اثر آبیاری با پساب فاضلاب تصفیه‌ شده شهری روی عملکرد و کیفیت گندم و برخی ویژگی‌های خاک در منطقه سیستان

A field study was conducted at the Zabol Agricultural Research Center during the years (2003-2004) to investigate the effect of irrigation with treated municipal wastewater on the yield and quality of wheat and some soil properties. Irrigation treatments were: T1: Irrigation of wheat with well water during entire period of growing season T2: Irrigation of wheat with well water until the begging of flowering stage, and irrigation with wastewater in every other turns of irrigation T3: Irrigation of wheat with well water until the beginning of booting stage, and irrigation with wastewater in every other turns of irrigation T4: Irrigation of wheat with well water until the begging of tilling stage, and irrigation with wastewater in every other turns of irrigation and T5: Irrigation of wheat with wastewater during entire period of growing season. A complete randomized block design with four replications was adopted for this experiment. The soil was sandy loam with no limitation for internal drainage. Chemical and physical aspects of soil were measured during the experiment. Grain yield, yield components and chemical composition of wheat grain were also measured. The results showed that yield of wheat and total biomass production were statistically significant in T3, T4 and T5 compared with the control treatment. Plant height, width and length of flag leaf, numbers of fertile tillers, length of panicle, numbers of grains per panicle and weight of 1000 grains were also statistically significant with the control treatment. Percentages of protein were statistically different among various irrigation treatments. No significant changes in accumulation of heavy metals in soil and plant grains were observed. The increase of SAR, ECe, O.C% and total nitrogen in the T4 and T5 were statistical significant compared with the control treatment. In summary, for sustainable use of Zabol municipal wastewater, the growth stages of wheat should be irrigated with municipal wastewater and other growth stages should be irrigated with nonsalinty water, so that the maximum yield is obtained and soil salinitisation and sodication is prevented.