Water Efficiency Archives

2012 Chile

Effect of soil water-to-air ratio on biomass and mineral nutrition of avocado trees

Authors: Gil, P.M.; Bonomelli, C.; Schaffer, B.; Ferreyra, R.; Gentina, G.

In Chile, expansion of avocado production has resulted in many orchards established in marginal soils that are poorly drained and have high soil water-to-air ratios when soil moisture is at field capacity. However, avocado trees are sensitive to poor soil aeration. A study was conducted to determine the effects of different soil water-to-air ratios (W/A) on biomass and nutrient content of avocado trees. Two-year-old avocado trees were grown for 2 seasons in containers in soils, with different W/A,

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2014 Chile

Effect of soil available water depletion on plant water status, fruit size and yield of avocado trees cv. 'HASS'

Authors: Ferreyra, R.; Selles, G.; Gil, P.; Celedon, J.; Maldonado, P.

The objective of this study was to define the soil available water depletion (SAWD) in avocado, in order to use it as a criterion for irrigation programs in soils of fine texture and low aeration capacity. to determine appropriately the fraction of soil SAWD we performed three independent trials: Trial 1: We evaluated two treatments: T1, irrigation to 100% ETc and then without irrigation for 13 days, until the SAWD reached 60%, and T2: daily irrigation replacing 100% of the evapotranspiration of

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2008 Chile

Soil air content effects on the water status of avocado trees

Authors: Ferreyra, R.; Maldonado, P.; Celedon, J.; Gil, P. M.; Torres, A.; Selles, G.

Avocado trees evolved in Andisoils, which are considered the optimum type of soils for tree growth due to their physical properties; mainly low bulk density (0.5 - 0.8 g cm(-3)) and high macro porosity (similar to 46%). In Chile, avocado orchards are mostly located in fine textured soils, with bulk densities between 1.3 and 1.5 g cm(-3) and macro porosities close to 15%. Due to this fact, there are severe problems of poor root aeration which, in part, are responsible for the low production levels

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2021 Colombia

Avocado cv. Hass Needs Water Irrigation in Tropical Precipitation Regime: Evidence from Colombia

Authors: Erazo-Mesa, E.; Ramírez-Gil, JG.; Sánchez, A.E.

The primary natural source of water for the Hass avocado crop in the tropics is precipitation. However, this is insufficient to provide most crops’ water requirements due to the spatial and temporal variability. This study aims to demonstrate that Hass avocado requires irrigation in Colombia, and this is done by analyzing the dynamics of local precipitation regimes and the influence of Intertropical Convergence Zone phenomena (ITCZ) on the irrigation requirement (IR). This study was carried out

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2022 Colombia

Surface soil water content as an indicator of Hass avocado irrigation scheduling

Authors: Erazo-Mesa, E.; Gómez, E.H.; Sánchez, A.E.

This study aims to determine whether Hass avocado irrigation can be triggered based on the surface soil water content (SSWC). To address this question, the soil water dynamics from three Hass avocado orchard plots located in Valle del Cauca (Colombia) was simulated using a model provided by Hydrus-1D software, which was calibrated through the genetic algorithm NSGA-II and validated using the soil matric potential measured at several depths at nine monitoring stations installed in the three plots.

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2013 Multiple

The water relations and irrigation requirements of avocado (persea americana mill.): a review

Authors: Carr, M.K.V.

The results of research on the water relations and irrigation need of avocado are collated and reviewed in an attempt to link fundamental studies on crop physiology to irrigation practices. Background information is given on the centre of origin (Mexico and Central America) and the three distinct ecological areas where avocados are grown commercially: (1) Cool, semi-arid climates with winter-dominant rainfall (e.g. Southern California, Chile, Israel); (2) Humid, subtropical climates with summer-dominant rainfall (e.g. eastern Australia, Mexico, South Africa); and (3) Tropical or semi-tropical climates also with summer-dominant rainfall (e.g. Brazil, Florida and Indonesia). Most of the research reported has been done in Australia, California, Israel and South Africa. There are three ecological races that are given varietal status within the species: Persea americana var. drymifolia (Mexican race), P. americana var. guatemalensis (Guatemalan race) and P. americana var. americana (Antillean, West Indian or Lowland race). Interracial crossing has taken place. This paper summarises the effects of water deficits on the development processes of the crop and then reviews plant-water relations, crop water requirements, water productivity and irrigation systems. Shoot growth in mature trees is synchronised into flushes. Flower initiation occurs in the autumn, with flowering in late winter and spring. Flowers form on the ends of the branches. A large heavily flowering tree may have over a million flowers, but only produce 200-300 fruits. Fruit load adjustment occurs by shedding during the first three to four weeks after fruit set and again in early summer. Water deficits during critical stages of fruit ontogeny have been linked to fruit disorders such as ring-neck. Reproductive growth is very resistant to water stress (compared with vegetative growth). Avocado is conventionally considered to be shallow rooted, although roots extend to depths greater than 1.5 m. The majority of feeder roots are found in the top 0.60 m of soil and root extension can continue throughout the year. Leaves develop a waxy cuticle on both surfaces, which is interrupted by stomata on the abaxial surface (350-510 mm(-2)), many of which are blocked by wax. Stomata are also present on the sepals and petals at low densities (and on young fruit). During flowering, the canopy surface area available for water loss is considerably increased. Stomatal closure is an early indicator of water stress, which together with associated changes in leaf anatomy, restricts CO2 diffusion. There have only been a few attempts to measure the actual water use of avocado trees. In Mediterranean-type climates, peak rates of water use (in summer) appear to be between 3 and 5 mm d(-1). For mature trees, the crop coefficient (K-c) is usually within the range 0.4-0.6. The best estimate of water productivity is between 1 and 2 kg fruit m(-3). Soil flooding and the resultant reduction in oxygen level can damage roots even in the absence of root rot. Avocado is particularly sensitive to salinity, notably that caused by chloride ions. Rootstocks vary in their sensitivity. Both drip and under-tree microsprinklers have been/are successfully used to irrigate avocado trees. Mulching of young trees is a recommended water conservation measure and has other benefits. A large proportion of the research reviewed has been published in the 'grey' literature as conference papers and annual reports.Sometimes, this is at the expense of reporting the science on which the recommendations are based in peer-reviewed papers. The pressures on irrigators to improve water productivity are considered.

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