Search

Irrigation management strategies based on soil–plant–climate interactions are the key to improving water productivity and maintaining optimum yield and quality for apple orchards growing under Mediterranean conditions where water availability for irrigation is significantly decreasing. Thus, an experiment was carried out to investigate the effect of different irrigation levels on the yield, fruit quality, and water status of microsprinkler-irrigated apple trees (Malus domestica 'Fuji') located in a Mediterranean region in the central part of Chile. Four irrigation treatments were applied to a commercial orchard during the 2011/12 and 2013/14 growing seasons as follows: 125%, 100%, 75%, and 50% of actual evapotranspiration (ETa). Fruit yield (Y), crop load (fruits per tree, FP), fruit size (fruit weight (FW) and fruit diameter (FD)), fruit quality (firmness (FF), contents of soluble solids (SS), and starch (ST)), water productivity (WP), midday stem water potential (Ψ stem), and water stress integral (WSI) were measured in each growing season. The results indicate that trees at 125% and 100% ETa reached an average Ψ stem near − 1.0 MPa, whereas trees at 75% and 50% ETa reached Ψ stem ∼ − 1.5 MPa. With the exception of FP, irrigation treatment had significant effects on Y, FW, FD, FF, SS, ST and WP. In this regard, the apple trees irrigated at 50% ETa produced fruits with the highest SS, FF, and WP, but the Y and fruit size (FW and FD) were significantly reduced because of severe water stress (average Ψ stem ranged from −1.35 to −1.88 MPa). Apple trees with the 100% and 125% ETa treatments produced higher Y, FW, and FD than those with the 75% ETa treatment. In addition, the irrigation amount for apple trees irrigated at 125% ETa was 15% greater than for those irrigated at 100% ETa, but the yield and fruit quality were similar in both treatments. Finally, this study suggested that irrigation scheduling based on 100% ETa and Ψ stem closed to − 1.5 MPa could be a suitable strategy for microsprinkler-irrigated apple (cv. Fuji) orchards growing in Mediterranean climate areas. • Irrigating apple trees (cv Fuji) at 50% or 75% actual evapotranspiration (ETa) saved water but significantly reduced yield. • Over-irrigating apple trees at 125% ETa significantly reduces water productivity.100% ETa had great potential to increase yield and water savings. • Midday water potentials (Ψstem) > −1.5 MPa does not reduce the yield and quality of apple. • 100% ETa and Ψstem close to − 1.5 MPa was a suitable irrigation strategy for the irrigated apple orchard. [ABSTRACT FROM AUTHOR]

Due to drought intensification in Mediterranean-type climates, raspberry growers need to implement irrigation scheduling to save water without decreases in yield and fruit quality. A study was performed to evaluate the effects of four irrigation levels on yield (Y), fruit number (FM2), fruit weight (FW), water productivity (WP), fruit quality (titratable acidity (TA), soluble solids (SS), weight to volume ratio (WV)), midday stem water potential (Ψ stem), and water stress integral (WSI) in a furrow-irrigated red raspberry (Rubus ideaus L. 'Heritage') orchard. An experimental plot was established within a commercial raspberry orchard located in the Colbún valley, Maule Region, Chile, during the 2012/13 and 2013/14 growing seasons. The irrigation treatments were 125 (T 1, farmer irrigation management), 100 (T 2), 75 (T 3) and 50% (T 4) of crop evapotranspiration (ETc). The results showed significant differences among treatments for Y and FM2, with the highest and lowest values observed under the T 3 and T 1 treatments, respectively. The T 4 treatment had the highest values of WSI and WP compared to the other treatments. The effects of irrigation levels were not significant for SS and WV, but the lowest TA was observed under the T 1 treatment. Results suggested that water application based on the 75% of ETc associated with Ψ stem > −1.0 MPa was the most appropriate irrigation strategy for the furrow-irrigated red raspberry orchard because it had the highest Y (9.25 kg m−2) and saved water by 20–28% compared to the 125% and 100% ETc treatments. • Over- and under irrigation reduced significantly yield in a furrow-irrigated red raspberry orchard. • Raspberry plants irrigated at 75% of actual evapotranspiration (ETc) had the highest yield and water productivity. • Raspberry plants irrigated at 75% of ETc had midday stem water potential (Ψ stem) > −1.0 MPa. • Ψ stem values and 75% of ETc seem to be an appropriate irrigation management strategy in furrow-irrigated raspberry orchards. [ABSTRACT FROM AUTHOR]

