a1 International Center for Agricultural Research in the Dry Areas (ICARDA), PO Box 5466, Aleppo, Syria
Following a survey of fertilizer use on farmers' barley fields in northern Syria and very positive results from barley fertilizer trials on ICARDA research stations, a programme of researcher managed trials on farmers' fields indicated considerable potential for yield increase from the use of nitrogen and phosphorus fertilizers across a range of environments. It was then necessary to test and demonstrate the effectiveness of fertilizers in farmers' hands. A researcher managed trial (RMT) and a farmer managed trial (FMT), with similar fertilizer treatments, were compared over the winter cropping season on each of 10 on-farm sites in 1987/88 and 20 sites in 1988/1989. Despite large differences in rainfall between the two seasons (means across sites, 422 mm in 1987/88 and 174 mm in 1988/89), yield responses to fertilizer were similar in both seasons, with only marginal yield differences between researcher and farmer managed trials. Crop sequence had no effect on the pattern of fertilizer response in either type of trial. Once the effectiveness of fertilizers had been tested in farmers' hands, demonstration trials were conducted in the following two years to transfer the technology to farmers in the barley growing areas of northern Syria.
Ensayos conducidos por agricultores e investigadores en Siria
(Accepted May 21 1993)