term land use changes on deep soil hydrological processes in the Loess Plateau, China

Land use change can significantly affect soil hydrology in arid and semi-arid regions, making it crucial to understand the relationship between vegetation roots and soil moisture. Current models often fail to predict root growth and its impacts on water dynamics accurately. Our work presents a novel model that seamlessly integrates the Community Land Model (CLM) with the Soil & Water Assessment Tool (SWAT). Furthermore, it enhances the root module within the CLM, enabling more accurate simulations of dynamic root depth and distribution across varying tree ages. This improvement particularly considers the crucial processes of dormancy and plant maturity. Soil moisture and root patterns under apple trees of varying ages and in wheat fields on the Loess Plateau was analyzed. Our findings indicate that our dynamic root depth model outperforms traditional static models, and can accurately reflect soil moisture levels with high precision (R2 = 0.80–0.81; Nash-Sutcliffe efficiency (NSE) = 0.65–0.75). In contrast to methods that utilize fixed root depths, dynamic root simulation can provide new insights. As apple orchards mature, the roots of 22-year-old apple trees have been found to reach a depth of 21 m in the soil. Conversely, the maximum root depth of wheat is limited to 1.9 m. This latter finding aligns more closely with the measured root depths, highlighting the accuracy of dynamic simulations. This model reveals that older apple orchards show decreased soil moisture at greater depths (>20 m), contrasting with wheat fields that affect moisture mostly within the top 2 m. Our results underscore the crucial role of dynamic modeling in comprehending root-soil water interactions. Furthermore, they imply that extended orchard cultivation practices can lead to a substantial depletion of deep soil moisture. Specifically, over a period of 1 to 22 years, a water deficit of up to 85 mm yr−1 has been observed. For a 22-year-old forest, the D-D (dynamic distributions of coarse and fine roots) method calculates a significant cumulative deep Soil Water Storage loss. Over the course of 22 years, this loss amounts to 1664 mm, which is almost three times compare to the annual rainfall recorded. Such a large loss has the potential to significant impact on groundwater recharge. This highlights the need for careful consideration in future afforestation efforts to prevent increased soil aridity.

Land suitability and human adaptation: River Siang from Sangam to Pongging, Arunachal Pradesh, India

Land suitability in mountainous regions profoundly influences human adaptation strategies, particularly in environments shaped by morphometric characteristics. This study focuses on the Siang river valley from Sangam to Pongging, Arunachal Pradesh, India, employing Land Suitability Analysis (LSA) to assess terrain viability for settlement, and orchard cultivation. Key determinants such as topographic features, drainage morphometry, and infrastructural accessibility were analyzed to develop thematic maps delineating optimal zones for different land uses. The research underscores how geomorphic attributes and accessibility influence settlement patterns and orchard suitability, with lower elevations proving favorable for settlements and orchards due to accessible topography and climatic conditions. By integrating spatial analysis techniques and assessing variables like elevation, slope, and proximity to infrastructure by euclidian distance and pareto principle (80/20 rule), this research provides a comprehensive framework for informed land use planning. Strategic planning recommendations emphasize sustainable practices and community engagement to balance development needs with environmental preservation in Arunachal Pradesh's rugged terrain. It advocates for collaborative efforts between stakeholders to optimize land utilization and foster resilient development amidst challenging environmental conditions. This initial attempt aims to raise awareness among land users, planners, research workers, and administrators to ensure proper and effective land management.

Severe nitrogen leaching and marked decline of nitrogen cycle-related genes during the cultivation of apple orchard on barren mountain

