Conservation tillage increases carbon sequestration of winter wheat-summer maize farmland on Loess Plateau in China - Fig 3

Season variations of root respiration (a, 2013–14; b, 2014–15) and its ratio (c, 2013–14; d, 2014–15) during the cycle of wheat-maize rotation in 2013–2015 in Yangling, China. (NTS: no tillage with straw mulching; RTS: rotary tillage with straw incorporation; STS: chisel plow tillage with straw incorporation; CT: conventional moldboard plowing tillage without crop straw).