Fruit Set Stage Research Articles

Recent changes in thermal indices in Mango cv Dashehari under subtropical climate

Systematic recording of changes in thermal indices at tree phenological stages is prerequisite to understand the impact of environmental factors on mango. Keeping this in view, latest information on growing degree day units, heliothermal and photothermal units were cumulated at flowering, fruit set, fruit development and maturity stages in mango cv Dashehari during growing season of 2021 and 2022. Recent data showed variability in environmental indicators during critical reproductive stages. Highest weekly mean maximum temperature of 39.50 and 44.21°C were recorded in 2021 and 2022 fruiting cycles while minimum temperature showed 1.29°C during 2022 and 3.79°C in 2021. During 2022, bright sunshine hours had maximum value of 15.59h whereas in 2021, 10.7 h. During reproductive stage, weekly mean pan evaporation of 4.46 to 10.01 mm/day was recorded in 2021 fruiting cycle; in contrast, in the next season, 4.77 to 10.06 h was observed. Weekly average growing degree day from January to June varied between 860.51 to 2347.91°Cd and 917.16 to 2597.30°Cd respectively in 2021 and 2022 growth cycles. The heliothermal units had 3094.05 to 17727.54 and 3534.42 to 23219.79°Cdh with photothermal of 8932.92 to 32084.15 and 9517.23 to 35498.52 °Cdh respectively in 2021 and 2022 fruiting seasons. The flowering stages experienced lower heat accumulation in 2021 as compared to 2022 fruiting seasons. It was observed that peanut and marble phase had around 884.48 to 1606.44°Cd GDD across fruiting season. Maturity period had 1655.41 to 2597.3°Cd GDD across seasons. Histographic distribution of these thermal indices at vegetative, flowering, fruit setting to maturity had indicated widespread distribution pattern of GDD, HTU and PTU across seasons. It was found that a 1500 to 1600°Cd GDD at frequency level of <5 per cent in 2021 marble stage while the same GDD at 6 per cent frequency level with higher 1600 to 1700°Cd class intervals at <2 per cent was noted in the next season fruiting. Such widespread distribution indicated the affect of climatic factors at each stage and season. Lower fruit production of 6 to 8 t ha-1 was accorded due to severe atmospheric aberration during the 2022 cropping cycle. Results suggested the impact of environmental factors on tree performances and thus resource conservation practices needs to be followed rigorously to attain optimum yield of mango at subtropics.

Assessment of phenological and physicochemical characteristics of peach (Prunus persica L.) varieties in Mustang, Nepal

This research was conducted at the Temperate Horticulture Development Center (THDC), Mustang, Nepal, to study flowering phenology and evaluate the physicochemical characteristics of five peach varieties (Surprise, Benedict, Peregrine, Local Khallya and Early Red) from February to September 2023. This research was conducted on a randomized complete block design with four replications and five treatments (fruit trees of a particular variety were replicated four times). The flowering phenology of varieties was studied by dividing the developmental stages of a flower into eight different stages: first swelling, calyx green, calyx red, first pink, first bloom, full bloom, petal fall and fruit set. The completion of each phenological stage was marked from a reference date. Physicochemical analysis of fruits was performed following UPOV guidelines of peach. Physical characteristics were encompassed in individual fruit weight, fruit length, fruit volume, fruit size (length and width), stone weight, stone size (length and width) and mesocarp thickness and in chemical characteristics, pH, total soluble solids (TSS), titratable acidity (TA) and TSS/TA ratio were included. The study of flowering phenology revealed that Early Red was found to be the earliest (60.50 DARD) to reach the fruit-set stage. The highest and lowest fruit weights were measured in Benedict (153.85 g) and Early Red (46.5 g), respectively. Finally, chemical analysis revealed that TSS/TA was found to be maximum in Benedict (12.38) and minimum in Early Red (6.03). It can be concluded that Early Red was the earliest maturing variety among the varieties. Also, Benedict was found to be the superior in terms of sweetness and size.

