weeds in wheat (triticum aestivum l.) fields have always been a big problem in iran and worldwide and must be managed by non-chemical especially cultural methods. a field experiment as factorial based on a randomized complete block design with four replications in a 1000 m2 field in research farm of shirvan college of agriculture was conducted during 2007-2008. treatments included wheat densiti...

BACKGROUND The purpose of this study was to quantify the physical exertion during tree planting work and to examine the relationships between exertion, task efficiency, and productivity. METHODS Heart rate (HR) was monitored on 34 tree planters while they worked. HR data was collected for a complete working day on 19 subjects and for shorter periods of time on 15 subjects. Video of work tasks...

Nitrogen fertilizer is commonly applied to winter wheat in the High Plains to achieve moderate to high yields. Typically, anhydrous N is applied in the summer or early fall with a tillage operation. Some growers apply liquid N in the spring if winter and spring moisture are high to take advantage of higher yielding condition. Phosphate fertilizer is less frequently used on winter wheat than N f...

This study was carried out to investigate the yield response of 2 soybean (Glycine max (L.) Merrill) cultivars to different planting dates and plant populations and to examine the relationships of seed yield with leaf area index (LAI) and total dry matter (TDM) during the vegetative and reproductive periods for planting dates, plant populations, and cultivars. Two soybean cultivars, A3127 (earl...

Raised-field agricultural systems were exploited extensively by pre-Columbian Andean civilizations and now are used less extensively by contemporary Bolivian and Peruvian farmers as a method for farming the perennially wet soils of the intermontane pampas of the Andean high altiplano. The raised-field agricultural systems are linear or semi-linear raised planting platforms interspersed with sha...

Knot-related defects are the major cause of timber quality degradation, and diminishing this kind of defects is an important issue in forest management. For the purpose of clear-wood production, knot attributes and branch occlusion of Betula alnoides under natural pruning were investigated in a 14-year-old experimental plantation with five planting densities ranging from 500 to 3333 stems per h...