نتایج جستجو برای: crop

تعداد نتایج: 68120  

2014
Blessing Mhlanga

Conservation agriculture (CA) is promoted as a cropping system that has potential to alleviate poor crop yields in smallholder farming while protecting the environment. It involves maintenance of permanent soil cover, diverse crop rotations and/or interactions; and minimum soil disturbance. CA is associated with crop residue management challenges due to low crop biomass yields and crop-livestoc...

2016
Alex Wu Youhong Song Erik J. van Oosterom Graeme L. Hammer

The next advance in field crop productivity will likely need to come from improving crop use efficiency of resources (e.g., light, water, and nitrogen), aspects of which are closely linked with overall crop photosynthetic efficiency. Progress in genetic manipulation of photosynthesis is confounded by uncertainties of consequences at crop level because of difficulties connecting across scales. C...

2012
Songhao Shang

Crop water requirement is essential for agricultural water management, which is usually available for crop growing stages. However, crop water requirement values of monthly or weekly scales are more useful for water management. A method was proposed to downscale crop coefficient and water requirement from growing stage to substage scales, which is based on the interpolation of accumulated crop ...

2002
Thomas C. Griggs Willie Riggs

Factors affecting forage production, quality, marketing, and utilization include urbanization; availability of crop production resources; approaches to environmental stewardship; and other social and economic forces. Two factors of particular interest are 1) availability of pesticides for use in alfalfa and other forage crops; and 2) new laboratory procedures for predicting forage nutritional v...

Journal: :Agriculture, Ecosystems & Environment 2016

2009
Martin Schönhart Erwin Schmid Uwe A. Schneider

Crop rotations are an important factor for the design and implementation of sustainable agricultural systems. Integrated agricultural land use models increasingly acknowledge the role of crop rotations by assessing economic and environmental impacts of agricultural production systems. However, insufficient data on crop rotations often challenge their implementation. In this article, we present ...

2013
M. A. Yost M. P. Russelle J. A. Coulter P. V. Bolstad

To gain perspective on alfalfa-annual crop rotations in the upper Midwest, USDA-National Agricultural Statistics Service cropland data layers and Soil Survey Geographic Database layers were combined for six states (North Dakota, South Dakota, Nebraska, Minnesota, Iowa, and Wisconsin) and seven years (2006-2012). Soil texture and geographic location both significantly affected the length of the ...

2007
Jianbing Zhang Yeping Zhu Liping Zhu

In order to simulate growth and yield of crop in field scale, crop simulation models always require a lot of initial parameters. WebGIS is a powerful tool for obtaining, managing and analyzing spatial data on the Web. With the support of WebGIS, crop models based on web services can be easily run on the web by remote client and provide decision information and measures for crop production. In t...

2004
James B. Holland

Exotic germplasm refers to crop varieties unadapted to a breeder’s target environment, and is an important resource for crop improvement. Because genetic diversity within elite cultivars of a crop is limited compared to the variability within the species and its relatives worldwide, genes from exotic germplasm can protect the crop against new biotic and abiotic stresses, and may represent uniqu...

2015
Brian A Pace Helen M Alexander Jason D Emry Kristin L Mercer

Domestication has resulted in selection upon seed traits found in wild populations, yet crop-wild hybrids retain some aspects of both parental phenotypes. Seed fates of germination, dormancy, and mortality can influence the success of crop allele introgression in crop-wild hybrid zones, especially if crop alleles or crop-imparted seed coverings result in out-of-season germination. We performed ...

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