Effects of Irrigation and Fertigation on Seedless Watermelon Yield in Southern Indiana

Indiana cultivates approximately 7000 acres of watermelons (Citrullus lanatus) every year, with the majority of production concentrated in southern Indiana, thus making this region a key area for watermelon production in the United States. Diverse irrigation and fertilization practices are used for watermelon production in the region, yet their effects on production outcomes remain poorly understood. To address this knowledge gap, this study investigated the impact of existing practices on watermelon yield to optimize irrigation and fertilization practices for improved production. The experiment was conducted at the Southwest Purdue Agricultural Center, Vincennes, IN, USA, during the 2022 and 2023 watermelon seasons. The following four treatments were applied: high irrigation, low irrigation, no irrigation, and fertigation. The fertigation treatment received the same water application as the high irrigation treatment, but with frequent fertilizer application with irrigation; however, fertilizers were applied before planting in the high, low, and no irrigation treatments. Although soil moisture levels at the different depths varied notably among treatments, no significant differences in yield by weight were observed. The minimal impact of irrigation on watermelon yield suggested that sufficient water is stored in the soil to prevent yield-reducing stress during dry periods. However, the high irrigation and fertilization treatments produced more fruit than the low irrigation and no irrigation treatments. The dry periods during both years coincided with the watermelon fruit-setting stages, potentially contributing to the lower fruit set in the low irrigation and no irrigation treatments. Fertigation showed a higher early yield in 2022 than that of the other treatments. An analysis of soil and tissue nitrogen levels indicated that solely applying nitrogen before planting could lead to excessive soil nitrogen during vegetative growth. This excess nitrogen might delay flowering and harvest. This project offers insights into enhancing irrigation and fertilization practices for watermelon production in southern Indiana, provides recommendations, and discusses future research directions.

Thrips (Thysanoptera: Terebrantia) in Nectarine Orchards in North-East Spain: Species Diversity and Fruit Damage.

Thrips constitute one of the main nectarine pests, with damage either in flowering or before harvesting (silvering). Several species are associated with damage to flowers, but Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) is the main species associated with summer damage in Europe. Tree canopies of nectarine orchards under organic and integrated management were sampled in Lleida and Girona at four key moments of the season (bud burst, full flowering, fruit setting stage, and colorization of the fruit) during 2021 and 2022 to determine the species composition in the area and the damage caused during fruit maturation. Adult individuals in flowers, leaves, and fruit surfaces were collected and identified, and silvering damage to the fruit surface was assessed in the Lleida area. Fifteen species in Lleida and 10 species in Girona were collected from the tree canopy. Organic orchards in Lleida showed lower populations and silvering damage levels when compared with integrated orchards. Thrips fuscipennis Haliday (Thysanoptera: Thripidae) 1836 was the main species in Lleida during harvest, and Frankliniella occidentalis (Pergande) 1895 was the main species in Girona. Due to their predominance, both species were associated with silvering damage during fruit maturation.

Estimating Leaf Area Index in Apple Orchard by UAV Multispectral Images with Spectral and Texture Information

The Leaf Area Index (LAI) strongly influences vegetation evapotranspiration and photosynthesis rates. Timely and accurately estimating the LAI is crucial for monitoring vegetation growth. The unmanned aerial vehicle (UAV) multispectral digital camera platform has been proven to be an effective tool for this purpose. Currently, most remote sensing estimations of LAIs focus on cereal crops, with limited research on economic crops such as apples. In this study, a method for estimating the LAI of an apple orchard by extracting spectral and texture information from UAV multispectral images was proposed. Specifically, field measurements were conducted to collect LAI data for 108 sample points during the final flowering (FF), fruit setting (FS), and fruit expansion (FE) stages of apple growth in 2023. Concurrently, UAV multispectral images were obtained to extract spectral and texture information (Gabor transform). The Support Vector Regression Recursive Feature Elimination (SVR-REF) was employed to select optimal features as inputs for constructing models to estimate the LAI. Finally, the optimal model was used for LAI mapping. The results indicate that integrating spectral and texture information effectively enhances the accuracy of LAI estimation, with the relative prediction deviation (RPD) for all models being greater than 2. The Categorical Boosting (CatBoost) model established for FF exhibits the highest accuracy, with a validation set R2, root mean square error (RMSE), and RPD of 0.867, 0.203, and 2.482, respectively. UAV multispectral imagery proves to be valuable in estimating apple orchard LAIs, offering real-time monitoring of apple growth and providing a scientific basis for orchard management.

