fertilizer practices for multiple cropping patterns (122) , This is 

 especially true for vegetable crops because of their high crop value, 

 intensive cultivation, and responsiveness to fertilization (10^), Soil 

 and fertilizer managenent studies in multiple cropping usually deal with 

 yield responses to residual fertilizers (,21, 33> 13^. 136) or to applied 

 fertilisers in continuous cropping (75 > 91 » 152, 153)- Associated with 

 these studies are effects of previous crops on yields of succeeding 

 crops (6, 13, 87, 38, 102, 112, 137, l^if, 143). These studies provide 

 some bases for fertilizer recommendations in sequential cropping sys- 

 tsras. 



In sequential, cropping patterns, the basic precept is that the 

 farmer manages only one crop at a time, From the soil management point 

 of view, improved practices for single crop stands are not entirely 

 applicable to sequential cropping systems because of the influence of 

 previous crops on soil physical properties, water, and nutrient availa- 

 bility to succeeding crops (1^3) • Soil and fertilizer m.anagement 

 practices should be geared to the crop sequence or rotation rather 

 than to individual crops. 



Sanchez (1^3) stated that the residual effects of N fertilization 

 are influenced by many variables such as the: rate of application, reco- 

 very of added fertilizer by previous crop, leaching, immobilization, 

 denitrification, and rainfall pattern. Thus, residual effects should 

 be considered in fertilizing succeeding crops. For example, in India, 

 soybean yields increased from 1,3 to 1.9 tons/ha when 11 application 

 to the preceding rice crop was increased from to 13C kg/ha (136). 

 The residual N fertilizer, however, decreased nodulation in soybean. 



