Forty factorial experiments with 4 levels of N (0, 40, 80, and 120 kg N/ha and 4 levels of P (0, 8.8, 17.5, and 35 kg P/ha) with two replicates were conducted in farmers’ fields during two consecutive seasons in 1987 and 1988. The sites chosen had different soil fertility levels and the precedent crop was either local lentil (Lens esculentium), local chickpea (Cicer arietinum), or summer crop, such as watermelon (Citrullus sp.) or sunflower (Helianthus annum).