Effects of the drought induced stress on the flowering and the fruit set stages in tomato collection

Effects of the drought induced stress on the flowering and the fruit set stages in tomato collection

Effect of Foliar Application of Potassium Fertilizer on Yield, Fruit Quality, and Cold Hardiness of Vitis spp. ‘Chambourcin’

ABSTRACT Temperate regions experiencing sub-zero temperatures negatively impact grapevine yield. Potassium has been claimed as a cryoprotectant to improve cold hardiness in grapevine. This study investigated the effect of foliar application of liquid potassium-based fertilizer, ReaXTM, on cold-hardiness of grapevine Vitis spp. “Chambourcin” along with its effect on yield and fruit quality. The vines were sprayed four to five times between the fruit set and veraison stage at a concentration of 1.5% (v/v) for two consecutive seasons. Petioles were analyzed for nutrients, clusters for yield and fruit quality, and cold hardiness was determined by differential thermal analysis and bud injury assessment. Potassium deficiency was observed in all treatments, and its content did not increase significantly in treated vines. Berry potassium levels and total soluble solids were generally higher in K-treated vines, however, there was no significant effect on yield and other fruit quality traits. Significant differences in cold hardiness levels were observed in both dormant seasons. Foliar application of potassium is a promising cultural practice to increase cold hardiness, but further studies are needed to understand the limits of its effectiveness.

Optimizing deficit drip irrigation to improve yield,quality, and water productivity of apple in Loess Plateau of China

ContextDeficit drip irrigation is an advanced agricultural technology widely promoted and applied around the world to maintain/increase yield and quality while simultaneously minimizing water consumption. However, there is still a lack of comprehensive research on the effects of deficit drip irrigation at different stages on apple yield, water productivity, and quality. ObjectiveThe aim was to investigate the effects of deficit drip irrigation treatments (DDITs) on apple yield, quality, and water productivity (WP), and optimize the deficit drip irrigation strategy for apples in the Loess Plateau of China. Methodsa two-year field experiment was conducted with 17 irrigation treatments, including a control treatment (CK, full irrigation (FI)) and four DDITs (D15%, D30%, D45%, D60%) during the bud burst to leafing stage (I), flowering to fruit set stage (II), fruit expansion stage (III), and fruit maturation stage (IV). The optimal irrigation management was determined using the fuzzy Borda combined model, which was based on four different single evaluation models of the TOPSIS method, principal component analysis (PCA), grey correlation analysis (GCA), and membership function analysis (MFA). ResultsThe DDITs at stage IV decreased midday leaf water potential (Ψs) by 2.57–20.00% compared with CK, and the difference of Ψs between IV-D30%, IV-D45%, IV-D60%, and CK were significant in two years (P<0.05). DDITs at stages I, II, and IV improved fruit weight (FW), fruit shape index (FSI), and fruit firmness (FN), but did not significantly affect fruit water content (FWC). The DDITs at stages III and IV significantly enhanced total soluble solids (TSS), soluble sugars (SS), and vitamin C (Vc) in 2021 and 2022, but a notable decrease in titratable acidity (TA) was observed. ConclusionsDDITs at stage IV exhibited the highest comprehensive benefit of apple, followed by DDITs at stages I and II, and DDITs at stage III had the lowest values. The DDITs of D15%, D30%, CK, and D15% at stages I, II, III, and IV were identified as the optimal irrigation strategy to improve apple yield, quality, and WP. ImplicationsOur findings can guide the development of appropriate irrigation strategies for apple cultivation in Loess Plateau of China, promoting efficient and sustainable apple production.

Impact of climatic variations in horticulture sector, Kinnaur, Himachal Pradesh, India

Climate change has an impact on the horticulture crops of Himachal Pradesh in relation to the varying climatic conditions in the Himalayan Region. The purpose of the study was to determine how frequently these differences in horticultural crops occur in the Kinnaur district of Himachal Pradesh since the horticulture industry in Himachal Pradesh greatly benefits from this district. Long-term temperature (maximum, minimum, and diurnal) and rainfall data from 1990 to 2020 were analyzed for different phenological stages (pre-flowering, flowering, and fruit setting). The findings revealed that the average maximum and diurnal temperatures were found to have increased significantly, at the rate by 0.027 °C and 0.042 °C, respectively, during the flowering stages. However, there were no appreciable changes in the variations for other phenological stages. Under trend analysis of crop yield, the productivity of Pear and Almond notably fell over the past 20 years, at -0.029 t/ha/year and -0.016 t/ha/year, respectively, whereas Walnut productivity climbed at 0.008 t/ha/year. The relationship or impact between the climate and the crop was also examined in addition to the trend analysis for crop and climatic variables. The results showed that among the three phenological stages, Apple and Apricot were highly impacted (54.4%) during pre-flowering stage, followed by Apricot, i.e., 72.6% during flowering, and Grapes (53.2%) during the fruit setting stage. In the current situation, climate fluctuations had a favorable effect on Apples, Walnuts and Grapes while having a negative effect on Apricots, Plums, Pears and Almonds.

