Research Projects
Nodulation in V. unguiculata with Rhizobium or Bradyrhizobium after Treatment with Biosolids Principal Investigators: Drs. Carolyn Cousin & Jean Grant, Department of Biological & Environmental Sciences
This project examines the response of blackeye pea plants to different biosolids treatments; and determines the genetic diversity of the Bradyrhizobium populations in soil treated with different concentrations of biosolids. The blackeye pea (Vigna unguiculata) is a legume that is grown in regions of Africa, Asia, and the Americas. It is cultivated on a wide range of soils because it can tolerate high temperatures and drought weather conditions. An important source of protein, the blackeye pea is used for human consumption. Biosolids are organic materials produced by wastewater treatment facilities in large metropolitan areas, such as the District of Columbia. This area does not possess land space sufficient to dispose of the biosolids and elimination of this material has been problematic. One solution to the disposal problem would be to use composted biosolids for fertilizer. The recycling of biosolids would save rapidly diminishing landfill space, replenish nutrients removed from the soil during gardening and prevent erosion. Moreover, biosolids may play a significant role in nodule formation and nitrogen fixation. Nodulation occurs when bacterium, such as Bradyrhizobium, comes in contact with the root of Vigna unguiculata (the blackeye pea plant) to form a mutually beneficial relationship. The benefit provided the plant is nitrogen, fixed in the form of ammonia, while the bacteria benefit from protected environment and a direct nutrient supply. Improving nitrogen fixation and increasing plant yield in the Washington Metropolitan Area is a major goal of this project.
Effects of Using Organic Wastes as Soil Amendments in Urban Horticultural Practices in the District Principal Investigator: Dr. James R. Allen, Agricultural Experiment Station
This study is designed to determine the effects of composted organic wastes as soil amendments in helping to alleviate some of the adverse environmental problems caused by accumulated leaching and runoff of nitrate and phosphate fertilizers in our local waterways. There is a significant increase in the number of gardeners using composted waste as soil amendment in urban gardening. Results show that vegetables such as bell peppers, lima beans, snap beans, turnips, mustard, tomatoes, and zucchini squash produced a yield as good or better in plots in which composted waste was the soil amendment as in those given recommended rates of commercial fertilizer.
A Sustainable Low-Input Cropping System for Urban Gardens in the District of Columbia Principal Investigator: Dr. James R. Allen, Agricultural Experiment Station
As an effort to enhance the productivity of the increasing number of urban gardeners, the Agricultural Experiment Station has established a research and training program to develop and implement "environmentally friendly" sustainable cultural techniques. Cultural techniques to be implemented will emphasize low-input culture. Such low-input will include the use of composted waste instead of commercial fertilizer, the major soil amendment (intercropping of legumes with non-legumes to enhance soil nitrogen), and crop rotation along g with intercropping to prevent the build up of disease and insect infestation. Attempts are also being made to develop a sequential cropping system aimed at prolonging the period when gardens can remain productive each year. These cultural techniques are being researched in field plots at the Muirkirk Research Farm. After data analysis, specific recommendations will be made available to gardeners.
For more information about AES (and/or its research projects), contact Dr. Gloria S. Wyche-Moore, Associate Director, at (202) 274-7124 (gwychemo@udc.edu). |