Limited available lands have led to the widespread practice of establishing orchards on barren mountains to expand apple cultivation in China. However, improper nitrogen (N) management strategies in intensive orchards escalate costs and also contribute to environmental contamination. A long-term field experiment was conducted in a representative apple-producing area in Shandong Province, China, to assess the environmental risks associated with newly established orchards. This research utilized lysimeters and soil metagenomic sequencing to investigate N leaching loss and the functional microbial profiles associated with the N cycle during apple cultivation on barren mountains. Five treatments were implemented: no inorganic N fertilizer, traditional farmer's fertilization, drip irrigation with a water-soluble fertilizer, resin-coated urea, and grass interplanting. Among treatments involving inorganic N, the total N leaching rate ranged from 16.5% to 30.7% of the total N fertilizer input. Notably, in treatments with equivalent N fertilizer applications, the water-soluble fertilizer treatment exhibited the highest N leaching loss rate -(20.2–29.0%), while the grass interplanting and resin-coated urea treatments showed significantly lower rates of N leaching loss (17.0–24.9% and 15.2–24.5%, respectively). The abundance of N cycle-related genes experienced a marked decline (17.1–18.8%) during the cultivation of orchards on barren mountains. The water-soluble fertilizer treatment displayed the highest potential for nitrification, contributing to elevated N leaching. Both resin-coated urea and traditional farmer's fertilization treatments exhibited the highest abundance of genes associated with N2O emission risk to the atmosphere. However, the grass interplanting treatment, while effectively reducing N leaching, also triggered the most pronounced soil acidification. Spearman correlation analysis revealed that the decline in pH, coupled with an increase in soil NO3--N concentration and electrical conductivity (EC), were the primary factors contributing to the reduction in the abundance of key N cycle functions. In summary, excessive use of inorganic N fertilizer in orchard environments led to increased N leaching, altered soil physicochemical properties, and significant impacts on N cycle-related genes. The elevated ionic strength in soils might be responsible for both the high N leaching loss and the decrease in N cycle function abundance. In intensive orchard cultivation, each N fertilization strategy mentioned above comes with its environmental drawbacks. Further investigation is warranted to achieve a balance between productivity and environmental protection.

Sustainable Management of Land, Water and Crop in Hills of North East India

Hill agriculture in Northeast India has tremendous potential to grow and contribute towards improving productivity, enhancing food and nutrition security, reducing rural poverty and accelerating the overall economic condition of the region due to its rich land, abundant water resources and favorable climate. The North-eastern region lying between 21.5oN - 29.5oN latitudes and 85.5oE - 97.3oE longitudes comprises eight states - Assam, Arunachal Pradesh, Meghalaya, Manipur, Mizoram, Nagaland, Tripura and Sikkim. The growth potential of hill farming has remained under-exploited due to various reasons like lack of system-specific production technologies, poor infrastructure (transport, markets, processing) and underdeveloped institutions (credit, extension, information, insurance), inaccessible habitations, diverse socio-cultural and fragmented land holdings. In hilly areas, jhum cultivation provides a basis for subsistence farming, maintenance of cultural values and social stability at low population density. But in the present context, this system cannot sustain increased demographic pressure. Moreover, shifting cultivation also causes problems of land degradation, accelerated deforestation, out of control forest fires ultimately affecting climate change. Therefore, adoption of various agro techniques as an alternative to jhuming may prove to be a boon for the overall growth of the region. Cultivation of plantation crops and orchards established on hill slopes will prevent soil erosion. Watershed development also plays an important role in sustaining the natural resource base and improving the productive potential of hill states. The hill states have the potential for production of vegetables in off-season that has greater demand in neighboring plains when there is scarcity of supply as this region is bestowed with the most congenial climatic conditions for the production of under-exploited agricultural and horticultural crops that provides many fold employment opportunities in agro-based industries, packaging, storage, preservation, canning and transportation.

Usage of irrigation elements by means of water-efficient technology in irrigating intensive apple gardens through soil and dynamics of seeping moisture

The article presents the results of theoretical and experimental research on the cultivation of intensive orchards with the method of watering through the soil. These methods and elements are for the first time applied to intensive gardens. During the research, we studied both the movement and height of the wetting contour over time H, the radius of the width L, and the curve area of the irrigation norm W m3/ha were relatively chosen.

