Parametri di sviluppo e gestione della risorsa idrica in opuntia ficus-indica.

Dry matter accumulation and seasonal partitioning in mature Opuntia ficus-indica (L.) Mill. fruiting trees

Aim of this study was to understand the allocation of biomass into different canopy and root components and to measure the stem area index and its partitioning by cladode functionality (age), for fruiting Opuntia ficus-indica (OFI) Gialla trees, spaced 6x5 m apart and trained to a globe. The net primary productivity (NPP), calculated taking into account dry weight gain for above-ground vegetative components of OFI trees was 3.6 t C ha –1 . Including the fruit component and 1 st flush current-year cladodes, NPP of above-ground components becomes 12 t ha –1 , equivalent to 5.4 t C ha –1 . Current-year cladodes were the highest C sink (49% of total annual C fixed in the canopy), secondary grow…

CO2 FLUXES OF OPUNTIA FICUS-INDICA MILL. TREES IN RELATION TO WATER STATUS

Gas exchange pattern in O. ficus-indica(OFI), refers to the Crassulacean Acid Metabolism (CAM); trees have nocturnal stomata opening, so net CO2 uptake and water loss occur during the cooler part ofthe 24-hour cycle. Succulent cladodes skip severe periods of drought through their water storer tissue (parenchyma). To study carbon fluxes in stress and no stress conditions, an experiment was carried out on 3-year-old irrigated and non-irrigated OFI potted trees; whole tree gas exchange was measured continuously with a balloon system made up by a portable Infrared Gas Analyzer. Continuous measurements(nighttime) during the summer season were useful to assess differences in carbon uptake under s…

Determination of Evapotranspiration and Crop Coefficient of Cactus Pear (Opuntia ficus-indica Mill.) with an Energy Balance Technique

A micrometeorological approach based on surface renewal technique was adopted to estimate evapotranspiration fluxes and crop coefficient data from an irrigated cactus pear (Opuntia ficus-indica Mill.) orchard under Mediterranean climatic conditions. High-frequency temperature readings were taken above the canopy top in order to get surface renewal sensible heat flux values (HSR). These values were compared against eddy covariance sensible heat fluxes (HEC) for calibration. Latent heat flux (or evapotranspiration, ET) was obtained as the residual of the energy balance equation using HSR. In field measurements of biophysical crop features, physiological characteristic and soil hydraulic compo…

Determination of Evapotranspiration and Annual Biomass Productivity of a Cactus Pear [Opuntia ficus-indica L. (Mill.)] Orchard in a Semiarid Environment

A micrometeorological approach based on the surface energy balance was adopted to estimate evapotranspiration fluxes and crop coefficient data from an irrigated cactus pear [Opuntia ficus-indica L. (Mill.)] orchard under Mediterranean climatic conditions. Highfrequency temperature readings were taken above the canopy top to get sensible heat flux values (HSR) using the surface renewal technique. These values were compared against eddy covariance sensible heat fluxes (HEC) for calibration. Latent heat flux (or evapotranspiration, ET) was obtained by solving the daily energy balance equation. Measurements of soil hydraulic components were integrated with the analysis of the surface energy flu…

Fruit productivity and carbon gain of Opuntia ficus-indica (L.) Mill. trees

Opuntia ficus-indica (OFI) tree and orchards efficiency has been poorly studied, in terms of relation between orchard lay out, light interception, and cropping efficiency. Apparently, there is no other way to increase orchard production than increasing the number either of trees ha-1 or fertile shoots tree-1, considering that a fruit count higher than 6-7 cladode-1 reduces fruit harvest size. The first option requires a reduction of unit tree size and canopy volume. The second option implies the use of large trees that often reduce their efficiency 12-15 years after planting. In 15-year-old OFI trees spaced 6 5 m apart trained to a globe and 2.5-3.0 m high, stem area index (SAI) calculated …

Influence Of within-tree and environmental factors On fruit quality of cactus Pear (O. ficus-Indica)

Introduction. Opuntia ficus-indica fruit quality was studied, in the main sites for cactus pear cultivation in Italy, with the ultimate goal of understanding the main sources of variability and increasing crop value. Materials and methods. A first study was carried out in 2006 on mature Opuntia ficus-indica trees, cvs. Gialla and Rossa, grown in ten commercial orchards located in the main sites for their cultivation in Italy. Trees were managed to produce an out-of-season crop in October, through the removal of the spring flush at bloom time, during the first week of June. Trees had a similar crop [(52 ± 10) kg of fruits•tree-1], and no more than six fruits were left on each of the fruiting…

COME MASSIMIZZARE LA QUALITÀ DELL’OLIO DI CERASUOLA

Crop Coefficient Curve for Paddy Rice from Residual Energy Balance Calculations

AbstractThe crop coefficient (Kc) values of rice paddy are important for estimating accurate rice crop evapotranspiration (ETc), water transfers planning, efficient irrigation management, and hydrological studies. In this study, ETc was measured and a generalized Kc curve was calculated for paddy rice in the Sacramento Valley, California. Field experiments were conducted in three rice paddy fields during the 2011–2013 growing seasons. Surface renewal analysis, after calibration using eddy covariance method, was applied to obtain sensible heat flux values from high-frequency temperature readings; latent heat flux densities were characterized by the residual of the energy balance method. The …

CO2 fluxes of O. ficus-indica plants and single cladodes in relation to water stress

Influence of within-tree and environmental factors on fruit quality of cactus pear (Opuntia ficus-indica) in Italy

Introduction . Opuntia ficus-indica fruit quality was studied, in the main sites for cactus pear cultivation in Italy, with the ultimate goal of understanding the main sources of variability and increasing crop value. Materials and methods. A first study was carried out in 2006 on mature Opuntia ficus-indica trees, cvs. Gialla and Rossa, grown in ten commercial orchards located in the main sites for their cultivation in Italy. Trees were managed to produce an out-of-season crop in October, through the removal of the spring flush at bloom time, during the first week of June. Trees had a similar crop [(52 ± 10) kg of fruits·tree–1 ], and no more than six fruits were left on each of the fruiti…

CO2 uptake of Opuntia ficus-indica (L.) Mill. whole trees and single cladodes, in relation to plant water status and cladode age

Most of net photosynthesis determinations in Opuntia ficus-indica come from measurements on individual cladodes. However, they have limitations when used to scale up to whole canopy gas exchange, because a large variability of carbon assimilation may occur within the canopy, due to, among others, differences in cladode age and intercepted radiation or individual cladode response to abiotic stresses. The aim of this work was to evaluate the application of open gas exchange chambers, simultaneously applied around the whole canopy, to measure net CO 2 uptake, continuously over a 24 h period, in single Opuntia ficus-indica (L.) Mill. potted trees and in relation with their water status. Net CO2…