Estimating Sufficiency Norms in Compositional Nutrient Diagnosis (CND1) Method for Shahroudi Table Grape

In order to determine the optimum norms for nutrients in table grape cv. Shahroudi, an experiment was done in 54 vineyards in Shahroud region. The vineyards were grouped into low (n1= 41) and high (n2= 41) yielding groups using mathematical approach. Cumulative variance ratio function was used as cubic functions to obtain cutoff yield at 33.78 t ha-1 by mean calculation for high yielding samples. Preliminary CND norms were calculated as follows: , ¡=26.53,=35.43¡,¡¡ ¡ , ¡.
Nutrient sufficiency norms were determined using mean results of high yielding grape tissue samples. The sufficiency norms included: N=2.56±0.436, P=0.57±0.150, K=1.04±0.149, Ca=1.26±0.392, Mg= 0.752±0.116, Mn=33.9±0.001, Zn=24.8±0.008, Fe=106.4±0.001, Cu=7.02±0.0001, B=43.6±0.0007, Cl=0.72±0.137. The data showed that due to high Cl level [H1] and general deficiencies in Ca, Zn, and N in the leaf, the related yields were low in the studied samples.