Exclusion of soil macrofauna did not affect soil quality but increases crop yields in a sub-humid tropical maize-based system
Paul, B.K. ; Vanlauwe, B. ; Hoogmoed, M. ; Hurisso, T.T. ; Ndabamenye, T. ; Terano, Y. ; Ayuke, F.O. ; Pulleman, M.M. - \ 2015
Agriculture, Ecosystems and Environment 208 (2015). - ISSN 0167-8809 - p. 75 - 85.
conservation agriculture - organic-matter - microaggregate formation - agroecosystem function - aggregate stability - food security - termites - africa - tillage - biodiversity
Soil macrofauna such as earthworms and termites are involved in key ecosystem functions and thus considered important for sustainable intensification of crop production. However, their contribution to tropical soil and crop performance, as well as relations with agricultural management (e.g. Conservation Agriculture), are not well understood. This study aimed to quantify soil macrofauna and its impact on soil aggregation, soil carbon and crop yields in a maize-soybean system under tropical sub-humid conditions. A field trial was established in Western Kenya in 2003 with tillage and residue retention as independent factors. A macrofauna exclusion experiment was superimposed in 2005 through regular insecticide applications, and measurements were taken from 2005 to 2012. Termites were the most abundant macrofauna group comprising 61% of total macrofauna numbers followed by ants (20%), while few earthworms were present (5%). Insecticide application significantly reduced termites (by 86 and 62%) and earthworms (by 100 and 88%) at 0-15 and 15-30 cm soil depth respectively. Termite diversity was low, with all species belonging to the family of Macrotermitinae which feed on wood, leaf litter and dead/dry grass. Seven years of macrofauna exclusion did not affect soil aggregation or carbon contents, which might be explained by the low residue retention and the nesting and feeding behavior of the dominant termites present. Macrofauna exclusion resulted in 34% higher maize grain yield and 22% higher soybean grain yield, indicating that pest damage – probably including termites - overruled any potentially beneficial impact of soil macrofauna. Results contrast with previous studies on the effects of termites on plant growth, which were mostly conducted in (semi-) arid regions. Future research should contribute to sustainable management strategies that reduce detrimental impact due to dominance of potential pest species while conserving soil macrofauna diversity and their beneficial functions in agroecosystems.
Medium-term impact of tillage and residue management on soil aggregate stability, soil carbon and crop productivity
Paul, B.K. ; Vanlauwe, B. ; Ayuke, F. ; Gassner, A. ; Hoogmoed, M. ; Hurisso, T.T. ; Koala, S. ; Lelei, D. ; Ndabamenye, T. ; Six, J. ; Pulleman, M.M. - \ 2013
Agriculture, Ecosystems and Environment 164 (2013)1. - ISSN 0167-8809 - p. 14 - 22.
organic-matter dynamics - conservation agriculture - no-till - africa - systems - nitrogen - kenya - stabilization - protection - yields
Conservation agriculture is widely promoted for soil conservation and crop productivity increase, although rigorous empirical evidence from sub-Saharan Africa is still limited. This study aimed to quantify the medium-term impact of tillage (conventional and reduced) and crop residue management (retention and removal) on soil and crop performance in a maize–soybean rotation. A replicated field trial was started in sub-humid Western Kenya in 2003, and measurements were taken from 2005 to 2008. Conventional tillage negatively affected soil aggregate stability when compared to reduced tillage, as indicated by lower mean weight diameter values upon wet sieving at 0–15 cm (PT <0.001). This suggests increased susceptibility to slaking and soil erosion. Tillage and residue management alone did not affect soil C contents after 11 cropping seasons, but when residue was incorporated by tillage, soil C was higher at 15–30 cm (PT*R = 0.037). Lack of treatment effects on the C content of different aggregate fractions indicated that reduced tillage and/or residue retention did not increase physical C protection. The weak residue effect on aggregate stability and soil C may be attributed to insufficient residue retention. Soybean grain yields tended to be suppressed under reduced tillage without residue retention, especially in wet seasons (PT*R = 0.070). Consequently, future research should establish, for different climatic zones and soil types, the critical minimum residue retention levels for soil conservation and crop productivity.
