Miguel Quemada

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Crop residue decomposition is generally described by exponential decay functions with empirically determined decay constants. The most common time scales used are days after application (DAA), degree-days (DD) and decomposition-days (DCD). We propose a new time scale (corrected degree-days, CDD) that reflects the effect of moisture on decomposition by(More)
Quantification of drainage and nitrate leaching from cropping systems is necessary to optimize N-fertilizer application and determine the impact on groundwater quality. The objectives of this work were to (i) assess the use of capacitance probes for the continuous determination of the volume of drainage water and the amount of nitrate leached in a crop(More)
Limited data are available relating water potential (Ψ) to crop residue water content (Θ), although this relationship is important to study decomposition and moisture retention of the residue layer in no-till systems and other agricultural situations where residues are used. The objectives of this study were (i) to determine the characteristic moisture(More)
A meta-analysis of the most representative Spanish nutrition studies was carried out to identify inadequate intakes of vitamins, A, B1, B6, C, E, folate, iron, and calcium in children aged 4 to 18. Information on vegetable, fruit and fruit juice/beverage intake was also solicited. Data drawn from the selected studies yielded a total of 6540 children and(More)
A better understanding of the effect of temperature (T) and moisture on soil microbial activity should improve our ability to predict N mineralization from soil organic matter and crop residues. The objective of this study was to evaluate the effects of water potential (ψ) and T on C and N mineralization from unamended Cecil loamy sand soil (clayey,(More)
Integrating cover crops (CC) in rotations provides multiple ecological services, but it must be ensured that management does not increase pre-emptive competition with the subsequent crop. This experiment was conducted to study the effect of kill date on: (i) CC growth and N content; (ii) the chemical composition of residues; (iii) soil inorganic N and(More)
The objective of our study was to establish a methodology to determine drainage and nitrate leaching in unevenly irrigated vegetable crops. It was conducted in a tomato crop (Lycopersicum esculentum Mill) with drip irrigation in the summer of 2000 in the Ebro Valley, Spain. Two soil management techniques and two irrigation treatments were evaluated bare(More)
This study evaluates the effect of planting three cover crops (CCs) (barley, Hordeum vulgare L.; vetch, Vicia villosa L.; rape, Brassica napus L.) on the direct emission of N₂O, CO₂ and CH₄ in the intercrop period and the impact of incorporating these CCs on the emission of greenhouse gas (GHG) from the forthcoming irrigated maize (Zea mays L.) crop. Vetch(More)
Cover crops have long been touted for their ability to reduce erosion, fix atmospheric nitrogen, reduce nitrogen leaching, and improve soil health. In recent decades, there has been resurgence in cover crop adoption that is synchronous with a heightened awareness of climate change. Climate change mitigation and adaptation may be additional, important(More)