Soil macrofauna diversity and population dynamics in Indian Himalayan agroecosystems

Abstract

Soil macrofauna diversity in Himalayan mountain agroecosystems has received negligible attention despite people’s dependence on soil fertility that determines crop yield for their sustenance. This study was carried out with the objective to determine differences in soil macrofauna taxonomic groups and abundance with soil depth (0–30 cm) in irrigated and non-irrigated wheat and rice crops of two dominant Himalayan mountain agroecosystems. At both the sites, a total of 11 macrofauna groups and 23 families were recorded. Macrofauna population across both crop seasons for non-irrigated fields was significantly greater (P < 0.05) than in irrigated fields. Macrofauna population significantly differed (P < 0.001) with soil depth and significantly declined with increasing soil depth (P < 0.001). The top soil (0–10 cm depth) contributed over 80% of the total macrofauna population. Macrofauna diversity in non-irrigated fields (H′ = 2.10) was greater than in irrigated fields (H′ = 1.86), but β diversity was greater in irrigated fields (1.67 vs 1.76). The two agroecosystem types significantly differed (P < 0.05) with soil depth and crop season. On the basis of presence or absence, the macrofauna groups were categorised as (i) present in soil year-round but exhibiting high density during warm and wet rainy season and (ii) present in soil only during the warm and wet rainy season. The non-irrigated fields had greater abundance of Coleoptera, Dermaptera, Hemiptera and Isoptera than the irrigated fields. This study highlights that the Himalayan mountain crop fields host a rather diverse and abundant macro-invertebrate community that should be efficiently used to promote soil fertility.