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| Martínez G,Ingrid; Zagal V,Erick; Ovalle M,Carlos; Coûteaux,Marie-Madeleine; Stolpe,Neal B; Valderrama V,Natalia. |
| The ecosystems of the Mediterranean interior dryland of Chile, dominated by an espinal agroecosystem of Acacia caven (Molina) Molina, show low productivity as a result of soil degradation. The objective of this study was to evaluate litter decomposition of A. caven and Lolium multiflorum Lam. in espinal ecosystems: well preserved (Wp) 50 to 80%, typical (Pd) 25 to 50%, and degraded (De) with 10 to 25% cover. During 420 d and starting in April 2004 until August 2005, weight loss in litter bags and chemical composition (hemicellulose, cellulose, lignin, non-structural components, ash, N, C, C/N ratio, and P) were determined by using near infrared reflectance spectroscopy (NIRS) and the Van Soest protocol. Weight loss ranged from 31 to 52% in L. multiflorum... |
| Tipo: Journal article |
Palavras-chave: Canopy cover; Weight loss; Litter bags; NIRS; Principal components. |
| Ano: 2010 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392010000300013 |
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| Undurraga D,Pablo; Zagal V,Erick; Sepúlveda W,Gloria; Valderrama V,Natalia. |
| Soil organic matter (OM) content is a quality indicator, but is an inadequate indicator in the short-term because these changes take place slowly, so dissolved organic components have emerged as an alternative. In volcanic soil subjected to different crop rotations with distinct land use intensity, dissolved organic C and N (DOC and DON) were determined as well as their relationship with total C and N contents in the soil, considering the effects of crop rotation, fertilization level, and soil depth. In humid samples of Humic Haploxerands collected at four depths up to 40 cm, DOC and DON contents were determined by extraction with K2SO4 and filtered. Results indicated interaction between the studied factors, DOC fluctuated between 67.8 and 151.7 mg kg-1... |
| Tipo: Journal article |
Palavras-chave: Organic matter; Dissolved organic matter; Total C; Total N; Volcanic soil. |
| Ano: 2009 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392009000300018 |
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| Martinez G,Ingrid; Ovalle,Carlos; Del Pozo,Alejandro; Uribe,Hamil; Valderrama V,Natalia; Prat,Christian; Sandoval,Marco; Fernández,Fernando; Zagal,Erick. |
| Chilean dryland areas of the Mediterranean climate region are characterized by highly degraded and compacted soils, which require the use of conservation tillage systems to mitigate water erosion as well as to improve soil water storage. An oat (Avena sativa L. cv. Supernova-INIA) - wheat (Triticum aestivum L. cv. Pandora-INIA) crop rotation was established under the following conservation systems: no tillage (Nt), Nt + contour plowing (Nt+Cp), Nt + barrier hedge (Nt+Bh), and Nt + subsoiling (Nt+Sb), compared to conventional tillage (Ct) to evaluate their influence on soil water content (SWC) in the profile (10 to 110 cm depth), the soil compaction and their interaction with the crop yield. Experimental plots were established in 2007 and lasted 3 yr till... |
| Tipo: Journal article |
Palavras-chave: Neutron probe; Penetrometer resistance; Oat; Subsoiling; Water erosion; Wheat. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000400018 |
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| Claret M,Marcelino; Urrutia P,Roberto; Ortega B,Rodrigo; Best S,Stanley; Valderrama V,Natalia. |
| Consumption of water contaminated with nitrates is associated with important health effects such as methemoglobinemia and gastric cancer. Intensive agriculture, which uses large quantities of N fertilizer, is the main source of nitrates in water systems. There are several strategies to reduce leaching and increase Nitrogen Use Efficiency (NUE). An experiment was conducted with spring wheat (Triticum aestivum L.) under sprinkler irrigation (center pivot) to determine if adjusted N applications using precision agriculture tools and plant demand resulted in a lower groundwater nitrate load. Evaluated treatments were: produced fertilization (Pr), precision agriculture (Pa), chlorophyll meter (Sm), and control without N (W/N). The ceramic capsule methodology... |
| Tipo: Journal article |
Palavras-chave: Nitrates; Precision agriculture; Chlorophyll meter; Wheat. |
| Ano: 2011 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0718-58392011000100018 |
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