A Comprehensive Assessment of the Morphological Development of Inflorescence, Yield Potential, and Growth Attributes of Summer-Grown, Greenhouse Cherry Tomatoes

Understanding how cherry tomatoes respond to variations in greenhouse microclimate is crucial for optimizing tomato production in a controlled environment. The present study delves into the intricate relationship between summer-grown cherry tomatoes (Cheramy F1) and greenhouse conditions, exploring the influence of these conditions on growth attributes, inflorescence development, and yield potential. The aim of the study was to characterize the chronology of reproductive events, specifically flowering and fruit stages, in correlation with the prevailing greenhouse climate during the development of the first ten inflorescences on the plant. The performance of each inflorescence has been ranked based on available data, which involve a comparative analysis of both the time duration (number of days) and the frequency of yield-contributing traits, specifically the total number of flowers at the anthesis stage. The duration of each stage required for completion was recorded and presented as a productivity rate factor. Greenhouse conditions exhibited variations during the vegetative and reproductive stages, respectively, as follows: temperature - 25.1 °C and 21.33 °C, CO2 levels - 484.85 ppm and 458.85 ppm, light intensity - 367.94 W/m2 and 349.52 W/m2, and humidity - 73.23% and 89.73%. The collected data conclusively demonstrated a substantial impact of greenhouse microclimate on plant growth, productivity, and inflorescence development. The development of flowers and fruit has been categorized into five stages: the fruit bud stage (FB), the anthesis stage (AS), the fruit setting stage (FS), the fruit maturation stage (FM), and the fruit ripening stage (FR). An irregular productivity and development response was noted across the first (close to roots) to the tenth inflorescence. Inflorescence 5 demonstrated the highest overall performance, followed by inflorescence numbers 4 and 6. The study findings provide valuable insights for enhancing greenhouse operations, emphasizing the improvement of both the yield and growth of cherry tomatoes while promoting environmental sustainability. A statistical analysis of variance was used to rigorously examine the presented results, conducted at a confidence level of p &lt; 0.05.

Gibberellin acid 4 and 7 increase indole-3-acetic acid production and induce cell division via PbCRF4-mediated activation of PbYUCCA6 expression in ‘Dangshansu’ pear

The role of gibberellins in inducing cell division is now widely recognized; however, the underlying mechanisms remain to be clarified. Here, we demonstrate that gibberellin acid 4 and 7 (GA4+7) can induce active cell division leading to ovary expansion as CPPU (N-(2‑chloro-4-pyridyl)-N’-phenylurea) at the early fruit setting stage in ‘Dangshansu’ pear (Pyrus bretshneideri Rehd.). Transcriptomic analysis showed PbCYTOKININ RESPONSE FACTOR4 (PbCRF4) was activated in response to GA4+7 and CPPU, suggesting a candidate gene correlated to gibberellin-induced cell division during early fruit development. Overexpression and RNA interference of PbCRF4 in pear calli demonstrated a role of PbCRF4 in regulating fruit cell proliferation and increased indole-3-acetic acid (IAA) biosynthesis. Ectopic overexpression of PbCRF4 in tomato produced flat fruits with no pointed tips, decreased the fruit index, and increased the pericarp thickness and IAA content. Silencing of SlCRF4 in tomato led to pointed-tip fruits with a relatively low IAA content and reduced pericarp thickness. Furthermore, PbCRF4 transcriptionally activated indole-3-pyruvate monooxygenase 6 (YUCCA6) to increase IAA content in pear. Taken together, this study reveals that GA4+7 induces cell division and an increase in IAA content via regulating PbCRF4 to activate the expression of PbYUCCA6, thereby contributing to the control of fruit shape.

