scholarly journals Runoff mitigation via micro‐dams and conservation tillage – numerical modelling of runoff and erosion from maize field trials

Author(s):  
Stephan Sittig ◽  
Robin Sur ◽  
Dirk Baets
Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1254
Author(s):  
Marcus Jones ◽  
Marin Harbur ◽  
Ken J. Moore

Plot size has an important impact on variation among plots in agronomic field trials, but is rarely considered during the design process. Uniformity trials can inform a researcher about underlying variance, but are seldom used due to their laborious nature. The objective of this research was to describe variation in maize field trials among field plots of varying size and develop a tool to optimize field-trial design using uniformity-trial statistics. Six uniformity trials were conducted in 2015–2016 in conjunction with Iowa State University and WinField United. All six uniformity trials exhibited a negative asymptotic relationship between variance and plot size. Variance per unit area was reduced over 50% with plots 41.8 m2 in size and over 75% when using a plot size >111.5 m2 compared to a 13.9 m2 plot. Plot shape within a fixed plot size did not influence variance. The data illustrated fewer replicates were needed as plot size increased, since larger plots reduced variability. Use of a Shiny web application is demonstrated that allows a researcher to upload a yield map and consider uniformity-trial statistics to inform plot size and replicate decisions.


2018 ◽  
Vol 10 (2) ◽  
pp. 330 ◽  
Author(s):  
Richard Makanza ◽  
Mainassara Zaman-Allah ◽  
Jill Cairns ◽  
Cosmos Magorokosho ◽  
Amsal Tarekegne ◽  
...  

2018 ◽  
Vol 10 (11) ◽  
pp. 1
Author(s):  
Theodore G. Blumenschein ◽  
Kelly A. Nelson ◽  
Peter P. Motavalli

Corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production in claypan soils in the north central U.S. may be constrained by the presence of acidic subsoils. Subsoil acidity can inhibit root growth leading to decreased drought tolerance and grain yields. In conservation tillage systems, management options to incorporate gypsum applications may be limited; thereby reducing available practices to lower subsoil acidity. The objective of this study was to determine the effects of surface placement of gypsum compared to a new practice for deep vertical placement of gypsum on corn and soybean plant growth and yields in a conservation tillage system. Field trials were conducted from 2012 to 2016 in northeast Missouri (USA) with treatments of gypsum (0, 2.9, and 5.2 Mg ha-1) broadcast on the soil surface or applied in a deep vertical band to a depth of 51 cm. Surface and deep banding of gypsum had inconsistent effects on corn and soybean plant heights, plant population and yields. However, deep banding of gypsum resulted in a 6.4 to 9.8% decrease in corn yields and a 9.9 to 13.0% decrease in soybean yields depending on the time after application. These results indicate that further research is warranted in conservation tillage systems in claypan soils to examine modification to the deep vertical placement practice or combining applications of surface-applied gypsum and deep placement of lime in order to develop a practice that will be more effective in overcoming subsoil acidity.


2019 ◽  
Vol 20 (1) ◽  
pp. 29-34 ◽  
Author(s):  
Yuba R. Kandel ◽  
Leonor F. S. Leandro ◽  
Daren S. Mueller

Conservation tillage has become a common practice of soybean farming in the Midwestern United States owing to the benefits of soil and moisture conservation. Field trials were established in a field with a history of sudden death syndrome (SDS; caused by Fusarium virguliforme) in Iowa in 2011 and evaluated for five consecutive years to determine the impact of tillage on SDS and yield. The experiment was laid out in a split-split-plot design with four replicates. The main plot factor was tillage (no-till both crops, no-till corn and chisel plow soybean, and disc corn and chisel plow soybean), and each main plot was divided into subplots of corn or soybeans (in a 2-year rotation). Each subplot was again divided into two subsubplots, in which two soybean cultivars, moderately susceptible (MS) and moderately resistant (MR) to SDS, were planted each year. Root rot and SDS disease index (FDX) differed among years, because some years were more favorable for the disease than the others. However, tillage did not affect any parameters, including yield, in any year (P > 0.05). Cultivar effect was significant for each parameter occasionally. When significant, the MR cultivar had lower root rot and FDX and greater yield than the MS cultivar. These data suggest planting resistant cultivars can be an effective management tactic, but tillage does not help for SDS management.


1995 ◽  
Author(s):  
B. B. Lahey ◽  
B. Applegate ◽  
K. McBurnett ◽  
J. Biederman ◽  
L. Greenhill ◽  
...  

2007 ◽  
Author(s):  
George Bohrnstedt ◽  
Jeanne Poduska ◽  
Mike Garet ◽  
Sheppard Kellam ◽  
David Myers

2013 ◽  
Vol 10 (01) ◽  
pp. 33-37 ◽  
Author(s):  
M. Klinkman ◽  
D. Goldberg

SummaryThis paper describes the necessity of adapting the major classifications of mental disorders exemplified by the ICD-11 and the DSM-5 for the special needs of primary medical care. An earlier version of the classification – the ICD-10-PHC – is described, and the process of adapting it is described in detail. The new 28 item version of the classification is described, and the procedures to be adopted in the Field Trials to be held during 2013 are set out, together with the specific problems these field trials will address.


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