Irrigation scheduling and regulated deficit irrigation in stone fruits

In recent years the interest for applying irrigation techniques aiming to reduce water consumption has increased, mainly in areas with scarce water resources. We studied the effect of different regulated deficit irrigation (RDI) strategies on peach (Prunus persica (L.) Batsch cv. "Catherine") performance in Murcia (SE Spain) during three consecutive growing seasons. Three irrigation strategies were established: a control treatment, irrigated to fully satisfy the crop water requirements and two RDI treatments (moderate and severe) based on measurements of stem water potential (Ψs). Pruning weight, percentage of fruit categories, fruit diameter, crop load and yield were determined for each treatment. The results indicated that RDI treatments significantly reduced pruning weight. However, no significant differences were detected in terms of reproductive growth, fruit categories and yield. In the case of water productivity, the values for the RDI treatments were higher than those from the control. These results and water savings up to 50% indicate that RDI strategies constitute a possible solution against water shortages in areas such as the south-eastern region of Spain, although sustainability must be studied in the medium-long term.This study was supported by CONSOLIDER INGENIO 2010 (MEC CSD2006-0067)

Growth, heavy metal status and yield of salt-stressed wheat (Triticum aestivum L.) plants as affected by the integrated application of bio-, organic and inorganic nitrogen-fertilizers

Efforts have been made to use the integrated application of bio-, organic and inorganic nitrogen (N)-fertilizers to decrease waste accumulation, and to minimize nutrient losses and yield contamination with heavy metals for human nutrition and health. Therefore, a field experiment was conducted to assess the effect of integrated applications of organic manures, bio-fertilizer and/or mineral-N fertilizers on growth, yield, some chemical constituents and shoot and yielded grain heavy metal contents of wheat (Triticum aestivum L. cv. Sakha 93) plants grown under salinity stress (ECe = 7.84 dS m-1). Results showed that, the treatment comprised of ⅓NH4NO3 (55 kg N ha-1) + Cerealine (bio-fertilizer; 4 Kg ha-1) + cattle manure (10 t ha-1) was found to be most effective, producing the best status of growth characteristics, osmoprotectants concentrations, essential nutrient contents, shoot heavy metal concentrations, and grain yield and its content of heavy metals compared to the all other treatments. The treatment comprised of Cerealine (4 Kg ha-1) + cattle manure (20 t ha-1) was occupied the second order. We can recommend to use the integrated treatment of ⅓NH4NO3 (55 kg N ha-1) + Cerealine (bio-fertilizer; 4 Kg ha-1) + cattle manure (10 t ha-1) effectively in saline soils to improve wheat growth and yield with minimum contents of heavy metals for human health and nutrition

Effects of regulated deficit irrigation on physiology, yield and fruit quality in apricot trees under Mediterranean conditions

Scarce water resources mainly in arid and semi-arid areas have caused an increasing interest for applying irrigation protocols aiming to reduce water spends. The effects of regulated deficit irrigation (RDI) on the performance of apricot trees (Prunus armeniaca L. cv. “Búlida”) were assessed in Murcia (SE Spain), during three consecutive growing seasons (2008-2010). The hypothesis was that RDI would not restrict yield but increase fruit quality while saving water. Two irrigation treatments were established: i) control, irrigated to fully satisfy crop water requirements (100% ETc) and ii) RDI, that reduced the amount of applied water to: a) 40% of ETc at flowering and stage I of fruit growth; b) 60% of ETc during the stage II of fruit growth and c) 50% and 25% of ETc during the late postharvest period (from 60 days after harvest). Stem water potential, gas exchanges, trunk cross-sectional area (TCSA), fruit diameter, yield and fruit quality traits were determined. Vegetative growth was decreased by the use of RDI (12% less TCSA on average for the three years), whereas yield was unaffected. In addition, some qualitative characteristics of the fruits, such as the level of soluble solids, sweetness/acidity relation and fruit colour, were improved by the use of RDI. These results and average water savings of approximately 30%, lead us to conclude that RDI strategies are a possible solution for irrigation management in areas with water shortages, such as arid and semi-arid environments

Aplicación de estrategias de riego deficitario controlado en albaricoquero

Se estudiaron los efectos de estrategias de riego deficitario controlado (RDC) sobre albaricoqueros de 9 años de edad (Prunus armeniaca L. cv. “Búlida”) injertados sobre patrón franco de ‘Real Fino’. Para ello, se establecieron 2 tratamientos de riego, uno de riego control, que se regó satisfaciendo los requerimientos hídricos del cultivo (100% ETc) y un tratamiento de RDC, que consistió en reducir los aportes de agua con respecto a la ETc en los períodos no críticos en este cultivo: a) 40% de la ETc desde floración hasta el final de la primera fase de crecimiento del fruto; b) 60% de la ETc durante la segunda fase de crecimiento del fruto y c) 50% y 25% durante la post‐cosecha final (60 días después de recolección), diferenciando 2 períodos de 30 días, el primero al 50% de la ETc, y otro hasta la caída de hojas al 25% de la ETc. Los resultados obtenidos indican que el albaricoquero es una especie adecuada para realizar estrategias de RDC, debido principalmente a la clara separación entre el crecimiento vegetativo y reproductivo y, también al efecto de crecimientos compensatorios que se producen en los frutos que han estado bajo RDC, lo cual hace que finalmente no se produzcan mermas significativas de calibre. Además, ciertas características cualitativas, como el nivel en sólidos solubles, sabor y coloración de la fruta, se ven incrementadas. Estas dos razones, junto con ahorros de agua vía riego, del 39%, conducen a que estrategias de RDC puedan suponer una clara alternativa en zonas con infradotación hídrica, como es el sureste español.Este estudio fue cofinanciado por tres proyectos: IRRIQUAL (EU‐FP6‐FOOD‐CT‐2006‐023120), CONSOLIDER INGENIO 2010 (MEC CSD2006‐0067) y SÉNECA (05665/PI/07) concedidos a los autores

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

Effects of regulated deficit irrigation on physiology and fruit quality in apricot trees

The effects of regulated deficit irrigation (RDI) were studied on 9 year-old apricot-trees (Prunus armeniaca L. cv. �Búlida�) grafted on �Real Fino� rootstock. Two irrigation treatments were established. The first, a control treatment, was irrigated to fully satisfy the crop water requirements (100% ETc) and the second, a RDI treatment, was subject to water shortage during the non-critical periods of crop development, by reducing the amount of applied irrigation water to: a) 40% of ETc from flowering until the end of the first stage of fruit growth; b) 60% of ETc during the second stage of fruit growth and c) 50% and 25% of ETc during the late postharvest period (that starts 60 days after harvesting), for the first 30 days and until the end of tree defoliation, respectively. The results indicated that the apricot tree is an appropriate species to apply RDI thanks to the clear separation between their vegetative and reproductive growths and its ability to recover the fruit diameter reduction suffered during RDI application. Furthermore, some qualitative characteristics such as the level of soluble solids, fruit taste and the colour of the fruit are enhanced. These two reasons, together with irrigation water savings of 39%, emphasize the RDI strategies as a possible solution in areas with water shortages, like the south-eastern region of Spain