The Effects of Gibberellic Acid and Cane Girdling of Applications on Crimson Seedless Grape Variety of Cluster and Berry Characteristics

‘Crimson Seedless’ grape variety is a late maturity and small berry size. Berry size is one of the most important quality parameters of table grapes. This trial was carried out in the Crimson Seedless (Vitis vinifera L.) grower vineyard in Sarıgöl (dadağlı) locality of Manisa province in the 2022 vegetation period. A randomized complete block design was used with vines as blocks and clusters as the experimental unit’s four treatments and four replications. Vine bunches of Crimson Seedless grape variety, ten years old, were sprayed extensively with a GA3 (Gibberellic Acid) solution (20 mg L-1) on the 25th of April 10th of May, and 10th of June/2022, while girdling (G) was applied from removing 3 mm diameter bark all around from 10 cm below the top of the vine trunk at fruit set stage. Control (C) only water was sprayed. This study aimed to reveal gibberellic acid and cane girdling applications on Crimson Seedless cluster and berry characteristics. Harvest (oBrix 19) was done on the 10th of October/2022 and after that, the cluster weight (g), cluster length (cm), cluster width (cm), berry weight (g), berry length (mm), berry diameter (mm), berry length/berry diameter, total soluble solid, total acidity and maturity index were determined in fresh fruit samples randomly taken from each vine. It was found that all applications generally had statistically (P

Root-zone aeration improves fruit yield and quality of tomato by enhancement of leaf photosynthetic performance

Heavy irrigation and soil compaction cause hypoxic stress in plant roots, which limits crop growth. This issue can be solved by root-zone aeration, but the photophysiological responses of crop plants to the dissolved oxygen (DO) concentration in irrigation water remain unclear. Here, a greenhouse plot experiment was conducted to investigate the changes in leaf photosynthesis and plant growth of tomato (Solanum lycopersicum L. cv. ‘Omanda 3′) under aerated irrigation with various DO concentrations. Plants were treated with three different levels of aeration: 5 mg L–1 DO (conventional subsurface irrigation as a non-aeration control), 15 mg L–1 DO (low aeration treatment), and 30 mg L–1 DO (high aeration treatment). Compared with the control, the aeration treatments promoted electron transport from the primary to secondary plastoquinone acceptors (QA to QB) of photosystem II (PSII) and increased leaf net photosynthetic rate in plants at the seedling, fruit expansion, and maturation stages. The opposite effects of aeration treatments were observed at the flowering and fruit-setting stage. The enhancement of leaf photosynthetic performance contributed to improved plant growth, fruit yield, and quality of tomato as a result of increased oxygen supply in the root zone. The aeration treatments additionally facilitated the biosynthesis and transport of photosynthetic carbon assimilates in plant tissues, as evidenced by increased starch and sucrose contents in the leaves and sucrose content in the roots. However, under the high aeration level, excessive transport of sucrose from leaves to roots hindered further improvements in tomato yield and biomass at the maturation stage. Based on plant photophysiological and yield performance, aerated irrigation with a low concentration of DO (15 mg L–1) is recommended for greenhouse tomato crops during the seedling, fruit expansion, and maturation stages, and there is no need of root-zone aeration at the flowering and fruit-setting stage.

Responses of grape yield and quality, soil physicochemical and microbial properties to different planting years

As an economically important fruit crop, continuous cropping of grapes can potentially impact soil health resulting in decreased yields. However, the mechanism of how soil microecological environment affects grape quality at different growth stages is not fully understood. A field experiment was conducted to investigate the effects of continuous grape cultivation for 0, 7, and 12 (CK, G7Y and G12Y) years on soil physicochemical properties and microbial community at different growth periods and soil depths, as well as on grape yield and quality. The results showed that grape yield, aroma compound contents, soil and grape leaf nutrients decreased significantly with the increase of planting years, soil acidification and secondary salinization intensified. Compared to G7Y, the relative abundance of the beneficial soil microorganisms Mortierella, Bacillus and Pseudomonas decreased significantly in G12Y, while the relative abundance of the potential pathogenic fungi Pseudaleuria and Aspergillus increased significantly. In addition, the nutrient content and biomarkers in the subsoil were lower than those in the topsoil. Particularly, the fruit setting stage appeared to be more sensitive to shifts in soil microbial communities over different planting years. Correlation analysis showed that grape yield was positively correlated with Bacillus and Mortierella, and negatively correlated with Fusarium. Grape yield was more sensitive to phosphorus and potassium fertilizers than to nitrogen fertilizer. In conclusion, continuous cropping reduced the content of soil nutrients and the number of soil beneficial microorganisms, increased the abundance of soil pathogenic microorganisms, and jointly caused changes in grape yield and quality. Therefore, it is necessary to optimize the management strategies to improve the soil microbial diversities especially beneficial microbial diversity to maintain the soil health and then to promote sustainable production of vineyards.

