An assessment of Soil Fertility Management strategies in Agroecosystems (biomass transfer technology) on Belowground Biodiversity-Soil macrofauna biomass

Citation:
Ayuke FO, Opondo-Mbai ML, Rao MR, Swift MJ. "An assessment of Soil Fertility Management strategies in Agroecosystems (biomass transfer technology) on Belowground Biodiversity-Soil macrofauna biomass.". In: proceedings of the 8th Tropical Soil Biology and Fertility and Programme African Network meeting. Arusha, Tanzania; 2001.

Date Presented:

7-10 May

Abstract:

During 1997 short rains (Oct 1997-Feb 1998), a study was undertaken to assess how biomass transfer within
agroecosystem influence soil biodiversity (soil macrofauna biomass). This was part of a larger experiment conducted to test the hypothesis that diversity, abundance and function of soil invertebrate fauna are related to the quality of organic residues used. Leaf biomass of tithonia (Tithonia diversifolia [Hemseley) A. Grey) biomass and senna (Senna spectabilis D.C. & H.S. Irwin) biomass at 5 t ha -1 dry weight were incorporated into the soil and these were compared with the control without any input and fertilizer at 120 kg N, 150 kg P and 100 kg K ha-1 from urea and triple super phosphate (TSP). Macrofauna biomass (fresh weight), was monitored in soil monoliths (25cm x 25cm x 30cm) at the beginning of the season, six weeks after sowing maize and at maize harvest. Addition of organic residues increased faunal biomass substantially over the fertilized and unfertilized controls. Whereas senna increased total biomass by 45% and tithonia by 49%, the two organic residues did not differ significantly between them. Addition of either senna or tithonia significantly increased earthworm biomass by 390% over no input control. Even though termite biomass increased by 160% in senna and 120% in tithonia over no input control, F test was not significant because of high variability between replications of the same treatment. Fertilizer use did not change biomass of termites and earthworms. This study shows that: (1) addition of organic residues significantly increase faunal biomass indicating a likelihood that soil invertebrate functions can be manipulated by external inputs of organic residues (2) under arable land use system characterized by low amount, range and diversity of food resources, quality of organic residues do not play a significant role in influencing foraging behaviour of soil invertebrates. It therefore remains to be demonstrated whether mixing litter of organic residues of different quality may change this foraging behaviour and consequently the invertebrate functions in agroecosystem.

Key words: Biomass transfer, macrofauna, biomass, earthworms, termites

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