Responses of diversity and carbon and nitrogen cycling genes of soil microorganisms to pomegranate (Punica granatum L.)/faba bean (Vicia faba L.) intercropping

The negative impacts of continuous cropping and long-term single crop planting on soil quality significantly restrict the high yield cultivation of perennial orchards. Intercropping can facilitate continuous cropping and improve the quality of the soil environment. However, it is still unclear whether the interplanting of faba bean in perennial orchards will increase the concentration of soil nutrients, change the composition of the soil microbial community, and increase the abundance of carbon (C) and nitrogen (N) cycling microorganisms. We interplanted faba beans in a perennial pomegranate orchard, and used sequencing and qPCR technology to study the effects on soil microbial diversity and C and N cycling genes. The results indicated that the interplanting of faba bean significantly increased the total N concentration by 28.6%, total phosphorus(P) concentration by 73.0% and available P concentration by 103.4%. The composition and structure of the soil microbial community were significantly changed, and the bacteria significantly enriched were Gaiellales and Rhizobiales at the order level and Nitrosomonadaceae at the family level. The fungi significantly enriched were Pezizomycetes at the class level, Pezizales and Sordariales at the order level, Ascodesmidaceae and Ophiocordycipitaceae at the family level, Cephaliophora, Parachaetomium, and Purpureocillium at the genus level, and Lilacinum, Lavendulum, Carinthiacum, Tropica, Chaetomium, and Delphinoides at the species level. The copy numbers of cbbL and nifH genes in soil were significantly increased by 79.9 and 168.5%, respectively. Changes in major nutrient elements explained 71.2% of the variance at the family level for bacteria and 46.0% of the variance at the family level for fungi. These results provided a scientific basis for the improvement of soil environmental quality and soil microorganisms by interplanting cash crops in perennial orchards.

Modelling 2050 Water Retention Scenarios for Irrigated and Non-Irrigated Crops for Adaptation to Climate Change Using the SWAT Model: The Case of the Bystra Catchment, Poland

The paper presents the estimated changes in the soil water content, the total runoff, the sediment yield and the actual evapotranspiration for the small Bystra catchment in the east of Poland. The findings are based on the results of three simulations covering the years of 2041–2050. The simulations were based on a calibrated and validated SWAT model (2010–2017). The first variant covers just the climate change and the existing structure of soil cultivation for the three regional climate models supported by the EC-EARTH global climate model in the emission scenarios RCP4.5 and RCP8.5. Variants two and three are based on the first variant in terms of the changing climate. The second variant, however, involves placing a pond in each farm in the catchment, while the third variant involves designing huge reservoirs as a result of land consolidation. Variants two and three occur in five adaptation scenarios each. The first adaptation scenario (V2.1 and V3.1) involves only increasing the number of ponds on the farm or increasing the number of reservoirs for non-irrigated arable land crops, i.e., WWHT (winter cereals), BARL (spring cereals), CANP (rapeseed) and CRDY (other crops). The second adaptation scenario (V2.2 and V3.2) involves growing vegetables without irrigation (instead of cereals). The third adaptation scenario (V2.3 and V3.3) involves growing vegetables with irrigation (instead of cereals). The fourth adaptation scenario (V2.4 and V3.4) involves partial cultivation of vegetables and cereals. The fifth adaptation scenario (V2.5 and V3.5) involves partial cultivation of orchards and cereals. The adaptation scenarios of the irrigation of vegetables from deep water-bearing layers (second variant) or reservoirs (third variant) contribute to the increase in water content in the soil, especially in summer, in comparison with the adaptation scenarios for vegetable cultivation without irrigation. What is more, the actual evapotranspiration was higher in the adaptation scenarios involving irrigation than in scenarios without irrigation. It is known that the changes in water content in soil and the intensification of water erosion are gravely affected by modifications in crops and soil cultivation. A change from cereal cultivation to irrigated vegetable cultivation or orchards increased the water content in the soil in most climatic projections. However, the increase in the number of ponds in the second variant had little impact on the soil water content, actual evapotranspiration and overall runoff, while the erosion loss decreased. With the lower precipitation levels in the years 2041–2050 relative to 2010–2017, as presented in the emissive scenario RCP 4.5, the soil water content decreases by up to 14% for most variants. Total runoff for most variants will also be lower by 4–35%. The percentage change in sediment yield will fluctuate between −86% and 116%. On the other hand, the actual evapotranspiration for most variants will be higher. With higher precipitation levels in the years 2041–2050 relative to 2010–2017, as presented in the emissive scenario RCP 8.5, the soil water content changes slightly from −7% to +3%. Total runoff for most variants will also be higher by as much as 43%. Sediment yield for most scenarios may increase by 226%. The actual evapotranspiration for most variants will also be higher. Irrigation variants tend to increase soil available water while increasing evapotranspiration and total outflow in the catchment as compared to non-irrigated LULC. The largest increase in the soil water content is observed in most irrigation variants for RCP 4.5 (annual average 316–319 mm) (V2.3-V2.5, V3.2, and V3.3) and RCP 8.5 (annual average 326–327 mm) (V2.3-V2.5 and V3.3) as compared to V1 (BaU) (315 mm–RCP 4.5 and 324 mm–RCP 8.5) for the years 2041–2050. On the other hand, the lowest increase in soil water content is observed in the V3.5 variant, with an annual average of 292 mm for RCP 4.5 and an annual average of 311 mm for RCP 8.5. Thus, for future climate change scenarios, irrigation with water reservoirs (ponds and storage reservoirs) should be considered. The study proves the rationale behind building ponds in small catchments in order to increase water resources in a landscape and also to counteract adverse effects of climate changes, i.e., sediment outflow and surface water erosion.

