Effects of soil management practices and irrigation on plant water relations and productivity of chestnut stands under Mediterranean conditions

Abstract

The effects of different soil management practices and irrigation on plant water relations, physiological response and productivity of chestnut stands in Northeastern Portugal were assessed during four growing seasons (2003 to 2006). Treatments were: conventional soil tillage up to 15-20 cm depth with a tine cultivator thrice a year (CT); no tillage with spontaneous herbaceous vegetation (NV); no tillage with rainfed seeded pasture (NP); and no tillage with irrigated seeded pasture (NIP). Results suggest that soil water availability was the most critical parameter for chestnut productivity over the study period. In all treatments, high predawn leaf water potentials (-0.40 to -0.55 MPa) were observed during the dry seasons of 2003, 2004 and 2006, showing no critical conditions for plant productivity, which is ascribed to water availability in deep soil layers. In contrast, in 2005, an extremely dry year, water potentials decreased and varied from -1.46 to -1.72 MPa in late summer, showing unfavourable conditions for nut production. Maintenance of spontaneous herbaceous vegetation without irrigation enhanced productivity of chestnut stands as compared with the conventional tillage system and the no tillage system with seeded pasture. Productivity in the soil watering system (NIP treatment) was not significantly different from that observed in the NV treatment. Therefore, studies on the irrigation strategy should be developed, in order to increase its efficiency especially in stands with young trees.

Study of morphological and chemical diversity in chestnut trees (var. “Judia”) as a function of temperature sum Estudio de la diversidad morfológica y química del fruto de castaña (var. “Judia”) en función de la suma de la temperatura

“…Martins et al (2010) demonstrated that even when trees are subjected to prolonged periods of little or no precipitation, as it happened in 2005 (precipitation in May-September, between 60 and 100 mm), predawn leaf water potential in adult tress was preserved at 70.60 to 70.80 MPa from May to October and no significant differences between watered and non-watered plants were found. These authors explained it as being the consequence of the available water stored in the soil deep layers for the root system.…”

Response, Tolerance and Adaptation to Abiotic Stress of Olive, Grapevine and Chestnut in the Mediterranean Region: Role of Abscisic Acid, Nitric Oxide and MicroRNAs

“…In the lowest altitudes, photosynthesis rate decreases around 40%, indicating that chestnuts under these climatic conditions, nowadays start to suffer from abiotic stresses, mainly due to the heat stress. Regarding internal water balance, Martins et al, (2010) have demonstrated that adult trees can be saved from water stress, since they can continuosly absorb water from deep soil layers and so preserving predawn leaf water potential in the range of -0.6 to -0.9 MPa. Additionally, the European chestnut ecotypes coming from wet sites are more locally adapted and less plastic than those from dry sites and hence more vulnerable to the climate changes .…”

Monitorizar para regar: o caso do castanheiro (Castanea sativa)

“…A maior região produtora de castanha portuguesa, Trás-os-Montes, é regularmente afetada por períodos de seca estivais que podem pôr em causa a produtividade dos soutos, nomeadamente nos soutos jovens e se instalados em solos pouco profundos, compactos e pedregosos (Martins et al, 2010). Sendo a água uma das maiores, senão a maior, condicionante na produtividade das culturas, a introdução da rega no castanheiro é uma realidade próxima.…”

“…No caso do castanheiro, o Ψ base e o Ψ md são os mais estudados (Gomes-Laranjo et al, 2008). Considera-se que o castanheiro tem um nível hídrico adequado quando Ψ base se encontra dentro do intervalo -0.4 a -0.6 MPa (Martins et al, 2010) e que a taxa fotossintética é máxima quando Ψ md está perto de -1 MPa (Gomes-Laranjo et al, 2008;Martins et al, 2010). Não existe conhecimento acerca dos valores ótimos de Ψ ramo no castanheiro bem regado.…”

“…A automatização e o registo contínuo de valores são possíveis com alguns destes equipamentos, facilitando o acesso aos dados por parte do utilizador. O maior constrangimento no uso dos sensores de solo, nomeadamente em árvores adultas, está relacionado com o enorme e irregular volume de solo ocupado pelas raízes (Martins et al, 2010;Silva, 2010) o que condiciona a total cobertura do solo (seja horizontalmente seja verticalmente) pois isso acarretaria um custo elevadíssimo ao produtor. Desta forma, deve-se assumir um compromisso de monitorizar diferentes profundidades do solo, no mínimo até aos 80 cm, e optar por se colocarem sensores em zonas representativas e distintas no souto.…”