Root length dynamics in agroforestry with Gliricidia sepium as compared to sole cropping in the semi-deciduous rainforest zone of West Africa |
| |
Authors: | Götz Schroth Wolfgang Zech |
| |
Institution: | (1) Institute of Soil Science and Soil Geography, University of Bayreuth, D-95440 Bayreuth, Germany |
| |
Abstract: | Tree root systems may improve soil fertility through carbon inputs, uptake of leachable nutrients and maintenance of soil
biomass, but can at the same time reduce crop yields by competition for water and nutrients. Quantitative information about
the positive and negative effects of tree roots and their changes in space and time are necessary for the optimization of
agroforestry associations. An alley cropping experiment was layed out as a randomized complete block design on a Plinthic
Lixisol/Ferralic Cambisol with Gliricidia sepium hedgerows at 5 m distance, including a sole cropping control. The development of root systems was monitored by sequential
soil coring (eight samplings) during one year, with maize and groundnut as crops. Additional information is presented from
a single sampling for rice during the foregoing year. Pronounced fluctuations of live root length density indicated an important
variability in the nutrient and water uptake capacity of the vegetation. At low total root length density, the hedgerows affected
the root development in the agroforestry plots directly by the presence of their root systems. At high root length density,
they affected root development mainly by improving crop root growth and influencing the composition of the spontaneous vegetation.
The root length density of the hedgerows was too low to compete with the crops for soil resources. The hedgerows tended to
increase root length densities in the subsoil when few roots were present, thus possibly reducing the risk of nutrient leaching.
However, the length density of the perennial root systems decreased during the cropping season, presumably as an effect of
repeated pruning, and attained minimum values almost at the same time as the crops. Trees with denser root systems which are
less frequently pruned may be more efficient in achieving closer nutrient cycles, though at the cost of higher root competition
with crops. |
| |
Keywords: | alley cropping Chromolaena odorata Gliricidia sepium groundnut maize rice root length density |
本文献已被 SpringerLink 等数据库收录! |
|