نتایج جستجو برای: continuous cropping

تعداد نتایج: 270193  

2006
M. Liebig L. Carpenter-Boggs N. Barbour

Soil biological quality can affect key soil functions that support food production and environmental quality. The objective of this study was to determine the effects of management and time on soil biological quality in contrasting dryland cropping systems at eight locations in the North American Great Plains. Alternative (ALT) cropping systems were characterized by greater cropping intensity (...

2012
K. Waha C. Müller A. Bondeau J. P. Dietrich P. Kurukulasuriya J. Heinke H. Lotze

Multiple cropping systems provide more harvest security for farmers, allow for crop intensification and furthermore influence ground cover, soil erosion, albedo, soil chemical properties, pest infestation and the carbon sequestration potential. We identify the traditional sequential cropping systems in ten sub-Saharan African countries from a survey dataset of more than 8600 households. We find...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه شاهد - دانشکده دندانپزشکی 1394

مقدمه و هدف : از زمانی که خواص فیزیکی ni-ti در سال 1988 شرح داده شده است، فایل های روتاری نیکل-تیتانیوم (ni-ti) به طور گسترده در درمان های اندودنتیک استفاده می شوند. این فایل ها مزایای زیادی نسبت به فایل های استنلس استیل (stainless steel) دارند. علی رغم این مزایا به نظر می رسد فایل های ni-ti نسبت به شکستن آسیب پذیرتر هستند. اخیرا فایل های نیکل تیتانیوم reciprocating معرفی شده ادعا می کنند مقاوم...

2000
Audun Korsaeth Ragnar Eltun

For a cropping system to be sustainable, should not only the soil nitrogen (N) content be preserved but also the N runoff be minimised. Finding a simple but robust way to estimate N runoff would thus be a great advantage when evaluating cropping systems. In this study all major N flows in six different cropping systems, each covering 0.18 ha of a separately pipe drained field lysimeter, located...

2016
Aaron F. Fox Tania N. Kim Christine A. Bahlai J. Megan Woltz Claudio Gratton Douglas A. Landis

Maize stover is beginning to be used as a cellulosic biofuel feedstock in the Midwestern United States; however, there are concerns that stover removal could result in increased soil erosion and loss of soil organic matter. Use of a winter cover crop following maize harvest has the potential to mitigate these impacts and may have additional benefits by providing continuous living cover in annua...

Journal: :Journal of nematology 2006
M D Petrillo W C Matthews P A Roberts

The virulence index of three Meloidogyne incognita field isolates to the resistance gene Rk in cowpea was 0%, 75%, and 120%, with the index measured as reproduction on resistant plants as a percentage of the reproduction on susceptible plants. Continuous culture of the 75% virulent isolate on susceptible tomato for more than 5 years (about 25 generations) resulted in virulence decline to about ...

2018
Confidence Duku Sander J Zwart Lars Hein

In recent decades, there have been substantial increases in crop production in sub-Saharan Africa (SSA) as a result of higher yields, increased cropping intensity, expansion of irrigated cropping systems, and rainfed cropland expansion. Yet, to date much of the research focus of the impact of climate change on crop production in the coming decades has been on crop yield responses. In this study...

اصغری, جعفر, سمیع زاده, حبیبالله , محسن آبادی, غلام‌رضا, مرادی, پرستو ,

In order to evaluate the benefits of maize, pinto bean and naked pumpkin triple cropping, an experiment was carried out as a randomized complete block design with three replications at Faculty of Agricultural Science, University of Guilan, Rasht, Iran in 2012. The treatments consisted of maize, pinto bean and naked pumpkin sole cropping (100, 75 and 50% of conventional densities), maize – pinto...

2017
Jesse B. Naab George Y. Mahama Iddrisu Yahaya P. V. V. Prasad

Conservation agriculture (CA) practices are being widely promoted in many areas in sub-Saharan Africa to recuperate degraded soils and improve ecosystem services. This study examined the effects of three tillage practices [conventional moldboard plowing (CT), hand hoeing (MT) and no-tillage (NT)], and three cropping systems (continuous maize, soybean-maize annual rotation, and soybean/maize int...

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