Effects of Bio-Amendment of Coconut Dust with Empty Fruit Bunch Compost on the Efficacy of Mycorrhizae Under Deficit Fertigation

It has been known that the application of beneficial fungi and compost, has a favourable effect on easing water deficiency stress in plants, hence helping to boost agricultural activities in times of climate uncertainty. In this study, the influence of arbuscular mycorrhizal fungi (AMF) in combination with oil palm empty fruit bunch compost (EFB) on the growth, yield, and physiology of chilli under deficit fertigation was investigated. Throughout the study, five-week-old chilli seedlings were fertigated daily with 100% and 60% of daily evapotranspiration (ET) readings. Three days after transplanting, 10g of sandy soil containing roughly 120-150 mycorrhizal spores was applied to the root zone. Physiological data such as real-time photosynthesis and stomatal conductance were measured at vegetative, early flowering, fruit setting, and maturity or harvesting stages. Meanwhile, yield and morphological measurements were recorded at the end of the study. It was discovered that the addition of EFB to the coconut coir dust media enhanced the beneficial effects of AMF on all parameters including total biomass, chlorophyll fluorescence Fv/Fm, total chlorophylls, photosynthesis rate and stomatal conductance regardless of fertigation levels. The study also revealed that AMF inoculation alone was less effective than non-inoculation + EFB. In conclusion, it is suggested that incorporation of AMF and EFB compost positively affect the yield, growth and physiology of chilli under deficit fertigation.

Influence of Interaction between Fertilizer and Micronutrient Spray on Growth, Yield and Quality of Guava under Ultra High Density Orcharding System

A field experiment was conducted for two consecutive years (2012-2013 and 2013-2014) on a 5-year-old guava orchard of cv. Sardar was planted at a spacing of 1.0 m x 2.0 m in Ranchi. The objective of this investiation was to know the influence of interaction between the basal and foliar application of fertilizers of guava cv. Sardar under ultra-high-density planting system in eastern plateau and hill conditions. The experiments were set up in a split-plot design with four fertilizer doses 100%NPK i.e.580 g N, 270 g P, 400g K/plant; 60%NPK i.e. 348gN, 162gP, 240g K/plant; 40%NPK i.e. 232gN,180gP 160g K/plant; 20%NPK i.e.116gN 54gP 80g K/plant as main plots and four different foliar sprays as boric acid (0.4%), zinc sulphate (0.2%), boric acid (0.4%) + zinc sulphate (0.2%) and water spray as subplots with four replications. The NPK fertilizer dose was applied at an interval of every two months from June 12 to April 14 (A total of twelve times/ two year) in a 1m radius around the tree trunk (drip line of trees). The foliar application of micronutrients was sprayed at the rate of 750 ml/ tree at flowering and fruit set stage during June 12 and August 14 (Total of Four times/ two years). In our two-year study, the experimental results indicated that 60% NPK fertilizer dose resulted in maximum trunk girth (55.33 mm) and girth of primary branches (43.77mm), while, a maximum per cent increase in trunk girth (15.81%) and girth of primary branches (18.62%) were recorded in 100% NPK fertilizer dose. However the maximum number of flowers per plant (18.66), number of fruit per plant (17.10) and fruit weight/ plant (3.65kg/plant) were recorded in 100%NPK fertilizer dose, which was at par with 60% NPK Fertilizer dose.

