Results of the second five year period of an intensive production scheduleof four vegetal crop for processing.

The inuence of herbicides and fertilizers on yield of four vegetable crops produced for processing during the second ve year segment of a long term production sequence are reported. Annually, beginning in September I980, through September 1985, the four vegetables grown were: broccoli, spinach, pickling cucumbers and snap beans. With the exception of 1981, when snap beans preceded pickling cucumbers, the sequence followed was: broccoli, spinach, pickling cucumbers and snap beans. Three herbicides and a no herbicide treatment and twelve different fertilizer treatments were applied. The average growth to harvest period required for transplanted broccoli was 89 days. For directly sown spinach, pickling cucumbers, and snap beans, the average time to harvest was 74, 58 and $5 days respectively. During the period of a year, the eld accommodated growing crops an average of 276 days. Broccoli yield varied from year to year and showed decreasing trend. In 1984 and 1985, the decreasing trend was pronounced due to the low temperature injury occuring shortly before commercial maturity of the heads; neither fertilizers nor herbicides had any inuence on broccoli production. Spinach production did not vary according to years but it was increased by nitrogen application. Spinach plants fertilized solely with nitrogen produced almost twice as much more when grown in soil which had no herbicide treatment than plants grown in soil treatment with herbicides. Pickling cucumber production was higher when grown in spring following spinach instead of following snap beans in autumn when plant suffered from heavy powdery mildew attacks. With major elements, pickling cucumber produced a little more when treated with higher rate of phosphorous and lower rate of nitrogen. Snap beans yielded more when treated with lower fertilizer rates. Salt accumulation in the soil due to fertilizer application was responsible for reduction of snap bean production. Yield index calculated for each crop showed that yield and phosphorous efciency were depressed most by the herbicides alachlor and cycloare. Correlation made between yields of the four crops showed that because of their position in sequence and fertilizer and herbicide treatments, spinach was more related to broccoli and less to snap beans and pickling cucumber while snap beans was inversely related to all the other three crops. The model under study is an excellent tool for assessing the effects of repeated herbicide and fertilizer treatments. However, it is not recommended for use by farmers without cautious and through planning to understand how herbicides and fertilizers interact and inuence yield performance for specific crops.