Balance hídrico y respuesta del melocotonero extratemprano al riego deficitario

El objetivo de la tesis consistió en la determinación de las necesidades hídricas y respuesta del melocotonero extratemprano a riegos deficitarios. Las necesidades hídricas fueron determinadas mediante balance de agua y los coeficientes de cultivo propuestos pueden ahorrar un 16% de agua de riego. La producción en los tratamientos de riego deficitario fue significativamente menor que la del control aunque aquellos fueron más eficientes. La dinámica radical mostró un crecimiento continuo con diferentes tasas disminuyendo durante el crecimiento del fruto. Los riegos deficitarios disminuyeron los crecimientos radicales. Los sensores de capacitancia resultaron ser unas herramientas adecuadas para el control en continuo del contenido de agua en el suelo. The thesis focused on the determination of the water requirements and the early peach response to deficit irrigation. Water requirements were determinate using the water balance method and the propose crop coefficient would result in savings of 16% in irrigation water. Yield in the deficit treatments was significantly lower than the control treatment but, in terms of water use efficiency, the deficit irrigation treatments were more efficient than the over-irrigated trees of the control treatment. Root dynamics showed a continuous growth throughout the year with different growth rates, slowing down during the maximum fruit growth period. Water deficit limited root growth. The capacitance probes are suitable tools for monitoring the soil water content in real-time

Effects of soil tillage on runoff generation in a Mediterranean apricot orchard

Two different soil tillage practices (perforated topsoil and mini-catchments) were compared with no tillage (control) in an assay to reduce runoff, promote infiltration and take advantage of rainfall in a drip irrigated, hillside apricot orchard under semi-arid Mediterranean conditions. In addition, the efficiency of water harvesting was quantified for the purpose of saving irrigation water. To predict runoff generation in the three treatments, the best fit was obtained with a two-parameter exponential model, which included the product of rainfall amount and rainfall intensity as independent variable. The model explains, on average, 92% of runoff generation for three soil tillage treatments. The antecedent soil moisture content may account for part of the unexplained runoff generation. More than 30% of the rainfall was lost by runoff in the control treatment, underlining the potential risk of sloping plantations for water and soil conservation. Both soil tillage treatments (mini-catchments and perforated topsoil) decreased the runoff by an 80% compared to the control treatment. During the experimental period, the mini-catchment treatment collected 86% and the perforated topsoil 57% more than the control, providing mean irrigation water saving of about 11 and 9%, respectively. Even these relatively modest figures are very valuable in South-east Spain which suffers from severe droughtsThe authors are grateful to I. Marco for his assistance and to the Comisión Interministerial de Ciencia y Tecnología for supplying grants (HID1999-951; AGL2000-0387-C05-04) for this study.Peer reviewe

Effects of soil tillage on runoff generation in a Mediterranean apricot orchard

Two different soil tillage practices (perforated topsoil and mini-catchments) were compared with no tillage (control) in an assay to reduce runoff, promote infiltration and take advantage of rainfall in a drip irrigated, hillside apricot orchard under semi-arid Mediterranean conditions. In addition, the efficiency of water harvesting was quantified for the purpose of saving irrigation water. To predict runoff generation in the three treatments, the best fit was obtained with a two-parameter exponential model, which included the product of rainfall amount and rainfall intensity as independent variable. The model explains, on average, 92% of runoff generation for three soil tillage treatments. The antecedent soil moisture content may account for part of the unexplained runoff generation. More than 30% of the rainfall was lost by runoff in the control treatment, underlining the potential risk of sloping plantations for water and soil conservation. Both soil tillage treatments (mini-catchments and perforated topsoil) decreased the runoff by an 80% compared to the control treatment. During the experimental period, the mini-catchment treatment collected 86% and the perforated topsoil 57% more than the control, providing mean irrigation water saving of about 11 and 9%, respectively. Even these relatively modest figures are very valuable in South-east Spain which suffers from severe droughtsThe authors are grateful to I. Marco for his assistance and to the Comisión Interministerial de Ciencia y Tecnología for supplying grants (HID1999-951; AGL2000-0387-C05-04) for this study.Peer reviewe

Response of early-peach [Prunus persica (L.)] trees to deficit irrigation

The effect of different irrigation strategies in water relations, vegetative growth and yield of early maturing peach trees, growing in Murcia, (Spain) was studied during two years. Treatments consisted on: a control T1, full irrigated (150% of ETc); T2, continuous deficit irrigation at 50% of ETc; T3, regulated deficit irrigation (RDI), irrigated at 100% of ETc only during stage III of fruit growth and 25% the rest of the growing season; and T4, with automatic control of irrigation based on capacitance FDR-type probe data, varying threshold values. The results indicated that irrigation deficits in T2 and T3 treatments induced the lowest soil water content and stem water potential(?stem) values during the postharvest period (e.g. ?stem up to �1.8 MPa in T3 during summer 2008); thus, a reduction in trunk growth and pruning weight, respect to control treatment values, was noted in both years. Also, peach yield was significantly reduced in both deficit irrigated treatments. The greatest irrigation water saving in T3 treatment (�60%) caused the higher water use efficiency values in this treatment. For these reasons, water deficit during the postharvest periods (extended in the early maturing varieties) must be limited if fruit yield is not to be reduced. Irrigation scheduling based on capacitance probes have become a useful tool in the control of soil water content. When threshold values were precisely defined, the slight water deficits limited only vegetative growth while maintaining similar peach yield to that of well irrigated trees

