Belowground Carbon and Nitrogen on a Thinned and Un-Thinned Seasonally Dry Tropical Forest

The aim of this study wasto quantify the dynamics of herbaceous biomass and fine root productivity, andtheir relationship to stocks of carbon and nitrogen, in the Vertisols of twoadjacent watersheds of a seasonally dry tropical forest (SDTF) under twodifferent types of ground cover. The two watersheds are located in the countyof Iguatu in the State of Ceara, Brazil. The control watershed of 2.1 ha, hasbeen under regeneration for 35 years (RC35), while the secondwatershed (1.1 ha) was subjected to thinning for a period of 5 years (TC5).The sampled variables were herbaceous shoot biomass, fine roots, gravimetricmoisture, the isotope δ13C (‰),total soil carbon (TSC) and total nitrogen (TN) in the 0 - 20, 20 - 40 and 40 -60 cm layers, between April 2013 and March 2014. To quantify herbaceous shootbiomass, samples were taken monthly. For TSC and TN, the campaigns were heldevery two months. The data underwent analysis of means and were compared by t-test (p 5, there was an increase in the stocks of TSC and TN of 151and 137% respectively in the 40 - 60 cm layer, in relation to RC35.The implementation of thinning in a SDFT is seen as a management alternative tobe considered in sustainability programs in the semi-arid region, contributingto maximising the production of herbaceous forage for feeding large and smallruminants, and for bee pasture, in addition to increasing the stock of carbonin the soil of SDFT and reducing global warming.