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Unamunzaga O.,NEIKER Basque Institute for Agricultural Research and Development | Besga G.,NEIKER Basque Institute for Agricultural Research and Development | Castellon A.,NEIKER Basque Institute for Agricultural Research and Development | Uson M.A.,University of Zaragoza | And 3 more authors.
Soil Use and Management | Year: 2014

Soil physical properties influence vineyard behaviour; therefore, the knowledge of their spatial variability is essential for making vineyard management decisions. Little work has been conducted at high spatial resolution on soil properties at depths lower than 0.30 m which is of special relevance to perennial crops. The objectives of this work were to (i) analyse the spatial and vertical variability of soil depth, particle size fractions and water-holding capacity (WHC) by geostatistical techniques; (ii) study the causes of the variability, with additional information from classical soil sampling; and (iii) assess the significance of WHC through its relationship with vine vigour. The work was carried out in a vineyard of eight hectares within the D.O.Ca. Rioja (northern Spain). Soil variability was determined via grid sampling at three depth ranges (0-0.30, 0.30-0.60 and 0.60-0.90 m). A conventional soil survey provided additional information on soil variability. Clay, sand and silt fractions, soil organic matter content, WHC and pruning weight were determined. Most soil properties had strong or moderate spatial dependence, with the exceptions of sand at 0.30-0.60 m and silt in the topsoil. Topography and soil erosion caused the spatial variability of soil depth and contributed to the spatial distribution of particle size fractions in the topsoil, while the heterogeneity of parent material influenced the spatial pattern of soil properties at 0.60-0.90 m. The WHC and soil depth spatial distributions related well to that of vine vigour, demonstrating the importance of knowing the spatial variability of these soil properties. © 2014 British Society of Soil Science. Source

Villar N.,NEIKER Basque Institute for Agricultural Research and Development | Aizpurua A.,NEIKER Basque Institute for Agricultural Research and Development | Castellon A.,NEIKER Basque Institute for Agricultural Research and Development | Ortuzar M.A.,University of the Basque Country | And 2 more authors.
Soil Science | Year: 2014

Estimating soil N mineralization is important for determining the amount of N fertilizer needed to obtain optimum yields at minimal environmental and economic costs. The aim of this work was to determine the most appropriate laboratory method for the estimation of N mineralization during a winter wheat-growing season in calcareous soils under a humid Mediterranean climate. Laboratory methods were developed involving three chemical extractants, CaCl2, KCl, and NaHCO3, and several soil-drying and extraction temperatures. Soil N indexes calculated based on extractions were compared with potentially mineralizable N (No). Moreover, soil mineralization indexes estimated from both chemical extractions and aerobic incubation were related to apparent N mineralization and wheat N uptake in a pot experiment. The mineralization index estimated from an extraction with KCl boiled at 100°C (HotKCl) was the index that best correlated with No and the apparent mineralization under greenhouse conditions. The combination of preplant soil mineral N and the HotKCl N mineralization index was more strongly correlated with wheat N uptake than soil mineral N data alone. Consequently, estimation of N mineralization using HotKCl extraction is the most appropriate methodology for establishing N fertilizer use recommendations for wheat cultivation in calcareous soils under Mediterranean conditions. Copyright © 2014 Lippincott Williams & Wilkins. Source

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