Metabolite profiling and transcriptome analyses provide insight into the regulatory network of graft incompatibility in litchi.

Litchi is an important commercial fruit crop widely grown in the world. Graft incompatibility between rootstocks and scions is a major constraint for large-scale cultivation of litchi orchards, popularization of new and excellent litchi varieties, and associated industrial development. Further, the genetic mechanism of graft incompatibility is still unclear in litchi. To reduce the incompatibility problems, this study investigated metabolic and transcriptomic differences between graft compatible and incompatible rootstock-scion combinations of litchi. The result of metabolomics analysis showed that incompatible rootstock-scion interaction modified the profiles of several metabolic substances. However, various compounds of flavonoids, phenolic acids, and lignin predominantly exhibited significantly altered abundance in graft incompatible combinations. Transcriptome analysis identified that graft incompatibility induces dynamic gene differences. The majority of these differentially expressed genes were enriched in biosynthetic pathways of phenylpropanoids. The differential expressions of genes in these pathways could be linked to the differential abundance levels of flavonoids, phenolic acids, and lignin compounds. Integrated metabolomic and transcriptomic analyses revealed a strong relationship between differential genes and differential metabolites identified in this study. In addition, identified hub genes and metabolites were closely associated with graft incompatibility of litchi. This study characterized the abundance of metabolites and genes in graft incompatible combinations and further discussed the genetic mechanism of graft incompatibility in litchi. Our results provide a platform to dissect the molecular mechanisms of graft incompatibility in the litchi fruit.

The contribution of Horticulture 4.0 innovations to more sustainable horticulture

Robotics, artificial intelligence (AI) and sensor-based solutions offer the opportunity to meet the current challenges in horticulture. To accelerate the integration of these technologies in the horticultural sector, the German Ministry of Agriculture established the funding priority Horticulture 4.0. Twelve research and development (R&D) and a networking and transfer project are funded to ensure international competitiveness and increase sustainability. This paper focuses on potential digital applications to be implemented in horticultural farms and analyses the technologies at the meta level by literature review and qualitative research. First, the 4.0 technologies based in the R&D projects are classified according to Industry 4.0 visions and systemized by degree of digital assistance. Six projects focus on a complete automation of production steps in horticulture, four of them on intelligent pest management. Thus, a use case “Digital insect trap” was established with automated detection and counting of insect pests and a digital assistance system for pest management. The results of these analyses provide a basis for future research on technology assessment. The impacts of this use case on sustainability of horticultural production are identified. There are various technical and economic effects on farm management, e.g. investment costs, reduced working time, live pest monitoring without delay and pest management on a broader data base. Less use of pesticides and more biodiversity in field and orchard cultivation are identified as potential ecologic effects. There are no indications that the employment in horticultural farms is affected, but the safety of employee's work place when using autonomous systems could be identified as social effects.

