Beitrag in Konferenzband

Water relations of asparagus crop under different water supply and implications for plant-based irrigation scheduling


Details zur Publikation

AutorenlisteZinkernagel J., Kahlen K.

Jahr der Veröffentlichung2017

BuchtitelProceedings of the VIII International Symposium on Irrigation of Horticultural Crops

SerientitelActa Horticulturae

Serienzählung1150

Erste Seite385

Letzte Seite390

ISBN978-94-6261-145-0

DOI10.17660/ActaHortic.2017.1150.54

URLhttp://www.actahort.org/books/1150/1150_54.htm

SprachenEnglisch

Peer reviewed


Abstract
Irrigation plays a major role in the production of herbaceous crops, since they are highly sensitive to water shortage. Methods for irrigation scheduling using indirect measures of plant water demand (e.g., soil matric potential) result in well-known disadvantages (e.g., imprecise since not based on the actual plant demand, high leachate risk in sandy soils), whereas irrigation scheduling using direct measures of plant water demand (e.g., predawn leaf water potential (?PD)) might be more promising. Therefore, we aimed at developing a ?PD-based irrigation scheduling for asparagus as a model crop. First, we investigated the plants' responses to water stress and, second, identified stress thresholds related to ?PD. In a field trial in Geisenheim, Germany, 'Gijnlim' asparagus was grown in irrigated and non-irrigated plots (3 replications, randomized block design). Irrigated plots were watered, if soil tension was below -20 kPa. Parameters of gas exchange, plant growth, spear yield and osmotic adjustment (OA) were analysed with respect to the applied water amount and ?PD. As expected, lack of irrigation reduced shoot growth, yield and ?PD. Parameters of OA, turgor loss point, osmotic potential and modulus of elasticity, did not change. Thus, OA did not occur. However, stomatal conductivity and assimilation rate were significantly reduced for ?PD below -0.15 MPa, when ?PD-classes ranging from -0.10 to -0.15, -0.15 to -0.20 and <-0.2 MPa, respectively, were compared. This implies that ?PD-thresholds of herbaceous species lie far above of those of woody species already used in practice. Thus, herbaceous crops may challenge the irrigation management using ?PD as irrigation signal.