J. M. Abrisqueta

A comparison between minirhizotron and soil coring methods of estimating root distribution in young almond trees under trickle irrigation

SummaryThe minirhizotron method and the soil coring method were used to study the development of the root system (down to 105 cm) of almond trees cv. Atocha on ‘Pestaneta’ almond rootstock. The study was carried out during the first years of development of the trees under trickle irrigation. Most of the roots (about 80%) developed within the wetted zone of the trickle line in the top 60 cm of soil. The greatest root length density (RLD) was within 30 cm of the soil surface but decreased rapidly with depth. Outside the wetted zone, the greatest root development occurred at about 60 cm depth. When the RLD values obtained by the minirhizotron and soil coring methods were compared, the former was seen to underestimate the RLD values particularly in the top layers of soil so much so that the root distribution patterns established by the methods were not comparable. However, a significant relationship was established between the measurements obtained by both methods at different soil depths.

Water balance of apricot trees (Prunus armeniaca L. cv. Búlida) under drip irrigation

The water balance of drip irrigated apricot trees (Prunus armeniaca L. cv. Bulida grafted onto “Realfino” apricot rootstock) was determined during a 30-month-period. Two irrigation regimes based on the reduction coefficients of Class A pan evaporation (1 and 0.5) were used to determine the water consumed. The water balance parameters for these treatments are shown and discussed in detail. Overall, the trees receiving less water showed 35% less evapotranspiration. Crop coefficients calculated on the basis of the water balance over a 30-month-period led to a saving of almost 14% water, since the coefficients were slightly below those used in other apricot orchards in the same area.

Root dynamics of young almond trees under different drip-irrigation rates

SummaryThe influence of wood age, fruiting position and leaf area within the tree canopy on fruit mineral content and quality for several apple (Malus domestica Borkh.) cultivars was investigated. Size and Ca, Mg and K content of individual fruit on one-year (lateral and terminal positions), two-year and older than three-year wood were compared for cvs Royal Gala, Braeburn, Granny Smith and Fuji. Fruit on two-year spurs and one-year terminals was generally larger at commercial harvest than that on one-year laterals and spurs older than three years. Flower receptacles at full bloom were larger and fruit growth rates were greater from 60 to 100 d after full bloom on two-year spurs than on one-year laterals. Fruit Ca and Mg concentrations and contents at commercial harvest were highest for terminal fruit, but there was no consistent difference between fruit from other positions. One-year terminals had the greatest primary and bourse leaf areas, two-year spurs were intermediate and one-year laterals had the l...

Spatial representativity of the possible sites for measuring the water balance of apricot trees

Abstract The wide spatial variability of soil parameters together with the close relation between a soil’s texture and its hydrodynamic characteristics means that the sites where moisture is to be measured should be chosen carefully since the readings are often extrapolated to other sites where reading are not taken. Given that variations in texture behave as regionalized variables, a geostatistical analysis of soil texture is the most suitable and useful tool for identifying such sites. An isovalue map of d 50 obtained by kriging is described, which we propose can be used for locating soil moisture measurements sites for water balance studies in an apricot plantation.

Root development of almond rootstocks in a young almond orchard under trickle irrigation as affected by almond scion cultivar

SummaryMinirhizotrons were used to study the development of the root system (down to 100 cm) of almond trees cvs Atocha and Ramillete on ‘Pestaneta’ almond rootstock. The study was carried out during the first years of development of the trees under trickle irrigation. In ‘Atocha’ trees, with an upright growth habit, root development was greatest at a depth of between 60 and 100 cm; in ‘Ramillete’ trees, with a rather spreading growth habit, root development was greatest in the surface layers of the soil. However, in both graft combinations, most roots developed in the first 60 cm of depth. The root system dynamics in the whole soil profile throughout the annual cycle showed increases and decreases in root growth during the same periods for both scion/rootstock combinations; in both cases a decline in the root growth occurs coincided with the period when vegetative growth and rapid fruit development overlap.