New insights on the loess/paleosol Quaternary stratigraphy from key sections in the U.S. Midwest

Three key Quaternary loess/paleosol sections were examined in the Missouri Valley (Iowa), Eustis Ash Pit (Nebraska), and in the Wittsburg Quarry (Arkansas) to gain insights into the sedimentation, environment and climate change of the U.S. Midwest. Four loess units are present separated by three well-developed paleosols. Crowley's Ridge Loess (Oxygen Isotope Stage (OIS) 8) is pre-Illinoian in age, and is the oldest loess unit investigated. A well-developed paleosol, interpreted as Yarmouth Soil (OIS 7), is found in this loess in all three sections. Overlying the Yarmouth Soil is Loveland Loess (OIS 6) which has been pedogenically altered by the Sangamon Soil (OIS 5). It has luvisolic properties but a more clayey pedogenic texture than modern luvisols and has no clear eluvial horizon. The overlying Roxana Silt (OIS 4) is pedogenically altered. At Wittsburg and Missouri Valley, the Farmdale Soil (OIS 3) is developed in the Roxana Silt. Based on pedogenic features, we correlate this paleosol to that developed in the Gilman Canyon Formation at Eustis. In Missouri Valley and Eustis sections, the paleosol has chernozemic properties and therefore, the gleyic features observed at Missouri Valley are interpreted as later alterations. Overlying the Farmdale Soil is the widespread Peoria Loess (OIS 2).     

Loss of soil resources from water‐eroded versus uneroded cropland sites under simulated rainfall

Soil erosion is widespread in agricultural lands of the US Corn Belt. The objective of this study was to examine the impact of antecedent erosion on loss of soil under laboratory simulated rainfall. The soil was obtained from the surface layer of eroded (ER) and uneroded (UN) sites within a conservation agro‐ecosystem in central Ohio, USA. Air‐dried soil was subjected to a rainfall simulation for 60 min (dry run), and to another simulation (wet run) 24 h after the dry run. In the dry run, the cumulative water runoff, sediment yield, and soil organic carbon loss were higher in ER (12.3 L/m², 169.3 g/m², and 5.6 g/m², respectively) than in the UN (7.3 L/m², 22.6 g/m², and 0.9 g/m² respectively). An opposite trend was observed for the cumulative water infiltration (0.9 and 3.9 L/m², respectively). In the wet run, despite a similar cumulative water runoff from the two erosional phases (20.1 and 19.6 L/m² in ER and UN respectively), sediment yield and soil organic carbon loss were higher in ER (484.4 g/m², and 16.3 g/m² respectively) than in the UN (146.6 g/m², and 5.3 g/m² respectively). Also for the wet run, an opposite trend was observed for the cumulative infiltration (0.8 and 5.8 L/m² respectively). This study suggests that past erosional processes increase the susceptibility of remaining soil to accelerated erosion.     

甘肃中西部灌区沙化土地改良技术规程

由于甘肃省中西部大面积耕地不同程度沙化,严重影响作物生长和该区农业发展。通过近几年对沙化土壤改良剂配方、施用量、施用时间和方法等进行多年试验、示范并反复验证,研究提出了甘肃中西部灌区沙化土地改良技术,为了提高该技术的应用效果,从技术范围,规范性引用文件,术语定义,沙化土地改良技术的选地、整地平地、改良剂施用、施肥翻耕、第1茬作物选择、播种、田间管理、轮作模式、收获和改良效果等方面规范了甘肃中西部灌区沙化土地改良技术,以期为甘肃省及我国西北灌区的沙化地改良种植提供了科学依据,促进甘肃省乃至全国沙化地生态修复。     

Biophysical and socioeconomic factors explaining the extent of forest cover on private ownerships in a Midwestern (USA) agrarian landscape

As landscape fragmentation continues to escalate, it is imperative that we improve our understanding of the factors that contribute to the creation and retention of forest on privately-owned land to most effectively design and implement conservation policy. This article presents the percentages of variation in the proportion of forest on private ownerships across an agriculturally-dominated landscape in north-central Indiana, USA that can be explained by biophysical characteristics, landowner (socioeconomic) attributes, and private landowner assistance programs. While biophysical characteristics of the land accounted for the majority of variation explained (17.35%, p < 0.0001, n = 194), attitudinal and demographic attributes of the landowners contributed significantly to explaining additional variation (7.97%, p<0.0001), and overlapped with biophysical characteristics to explain another 17.31%. Program familiarity and enrollment did not explain a significant amount of the variation independent of either biophysical or landowner attributes. Private landowner assistance programs should broaden their objectives and increase incentives to appeal to the variety of landowners who possess the decision-making authority for most of the land in the region and the nation as a whole.     

2013年山东省中西部梨产区产业调研分析

2013年11月对山东省阳信、冠县、费县、历城、滕州等5个示范县梨的生产销售情况进行了调研,结果表明,上述5个县2013年梨的产量较2012年有所降低,但价格明显高于去年;同时,调查了山亭等5个县区2013年梨的生产情况。在此基础上,对山东省中西部梨产区的产业形势进行了分析,并提出了梨产业发展的建议。     

Geographical patterns in openland cover and hayfield mowing in the Upper Great Lakes region: implications for grassland bird conservation

Populations of many grassland bird species such as Grasshopper Sparrow (Ammodramus savannarum), Henslow’s Sparrow (A. henslowii), and Bobolink (Dolichonyx oryzivorus) have experienced considerable declines over the last century. To foster multi-species grassland bird conservation in the Upper Great Lakes (UGL) states of Michigan, Minnesota, and Wisconsin, we quantified geographic patterns within three sub-regional zones (e.g., North, Central, and South) of the UGL. Patterns of interest included the distribution and abundance of openland cover type (including managed pasture-hayland), the distribution, phenology, habitat affinity, and long-term population trends of ten grassland bird species, and (in particular) the geographic patterns in hayfield mowing and the temporal changes in hayfield cover. Approximately 10, 38, and 53% of the UGL openland was proportioned in the North, Central, and South zones, respectively. The distribution of hayland also varied by zone: North, 17%; Central, 46%; and South, 37%. In the central portion of the UGL where the greatest area is devoted to hay production, alfalfa—more intensively managed than mixed-grass hay—predominates. Although we found significance differences (P < 0.05) in hayfield mowing intensity between zones (with the majority of land under relatively low-intensity mowing found in the North Zone, particularly the Upper Peninsula of Michigan) no strong relationships were found between hayfield mowing patterns, other land cover-land use variables, and bird population trends at finer scales of study. Nonetheless, we suggest that the geographic patterns illustrated here provide useful information for grassland bird conservation planning across the UGL.