76 

 to increased yields in I977-78 than in I978-79. In general, the third 

 crop of southern pea produced low yields. 



Cropping pattern LM-LM-IM provided some biological stability but 

 yields of southern pea decreased with successive plantings. A high 

 degree of biological stability was observed in cropping pattern HM-LM-MM. 

 In cropping patterns HM-HM-HM and HM-MM-LM, inclusion of pole bean and 

 squash resulted in unstable yields due to improper time of planting. 



Crop and fertilizer management levels significantly influenced 

 total soluble salts (TSS) . Cropping pattern HM-HM-M resulted in higher 

 TSS among the four cropping patterns. Differences were apparent after 

 harvest of second and third crops. Fertilizer levels significantly 

 affected TSS only in cropping pattern HM-M-HM, where high levels of 

 fertilizer were applied. High TSS was due to high rates of fertilizer 

 and crop duration in pattern HM-HM-HM. The shorter the crop duration, 

 the higher the TSS content. 



In general, soil pH decreased after harvest of second and third 

 crops. Differences in soil pH after first and third crops were higher 

 in all cropping patterns except M-LM-M. Cropping pattern LM-LM-LM 

 maintained soil pH above 6.0, whereas cropping patterns involving HM 

 and a combination of HM, MM, and LM crops resulted in pK below 6.0 

 after the third crop. Fertilizer levels significantly affected soil 

 pH only after the harvest of third crops, but there was no tendency for 

 pH to decrease or increase with increasing fertilizer levels. 



Soil organic matter (OM) content decreased vdth successive crop- 

 ping in all cropping patterns except for JM-IM-JM. Differences among 

 cropping patterns were significant after harvest of third crops. Soil 

 OM decreased from O.9O to 0.54^ between the first and third crops in 



