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The first step to achieving ecological sustainability and intensification in agricultural systems is to have a comprehensive agroecological analysis of agricultural systems. This research analyzed the agroecological ecosystem of potato cultivation in the Torbat-e Heydariyeh Region of Iran over fifteen years (2001-2016). Based on the results, potato yield increased by 0.28 t ha-1 yr-1. The average potential yield of potato was calculated by the FAO method to be 64 t.ha-1. Also, the potential yield did not increase significantly during the study period. The average yield gap of potato was calculated to be 32.44 t ha-1. Also, with increasing yield, the yield gap showed a decreasing trend. The ecosystems experienced a steady rise in intensification, and the stability decreased. It was observed that although nitrogen fertilizer application was increased, its efficiency dropped from 110 kg tuber per kg of nitrogen fertilizer to 70 kg. Due to the decreasing trend of NUpE (Nitrogen uptake efficiency) and NUE (Nitrogen use efficiency) during the studied years, the NUE gap was the main factor in increasing nitrogen consumption, increasing intensification, and reducing stability in the studied systems. Therefore, changing the management method to increase the efficiency of nitrogen consumption can be suggested as the first step for moving towards ecological intensification and improving the sustainability of potato production systems. [ABSTRACT FROM AUTHOR]

Three different levels of biochar addition in soil (0, 1, 2 kg m-2) and simultaneous irrigation treatments (50, 85, and 120% of crop Evapotranspiration (ETc)) were applied to basil (Ocimum basilicum L.) for two consecutive years (2018 and 2019). Central Composite Design (CCD) was used as an experimental optimization method, and 13 given experiments were carried out. The study was performed at the research farm of the Ferdowsi University of Mashhad, Iran. The effects of these treatments were evaluated on biochemical attributes (total chlorophyll, total phenol, and total soluble carbohydrates) and morphological criteria (biological yield, height, seed yield, and harvest index). Then, all the results were statistically analyzed. The results revealed that biochar amendment in the soil decreased all examined biochemical characteristics. Meanwhile, biochar in the soil strengthened the morphological properties of the basil plant. Also, the basil plant significantly responded to the amount of irrigation levels. High levels of water treatments reduced total phenol and total soluble carbohydrates and raised all other measured factors. Statistical analysis shows no significant relationship between 2-way-interaction (biocharxirrigation) and measured factors, except total soluble carbohydrates. [ABSTRACT FROM AUTHOR]

Abstract: A simple model was constructed, tested and used to determine the potential yield of cumin (Cuminum cyminum). Using model outputs and data obtained from 228 fields, yield gap was determined. Yield gap varied considerably among regions (from 2.42 to 0.68 ton ha−1). Stepwise regression on data collected from fields showed that 73% of yield gap variation in 228 fields could be explained by fungal diseases (Fusarium oxysporum and Alternaria burnsii), inappropriate sowing dates and successive planting. Therefore, these were considered to be the main reducing factors in the studied regions, with 38% contributed by fungal diseases, 30% by sowing date and 5% by successive planting. When 67% of surveyed fields (averaged for all fields) were infected with these diseases and when there was a 3-mm increment in precipitation, infection increased about 1%. Our results indicated that 1% of the fungal infection increase equals to a yield loss of 150 kg per hectare. Sowing date of 63% of fields were also not within the appropriate range. Therefore, appropriate sowing date and all possible approaches to alleviate the effects of fungal diseases are the most fundamental advices to fill the gap between potential and actual yield of cumin in Khorasan provinces, Iran. Detailed descriptions of the model, important physiological parameters and other important state variables are also presented. [ABSTRACT FROM AUTHOR]

The article examines the chemical constituent of thymus transcaspicus essential oils in natural habitats in Iran. Study shows that the plant is primarily composed of carvacrol and thymol, and these are found higher in natural habitats. It finds out that these oils from various habitats differ due to chemotypes and various environmental conditions.