Assessing Sediment-Nutrient Export Rate and Soil Degradation in Mai-Negus Catchment, Northern Ethiopia

Table 4

Replacement costs for erosion-associated nutrients exported as N and P from the landforms and the entire catchment.

Landform	N exported^a; (kg ha^−1 y^−1)	Converted to urea; (kg ha^−1 y^−1)	Replacement cost as urea; (ETB ha^−1 y^−1)	P exported; (kg ha^−1 y^−1)	Converted to DAP; (kg ha^−1 y^−1)	Replacement cost as DAP; (ETB ha^−1 y^−1)	Total; RC^b,C; (ETB ha^−1 y^−1)	Total RC per landform^d; (ETB y^−1)
Rolling hills	4.23	9.20	29.52	0.03	0.16	0.57	30.09	3,761
Mountainous	10.36	22.52	72.32	0.08	0.43	1.55	73.86	13,443
Central ridge	8.66	18.83	60.52	0.09	0.47	1.71	62.22	19,910
Valley	11.56	25.13	80.71	0.10	0.50	1.81	82.52	20,795
Plateau	3.92	8.52	27.33	0.02	0.11	0.39	27.72	3,354
Escarpment	7.11	15.46	49.58	0.04	0.20	0.73	50.31	12,074
Reservoir	17.74	38.57	123.79	0.14	0.67	2.40	126.19	156,476
Average	9.08	19.75	63.39	0.07	0.36	1.31	64.70	32,830

DAP: diammonium phosphate; ETB: currency, Ethiopian Birr; 17 ETB∼€ 1 in May 2010 on average.
aPart of the N exported is converted to the N in DAP.
bRC: replacement cost for both N and P exported as urea and DAP.
cThe price of each 100 kg of urea and DAP in 2010 crop season was 320 and 360 ETB, respectively.
dColumn 8 multiplied by the area of each landform which is found in Table 2.