Approach for graph-based individual branch modelling of meadow orchard trees with 3D point clouds

The cultivation of meadow orchards provides an ecological benefit for biodiversity, which is significantly higher than in intensively cultivated orchards. However, the maintenance of meadow orchards is not economically profitable. The use of automation for pruning would reduce labour costs and avoid accidents. The goal of this research was, using photogrammetric point clouds, to automatically calculate tree models, without additional human input, as basis to estimate pruning points for meadow orchard trees. Pruning estimates require a knowledge of the major tree structure, containing the branch position, the growth direction and their topological connection. Therefore, nine apple trees were captured photogrammetrically as 3D point clouds using an RGB camera. To extract the tree models, the point clouds got filtered with a random forest algorithm, the trunk was extracted and the resulting point clouds were divided into numerous K-means clusters. The cluster centres were used to create skeleton models using methods of graph theory. For evaluation, the nodes and edges of the calculated and the manually created reference tree models were compared. The calculated models achieved a producer’s accuracy of 73.67% and a user's accuracy of 74.30% of the compared edges. These models now contain the geometric and topological structure of the trees and an assignment of their point clouds, from which further information, such as branch thickness, can be derived on a branch-specific basis. This is necessary information for the calculation of pruning areas and for the actual pruning planning, needed for the automation of tree pruning.

Assessment of Soil Redistribution Following Land Rehabilitation with an Apple Orchard in Hilly Regions of Central Iran

This study was executed to explore soil redistribution and soil quality changes induced by land degradation and then rehabilitation by orchard plantation in different slope positions in a semi-arid region in central Iran. A total of 72 surface soil samples (0–30 cm) were collected from three land uses (natural rangelands, dryland farming, and apple orchards) in four slope positions (shoulder, backslope, footslope, and toeslope). The soil physicochemical properties and magnetic parameters were measured, and soil redistribution was determined in the selected soil samples using the 137Cs technique. The results showed that rangeland degradation and, subsequently, rainfed cultivation, led to a significant decline in the soil quality indicators, such as soil organic matter (SOM), total nitrogen (TN), available potassium (Kava), and available phosphorous (Pava), thus incurring further soil loss, as determined by the 137Cs technique. Conversely, the conversion and rehabilitation of drylands to apple orchards cultivated on the contour terraces improved soil quality significantly and decreased soil loss (p < 0.05) and soil quality grade (p < 0.01). Additionally, the findings indicated that slope positions relative to land use change had a reasonable impact on the variability of soil properties and soil loss and deposition. The results of 137Cs analysis showed that the drylands had the highest soil loss (185.3 t ha−1 yr−1) and maximum sedimentation (182. 5 t ha−1 yr−1) in the shoulder and footslope positions, respectively. The random forest model applied between 137Cs inventory and soil properties indicated that calcium carbonate equivalent (CCE), TN, Pava, Kava, and bulk density (ρb) could explain 75% of the total variability in 137Cs inventory with high R2 (0.94) and low RMSE (111.29). Magnetic measurements have shown great potential as a cost-effective and fast method for assessing soil redistribution in hilly regions, as confirmed by the findings of the 137Cs analysis, which agreed well with the magnetic susceptibility at low frequency (χlf). Overall, the results confirmed that restoring abandoned dryland by orchard cultivation may improve soil quality and diminish soil loss in the semi-arid region of Iran. However, further research is required to assess other aspects of the ecosystem affected by this restoration.

Fertilizer-induced nitrous oxide emissions from global orchards and its estimate of China

The fruit has become the third-largest agricultural planting industry after cereals and vegetables in China. Fertilization regimes (e.g., application rate and method) in fruit orchards typically differ from cereal croplands, which would incur a pronounced difference in fertilizer-induced nitrous oxide (N2O) emissions between them. However, fertilizer-induced direct N2O emissions from orchard fields remain poorly understood. We conducted a field experiment in a peach orchard and a global meta-analysis of N2O emissions from fruit orchards. The emission factor (EF) of fertilizer N for N2O averaged 0.81%, with a background N2O emission of 3.4 kg N ha–1 yr-1 in our field study. A global meta-analysis suggested that the linear regression model was the best to fit N2O emissions by fertilizer N input for most fruit types compared to the nonlinear models. When averaging all global data, the linear model projected the EF of N2O from orchards to be 0.84%, with the background emission of 1.96 kg N ha–1. The estimate of direct N2O derived from the orchard-specific nonlinear model was substantially lower than those from the nonlinear model with global cropland measurements. The fertilizer-induced direct N2O emission from Chinese orchards during the 2000s was estimated to be 32–49 Gg N yr–1, equivalent to about 14% of total direct N2O emissions from Chinese uplands. Therefore, orchard cultivation constitutes a hotspot of N2O emissions in the agricultural sector, and priority should be given to emissions reduction to achieve the transition to climate-smart agriculture.

