Tao Jun ^a, Gu Wei ^a, Bryan Griffiths ^b, Liu Xiaojing ^c, Xu Yingjun ^a, Zhang Hua ^a

^a State Key Laboratory of Earth Surface Process and Resource Ecology, Beijing Normal University, Beijing 100875, China;

^b Teagasc, Environment Research Centre, Johnstown castle, Wexford, Ireland;

^c Center for Agricultural Resources Research, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, 286 Huaizhong Road, Shijiazhuang, Hebei 050021, China.

 

Abstract: We studied the effects of maize residue application on some life-cycle parameters of the earthworm Aporrectodea trapezoides (Duges, 1828) in saline agricultural soils with electrical conductivity (EC) ranging from 1.58 to 7.35 dS m^-1. This experiment was carried out under controlled laboratory conditions for 150 days. Results showed that soil salinity significantly affected the growth and reproduction of earthworms, decreasing survival, numbers and mean fresh weights of adults, juveniles and cocoons. Maize residue application gave a greater survival of earthworms at all salinity levels, but the differences were only significant at an EC of 7.35 dS m^-1, although the mean weight of adult earthworms was significantly increased by maize residue application at all salinity levels. At an EC of 1.58 dS m^-1 and 3.35 dS m^-1, the application of maize residues gave significantly higher numbers of cocoons and juveniles, but in soils with 5.26 dS m^-1 and 7.35 dS m^-1 earthworms did not produce any cocoons over the experimental period, irrespective of maize residue application. These results indicated that maize residue application alleviated the negative effects of soil salinity on the growth and reproduction of A. trapezoids up to 3.35 dS m^-1, above which maize residues only increased the growth but not on the reproduction of earthworms.

 

Keywords: Soil salinity; Maize residues; Earthworm; Reproduction; Coastal area.