Carbon and nutrient balances in three mountain oases in Northern Oman

Carbon (c) and nitrogen (n) fluxes of two cropping systems in three mountain oases of al jabal al-akhdar mountains of northern oman were determined in 2008/09 and 2009/10. these comprised garlic at ash sharayjah (1,900 m asl) and masayrat (1,030 m asl), pomegranate in ash sharayjah and qasha’ (1,640 m asl), and date palm groves at masayrat. goat manure was applied to garlic fields at 47 and 40 t dry matter (dm) ha-1 at ash sharayjah and 42 and 37 t dm ha-1 at masayrat. pomegranates at ash sharayjah and qasha’ received cattle dairy manure at 66 and 60 t dm ha^-1 yr^-1. annual total gaseous c losses varied from 20.9 to 61.2 t c ha^-1 to which ch4-c contributed < 2%. total annual c surpluses were 12.5 t ha^-1 in garlic fields at ash sharayjah, while c deficits of -5.5 t ha^-1 were obtained at masayrat. annual c surpluses in pomegranate and date palm were 16.7, 7.5, and 1.7 t ha^-1 in ash sharayjah, qasha’, and masayrat. date palm groves had total annual n surpluses of 1857 kg n ha^-1 while pomegranate fields at ash sharayjah and qasha’ had annual surpluses of 1414 and 1500 kg n ha^-1.