In order to evaluate the computerized fertilizer recommendation model developed by the Soil and Water Research Institute for wheat, an experiment was conducted in Golpaygan area designed in four treatments. T1= Control; T2= Computerized recommendation; T3= 30 percent less than T2; T4= 30 percent more than T2 + 150kg potassium sulfate (SOP).
This trial was designed in randomized complete block with four replications in three different regions with two different water sources, in sodic/saline soil conditions. The trial was conducted in agricultural year 1998-99.
The concentrations of N, P, and K in the first plot were 0.1 percent, 6.2 and 400 mg/kg. In the second plot the values were 0.1 percent, 6.0 and 430 mg/kg respectively, and in the third plot the values were 0.1 percent, 26.2 and 780 mg/kg respectively. Electrical conductivity for water in the first and the second plots was 4.54 and for third plot was7.36 dS/m. Analysis of treatments showed that fertilizer treatments had a significant difference with the control.
Grain yield in T1 was 863 kg/ha and in T2, T3 and T4 were 3942, 2321 and 4418 kg/ha respectively. All treatments were significantly different from the control and the difference between T1, T2, T3 was significant (P=0.01) but the difference between T4 and T2 was not significant (P=0.05).
The weight of 1000 grains difference between treatments and control was significant. It was 32.52 gr in T1, and in T2, T3, T4 were 46.36, 38.83 and 49.93 and was significant (P=0.05) between T2 and T4. Protein content was higher in treatments in comparison with the control and between T4 and control the difference was significant. Protein percentage in control was 12.6 and in T2, T3 and T4 were 13.45, 13.49 and 13.88 respectively. Nitrogen percentage in the straw was higher in treatments than control, but the difference was not significant. Nitrogen percentage in straw in the control was 0.30, and in T2, T3, and T4 were 0.37, 0.35, 0.44 respectively. Chloride, P, and K concentrations in grain were not significantly different between treatments and the control