Deficit drip irrigation improves kiwifruit quality and water productivity under rain-shelter cultivation in the humid area of South China

Comprehending crop responses to water deficit at different growth stages is crucial for developing effective irrigation strategies. Different water deficit treatments (WDTs) were applied to the kiwifruit vines to investigate the effect of water deficit during different growth stages on the fruit quality, yield, and water productivity (WP); subsequently, the technique for order preference by similarity to an ideal solution method (TOPSIS) was employed to determine optimal treatments for kiwifruit cultivation. A total of 17 irrigation treatments were applied, including one control treatment (CTL, full irrigation) and four WDTs (denoted as D15%, D25%, D35%, and D45% respectively) during the bud burst to leafing (I), flowering to fruit set (II), fruit expansion (III), and fruit maturation (IV) stages. Results showed that WDTs during I, II, III, and IV decreased evapotranspiration (ET) over the whole growth period of kiwifruit vines by 1.2–3.8, 1.5–4.4, 4.7–14.3, and 6.9–21.3% compared with CTL, respectively. WDTs during stages I and II increased fruit volume (Vf) and fruit weight (FW), while exhibiting no significant impact on yield, WP, and chemical quality of kiwifruit. WDTs during stage III improved fruit firmness (Fn), total soluble solids (TSS), and titratable acidity (TA); however, it also caused severe reduction in Vf, FW, yield, and WP. Appropriate WDTs during stage IV significantly improved Fn, TSS, TA, vitamin C (Vc), and WP without compromising Vf, FW, and yield of kiwifruit. The IV-D25% treatment was determined to be the optimal treatment for improving fruit quality and WP of kiwifruit while maintaining yield, which increased TSS, TA, Vc, and WP by 9.1, 6.1, 19.2, 4.6%, respectively; the combination of D25%, D25%, full irrigation, and D25% treatments during stages I, II, III, and IV should be a viable irrigation strategy to simultaneously achieve high yield, quality, and WP of kiwifruit.

Synergistic effect on soil health from combined application of biogas slurry and biochar

Biogas slurry and biochar, as typical by-products and derivatives of organic waste, have been applied in agricultural production to improve the soil carbon (C) pool. However, whether the combined application of biogas slurry and biochar produces synergistic effects on the soil C pool and soil health requires quantitative clarification. In this study, we performed a pot experiment to analyze the changes of soil organic carbon (SOC), potassium permanganate-oxidized carbon (POXC), mineralizable carbon (MC), soil β-glucosidase (S-β-GC), and soil protein (SP) in different treatments at the flowering and fruit-setting stages, and full fruit stage of tomato by establishing two base fertilizer modes (base fertilizer N and base biogas slurry N), three topdressing modes (topdressing chemical fertilizer N, topdressing 50% biogas slurry N + 50% chemical fertilizer N, and topdressing biogas slurry N), and two biochar levels (no addition and 3% biochar addition). During the full fruit period, the SOC content of bottom applications of biogas slurry and topdressings of biogas slurry significantly increased by 9.92–15.52% and 13.02–18.26%, respectively (P < 0.05), when compared to chemical fertilizer bottom applications and topdressings of chemical fertilizer. When compared to non-biochar treatment, the SOC content of the biochar considerably increased by 52.56–58.94% (P < 0.05). Moreover, biogas slurry treatment increased the MC, steady-state C, and C pool index, and decreased the S-β-GC, C pool efficiency, C pool activity, and C pool activity index. Application of biogas slurry initially reduced POXC, SP, the C pool management index, and the soil quality index; nonetheless, these indicators eventually recovered or even exceeded the result of single application chemical fertilizer. Overall, the combined application of biogas slurry and biochar strongly increases the soil C pool, improves soil health, and reduces the short-term negative effects of using only biogas slurry.

Optimizing water and nitrogen management strategies to improve their use efficiency, eggplant yield and fruit quality.

