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Since the dawn of civilization, humans have utilized microbial organisms of various sorts for food and agricultural production. More recently, microbes have been used for pesticidal, and environmental management purposes. With the advent of the development of recombinant DNA technology to genetically alter microbes, it became necessary for Federal regulators to assess the appropriate level, format, and application of their regulatory authorities. In 1986, the Of fi ce of Science and Technology Policy issued the Coordinated Framework for Regulation of Biotechnology. The Coordinated Framework constituted a comprehensive regulatory policy for biotechnology that, in essence, concluded that no new statutory authorities were necessary to effectuate a robust and ef fi cient regulatory program for the products of biotechnology.

Studies were conducted to compare N mineralization rates in salt-amended nonsaline soils to naturallyoccurring saline soils. NaC1, CaC12, and Na2SO4 were added to nonsaline soils at rates that produced electrical conductivities of the saturation extracts (ECe) of 5, 10, 15, and 20 dS m 1. Saline soils with similar properties were leached to the same EC~ levels. N mineralization in the Chino soil was inhibited by salt addition, particularly with sodium and calcium chlorides. In the Domino soil there was some inhibition of N mineralization with the chloride salts, but enhancement with Na2SO 4 was observed. Nitrification in both soils was more sensitive to salt addition than ammonification.N mineralization occurred more slowly in both leached saline soils compared to the salt-amended soils. Leached saline soils often accumulated greater amounts of inorganic N compared to their native saline counterparts, particularly with the 5dSm ~ Chino soil (native, 44dSm ~) and with the 5, 10, 15 and 20 dS m ~ Domino soils (native, 32 dS m ~). Kinetic parameters were estimated by the linear least squares (LLS) and the nonlinear least squares (NLLS) methods. Generally, the LLS transformation estimated greater values of potentially mineralizable N (No) and lower rate constants (k). With the NLLS equation, N o values for the leached saline soils were usually lower, and k values usually higher than in the salt-amended soils. The nonsaline controls generally had the highest N O and lowest k estimates. Average LLS rate constants for the salt-amended and leached saline soils were 0.055 and 0.083 for the Chino, and 0.104 and 0.137 week ~, respectively, for the Domino soils. With the NLLS equation, average k values for the salt-amended and leached saline soils were 0.087 and 0.089 for the Chino, and 0.181 and 0.387 week ~, respectively, for the Domino soils. These results suggest that N mineralization rates obtained in salt-amended nonsaline soils may nrot be representative of those in naturally-occurring saline soils.

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