Effects of Complementary Fertilization on Crop Yield and Chemical Composition of Pistachio Cultivars in Saline Conditions

An orchard experiment was conducted at Gonabad Pistachio Production Station., Khorasan, Iran (1998-2003). In some pistachio trees, especially in cv. Owhadi, leaf marginal chlorosis was already observed. Then, gradual drying of leaves extended to the leaves' centers up to midsummer. With respect to salinity problems, some researches were done. Two orchards of pistachio known as No.6 and No.7, were irrigated with waters of different electrical conductivities (ECiws) including ECiw1=7.45 desisimens/ meter (dSm-1) and ECiw2=11 dSm-1, respectively. The cultivars (cvs.) of Badami-sefid and Owhadi, budded on seedlings of Badami-Riz formed the scion-rootstock combinations. Experiments were done in the from of RCBD with repeated measurements. In block 1 of orchard 6, which had been previously increased in salinity, each tree received two times N fertilization in 2000. Nevertheless, in blocks of two orchards, each tree received a complementary fertilization in 2001. Experiment 2 with more cultivars was conducted during 1990-1999 in one of the pistachio orchards with ECiw of 10.29 dSm-1 in Khaf district, Khorasan. The results of combined analysis in the case of experiment 1, in different years and orchards revealed that quantitative yield of cv.Badami-Sefid was significantly higher than that of cv. Owhadi. In conditions of this experiment, alternate bearing was an important problem in cv. Owhadi. Complementary fertilization increased the yield of pistachios in 2003, significantly. The ranges of Cl and especially Na ion accumulation in leaves of tolerant cv. (Badami-Sefid) was less than those in the sensitive one. In block 1 of orchard 6, Ca and Mg absorption by plants was significantly reduced. This cation competition caused the yield of that block to be meaningfully reduced. However, N accumulation in leaf tissues of sensitive cv. was considerable, too. The higher N fertilization of block I in orchard 6 caused the N content of leaf tissues in orchard 6 (especially in block I of this orchard) to be meaningfully higher. In orchard 7 cation competition of Na was more considerable. The effect of salinity was not so problematic as to suppress the absorption of phosphate. Through heading back of some sensitive plants, done beneath the union graft points, it was observed that salt sensitivity was due to cultivar (grafts). In experiment 2, quantitative yield of Owhadi was considerable and no leaf damaging was observed. In establishing new pistachio orchards in saline conditions, one had better put these genetic diversities into serious consideration.