Browse on keywords: crop rotation nitrogen mineralization
Search results on 05/23/13
10475. Campbell, C.A., G.P. LaFond, A.J. Leyshon, R.P. Zentner, and H.H. Janzen. 1991. Effect of cropping practices on the initial potential rate of N mineralization in a thin Black Chernozem.. Can. J. Soil Sci 71:43-53.
Potentially mineralizable N (No) was examined as a possible indicator of soil organic matter change due to management, using soil from 30 yr rotation plots near Indianhead, Saskatchewan. A parameter called the initial potential rate of N mineralization (No x rate constant k at time =0) was effective in distinguishing both the absolute and qualitative changes in soil organic N due to various management practices. The results showed that fertilizers can be as effective as legumes, used either for green manure or hay, in increasing the quantity and improving the quality of soil organic matter. Organic matter changes were similar between a 6 yr soil-building rotation and fertilized continuous wheat, but higher than unfertilized continuous wheat.
10576. Janzen, H.H. and G.D. Radder. 1989. Nitrogen mineralization in a green manure amended soil as influenced by cropping history and subsequent crop.. Plant Soil 120:125-131.
In a greenhouse study, surface soil from long-term experimental spring wheat rotations was amended with 15N labelled legume green manure and subsequently cropped (canola and spring wheat) or incubated. N mineralization from both the indigenous soil N and from green manure was suppressed in cropped soil. Net N mineralization in the uncropped and cropped treatments averaged 73 and 43 mg/kg, respectively. This difference was attributed in part to enhanced biological immobilization in the rhizosphere. These data suggest that short-term N mineralization is favored by fallowing soil after green manure application whereas N retention in organic matter is favored by immediate cropping.