ECONOMICAL EFFECTIVENESS OF RE-GROWING APPLE TREES UNDER LONG-TERM FERTILIZATION

The essence of the economic efficiency of any production is determined by a profitable correlation between costs and financial results. One of the main factors in horticulture is a detailed choice of the constructions of the orchards and the determination of the most optimal farm practices in certain plantations taking into consideration their soil-climatic conditions under the highest efficiency of the cultivation. When economic efficiency of the production of fruit output is determined, the major indicators are profitability and a profitability level that shows the expediency of growing the crop with the application of required farm practices. The economic efficiency of replanted apple orchards along with long-term fertilization at various age-periods and fruiting was considered. It has been found out that during the period of growth and fruiting the efficiency and profitability of the orchard cultivation with the use of farm practices, in particular fertilization, are at a low level. This is predetermined by a low yield capacity of the apple trees. It was established that in the most productive period of fruiting of apple-tree plantations with the varieties Idared on seedling and vegetative M4 rootstock and Calville Snow on seedling rootstock, the use of organic and organo-mineral fertilization systems contributed to high return on investment and corresponding profitability of production, therefore these fertilization systems in strong and medium-growing plantations with full yield (at 17 22 t/ha) of non-irrigated apple-trees are profitable. The expediency of their use in non-irrigated horticultural agrocenosis with soil under naked fallow has been proved. Therefore, organic and organo-mineral systems can be successfully used in all fruit growing zones, especially in the southern regions where most of the plantations in horticultural farms, especially with limited irrigation, are grown with the soil content under fallow system. Also, the application of organic fertilizers can be successfully used when growing organic products. At the same time, as shown by many years of research, in fruit plantations with a lack of manure, chopped straw or other organic materials in equivalent amounts of dry matter can be successfully used as an organic fertilizer.

Monitoring three-decade dynamics of citrus planting in Southeastern China using dense Landsat records

Across Southeastern China, the expansion of citrus plantation has underpinned substantial economic development at the expense of forest cover and associated ecosystem services. The high-order complexity of citrus planting dynamics requires more detailed observations. To achieve this goal, we developed a novel monitoring scheme by integrating multi-epoch land cover classification and continuous change detection on the Google Earth Engine (GEE) platform using all available Landsat archives (1986–2018). First, a stable/changed area masking approach was adopted. Then, the GEE-based Continuous Change Detection and Classification (GEE-CCDC) algorithm was applied to detect the timing and position of citrus planting-related land cover changes. Finally, the effectiveness of the scheme was validated both spatially and temporally. We applied the proposed scheme in Xunwu, a typical County in Southeastern China where continuous expansion was disrupted by an outbreak of Huanglongbing (HLB, a destructive citrus disease). The validation results indicate that the multi-epoch classification effectively identified the stable, abandoned, and newly cultivated areas related to citrus planting. Within these areas, our monitoring of citrus planting dynamics had an overall temporal accuracy of 90.59% and a mean detection date deviation of −13.21 days (leading). Based on the change detection results, we found a two-stage change pattern, namely a continuous expansion period (1986–2016) followed by a disturbance period (2017–2018). Moreover, almost half of the orchards were cultivated in regions with an elevation and slope of 301–400 m and 11–20°. During the continuous expansion period, a total of 497.85 km2 natural lands were converted for citrus planting. Affected by the HLB outbreak, both orchard abandonment (114.66 km2) and new orchard cultivation (36.87 km2) were detected during the disturbance period. The proposed scheme offers a useful tool for cash crops management, and highlights the value of dense satellite data in monitoring the extent of ongoing human appropriation of natural ecosystems at a large scale and long-term.

