Carbon and nutrient balances in three mountain oases in Northern Oman

الملخص EN

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