Fertilizers and Subirrigation with Saline Water Affects Yield of Green Peppers in Lysimeters

ABSTRACT An experiment was undertaken at the McGill University experiment station at Ste-Anne de Bellevue, Canada, to study the effect of different fertilizers on green pepper yield as it is influenced by saline water supplied through a subirrigation system, which was used to supplement water stored in the soil. Green peppers (Capsicum annuum L.), cv. Bellboy, were grown in field lysimeters filled with a sandy loam soil. The lysimeters were covered with plastic sheets to prevent rainfall/surface water entry. Water having salinities of 1, 3, 5, and 7.5 dS·m−1, was applied through the bottoms of the lysimeters, and steady-state water tables were maintained at 0.45 or 0.9 m from the surface. The soil solution salinity in the soil profile remained less than 3.5 dS·m−1 during the growing season, and there was no appreciable increase in soil solution salinity in the root zone. Five rates of fertilizers were applied on the soil surface. The highest yield was obtained when all three nutrients, N, P, and K were applied at the recommended rates. The highest rate of N decreased pepper yield due to vigorous vegetative growth. Although the rate of P did not significantly increase yield when applied with K only, the yield significantly increased (P ≤ 0.05) when P was applied with K and N. Average yield ranged from 706 to 1,229 g/plant. There was no interaction of fertilizer with water table depth or irrigation water salinity. It appears that water with salinities up to 7.5 dS·m−1 could be used to supplement the stored fresh water in the soil profile using a subirrigation system for growing moderately salt-sensitive crops such as green peppers.