Promoting vegetation coverage using fertilization treatments in abandoned farmland in Mongolia

Abstract

We investigated the changes in vegetation responses following fertilization in abandoned farmland in Mongolia. Nitrogen (N), phosphorus (P) and potassium were sprayed alone or in combination on abandoned farmland on a typical steppe in Mongolia, and changes in soil nutrients, species composition and vegetation cover were investigated. Abandoned farmland had lower vegetation cover and soil N and P levels than natural grassland. Phosphorus fertilization significantly affected soil phosphate levels. Nitrogen fertilization in abandoned farmland effectively increased vegetation cover. Moreover, combined N and P fertilization increased plant cover over either element alone, possibly via improved uptake of nitrate ions and the promotion of growth. The effect of increasing cover following fertilization was primarily observed in the genus Artemisia. These results suggest that fertilization of abandoned farmland might not contribute to a return to natural steppe vegetation but rather increase the vegetation cover of annual forbs such as field weeds. Species composition did not appear to be affected by fertilization. This speaks to the difficulty of promoting species regeneration in abandoned farmland using fertilization alone. However, combining fertilization with the introduction of native plant material, e.g., seed sowing, may be beneficial in early restoration treatments, given the promotion of plant growth via fertilization and the importance of reducing wind erosion via the establishment of ground cover.