The effects of earthworm inoculation and cropping systems on upland rice systems were examined over a four-year period in the Highlands of Madagascar. Each year, endogeic earthworms Pontoscolex corethrurus (Rhinodrilidae) were inoculated (EW+) at a density of 75 ind m⁻² or were not inoculated (EW0). Inoculation was tested in three cropping systems: conservation agriculture (CA) and traditional tillage with or without residues restitution. Soil and plant properties were measured during the first three years while soil biological properties were assessed at the fourth year. At the end of the experiment, earthworm density was three-fold higher in EW+ than in EW0, demonstrating the success of the inoculation. Earthworm density was more important in CA than in tillage systems. Earthworm inoculation had higher significant effects on soil and plant properties than cropping systems. Earthworm inoculation had positive effects on soil macroaggregation (+43%), aboveground biomass (+27%), rice grain yield (+45%), and N grain amount (+43%). Intensifying earthworm activity in field conditions to meet the challenge of ecological transition is supported by our study.

During a survey of the soil macrofauna of Madagascar three giant earthworm species were collected in the eastern part of the island. One of them, Kynotus friderici Michaelsen, 1931, is a known species described as K. longus var. friderici Michaelsen, 1931 and elevated to species rank herein. The other two species, K. giganteus sp. n. and K. proboscideus sp. n., proved to be new to science. K. giganteus measures alive 1350–1400 mm in length, 20–25 mm in diameter; K. proboscideus alive is ca 500–600 mm long and 15–20 mm in diameter. All worms belong to the Malagasy endemic family Kynotidae.

The investigation of a small number of earthworms collected in Central Madagascar resulted in the discovery of two spe-cies new for science, Kynotus minutus and Kynotus parvus spp. nov. Apart from the descriptions and illustrations of thenew species, the two little-known species Kynotus alaotranus Michaelsen, 1907 and Kynotus michaelseni Rosa, 1892 arerecorded for the first time after the original description, and commented short diagnoses are provided. With the two newspecies described in this paper, the genus Kynotus now contains 20 species. The monogeneric earthworm family Kynotidae is endemic to Madagascar.

Earthworm casts are hotspots of the soil carbon cycle, with major processes driven by their microbial community. Although microbial interactions are likely to be central to these processes, our mechanistic understanding of soil microbial interactions remains very limited. Here we describe an innovative approach that combined long read metagenomics and metabarcoding co-occurrence graph to link ecological strategies of soil bacteria and their potential interactions. The dynamic of microbial interaction and carbon was tracked in casts produced by tropical earthworms of different ecological categories.,An ordination analysis applied on genome level traits involved in microbial interaction processes revealed three archetypal ecological strategies tightly linked with organic matter transformation: Decomposers / Consumers / Predators. Decomposers carried genes responsible for plant structural polymers decomposition and showed the highest connectivity, supporting their functional importance in the system. Consumers, with more genes involved in the use of simple molecules, increased their abundance during cast ageing, probably by benefiting of the liberation of oligomeric substrates by decomposers. Predators relied on type IV and VI secretion system genes and did not show specific co-occurrence pattern. Network connectivity in these cast communities correlated with CO₂ emission rates, but this relationship shifted from positive to negative with cast ageing, suggesting that the impact of bacterial interactions on carbon cycling depends on resource availability.,Our results suggest that bacterial interactions in earthworm casts emerge from a limited number of carbon acquisition strategies. Identifying the environmental drivers and ecological consequences of these strategies may prove essential to understand organic carbon cycling in biologically active soils.