Soil properties and weather conditions are known to affect soil N availability and plant N uptake; however, studies examining N response as affected by soil and weather sometimes give conflicting results. Meta‐analysis is a statistical method for estimating treatment effects in a series of experiments to explain the sources of heterogeneity. In this study, the technique was used to examine the influence of soil and weather parameters on N response of corn (Zea mays L.) across 51 studies involving the same N rate treatments that were performed in a diversity of North American locations between 2006 and 2009. Results showed that corn response to added N was significantly greater in fine‐textured soils than in medium‐textured soils. Abundant and well‐distributed rainfall and, to a lesser extent, accumulated corn heat units enhanced N response. Corn yields increased by a factor of 1.6 (over the unfertilized control) in medium‐textured soils and 2.7 in fine‐textured soils at high N rates. Subgroup analyses were performed on the fine‐textured soil class based on weather parameters. Rainfall patterns had an important effect on N response in this soil texture class, with yields being increased 4.5‐fold by in‐season N fertilization under conditions of “abundant and well‐distributed rainfall.” These findings could be useful for developing N fertilization algorithms that would prescribe N application at optimal rates taking into account rainfall pattern and soil texture, which would lead to improved crop profitability and reduced environmental impacts.

Land degradation is a problem that increasingly affects large areas of territories and affects various ecosystem services provided by coastal wetlands. These marine ecosystems provide valuable bene ts to the environment and to humans, including services such as coastal blue carbon sequestration (CBCS) the economic value of which is still poorly understood. This paper investigated land use/cover (LULC) changes in Moulay Bousselham lagoon (MBL) from 1971 to 2020 and their effects on CBCS variation. The transformation of LULC and their cumulative conversions in coastal wetlands were studied during the 1971-2010 and 2010-2020 periods based on LULC data. Then the InVEST model was used to quantify the carbon storage provided by coastal ecosystems in response to LULC changes. The results show that the overall area of strictly wetland habitats in the MBL has decreased by 8.83% since 1971. There were 94 types of LULC transformation over 1971-2020, with signi cant wetland losses marked by the conversion of wet lawn and juncus meadow to cropland. Using recent estimates of social cost of carbon (SCC) and CO 2 European Emission Allowances (EUA), the monetary value of CBCS service was calculated over the entire lagoon during the study period to reach gains between 371,053 and 3,803,295US$/y and losses between -10,127 and -103,806US$/y. If current trends of habitat loss continue, the capacity of coastal habitats to sequester and store CO 2 will be signi cantly reduced. The study shows that revenues from CBCS service can accelerate the implementation of wetland rehabilitation strategies that have a positive impact on climate regulation.

No abstract

No abstract

ABSTRACT:The last three decades have seen significant mining development in the northern regions of Canada, where the freeze and thaw cycle of permafrost and corresponding surface subsidence and heave represent a significant challenge at all mining stages, from the design of infrastructures to the monitoring of restored areas. Over the past ten years, SAR interferometry has been widely used to monitor ground surface deformation. With this technique, changes in phase between two SAR acquisitions are used to detect centimetre to millimetre surface displacements over a large area with high spatial resolution. This paper presents the results of a project that aims to develop a SAR solution to provide useful information for environmental monitoring and assessing the stability of mining sites. RADARSAT-2 and TerraSAR-X images acquired during the summer of 2014 were used to measure the displacements of ground surface, infrastructures and stockpiles caused by seasonal changes in permafrost extent. The study area is an open-pit mine located in Nunavut, northern Canada, in the continuous permafrost zone. Results shown that surface displacements calculated from RADARSAT-2 and TerraSAR-X are very similar and in agreement with scientific and terrain knowledge. Significant displacements were observed in loose soil areas while none was detected in bedrock and rock outcrop areas. The areas most affected by active layer changes showed surface subsidence during the thaw settlement period. Thus, InSAR can be used as a tool to guide the siting and design of new infrastructure as well as highlighting risks in areas of unstable terrain.