With improvement in living standards, consumer preferences for vegetables are changing from quantity- to quality-oriented. Water and nitrogen supply, as two major determinants of vegetable crop yield and quality, can be optimally managed to improve the yield and quality. To evaluate the response in yield, fruit quality, and water and nitrogen utilization of eggplant to different water and nitrogen management strategies, a 2-year (2021 and 2022) field trial under mulched drip irrigation was conducted. The growth period was divided into seedling, flowering and fruit set, fruit development, and fruit ripening stages. Three irrigation levels were applied during the flowering and fruit set stage: W0, adequate water supply (70%-80% of field water capacity, FC); W1, mild water deficit (60%-70% FC); and W2, moderate water deficit (50%-60% FC). In addition, three nitrogen application rates were applied: N1, low nitrogen level (215 kg ha-1); N2, medium nitrogen level (270 kg ha-1); and N3, high nitrogen level (325 kg ha-1). The irrigation and nitrogen rates were applied in all combinations (i.e., nine treatments in total). Adequate water supply throughout the reproductive period in combination with no nitrogen application served as the control (CK). The yield of the W1N2 treatment was significantly increased by 32.62% and 35.06% in 2021 and 2022, respectively, compared with that of the CK. Fruit soluble protein, soluble solids, and vitamin C contents were significantly higher under W1 than W2. Fruit quality was significantly higher under the N2 rate compared with the other nitrogen rates. The W1N2 treatment showed the highest water productivity, with a significant increase of 11.27%-37.84% (2021) and 14.71%-42.48% (2022) compared with that under the other treatments. Based on the average water-deficit degree and nitrogen application rate, W0 and N1 had the highest partial factor productivity of nitrogen. Assessment of the results using the TOPSIS (technique for order preference by similarity to an ideal solution) method indicated that mild water deficit in combination with the medium nitrogen application rate (W1N2) was the optimal water and nitrogen management strategy for cultivated eggplant. The present findings contribute novel insights into the sustainable cultivation of eggplant in an oasis arid environment.

Effects of water and fertilizer deficit regulation with drip irrigation at different growth stages on fruit quality improvement of kiwifruit in seasonal arid areas of Southwest China

For a long time, seasonal drought occurs frequently in Southwest China, and the management of water and fertilizer in kiwifruit orchards has no quantitative standards, which seriously affects the yield and quality of kiwifruit. Therefore, the effects of water and fertilizer deficit regulation with drip irrigation (WFDRDI) on the quality of kiwifruit at different growth stages were explored to achieve water and fertilizer saving, and green and efficient production of kiwifruit. We select ‘Jin Yan’ kiwifruit and set two water deficit levels (WD20% and WD40%) and three fertilizer deficit levels (FD15%, FD30% and FD45%) at bud burst to leafing stage (stage I), flowering to fruit set stage (stage II), fruit expansion stage (stage III) and fruit maturation stage (stage IV), respectively, with a full irrigation and fertilization as the control treatment (CK) in 2017 and 2018. Results showed that the WFDRDI at stage II and III had significant effect on fruit physical quality of kiwifruit, specifically, the III-WD40%FD30% and III-WD20%FD45% treatments significantly increased fruit firmness by 13.62 and 15.59% (P<0.05), respectively; the II-WD40%FD15% and III-WD40%FD15% treatments significantly increased dry matter by 8.19 and 6.47% (P<0.05), respectively; the III-WD20%FD15% treatment significantly increased single fruit weight and fruit volume by 9.33 and 12.65% (P<0.05), respectively; the II-WD20%FD15% treatment significantly increased fruit water content by 1.99% (P<0.05). The WFDRDI had an obvious effect on fruit chemical quality of kiwifruit. The III-WD20%FD45%, IV-WD40%FD15% and IV-WD20%FD30% treatments significantly increased vitamin C (Vc) content by 69.96, 36.96 and 34.31% (P<0.05), respectively; the III-WD40%FD15% and IV-WD40%FD15% treatments significantly increased total soluble solid (TSS) content by 3.79 and 17.05% (P<0.05), respectively, and significantly increased soluble sugar content by 28.61 and 34.79% (P<0.05), respectively; the contents of fructose, glucose and sucrose also had a significantly increasing trend, which was increased significantly by 5.58–19.63%, 40.55–60.36% and 54.03–54.92% in the III-WD40%FD15% and IV-WD40%FD15% treatments (P<0.05), respectively; sugar–acid ratio was increased significantly in the IV-WD40%FD15% treatment by 64.65% (P<0.05). The degree and duration of water and fertilizer deficit had a comprehensive effect on fruit quality of kiwifruit. The WFDRDI at stage II and III contribute to improving fruit physical quality, and the threshold of water and fertilizer deficit were 20 and 15%, respectively; stage III and IV are the critical periods for improving fruit chemical quality by water and fertilizer coupling effect, and the threshold of water and fertilizer deficit were 40 and 15%, respectively. Therefore, aiming at precise water and fertilizer saving, the I-WD20%FD30%, II-WD40%FD15%, III-WD40%FD15% and IV-WD40%FD15% treatments under WFDRDI during the whole growth period of kiwifruit were the best mode to improve quality and production of kiwifruit.