Document Type : Research Paper



Meta-analysis is compressive science and statistical analysis of a large content statistical results of different studies in order to the organization of findings. In this study, the effects of some agricultural operations were studied on grain yield, biological yield and harvest index of wheat. The treatments were included soil tillage, nitrogen fertilizer, salt stress, hydro-priming, osmopriming, hormopriming, and physical priming which tested using Hedges method. Therefore, the studies that have control treatment and other treatments, after the weighting of value of traits, effect size, and reaction relation and confidence range estimated. Meta-analysis results showed that nitrogen fertilizer in ranges of 50-250kg/ha caused increasing in grain yield, biological yield, and harvest index. The highest grain yield and biological yield achieved in 125-150 kg/ha and the most harvest index obtained in 230-250 kg/ha. Secondary, tillage in both of fields (irrigated and dry farming) decreased grain yield, biologic yield, and harvest index, so a reduction in dry farming was serious. The lowest (21.15%) and the highest (76.41%) of reduction in wheat production (grain yield) obtained in 4-6 and 12-16 ds/m.s, respectively. Outcomes also showed that hydro-priming, osmopriming, hormopriming have positive effects on grain yield, biologic yield, and harvest index, so that hydro priming increased biologic operation (23%), grain yield (16%) and harvest index (19%). Furthermore, osmopriming had 30% increasing effect in biologic yield and it was to 50% and 59% in biologic operation and seed operation while this effect has caused the small amount of 1% increase in harvest index. The influence of physical priming on characteristics was not significant and it just led to 3% increase grain yield. Overall, concludes emphasis on consuming 125-150kg/ha N, notice to results of replacing secondary tillage with current tillage in dry farming, advice to planting in soils and irrigation with salinity<4 µs/m.s, positive effects of hormo, hydro and osmopriming, as well as expressing of the goodness of meta-analysis method to detect and finalize the positive and negative effects of these different treatments on the production of wheat.


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