Non-irrigated Orchards Research Articles

Enhancing the Yield of Mature Olive Trees via Comparative Fertilization Strategies, including a Foliar Application with Fulvic and Humic Acids, in Non-Irrigated Orchards with Calcareous and Non-Calcareous Soils

This study investigated the impact of fertilization treatments on mature, forty-year-old, fully productive olive trees (Olea europaea L. cv. Koroneiki) in two non-irrigated orchards featuring contrasting soil types: non-calcareous–acidic and calcareous–alkaline. Over three years (2019–2021), seven distinct treatments were applied, involving inorganic soil fertilizers (traditional strategy) and foliar applications of a liquid organic product containing fulvic and humic acids. Fertilization significantly influenced physiological parameters, such as mineral nutrition, photosynthetic pigments of olive leaves, fruit yield, and oil production per tree, revealing noteworthy effects influenced by soil types and their interactions with treatments. Statistical analysis highlighted specific treatments, indicating that the foliar application of the organic product once a year in alkaline soil or biannually in acidic soil resulted in the highest observed fruit yield and oil production per tree. Indeed, contrary to the control–unfertilized trees, specific fertilization strategies resulted in an average increase of up to 47% and 73% in fruit yield per tree and up to 96% and 100% in oil production per tree in acidic and alkaline soil, respectively. Furthermore, consistently high yields were correlated with constant high values of the chlorophyll a/chlorophyll b ratio (2.3–3.3 in August for acidic soil) and leaf chlorophyll a concentration (55–66 mg/100 g f.w. in August for alkaline soil). This novel finding underscores the crucial role of these factors as prerequisites for achieving superior fruit production. Our results emphasize the potential of integrating foliar organic fertilization as a complementary strategy to traditional soil-based approaches. This is particularly relevant under non-irrigated/rainfed cultural conditions, emphasizing the significance of considering alternative fertilization practices for optimized olive orchard management.

Effects of Phenolic Compounds on Walnut Bacterial Blight in the Green Husk of Hungarian-Bred Cultivars.

The Persian walnut (Juglans regia L.) is the most grown nut tree crop in Central Europe. The aim was to study the full Hungarian walnut assortment with a distinct early spring phenology to detect the difference in phenolic profile in their green husks. Furthermore, the relationship between the presence and concentration of phenolic compounds and the tolerance/resistance of the observed cultivars to walnut bacterial blight was investigated. Examining the samples, significant differences were found between the concentrations of the different groups of phenolic compounds. Walnut blight immunity tests were also performed to clarify the role of phenolic compounds in the nut derived from a non-irrigated orchard. The Hungarian-bred local cultivars contained phenolic compounds in higher concentrations than the domesticated ones. There was a significant correlation between the budburst, as well as the pistillate flowers' receptivity and the concentration of juglone. Cultivars with a low concentration of phenolic compounds were the most susceptible to walnut bacterial blight, except 'Bonifác'.

Effect of cherry rootstocks on harvest and quality of fruits in non-irrigated orchard

Effect of cherry rootstocks on harvest and quality of fruits in non-irrigated orchard

Mild Water Stress Makes Apple Buds More Likely to Flower and More Responsive to Artificial Forcing— Impacts of an Unusually Warm and Dry Summer in Germany

Climate change may result in increasingly frequent extreme events, such as the unusually dry conditions that occurred in Germany during the apple growing season of 2018. To assess the effects of this phenomenon on dormancy release and flowering in apples, we compared irrigated and non-irrigated orchard blocks at Campus Klein-Altendorf. We evaluated bud development, dormancy release and flowering in the following season under orchard and controlled forcing conditions. Results showed that irrigated trees presented longer (39.2%) and thinner shoots compared to non-irrigated trees. In both treatments, apical buds developed a similar number of flower primordia per cyme (4–5), presenting comparable development and starch dynamics during dormancy. Interestingly, buds on non-irrigated shoots exposed to low chill levels responded earlier to forcing conditions than those on irrigated shoots. However, chill requirements (~50 Chill Portions) and bud phenology under field conditions did not differ between treatments. In spring, buds on non-irrigated trees presented a higher bloom probability (0.42) than buds on irrigated trees (0.30). Our findings show that mild water stress during summer influenced vegetative growth during the same season, as well as the response of buds to forcing temperatures and flowering of the following season. The differences between irrigation levels in the phenological responses of shoots under low-chill conditions point to a so-far understudied impact of water supply on chilling requirements, as well as subsequent bud behavior. Accounting for the effects of both the water status during summer and the temperature during the dormant season may be required for accurately predicting future tree phenology in a changing climate.

