Maize grain production,plant nutrient concentration and soil chemical properties in response to different residue levels from two previous crops     

Juan Hirzel  Pablo Undurraga  Lorenzo León  Marcelo Panichini  Jorge Carrasco  Jorge González 《Acta Agriculturae Scandinavica, Section B - Plant Soil Science》2020,70(4):285-293

ABSTRACT

The incorporation of previous crop residues in agricultural management benefits soil fertility, crop production, and environment. However, there is no enough information about maximum residue application level without negative effect over next crop yield. To evaluate maize (Zea mays L.) yield under short-time conservation management with incorporation and/or importation of different residue levels, a biannual rotation experiment was conducted in ash volcanic soil in south-central Chile. The experiment consisted of two previous crops, canola (Brassica napus L.) and bean (Phaseolus vulgaris L.), and four levels of residue incorporation (0%, 50%, 100%, and 200% of generated residue; from 0 to 21.4?Mg?ha^?1 for canola and from 0 to 19.0?Mg?ha^?1 for bean). Previous crop species and residue level affected some nutrients concentrations in grain and plant and some soil chemical properties, without effect in maize yield, which averaged 16.6?Mg?ha^?1. Bean residue increased Ca and reduced S in maize plant, increasing soil P, Ca, Mg and K (P?<?0.05). Maize grain Ca content was positively and proportionally affected by canola residue level and negatively and proportionally affected by bean residue level. All canola residue levels increased soil pH and Mg, but the highest level reduced soil S; soil P concentration increased proportionally with bean residue level. The highest bean residue level increased soil S. Different crop and levels of residue did not affect maize yield but did some plant nutrient concentration, and also affected some soil chemical properties.  相似文献   

The Monitoring of Cr(III) and Cr(VI) in Natural Water and Synthetic Solutions: An Assessment of the Performance of the Dgt and Dpc Methods     

Lorenzo Giusti  Sabine Barakat 《Water, air, and soil pollution》2005,161(1-4):313-334

The technique of diffusive gradients in thin films or diffusive gradient in thin films (DGT) has been used in this work for the in situ measurement of labile Cr(III) and Cr(VI) species. Direct measurement of Cr(VI) was also carried out in parallel with a field-based colourimetric technique based on the EPA 7196 diphenyl-carbohydrazide (DPC) method. The efficiency of the DGT and DPC methods were tested (a) in the laboratory, using synthetic solutions in the presence of realistic concentrations of Cr, humic substances (HS), and ethylenediaminetetraacetic acid (EDTA), and (b) in the field, in river water affected by effluents discharged by the tannery industry. The main advantage of the DGT method is that it allows the in situ separation of labile species of Cr(III) and Cr(VI), though there are still uncertainties about its performance in field conditions. The DPC method proved to be a fast, accurate, and relatively economical option for the field-based determination of Cr(VI). Sample acidification and ageing of unacidified samples from contaminated aquatic environments, produced significant errors in the determination of ‘dissolved’ Cr. The concentration of Cr(VI) determined by either the DGT or the DPC method exceeds recommended international guidelines.  相似文献   

Mapping and modeling forest tree volume using forest inventory and airborne laser scanning     

Sergio Tonolli  Michele Dalponte  Loris Vescovo  Mirco Rodeghiero  Lorenzo Bruzzone  Damiano Gianelle 《European Journal of Forest Research》2011,130(4):569-577

In this paper, we present a study on the efficiency of multi-return LIDAR (Light Detection Ranging) data in the estimation of forest stem volume over a multi-layered forest area in the Italian Alps. The goals of this paper are (1) to verify the usefulness of multi-return LIDAR data compared to single-return data in forest volume estimation and (2) to define the optimal resolution of a stem volume distribution raster map over the investigated area. To achieve these goals, raw data were segmented into a net, and different cell dimensions were investigated to maximize the relationship between the LIDAR data and the ground-truth information. Twenty predicting variables (e.g., mean height, coefficient of variation) have been extracted from multi-return LIDAR data, and a multiple linear regression analysis has been used for predicting tree stem volume. Experimental results found that the optimal resolutions of the net square cells were 40 m. The analysis indicated that in a mixed multi-layered forest, characterized by a complex vertical structure, the correct selection of the map spatial resolution and the inclusion of the secondary-return data were important factors for improving the effectiveness of the laser scanning approach in forest inventories. The experimental tests showed that the chosen model is effective for the estimation of stem volume over the analyzed area, providing good results on all the three considered validation methods.  相似文献   

Ultrafast laser-driven microlens to focus and energy-select mega-electron volt protons     

Toncian T  Borghesi M  Fuchs J  d'Humières E  Antici P  Audebert P  Brambrink E  Cecchetti CA  Pipahl A  Romagnani L  Willi O 《Science (New York, N.Y.)》2006,312(5772):410-413

We present a technique for simultaneous focusing and energy selection of high-current, mega-electron volt proton beams with the use of radial, transient electric fields (10(7) to 10(10) volts per meter) triggered on the inner walls of a hollow microcylinder by an intense subpicosecond laser pulse. Because of the transient nature of the focusing fields, the proposed method allows selection of a desired range out of the spectrum of the polyenergetic proton beam. This technique addresses current drawbacks of laser-accelerated proton beams, such as their broad spectrum and divergence at the source.  相似文献   

Ecological diversity of sediment rhizobacteria associated with Phragmites australis along a drainage canal in the Yellow River watershed     

Borruso  Luigimaria  Esposito  Alfonso  Bani  Alessia  Ciccazzo  Sonia  Papa  Marianna  Zerbe  Stefan  Brusetti  Lorenzo 《Journal of Soils and Sediments》2017,17(1):253-265

Journal of Soils and Sediments - Spatial distribution on a regional scale of the rhizobacterial communities of Phragmites australis stands was investigated along the Yellow River watershed, China....  相似文献