Soil Conditioners and Soil Moisture Regimes Influenced the Nodulation and Growth of Legume Crops.

Drought and elevated temperatures often inhibit growth and productivity of food legume crops in the Delmarva region.  The response of cowpea and soybean genotypes to four soil moisture regimes (25, 50, 75 and 100% field capacity) was examined in the greenhouse.  Soil was amended with three soil conditioners (Chicken manure, Tera-Sorb, Polysacaride gum).  Nodulation and nitrogen fixation potential of these two crops were also studied under adverse drought conditions.    Results indicate that legume species varied significantly in their growth responses to the various moisture regimes; with cowpea being the most tolerant species to drought stresses.  California Blackeye 5 was the only legume genotype that was severely suppressed by the 25 and 50% moisture regimes.  Growth, nodulation, and biological nitrogen fixation of soybean were influenced significantly by the various moisture regimes and the type of soil conditioner applied.  When soil was amended with Terra-Sorb either alone or in combination with poultry manure, growth of cowpea and soybean was enhanced significantly even at low levels of moisture regimes.