Early performance of three plum cultivars on different rootstocks in non-irrigated orchard

Growth and yield characteristics of three plum cultivars (Prunus domestica) ‘Elena’, ‘Tophit’ and ‘Cacanska lepotica’ grafted on seven different rootstocks were evaluated in the years 2010-2015. The tested material included St. Julien A as a standard, Jaspi-Fereley, Julior-Ferdor, St Julien 2, Pixy, MY-KL-A and Wangenheim seedling. Furthermore, ‘Tophit’ was assessed also on VVA1. The trees were planted in the experimental orchard of the Research and Breeding Institute of Pomology Holovousy in the Czech Republic. The orchard was established on medium fertile loamy soil in a non-irrigated plot in the autumn 2009. Planting distance was 5.5×2.7 m and the trees were trained to a central leader. The following characteristics were assessed: flowering intensity, yield, trunk cross sectional area (TCSA), crown volume, yield efficiency related to TCSA, yield efficiency related to crown volume, average fruit weight and suckering. We observed significant differences in growth and yields among the rootstock combinations in all of the cultivars. The most vigorous were MY-KL-A, St. Julien 2 and Jaspi-Fereley for all of the cultivars and also Julior-Ferdor for ‘Elena’ and ‘Tophit’. The least vigorous were Wangenheim seedling, Pixy and for ‘Tophit’ also VVA1. The production of suckers was generally at low level and dependent on grafted cultivar. All of the cultivars reached the highest yields on rootstock Jaspi-Fereley. The least productive were the trees on rootstock Pixy and in case of ‘Tophit’ also on VVA1. Similarly, the highest yield efficiency related to TCSA was on Jaspi-Fereley for all of the cultivars. Jaspi-Fereley had also a good yield efficiency related to crown volume and brought fruits of good weight. We concluded that Jaspi-Fereley is the best rootstock in non-irrigated orchards in our conditions for the first years of the growing period. Though it grows more than standard rootstock St. Julien A, it is precocious, highly productive and brings fruits of high weight.

Growing conditions do not affect allometric estimation of fresh fruit weight, but affect estimation of dry fruit weight of ‘Kent’ mango

An essential aspect of studies on fruit growth is the accurate and nondestructive on-field estimation of key variables of interest such as fresh or dry fruit weight. Allometric relationships between a key variable of interest and one or several easy-to-measure variables that are used as predictors are convenient and powerful tools for this goal. However, these relationships could be affected by different factors. Allometric relationships were built to assess fresh and dry fruit weight of 'Kenbt' mango, and the effects of growing conditions on these relationships were investigated. Length (L), orthogonal diameters (D1, D2), fresh and dry weights were recorded on individual fruits sampled at three dates during fruit growth in six orchards, one irrigated orchard on Reunion island and five irrigated and non-irrigated orchards in Senegal. Allometric relationships were estimated between fresh and dry fruit weights and the product LD1D2. The relationship between fresh fruit weight and LD1D2 was linear and unaffected by the growing conditions. The relationship between dry fruit weight and LD1D2 was allometric, i.e. followed a power function. It was then linearized by log-transformation of the two variables. The growing conditions did not affect the slope of this relationship, but affected the y-intercept. The y-intercepts estimated for each orchard were significantly correlated with the fruit dry matter content, which was also affected by the growing conditions. These results are discussed with regard to the significance of the studied relationships, and to the limits of the allometric method to estimate fruit weight. (Resume d'auteur)

An expert system for predicting orchard yield and fruit quality and its impact on the Persian lime supply chain