Canopy Index Evaluation for Precision Management in an Intensive Olive Orchard

The evaluation of the canopy in orchard cultivation is a key aspect for the main cultivation techniques, such as pruning, thinning, harvesting, production and improved fruit quality. The possibility of having a periodic screening of the state of development of the vegetation can be of practical support to growers. Research on the application of precision agriculture has provided tools for reading and interpreting crops, and the resulting information is potentially useful. Many of the systems under study provide after monitoring information processing systems that reduce the timeliness of intervention. Especially in intensive systems such as olive groves, knowing the precise intervention points is often essential. In the present work, a multi-parameter instrument was used for field monitoring on the agricultural tractor to analyse the canopy. The system allows measuring various indicators such as height and density of the canopy and the temperature and humidity of the ambient air and at the leaf level. The first evaluation of the data made it possible to identify areas with greater vegetative concentration and greater or lesser development. The system made it possible to identify with good approximation the homogeneous areas, based on the Canopy Index (CI) evaluation to be subjected to subsequent and specific management efforts, dividing them into low, ordinary, and high vegetative growth. The results highlight the possibility of directly combining operators able to intervene with the same passage, selecting based on differences in growth, typical varietal specificities, and areas of deficient development or that are affected by plant diseases, confirming the objective of defining the areas of the orchard that require different management and workload techniques.

Persistence and vertical distribution of neonicotinoids in soils under different citrus orchards chrono sequences from southern China

Continual input of neonicotinoid insecticides occurs in the citrus orchards from southern China. However, it is still unknown about the variations in the distribution and accumulation of neonicotinoids in soil profiles along a long-term chronosequence of cultivation and the driving factors contributing to these shifts. Here, changes of neonicotinoids in the 0–100 cm soil profiles with distinct orchard cultivation age (1, 10, and 20 years) were investigated, and their related factors were further determined. The results showed that the total levels of five target neonicotinoids (∑5NEOs) in the soil profiles were in the range of 0–25.76 ng/g dw. Imidacloprid was the most dominating neonicotinoid, followed by thiamethoxam. We observed higher neonicotinoid accumulations in the soil profiles from the citrus orchards after 10 and 20 years of cultivation. Neonicotinoids migrated deeper into the soil profiles in orchards with a longer time since cultivation. Imidacloprid, thiamethoxam, and the total amount of neonicotinoid (∑5NEOs) were mainly affected by the cultivation age of citrus orchards (accounting for 58.9% variance; P < 0.001); whereas clothianidin, acetamiprid, and thiacloprid were mainly influenced by soil depths (accounting for 66.9–85.2% variance; P < 0.05). Redundancy analyzes further indicated that the enhanced accumulation of neonicotinoids was mainly correlated with the increase of soil organic carbon (SOC) content and soil porosity, and the reduction of bulk density in the profiles of citrus orchards with increasing cultivation age. This study highlights the finding that we should give more concerns about the contamination and ecological risks of neonicotinoids in the orchards with a long cultivation age.

Magnesium and nitrogen drive soil bacterial community structure under long-term apple orchard cultivation systems

Apple replant disease (ARD) is a common and destructive disease in apple orchards with long cultivation histories. In the present study, soils from three apple orchards under cultivation for two years (G2), thirty years (G30), and forty years (G40) were used to investigate the key nutritional factors influencing soil bacterial community structure. Changes in nutrient concentrations in the orchard soil entailed reductions in concentrations of medium trace nutrients (magnesium [Mg], manganese, and nickel) and the increase in concentrations of macronutrients (total nitrogen [TN], total phosphorus, total potassium, available phosphorus, and available potassium) and soil organic carbon. As cultivation time was prolonged, bacterial community composition shifted from enrichment with oligotrophic Acidobacteria and plant growth-facilitated Streptomyces to increased abundance of copiotrophic taxa, Bacteroidetes and Firmicutes, and plant-growth-impairing Gemmatimonas, based on 16S rDNA (V4) amplicon sequencing data. In addition, the relative abundances of bacteria associated with fermentation function and the decomposition of some unique compound classes increased, while the relative abundance of bacteria associated with the nitrification function decreased. Among all the nutritional elements tested using distance-based multivariate linear model analysis, Mg and TN influenced community structure the most. The results provide novel insights into the associations between soil nutrients and shifts in microbial community structure under long-term apple orchard soil ecosystems.