As blueberries are susceptible to water stress and their future cultivation in semiarid Mediterranean areas will be challenged by drought, irrigation management strategies will be needed to optimize water productivity and maintain sufficient levels of fruit yield and quality. This study aim was to evaluate the effect of different irrigation levels on plant water status, yield, fruit quality, and water productivity in a drip-irrigated rabbiteye blueberry (Vaccinium ashei Reade 'Tifblue') orchard. Four irrigation treatments based on crop evapotranspiration (ETc) were applied to blueberry plants during two consecutive growing seasons (2012/2013 and 2013/2014): 125 (farmers' irrigation management, T 1), 100 (T 2), 75 (T 3), and 50 (T 4) % ETc. During the study, the average values of midday stem water potential (Ψ stem) were −0.85, −0.86, −0.97 and −1.11 MPa for the T 1 , T 2 , T 3, and T 4 treatments, respectively. Fruit weight (FW), yield (Y), fruits per plant (FP), soluble solids (SS), and the water stress integral (WSI) were significantly affected by the irrigation treatments. The water productivity (WP), juice pH, and weight/volume ratio were statistically similar among the treatments. The highest values of Y, FP, and FW were observed in the T 1 and T 2 treatments, while the lowest values were found in the T 4 treatment. In addition, the Y, FP, FW and WSI in the T 1 and T 2 treatments were significantly similar, but the total water application in the T 2 treatment was between 20% and 27% lower than that in the T 1 treatment. For the T 1 and T 2 treatments, the values of Y were between 8.8 and 9.4 kg plant −1, and the Ψ stem was >−0.85 MPa during the two growing seasons. The interaction between irrigation treatments and growing season was only significant for the FW, with the lowest values observed in the T 4 treatment during the 2012/2013 growing season. • Irrigation at 100% evapotranspiration (ETc) reduced water use without affecting yield and quality. • Irrigation at 100% ETc reduced the water use between 950 and 1130 m3 ha−1 season−1. • Irrigation at 100% ETc maintained midday stem water potential >−1.0 MPa. • Irrigation at 50% ETc significantly decreased fruit weight and yield. • Irrigation at 50% ETc increased soluble solids and the water stress integral. [ABSTRACT FROM AUTHOR]

Reference evapotranspiration (ETo) has a key role in irrigation scheduling. In this sense, the Hargreaves-Samani equation (HS) is a reliable and widely used method to estimate ETo. The HS equation just requires temperature and solar radiation data, making it a suitable method for places that lack of wind speed and relative humidity information. However, literature shows that a local calibration of its empiric parameter is needed for its complete application. This work shows a calibration for the Maule region in central-southern Chile. For this purpose, the Penman-Monteith equation from FAO-56 (PM) was considered as a reference, using a network of 400 meteorological stations between the 32° and 39° of south latitude for the 1973-2011 period. The calibration was based on the computation of the ratio of ETo calculated by HS and PM and the spatial behaviour of input variables and parameters. The spatial distribution was done by geographical weighted regression and ordinary Kriging with a linear variogram, assisted by a digital elevation model from the Shuttle Radar Topography Mission and surface reflectances from Moderate Resolution Imaging Spectroradiometer. The process of calibration was validated with daily data through all months, with comparative errors of 5% against PM. [ABSTRACT FROM AUTHOR]