In recent years academics and industrials have shown an interest in agricultural systems and their complex and non-linear nature, aiming to improve production yield in the agricultural field. Innovative strategies and methodological frameworks are thus required to assist farmers in decision making for an efficient and effective resource management. In particular, this research concerns the structural problem of the Persian lime supply chain in Mexico, which still leads to low production yield over short time periods with heterogeneous fruit quality and also to the emergence of excessive middleman businesses arising from a fragmentation between orchard and exporting companies that constitute the first two links in the associated supply chain. Based on the Persian lime production cycle, an Expert System (ES) using Fuzzy Logic involving an inference engine with IF—THEN type rules is presented in this paper. A Mamdani model codifies the decision criteria related to agricultural practices for growing Persian lime in non-irrigated orchards. The ES allows the farmer to boost production in orchards by modeling application scenarios for agricultural practices. A case study based on an exporting company׳s fruit supply is discussed, in which the ES proves to be a useful tool to aid the decision making involved in the application of agricultural practices in the orchard. Results show an increase in production yield and fruit quality in the orchard, as well as a better synchronization between orchard and exporting companies, with a significant impact on inventory levels of fresh fruit in the link Persian lime exporting company.

The effects of conservation tillage practices on the soil water-holding capacity of a non-irrigated apple orchard in the Loess Plateau, China

Six tillage practices were studied in an apple orchard located in the Loess Plateau from 2007 to 2009. The objective was to investigate the effects of tillage practices on the soil water-holding capacity in a non-irrigated orchard in China. The results showed that different tillage practices had varied effects on the water-holding properties. Subsoil tillage with straw mulching, plow tillage with straw mulching and no tillage with straw mulching showed a decrease in the soil bulk density and an increase in the soil porosity, soil saturated water content and soil moisture relative to plow tillage in bare soil (i.e., conventional tillage). Among these three tillage practices, the subsoil tillage with straw mulching and no tillage with straw mulching treatments had a significant effect on the soil porosity, soil saturated water content and soil moisture compared to the plow tillage with straw mulching treatment. These results indicate that the subsoil tillage with straw mulching, plow tillage with mulching and no tillage with mulching treatments improved the soil structure and water-holding capacity of the apple orchard. However, the no tillage with bare soil and no tillage with grass treatments increased the soil bulk density and decreased the soil porosity and soil moisture content compared to conventional tillage. This finding demonstrates that no tillage with bare soil and no tillage with grass had adverse effects on the soil structure and water-holding capacity. From the results of this study, we concluded that the subsoil tillage with straw mulching treatment is the optimum practice of the six studied treatments for improving the soil water-holding capacity in this non-irrigated apple orchard in the Loess Plateau of China.

Quantification of extraradical mycelium of Tuber melanosporum in soils from truffle orchards in northern Spain

Quantification of extraradical mycelium of black truffle (Tuber melanosporum) has been carried out in a natural truffle ground and in seven truffle orchards (around 20 years old) established in Tierra Estella and Valdorba sites, within the natural distribution area of the black truffles in Navarre (northern Spain). Specific primers and a Taqman® probe were designed to perform real-time PCR with DNA extracted from soil samples. Amplification of T. melanosporum DNA was obtained from 131 out of the 160 soil samples. The detection limit of the technique was 1.48 μg mycelium/g of soil. The extraradical mycelium biomass detected in the soil from the natural truffle ground was significantly greater (up to ten times higher) than the mycelium biomass detected in any of the orchards. Soil from productive, nonirrigated orchards in the Tierra Estella site contained significantly more extraradical mycelium than the rest of orchards irrigated, productive of T. brumale, or nonproductive. The comparison of soil mycelium biomass in nonirrigated evergreen oak orchards in both sites showed significantly more mycelium biomass in the Tierra Estella site. This study is the first attempt to quantify extraradical mycelium of T. melanosporum in the soil using Taqman® probes. The obtained quantitative results are of special interest to evaluate the fungal response to cultural treatments and to monitor the dynamics of the extraradical mycelium of T. melanosporum in the soil.

