A field experiment was conducted at Agriculture Research Institute Tarnab, Peshawar during 2010, to study the effect of different types of surfactants on Zinc efficiency in spinach yield. The experiment consisted of two different rates of Zinc Sulphate (0.5% and 1%) with three different surfactants (Aerial, Bonus and surf excel) and control (T1) without Zinc Sulphate and Surfactant. For T2, T3 and T4 the spray composition was (5gm) ZnSO4 + 2gm CaOH + 1gm surfactant (Aerial, Bonus and surf excel respectively) dissolved in 1L water for T5,T6 and T7 the spray composition was 10gm ZnSO4 + 4gm CaOH + 1gm surfactant (Aerial, Bonus and surf excel respectively) were dissolved in 1L water (Table 1). The experiment was laid out in RCB design with two factors having three replications. Basal dose of N-P @ 100-60 kgha-1 were applied in sub plots. A composite soil sample was collected before crop and analyzed for their physicochemical characteristics; the fertilizer was applied by band placement method. Soil samples were collected from each treatment before crop sowing and were analyzed for physicochemical characteristics of the composite soil.
2.1. Soil pH and EC
Soil pH and EC were determined in soil water (1:5) suspension. For this, 10g soil Sample was shaken with 100 ml distilled water for 30 min. After filtering, the extract was read for pH on pH meter (Inolab pH level) and EC on EC meter (DDC-308A Conductivity meter).
2.2. Soil Organic Matter
Walkley-Black procedure was used for soil organic matter. 1.0g soil sample was treated with 10 mL of 1 N K2Cr2O7 and 20 mL of concentrated H2SO4. After adding of 200 ml distilled water upon cooling, the suspension was filtered and filtrate was titrated against 0.5 N FeSO4 solution using ortho-phenopthaline as indicator with appearance of maroon color as end point. The amount organic matter was calculated from the number of moles of K2Cr2O7 utilized in the oxidation of organic C in soil.
