Cropland diversity has diminished with the advent of mechanized agriculture. In some cases, a single crop is grown year after year in the same field. The lack of diversity in crops rotated in a field has allowed pests to build up, reduced yields, and in some cases increased soil erosion and reduced soil quality. Recognizing these problems, efforts are underway in many farming regions to add mor...

BACKGROUND Plant domestication occurred independently in four different regions of the Americas. In general, different species were domesticated in each area, though a few species were domesticated independently in more than one area. The changes resulting from human selection conform to the familiar domestication syndrome, though different traits making up this syndrome, for example loss of di...

World trade talks have foundered recently, in part due to developing country demands that industrialised countries reduce their large farm support programmes to allow poor farmers in the global South to compete more fairly. But are subsidies really the problem? For some crops – most notably cotton and sugar – Northern subsidies clearly are a root cause of low international prices and unfair com...

 In order to evaluate the effects of cover crops on reduced weed biomass in hybrid sunflower an experiment was carried in the research stations, Natural Resources Medicinal Plants (Samian_Ardabile) with 3 replicates in 1390-1391. The first factor was considered three type of cover crops, winter rye, spring barley, winter wheat with 2 control treatment, second factor was mulch management at two ...

Transgenic crops producing insecticidal toxins from Bacillus thuringiensis (Bt) are widely used to control pests, but their benefits will be lost if pests evolve resistance. The mandated high-dose/refuge strategy for delaying pest resistance requires planting refuges of toxin-free crops near Bt crops to promote survival of susceptible pests. We report that pollen-mediated gene flow up to 31 m f...

Transgenic crops producing Bacillus thuringiensis (Bt) proteins have become a primary tool in pest management. Due to the intensive use of Bt crops, resistance of the fall armyworm, Spodoptera frugiperda, to Cry1F maize has occurred in Puerto Rico, Brazil, and some areas of the southeastern U.S. The sustainability of Bt crops faces a great challenge because the Cry1F-maize resistant S. frugiper...

Fibrous green crops can be separated by mechanical methods into two fractions: a highquality fibrous feedstuff for ruminants and a liquid rich in protein, sugars and minerals for non-ruminants. The yields of crude protein (CP) (nitrogenx6.~5) which can be obtained from grasses and legume crops are substantially greater than for other methods of crop or animal production (Davys, 1973) (Table I),...