Abstract
Although the drip irrigation technique has become widespread worldwide, and especially in Europe and Israel, it is used for only 2 percent of the total irrigated land in Japan. Because Japan receives sufficient rainfall throughout the year, farmers apparently do not consider it necessary to use an additional irrigation in open fields, except during occasional, extreme droughts. This study, however, verifies the hypothesis that using a drip irrigation technique can increase crop yields even in Japan’s open fields. A split-design experiment was conducted maintaining two irrigation treatments as main factor inputs and two different fertilizers as sub-factor inputs. The bell pepper was used as a test crop. The results showed that the crop yield, dry weight, and number of fruits increased in the drip-irrigated plots compared with the non-irrigated plots, regardless of fertilizer used. The crop yield differed significantly, especially in September and October when crop yields usually begin to decline. The most significant factor affecting the results appear to be the frequency of irrigation. This study indicates that if water is supplied daily to the crop using a drip irrigation technique, crop yields can be increased even in the open fields of Japan that receive sufficient rainfall.