Assessing the impact of soil degradation on food production
Bindraban, P.S. ; Velde, M. van der; Ye, L. ; Berg, M. van den; Materechera, S. ; Kiba, D.I. ; Tamene, L. ; Ragnarsdottir, K.V. ; Jongschaap, R.E.E. ; Hoogmoed, M. ; Hoogmoed, W.B. ; Beek, C.L. ; Lynden, G.W.J. van - \ 2012
Current Opinion in Environmental Sustainability 4 (2012)5. - ISSN 1877-3435 - p. 478 - 488.
conservation agriculture - carbon sequestration - land degradation - africa - erosion - yield - management - security - climate - trends
Continuing soil degradation remains a serious threat to future food security. Yet, global soil degradation assessments are based on qualitative expert judgments or remotely sensed quantitative proxy values that suffice to raise awareness but are too coarse to identify appropriate sustainable land management interventions. Studies in China and Sub Saharan Africa illustrate the considerable impact of degradation on crop production but also point to the need for solutions dependent on location specific agro-ecological conditions and farming systems.The development of a comprehensive approach should be feasible to better assess both extent and impact of soil degradation interlinking various scales, based on production ecological approaches and remote sensing to allow disentangling natural and human induced causes of degradation. A shared common knowledge base cataloguing hard-won location-specific interventions is needed for successfully preventing or mitigating degradation
|Effects of conservation agriculture on crop yields, soil aggregation, and C & N dynamics in a soybean-maize rotation in western Kenya
Paul, B.K. ; Ayuke, F. ; Gassner, A. ; Hoogmoed, M. ; Hurisso, T.T. ; Lelei, D. ; Ndabamenye, T. ; Six, J. ; Vanlauwe, B. ; Pulleman, M.M. - \ 2011
In: Abstract Book of the Wageningen Conference on Applied Soil Science on Soil Science in a Changing World, Wageningen, The Netherlands, 18-22 September2011. - - p. 211 - 211.
Reduced tillage systems and controlled traffic farming (CTF) are being implemented in the Netherlands to lessen compaction and improve soil physical quality. Changes observed in soil physical quality after reducing tillage and starting controlled traffic are often attributed to ecosystem engineers such as earthworms. Through the burrowing and casting behaviours of diverse earthworm species these soil physical functions may be affected differentially between reduced tillage systems. It was hypothesized that reduced tillage systems, where soil is not inverted during tillage, and controlled traffic will promote earthworm density and diversity and therefore encourage an improvement in soil physical quality (soil water retention and infiltration). Two replicated field experiments in randomized complete block designs were performed on organic farms in Flevoland, the Netherlands. The soils are marine loams and climatic data was collected from nearby weather stations. Different tillage treatments with or without controlled traffic were compared. Earthworm abundance, biomass and species were assessed during biannual sampling in the spring and fall of 2009, 2010 and 2011. Soil water retention, infiltration, penetration resistance, aggregate stability and saturated hydraulic conductivity were measured in the fall of 2010 and spring of 2011. Controlled traffic showed a significant positive effect on earthworm density, infiltration capacity and reduced penetration resistance. Data on the effect of tillage system is thus far not conclusive, possibly due to insufficient time for changes to occur, however data from an additional season will be added for this conference
|Soil and performance in convential and no-till systems in wester Kenya
Pulleman, M.M. ; Terano, Y. ; Ayuke, F. ; Hoogmoed, M. ; Vanlauwe, B. ; Brussaard, L. - \ 2010
In: Book of Abstracts of the AGRO2010, the XI European Society of Agronomy Congress, Montpellier, France, August 29 - September 3, 2010. - - p. 177 - 178.
A proposal for defining the geographical boundaries of Amazonia; synthesis of the results from an expert consultation workshop organized by the European Commission in collaboration with the Amazon Cooperation Treaty Organization - JRC Ispra, 7-8 June 2005
Eva, H.D. ; Huber, O. ; Achard, F. ; Balslev, H. ; Beck, S. ; Behling, H. ; Belward, A.S. ; Beuchle, R. ; Cleef, A.M. ; Colchester, M. ; Duivenvoorden, J. ; Hoogmoed, M. ; Junk, W. ; Kabat, P. ; Kruijt, B. ; Malhi, Y. ; Müller, J.M. ; Pereira, J.M. ; Peres, C. ; Prance, G.T. ; Roberts, J. ; Salo, J. - \ 2005
Luxembourg : EC (EUR 21808-EN) - ISBN 9789279000126 - 40 p.