53 



multiple range test, whereas treatment means from interactions between 

 crop and fertilizer management levels were compared using least signi- 

 ficant difference. Except for marketable yields, all data were analyzed 

 and treatment means compared using the statistical model for split-plot 

 design. 



Results and Discussion 



Shifts in Soil Properties 



Total soluble salts . Cropping pattern KM-HM-HM resulted in 

 higher TSS among the four cropping patterns (Fig. 5)> In cropping pat- 

 tern HM-HM-HM, application of medium to high levels of fertilizer 

 resulted in significant increase in TSS (Fig. 5) » whereas no significant 

 differences in TSS were found after harvest of the first crops in the 

 other cropping patterns. 



High soluble salts after pole bean and collard can be attributed 

 to fertilizer level and crop duration. Pole bean and collard are short 

 maturing crops compaxed to bulb onion. The low TSS after bulb onion 

 might have been the result of long and extended crop duration which en- 

 hanced more leaching and absorption of fertilizer salts. Sequential 

 planting of HM crops increased soluble salt accumulation, whereas 

 sequential planting of Wl, MM, and HM crops in combination stabilized 

 soluble salt levels. Previous studies (3'^i 73. 103, 161) showed that 

 large fertilizer applications to KM crops such as tomato, cabbage, 

 and celery resulted in high residual soluble salts at harvest. 



Soil reaction . Soil reaction (pH) was lowest after harvest of 

 second and third crops (Table 3) . Differences in soil pH after harvest 



