Leaf water potential and sap flow as indicators of water stress in Crimson ‘seedless’ grapevines under different irrigation strategies

Vitis vinifera L. cv. Crimson Seedless is a late season red table grape developed in 1989, with a high market value and increasingly cultivated under protected environments to extend the availability of seedless table grapes into the late fall. The purpose of this work was to evaluate leaf water potential and sap flow as indicators of water stress in Crimson Seedless vines under standard and reduced irrigation strategy, consisting of 70 % of the standard irrigation depth. Additionally, two sub-treatments were applied, consisting of normal irrigation throughout the growing season and a short irrigation induced stress period between veraison and harvest. Leaf water potential measurements coherently signaled crop-available water variations caused by different irrigation treatments, suggesting that this plant-based method can be reliably used to identify water-stress conditions. The use of sap flow density data to establish a ratio based on a reference ‘well irrigated vine’ and less irrigated vines can potentially be used to signal differences in the transpiration rates, which may be suitable for improving irrigation management strategies while preventing undesirable levels of water stress. Although all four irrigation strategies resulted in the production of quality table grapes, significant differences (p ≤ 0.05) were found in both berry weight and sugar content between the standard irrigation and reduced irrigation treatments. Reduced irrigation increased slightly the average berry size as well as sugar content and technical maturity index. The 2-week irrigation stress period had a negative effect on these parameters

On the early irrigation of gypseous lands in Spain

2 Files (11 Pags., 18 Pags.). The second file is the Supplementary material published with the article. This supplementary material is the transcript of a typewritten Report, in Spanish, authored by F. de los Ríos. This transcription was made by J. Herrero from a badly damaged carbon copy on onionskin paper. The definitive version is available at: http://onlinelibrary.wiley.com/journal/10.1002/(ISSN)1099-145XGypseous lands occur mainly in arid regions of the world, where irrigation is required for profitable agriculture. The study of gypseous soils has been neglected for years in the main stream of the soil science. Agriculture and, more recently, the environmental concerns are challenging research in the countries that have extensive gypsum outcrops. Those challenges have been obvious since at least the 1960s, when economic development in some of these countries led to the construction of new irrigation schemes and associated infrastructures. This paper presents examples of documents about agriculture on gypseous soils in Spain that might be applicable to similar situations elsewhere in the world.This work has been funded by the Spanish Government under the project CGL2015-71360-P and by the Spanish National Research Council (CSIC) under the project Icoop-2016SU0015.Peer reviewe

Harvesting water in a center pivot irrigation system: Evaluation of distribution uniformity with varying operating parameters

The main objective of irrigation is to apply the optimum amount of water to the crop root zone that is needed for its growth. Also, when irrigation systems are used to apply fertilizers and pesticides, the irrigation process becomes even more critical in terms of uniformity. Consequently, it is important for center pivot owners and operators to periodically check the uniformity of their systems in order to adjust all the operating parameters involved. To assess the real distribution uniformity of irrigated water, a study was conducted in southern Libya; this paper reports the results of water irrigation in a center pivot system with respect to the effects that the operating pressure (P), the spacing between sprinklers (S), and the height of sprinkler above the ground surface (H) show on the distribution uniformity. Several factors define the uniformity of water distribution; in this work the coefficient of uniformity CU, the low quarter distribution uniformity DUlq, and the coefficient of variation CV are considered. The highest values reached by the uniformity parameters with varying the operating conditions define the best operating practices under which the whole system works efficiently. The final results are given in terms of operating conditions able to save total costs in the studied area and in places characterized by similar geo-hydrological conditions