INFLUENCIA DEL CLIMA, HUMEDAD DEL SUELO Y ÉPOCA DE FLORACIÓN SOBRE LA BIOMASA Y COMPOSICIÓN NUTRIMENTAL DE FRUTOS DE AGUACATE ‘HASS’ EN MICHOACÁN, MÉXICO

The extended harvest season of ‘Hass’ avocado is due to the diversity of cultivation conditions and the occurrence of multiple vegetative flushes resulting in several bloom and harvest periods. The objective of this study was to evaluate the influence of three climatic conditions (subhumid semiwarm, humid semiwarm, and subhumid temperate), soil moisture regimes (with and without irrigation), and flowering period (“crazy”: August-September; “normal”: December-February; “marcena”: February-March), on biomass of different fruit parts and their nutrient composition. Six trees were selected from each of the six commercial orchards, choosing ten fruit of each tree per flowering season (≥21.5 % pulp dry matter). Fruits were separated in epidermis, pulp, testa, and embryo. Fresh weight (FW), dry weight (DW), dry matter (DM), and nutrient composition were determined for each part. Different to climate and soil moisture regimes, flowering period affected FW, DW, and DM of the fruit parts, as well as their nutrient composition, especially, K, Ca, Mg, S, Fe, Cu, Mn, Zn, and B. Under subhumid climate, the highest contents of N and Mn were obtained in epidermis; of N, P, K, Ca, and Mg in pulp; of Mg, S, Cu, and Mn in testa; and B in testa and embryo. Non-irrigated orchards had higher concentrations of Ca, S, and Cu in epidermis; P, K, Mn, Ca, and Cu in pulp; K, Mn, Cu in testa; and P, K, Mn in embryo. ADDITIONAL

Influence of habitat on nest location and reproductive output of Montagu’s Harriers breeding in natural vegetation

We examined distribution and breeding success of semi-colonial Montagu’s Harriers (Circus pygargus) in relation to habitat in Castellon province (eastern Spain). Breeding areas used by harriers at a 1-km2 scale were characterised by having intermediate percentages of scrub cover, their nesting habitat, and also had intermediate coverage of herbaceous crops and non-irrigated orchards. Out of all habitat variables considered, only the percentage of herbaceous crops within 500 m from individual nests had a positive and significant effect on breeding output of the species, suggesting that this habitat may be efficiently used by harriers to forage. Breeding output was also related to laying date and number of breeding neighbours within 500 m around nests, with pairs laying later and having a higher number of breeding neighbours showing lower fledged brood sizes. Number of neighbours (but not laying date) was positively related to scrub cover within 500 m and to cover of herbaceous crops within 2,000 m. Conservation actions for Montagu’s Harrier in the study area should be aimed at preserving areas of scrub with nearby presence of herbaceous crops or natural grasslands. However, habitat improvement for semi-colonial species such as Montagu’s Harrier may not result in a change of species distribution area, and good habitat areas may remain unoccupied, as social factors like presence of conspecifics play an important role in breeding area selection for these species.

Large-scale epidemiological study and spatial patterns of Verticillium wilt in olive orchards in southern Spain

Verticillium wilt (VW) is caused by the soilborne pathogen, Verticillium dahliae. The fact that available control measures are not completely effective, together with an increasing spread of the highly virulent defoliating pathotype (D) in the last two decades, makes VW one of the most threatening olive tree disease. For better management, epidemiology and spatial patterns of VW were investigated in an important olive-growing area in southern Spain. A sampling survey was conducted from 2002 to 2005 in 873 olive orchards, which were assessed for the presence of V. dahliae. PCR assays were used to identify the highly virulent defoliating (D) and nondefoliating (ND) pathotypes of V. dahliae. Ordinary kriging, a geostatistical tool that uses regression techniques for interpolation of spatial data, was applied to obtain predictive V. dahliae incidence maps and to evaluate the correlation between distance from the river and VW. Prevalence in olive orchards was 14.1%, with a disease incidence of 1.9% and mean incidence per olive orchard of 9.5%. Prevalence of the ND pathotype was higher (10.7%) than for the D pathotype (3.4%). VW was three times more prevalent in irrigated than in non-irrigated orchards (relative risk = 3.01) and there was a close association between the ND pathotype and irrigated orchards (relative risk = 2.03). Spatial pattern analysis showed several factors involved in the spread of the pathogen. VW was more prevalent in the north-west, suggesting the spreading of the disease from other bordering areas known to be contaminated, in southwest Spain. The D pathotype had a very restricted and aggregated distribution, suggesting the introduction of this pathotype in new olive orchards areas. The incidence map generated by kriging displayed an increase in north, northeast and south areas with numerous subareas with probabilities equalling or exceeding 53%, showing the effect of intensive agriculture (high plant density and irrigation) on incidence of the disease. Assessment of rivers-pathogen relationship revealed an association of VW with the distance to the nearest river, indicating that soils through the rivers' axis and previously cropped with horticultural crops susceptible to V. dahliae, have implications for the establishment of new olive orchards and the occurrence of the disease.