Production suitability of date palm under changing climate in a semi-arid region predicted by CLIMEX model

ObjectivesDate palm (Phoenix dactylifera L.), a member of the Arecaceae family is grown on large areas in the world with varying climatic and soil conditions. However, date palm productivity is severely being affected by ongoing climate changes. Identifying suitable production areas for date palm under changing climatic conditions could help to sustain its production. The objective of the current study was to predict the range expansion/contraction in the production areas of date palm in a semi-arid region. MethodsCLIMEX model was used to estimate the expected expansion/contraction in the potential distribution areas of date palm under current and future climatic conditions. Two climate change scenarios [(CCSs) i.e., A1B and A2] were used and production suitability was predicted for three timespans [i.e., 2030 (early-century), 2050 (mid-century) and 2100 (late century)]. ResultsThe model estimated significant suitable area (71.21%) for date palm cultivation under current climatic conditions. Climate change seemed to have no impact on production areas until early-century. However, range contraction (8 and 10% decline under A1B and A2 scenarios, respectively) in the suitable areas was predicted for mid-century. Nonetheless, severe range contraction (27.98 and 33% decline under A1B and A2 scenarios, respectively) was predicted in the production areas for late-century. Most of the climatically suitable areas during early-century became unsuitable during late-century. Moreover, the model predicted northward shift in the production areas for date palm. The range contraction was higher under A2 climate change scenario due to higher warming trend compared to A1B scenario. ConclusionThe results of the current study indicate that plenty of areas are suitable for date palm cultivation. Thus, date palm cultivation could be increased in these areas for augmenting the production. Climate warming will result in the range shifts; thus, cultivation of future orchards should be planned in the most suitable areas in order to avoid the negative consequences of climate change on date palm production in the country.

Functional Analysis of the Gibberellin 2-oxidase Gene Family in Peach.

Peach (Prunus persica L. Batsch) trees grow vigorously and are subject to intense pruning during orchard cultivation. Reducing the levels of endogenous gibberellins (GAs) represents an effective method for controlling branch growth. Gibberellin 2-oxidases (GA2oxs) deactivate bioactive GAs, but little is known about the GA2ox gene family in peach. In this study, we identified seven PpGA2ox genes in the peach genome, which were clustered into three subgroups: C19-GA2ox-I, C19-GA2ox-II, and C20-GA2ox-I. Overexpressing representative genes from the three subgroups, PpGA2ox-1, PpGA2ox-5, and PpGA2ox-2, in tobacco resulted in dwarf plants with shorter stems and smaller leaves than the wild type. An analysis of the GA metabolic profiles of the transgenic plants showed that PpGA2ox-5 (a member of subgroup C19-GA2ox-II) is simultaneously active against both C19-GAs and C20-GAs,which implied that C19-GA2ox-II enzymes represent intermediates of C19-GA2oxs and C20-GA2oxs. Exogenous GA3 treatment of shoot tips activated the expression of all seven PpGA2ox genes, with different response times: the C19-GA2ox genes were transcriptionally activated more rapidly than the C20-GA2ox genes. GA metabolic profile analysis suggested that C20-GA2ox depletes GA levels more broadly than C19-GA2ox. These results suggest that the PpGA2ox gene family is responsible for fine-tuning endogenous GA levels in peach. Our findings provide a theoretical basis for appropriately controlling the vigorous growth of peach trees.

What is the influence of agroecological and conventional crops under ant assemblages?

The objective of the study was to compare the richness and diversity of ant assemblages in an agroecological system under peach orchard, conventional system under peach orchard cultivation and native vegetation in rural properties located in a Pampa Biome. The study was conducted in four samplings in 2017: 1st and 09th March (summer); 24th and 31st July (winter); and four samplings in 2018: 23rd and 30th January (summer); 31st July and 07th August (winter). Pitfall traps were used. The assemblages were characterized and compared using richness, number of occurrences of ants, Shannon diversity (H'), equitability, rarefaction analysis and Chao 1. The association of the species with the samples was evaluated by a Principal Component Analysis (PCA). The agroecological system had the highest number of occurrences, while the conventional orchard the lowest number. Richness and abundance were greatest during the summer. The conventional peach orchard obtained the lowest H' for both seasons when compared to the agroecological orchard and native vegetation. The PCA explained 77.40% of the occurrence of ants in the environments and in the seasons. The results found demonstrated that conservationist systems tend to harbor greater wealth and diversity of ant assemblages, as well as occurring in native áreas.