DRIS تعيين حد متعادل عناصر غذايي درختان ليموشيرين در استان فارس با روش

DETERMINATION OF THE NUTRIENT NORMS FOR SWEET LIME TREES IN FARS PROVINCE BY DRIS

To determine DRIS norms for sweet lime trees in Fars province, yield and leaf analysis data (including N, P, K, Fe, Mn, Zn and Cu) were collected from 399 orchards (located in Jahrom, Darab. Fasa, Kazeroon and Firoozabad) and assessed in a period of four years. The results obtained were entered into a data bank. Nutrient data were expressed in different forms of DRIS norms and based on the yield data, orchards were categorized into low and high yield groups. Mean, coefficient of variation (C.V.) and variance (S) of diffrent forms of nutrient expression were calculated for low and high yield orchards and the ratio of variance of low yield orchards to high yield orchards (SB/SA) was also determined. Those forms of nutrient expression that had highest SB/SA, were selected as norms. The norms of leaf nutrients and the ratio between them were obtained for sweet lime as the following: N=2.66%, P=0.13%, K=1.71%, Fe=83.44 mg kg^-1, M.n=30.89 mg kg^-1, Zn=19.89 mg kg^-1, Cu=6.62 mg kg^-1, P/N=0.051, N/K=1.675. Fe/N=31.492, N/Mn=0.1, P/K=0.082, Fe/P=643.17, P/Mn=0.005, Fe/K=53.61, MnIK=18.84, Zn/K=12.09, Fe/Mn=3.083, Fe/Zn=4.922, Fe/Cu=14.96, Zn/Mn=0.745. Cu/Mn=0.246, Zn/N=7.47, N/Cu=0.577, Zn/P=150.068. P/Cu=0.0267, Cu/K=4.32 and Zn/Cu=3.99.