Nutrient constraints to tropical agroecosystemproductivity in long-term degrading soils

Submitted by Erin Rasmussen on

Publication Type:

Journal Article

Authors:

Source:

Global Change Biology, Volume 14, p.2810 (Submitted)

URL:

http://www.css.cornell.edu/faculty/lehmann/publ/GlobalChangeBiol%2014,%202810-2822,%202008%20Ngoze.pdf

Keywords:

chronosequence, fertilizer, long-term cultivation, nitrogen, phosphorus, soil fertility, soil, fertility repletion

Abstract:

Soil degradation is one of the most serious threats to sustainable crop production inmany tropical agroecosystems where extensification rather than intensification of agriculturehas occurred. In the highlands of western Kenya, we investigated soil nitrogen(N) and phosphorus (P) constraints to maize productivity across a cultivation chronosequencein which land-use history ranged from recent conversion from primary forest to100 years in continuous cropping. Nutrient treatments included a range of N and Pfertilizer rates applied separately and in combination. Maize productivity withoutfertilizer was used as a proxy measure for indigenous soil fertility (ISF). Soil pools ofmineral nitrogen, strongly bound P and plant-available P decreased by 82%, 31% and36%, and P adsorption capacity increased by 51% after 100 years of continuous cultivation.For the long rainy season (LR), grain yield without fertilizer declined rapidly ascultivation age increased from 0 to 25 years and then gradually declined to a yield of1.6Mgha

Taxonomy upgrade extras: 
chronosequence, fertilizer, long-term cultivation, nitrogen, phosphorus, soil fertility, soil
fertility repletion