Increased Yield Surplus of Vetch-Wheat Rotations under Drought in a Mediterranean Environment

Table 1

Some physical and chemical properties of the soil in the experimental site and the incorporated sewage sludge.

	Total N (%)	NH4 (ppm)	NO3 (ppm)	pH	Organic matter (%)	Conductivity (mS/cm)	CaCO3 (%)	Sand (%)	Silt (%)	Clay (%)
Soil	0.085	6.2	5.0	7.94	0.93	0.143	15	39	26	35
Sludge	3.6%	1072.4	117.6	5.67	18.8	6.13