Establishing Pecan Transplants

Pecan [Carya illinoinensis (Wangenh.) K. Koch] nursery transplants performed best on establishment in nonirrigated orchards when using large trees planted early in the dormant season. After 6 years, growth and survival of bare-root transplants were equal to that of containerized transplants when established during the dormant season. Reducing transplant trunk height by ≤75% at planting did not affect subsequent tree survival, although rate of height growth and tree vigor increased such that there was no difference between pruned and nonpruned trees after 3 years, except that pruned trees appeared to possess greater vigor. There also were no differences in growth or survival between augured and subsoil + augured planting sites within 6 years of transplanting, and there were no differences between root pruned (severe tap or lateral root pruning) and nonpruned trees.

Under- and Overtree Microsprinkler Irrigation for Frost Protection of Peaches

Spring frost events reduce fruit production in the southeastern United States more than any other factor, with some losses occurring in 5 out of 7 years. Orchard heaters, wind machines, and overhead irrigation are sound methods of reducing losses, but their relatively high cost is a major deterrent for fruit growers (Castaldi, 1990). A potentially leas-costly and more water- efficient approach to frost protection is overtree microsprinkling. Microsprinkler irrigation was applied either beneath or onto canopies of 4-year-old `Loring' peach [Prunus persica (L.)] trees at a rate of 38 liters/h per tree to evaluate the relative efficacy of low-volume undertree and overtree microsprinkling for frost protection. Overtree microsprinkling maintained flower bud temperatures 2C during a calm, radiative frost on 20-21 Mar. 1990 (minimum air temperature -4.4C), whereas undertree sprinkling provided 0.5C of air temperature elevation at a comparable height in trees (2 m). Twelve days later, fruit set was lower for nonirrigated and undertree-irrigated trees (none to one fruit/m of shoot length) than for trees irrigated with overtree microsprinklers (eight to nine fruit/m of shoot length). Economic analysis showed that capital costs of overtree microsprinkler systems increased annual costs of peach production by 8% to 13%, which required increased yield (or price per unit yield) of 17% to 20% before profits exceeded those of nonirrigated orchards, assuming all else equal. The estimated 1% increase in annual production costs of overtree microsprinkling compared to undertree microsprinkling appears to be justified by the increased efficacy of the overtree system.

The ecological adaptation of the Lutfi herder-horticulturists of south Iran

This report describes the subsistence and settlement patterns of the Lutfi herder-horticulturists of south Iran. While specialized intensive agriculturists and nomadic pastoralists have been much studied in the Middle East, mountain dwelling populations who combine a number of extensive subsistence techniques including foraging and horticulture have not been described. These often entail, as is seen in this case, some amount of movement or nomadism. The general pattern reported here is likely to have been quite widespread in highland Iraq, Iran, and Turkey where wild stands of fruit tree were once common. The Lutfi are semi-sedentary, spending most of their time in one seasonal camp. They move three times a year: from the main village to a temporary camp, to the orchard, and back to the main village. They are neither pastoral nomads nor sedentary agriculturists, but rather tend semiwild trees (vines, figs, and almonds) and rose bushes which produce fruits, nuts, and roses that they sell in order to buy agricultural and other products. Animals are secondary in their subsistence contribution but provide milk products, meat, skin, and hair the latter of which are used to manufacture containers and blankets. The pattern of seasonal movement is not determined by the requirements of the animals as in the case of other transhumant pastoralists. Lutfi subsistence is based on a combination of herding (mainly goats) and the cultivation of semi-wild, non-irrigated orchard and rose bushes in the high altitude (1500-2000 meters) of the Zagros mountains. The area is an extension of the chains of Zagros mountains which extend from northwest