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Nutrient cycling in an agroforestry system with runoff irrigation in Northern Kenya

Title data

Lehmann, Johannes ; Weigl, Doris ; Droppelmann, Klaus ; Huwe, Bernd ; Zech, Wolfgang:
Nutrient cycling in an agroforestry system with runoff irrigation in Northern Kenya.
In: Agroforestry Systems. Vol. 43 (1999) Issue 1-3 . - pp. 49-70.
ISSN 0167-4366
DOI: https://doi.org/10.1023/A:1026447119829

Abstract in another language

A nutrient balance was determined for sole and alley cropped Sorghum bicolor and Acacia saligna in a runoff irrigation system in Northern Kenya. Nutrient input including precipitation and runoff, and output through harvest and leaching were measured for N, P, K, Ca and Mg using adsorption resins, tensiometry and suction cups. Various management scenarios are discussed with respect to nutrient return. Nutrient input with rainfall was generally low in comparison to nutrient uptake or leaching losses. The irrigation water, however, constituted an important nutrient input, especially for Ca and Mg. Nutrient export with the harvest was large for N and K, but can effectively be reduced by a nutrient return with mulch. Nutrient leaching losses from topsoil (0 - 30 cm) were lower in the sorghum monoculture than in the treebased systems. In the subsoil (120 cm), however, leaching was effectively reduced by the trees. In the agroforestry system, leaching losses of N under the sorghum were 53 % lower than in the sorghum monoculture. This could be attributed to a higher root abundance and a higher ratio of nutrient uptake-to-leaching in the agroforestry system than in the monocultures indicating a higher nutrient efficiency. The lower leaching losses in the agroforestry system compared to the crop monoculture could not compensate for the additional nutrient export in tree biomass. A nutrient return by mulching crop residues and acacia leaves was essential for a positive nutrient balance in the agroforestry system. Combining annual and perennial crops provided a higher internal nutrient cycling than the monocultures.

Further data

Item Type: Article in a journal
Refereed: Yes
Additional notes: BAYCEER7329
BAYCEER15372
Institutions of the University: Faculties
Faculties > Faculty of Biology, Chemistry and Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Chair Soil Physics
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Former Professors > Professorship Soil Physics - Univ.-Prof. Dr. Bernd Huwe
Research Institutions
Research Institutions > Research Centres
Research Institutions > Research Centres > Bayreuth Center of Ecology and Environmental Research- BayCEER
Faculties > Faculty of Biology, Chemistry and Earth Sciences > Department of Earth Sciences > Former Professors
Result of work at the UBT: Yes
DDC Subjects: 500 Science
Date Deposited: 21 Aug 2015 06:51
Last Modified: 07 Mar 2016 10:11
URI: https://eref.uni-bayreuth.de/id/eprint/18692