Irrigation Archives

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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2019 Egypt

Influence of Irrigation Method and Fertilization Type on Avocado Yield and Quality

Authors: Darwish, W.M.; Elmetwalli, A.H.

This research study investigated the impact of watering method and fertilization on avocado yield and quality in newly reclaimed areas. The research attempted to choose the optimum irrigation system and fertilization type to improve avocado yield and quality. Different irrigation systems (micro-sprinkler, drip irrigation and combined approach of micro-sprinkler and drip) with different fertilization types (mineral fertilization, fertilization using fallen avocado leaves+mineral fertilization and

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2000 California

Long-Term Evapotranspiration from Coastal Avocado/Citrus Orchard

Authors: Grismer, M.

Very limited citrus and avocado orchard evapotranspiration data are available, and practically no published information is available considering citrus/avocado evapotranspiration ETc on steeply sloping fields in coastal climates. Often the data available are from measurements based on limited time periods, and season-to-season orchard water use variability is unknown. The objective of this project was to obtain such long-term-field ETc data. Of particular interest was determination of the monthly

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2017 Chile

Responses of avocado production to variation in irrigation levels

Authors: Holzapfel, E.; de Souza, J.A.; Jara. J.; Guerra, H.C.

The effects of four irrigation regimes on fruit production and size were evaluated for three seasons in a mature ‘Hass’ avocado orchard (Persea americana Mill.). The research was conducted in Chile’s Central Valley on a clay loam soil at the surface and sandy loam from 0.3 to 0.9 m. Climate zone is sub-humid, Mediterranean-type. A completely randomized block design was used with four applied water treatments (25, 50, 75, and 100% of reference evapotranspiration, ETo), estimated on the basis

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2011 Chile

Different levels of water and fertilizer application in 'Hass' avocado trees during four seasons in the Peumo Valley of Chile

Authors: Holzapfel, E.; Jara, J.; Valderrama, N.

A research study was carried out during four seasons between December 2003 to May 2007, in five years old ‘Hass’ avocado trees (Persea americana Mill.) in the Peumo Valley, Chile. Its objective was to analyze the effects of two doses of fertilizer and four differential levels of water application (25, 50, 75 and 100% of the theoretical water volume required by the plant) on the production and quality of the fruit. A split-plot experimental design with allocation in completely randomized blocks

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2012 Florida

Water savings, nutrient leaching, and fruit yield in a young avocado orchard as affected by irrigation and nutrient management'

Authors: Kiggundu, N.; Migliaccio, K.; Schaffer, B.; Li, Y.; Crane, J.

This project was designed to determine the effect of fertilizer rate and irrigation scheduling on water use, nutrient leaching, and fruit yield of young avocado trees (Persea americana Mill. cv. Simmonds). Seven nutrient and irrigation management practices were evaluated: (1) irrigation based on crop evapotranspiration (ET) with 50% fertilizer at a standard rate (FSR); (2) ET irrigation with FSR (typical for avocado production in the area); (3) ET irrigation with 200% FSR; (4) irrigation based on

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