NITROGEN MINERALIZATION IN NATIVE CULTIVATED AND ABANDONED FIELDS IN SHORTGRASS STEPPE

Publication Type:

Journal Article

Authors:

IHORI, T; Burke, IC; Hook, PB

Source:

PLANT AND SOIL, KLUWER ACADEMIC PUBL, Volume 171, Number 2, SPUIBOULEVARD 50, PO BOX 17, 3300 AA DORDRECHT, NETHERLANDS, p.203-208 (1995)

Keywords:

Bouteloua gracilis, land use, Nitrogen availability, recovery, SOIL FERTILITY, soil organic matter

Abstract:

We conducted a set of in situ incubations to evaluate patterns of N availability among dominant land uses in the shortgrass steppe region of Colorado, USA, and to assess recovery of soil fertility in abandoned fields. Replicated 30 d incubations were performed in 3 sets of native (never cultivated), abandoned (cultivated until 1937), and currently cultivated, fallow fields. Net N mineralization and the percentage of total N that was mineralized increased in the order: native, abandoned, cultivated Higher soil water content in fallow fields is the most likely reason for greater mineralization in cultivated fields, while higher total organic C and C/N ratios in native and abandoned fields may explain differences in mineralization between these land uses. Recovery of soil organic matter in abandoned fields appears to involve accumulation of soil C and N under perennial plants, but probable methodological artifacts complicate evaluation of the role of individual plants in recovery of N availability. Higher N mineralization and turnover in cultivated fields may make them more susceptible to N losses; recovery of N cycling in abandoned fields appears to involve a return to slower N turnover and tighter N cycling similar to native shortgrass steppe.