Root and aerial growth in early-maturing peach trees under two crop load treatments

The objectives of the paper were to study the pattern of root growth (measured by minirhizotrons) in relation to trunk, fruit and shoot growth and the effects of crop load on tree growth and yield in peach trees. Two crop load (commercial and low) treatments were applied in a mature early-maturing peach tree orchard growing in Mediterranean conditions. Root growth dynamics were measured using minirhizotrons during one growing season. Shoot, trunk and fruit growth were also measured. At harvest, all fruits were weighed, counted and sized. Roots grew throughout the year but at lower rates during the active fruit growth phase. Root growth was asynchronous with shoot growth, while root and trunk growth rates were highest after harvest, when the canopy was big enough to allocate the photo-assimilates to organs that would ensure the following season’s yield. Shoot and fruit growth was greater in the low crop load treatment and was accompanied by a non-significant increase in root growth. High level of fruit thinning decreased the current yield but the fruits were more marketable because of their greater size

Long-term summer pruning in peach trees. Is it an advisable cultural practice?

This work deals with the effects of pruning on vegetative growth, yield and fruit quality, along with the plant water status of extra early-maturing peach trees during four consecutive growing seasons (2012-2015). Trees were drip irrigated in the Mediterranean conditions of Murcia (Spain) in a clay-loam soil. Two pruning treatments were imposed: winter pruning (WP), which was carried out during dormancy (December) in order to maintain the vase-type tree architecture, and a summer pruning (SP) consisting of the elimination of the water sprouts just after harvest (May). Plant water status indicators were assessed from the midday stem water potential (Ψstem) with a pressure chamber. Canopy tree cover (TC) was obtained by zenithal imagen analysis. The percentage of effective shade was estimated from the TC and the solar angle. Yield and fruit quality were evaluated at each harvest. Fruits were separated in the field by manual calibration into 7 fruit diameter categories. The total pruning weight of SP trees was on average 12 kg tree-1 (dry matter), which is slightly higher than that of WP trees. The contribution of SP to total pruning was nearly 35%. TC was significantly lower in the SP treatment, which resulted in an improvement in the plant water status of about 0.10-0.30 MPa with respect to WP trees in summer, and leading to a reduction in water consumption during periods of high evaporative demand. No significant differences were detected between WP and SP treatments in the yield components studied. Summer pruning can be considered an acceptable cultural practice to mitigate the drought effects in early-maturing peach trees, while maintaining yield.This research was funded by Spanish National I+D+I Plan co-financed with European Union FEDER funds (AGL2013-49047-C02-2R, AGL2016-77282-C03-1R) and Seneca Foundation of Region of Murcia (19903/GERM/15). M.R. Conesa acknowledges the postdoctoral financial support received from Juan de la Cierva Program (FJCI-2017-32045)Peer reviewe

Root dynamics of peach trees submitted to partial rootzone drying and continuous deficit irrigation

The root dynamics of young early-season peach trees (Prunus persica L. Batsch, cv. Flordastar) were studied during one growing season. The trees were submitted to three drip irrigation treatments: T1 (control) irrigated at 100% of the estimated crop evapotranspiration (ETc) requirements, T2 (continuous deficit) irrigated at 50% ETc and T3 (partial rootzone drying, PRD, treatment), alternating irrigation from one half to the other every 2-3 weeks. Root length was measured frequently using minirhizotrons and a circular-vision scanner. Overall, root length density was reduced by ≈73% in the continuous deficit irrigated treatment and by ≈42% in the T3 treatment with respect to the well irrigated treatment. A roughly similar amount of water was applied in both deficit irrigated treatments (44 and 56% of T1, for T2 and T3, respectively), but the continuous deficit irrigation applied to both sides of the root system in T2 resulted in a greater reduction in root growth than in T3. The dynamics of the root growth were similar in the three treatments. In general, root growth declined during the fruit growth period and increased after harvest, reaching its peak in mid July. By late July, root growth had declined again, and an alternating pattern of growth between the aerial and root parts of the tree was observed. Roots were mostly located in the upper 0.55 m of soil and were particularly concentrated at 0.40-0.55 m. More than 88% of these roots were very thin, with diameters of <0.5 mm. The study looks at the impact of deficit irrigation on the phenological processes related with root growth, and will help in making decisions concerning fertigation in areas with scarce water resources where deficit irrigation strategies are considered desirable. © 2008 Elsevier B.V. All rights reserved.The study was supported by Ministerio de Educación y Ciencia (MEC) (AGL2006-12914-C02-01), Séneca Foundation, Murcia (03130/PI/05), IRRIQUAL (FP6-FOOD-CT-2006-023120), and Consolider-Ingenio2010 (CSD2006-0067) grants to the authors. O. Mounzer and W. Conejero received a fellowship from MEC-FPI (Spain) Y. García-Orellana from Fundayacucho (Venezuela) and I. Abrisqueta from I3P-CSIC (Spain).Peer Reviewe