%0 Journal Article
%T Impact of Indian Mustard (Brassica juncea) and Flax (Linum usitatissimum) Seed Meal Applications on Soil Carbon, Nitrogen, and Microbial Dynamics
%A Autumn S. Wang
%A Ping Hu
%A Emily B. Hollister
%A Katie L. Rothlisberger
%A Anil Somenahally
%A Tony L. Provin
%A Frank M. Hons
%A Terry J. Gentry
%J Applied and Environmental Soil Science
%D 2012
%I Hindawi Publishing Corporation
%R 10.1155/2012/351609
%X There is a critical need to investigate how land application of dedicated biofuel oilseed meals affects soil ecosystems. In this study, mustard (Brassica juncea) and flax (Linum usitatissimum) seed meals and sorghum-sudangrass (Sorghum bicolor) were added to soil at levels of 0, 1, 2.5, and 5% (w/w). Both the type of amendment and application rate affected soil organic C, total C & N, and C & N mineralization. Mustard meal amendment initially inhibited C mineralization as compared to flax, but >50% of mustard and flax organic C was mineralized within 51£¿d. Nitrogen mineralization was similar for flax and mustard, except for the 2.5% rate for which a lower proportion of mustard N was converted to nitrate. The mustard meal greatly impacted microbial community composition, appearing to select for specific fungal populations. The potential varying impacts of different oilseed meals on soil ecosystems should be considered when developing recommendations for land application. 1. Introduction There is currently great interest in the use of various biofuels to supplement fossil fuel supplies. One potential source of biofuels is the production of biodiesel from oilseed crops. Oilseeds, such as soybeans, have been cultivated for hundreds of years with much of the oilseed meal, or press-cake, remaining after oil extraction being used for food, animal feed, or other industrial purposes. However, the cultivation of additional oilseed varieties, at the scale necessary to provide a significant supplement to worldwide demands for fossil fuels, may saturate existing markets for these oilseed meal coproducts [1]. Additionally, in order to avoid competition between food and fuel supplies, there are growing efforts to focus upon and/or develop nonfood oilseed crops that are dedicated to the production of biofuels and other industrial products [2]. However, many of the seed meals from these non-food, dedicated biofuel crops, such as castor, contain compounds or toxins which limit their use as food or animal feed [3¨C5]. One alternative use for these oilseed meals is as a soil amendment. Oilseed meals contain substantial amounts of N and varying levels of other nutrients needed for plant growth. Additionally, land application of the oilseed meals may increase levels of soil C and contribute positively to the net C effect of biofuels. Although there has been a substantial amount of research on the use of meals from some oil-producing crops as organic fertilizers, there has been a relatively limited amount of research for many of the dedicated oilseed crops [6¨C8]. The
%U http://www.hindawi.com/journals/aess/2012/351609/