Botanical criteria of Baharkish Rangeland in Quchan, Khorasan Razavi Province, Iran

Rangelands are natural ecosystems containing a range of resources of genetic diversity and numerous plant species and its evaluation has always been essential. However, biodiversity is one of the most important components of habitat assessment and the identification and introduction of the flora of an area is one of the significant operations that can be used in order to optimize the utilization of the available natural resources. Baharkish rangeland is located at a distance of about 60 km south of the city of Quchan. The rangeland’s average elevation is about 2069 m above sea level, with its lowest at 1740 m and highest at 2440 m. Baharkish rangland in over a ten year period had the average annual rainfall of 337 mm and 998.2 mm evaporation as well as average annual temperature of 9.4°C, respectivelly. The results of the research conducted in the spring of 2014, showed that the total study area includes 77 species from 22 families with Poaceae, Asteraceae, Lamiaceae, Fabaceae, Apiaceae and Brassicaceae being the dominant families with 18%, 13%, 12%, 9%, 8% and 6% respectively. Classification of life form according to Raunkiaer method showed the dominance of the hemicryptophytes with the greatest abundance 41%, followed by Chamaephytes, Therophytes, Geophytes, Phanerophytes and Cryptophyte with 25%, 23%, 4%, 4% and 3% of species were the dominant life forms of the area. In terms of geographical distribution, the Irano-Turanian plant species with 64% obtained the maximum value.Keywords: Flora, Geographical distribution, Life form, Raunkiae

Can Superabsorbent Polymers Improve Plants Production in Arid Regions?

Superabsorbent polymers (SAPs) have shown to be quite effective and useful in acting as a reservoir for water and some nutrients in arid and semiarid regions. There are many studies in Iran that have been performed in relation to SAPs and their useful application in agriculture; however, there is still a lack of its applied definition in arid regions. Therefore, this study was conducted with the aim of doing a meta-analysis of the results of studies conducted in Iran and answering a general question about whether the application of SAPs has been effective in enhancing the production or not, and if so, how much of SAP is recommended. To conduct this research, articles published during 2006–2016 on the subject of the effects of different rates of SAP application on yield and yield components of crops (including cereals, legumes, and medicinal and grassland plants) were investigated. The results of the meta-analysis showed that the mean consumption rate of SAPs for cereals, legumes, and medicinal and grassland plants was 83, 322, 1031, and 210 kg ha−1, respectively, and that, at these SAP application rates, the mean seed yield in cereals, medicinal plants, and legumes increased by 15.2, 12.6, and 38% (equivalent to 1059, 345, and 452 kg ha−1), respectively, compared with the control. Dry matter response to superabsorbent application was slower compared with the seed yield response. The mean consumption of 83 kg ha−1 of superabsorbent for cereals increased seed yield by 15.2% on average. According to the results, it seems that the application of 100 kg SAP ha−1 is the most appropriate rate for increasing seed and dry matter yields and satisfying economic aspects. These study findings may shed light on the environment and socioeconomic concerns and improve efficacy and reduction of costs

Meta-analysis of Saffron (.Crocus sativus L) Agronomical Researches, with an Emphasis on the Consumption of Organic Fertilizers and Agronomical Practices in Iran

Studies that investigated the impact of organic fertilizers (manure, compost and biological fertilizers) and agronomical practices (density, method, date and depth of planting) on saffron yield have a long history in Iran. Due to the distribution and inconsistency in the results obtained from different studies, a meta-analytic approach was used in the current study. for this aim, 47 organic fertilizers studies and 44 agronomical practices studies were selected from 202 gathered studies and analyzed. The criteria for the selection of studies were the adequacy of data for the present meta-analysis. Among the individual fertilizer studies, manure fertilizer had the highest impact on saffron dry weight (g= 1.493) at 95% confidence interval. Average amount, 40 to 50ton/ha of cow manure, 20 to 30ton/ha of compost that is used as a combination with Biofertilizer (Nitroxin with Nitrogen-fixing bacteria) were more effective than higher amounts of these fertilizers will be alone. Among the agronomical practices studies, plant density had the highest and depth of planting had the lowest effect size on economical yield and number of flower. The optimal density for maximum yield was 50-100 corm per (m2), optimal consumed weight average 9-12 ton per hectare observed, optimal weight of any corm was 10-20 (g). Among planting methods, row-mass method was the best optimal (inter-planting was 20 cm and intra-planting 10 cm). The best planting dates was the end of May and the first decade of Jun. Optimal planting depth was 15-20cm. Homogeneity between organic fertilizers studies was accepted and the homogeneity between agronomical practices except depth of planting studies was accepted. This heterogeneity was caused by factors such as age of farms and different regions that had the most impact on heterogeneity and effect size. The present meta-analysis aims to provide a better understanding of agronomical and fertilizers management and offer the best possible management for this crop

Effects of corm origin, corm weight and nutrient foliar application on yield and qualitative traits of saffron (.Crocus sativus L)

In general, corm weight and nutrient management are considered as the most important factors in relation to quantitative and qualitative traits of saffron. In order to investigate the effects of mother corm origin, mother corm weight and nutrient foliar application on yield and qualitative traits of saffron, a field experiment was conducted as factorial layout based on a randomized complete block design with three replications at the Faculty of Agriculture, Ferdowsi University of Mashhad, Iran, during the years from 2012 to 2015. The mother corm origin (Iranian and Spanish corms), mother corm weight 8 g and lower (small), 8.1–15 g (medium) and 15.1-23 g (large) and nutrient foliar application (application and control) were considered as the first, second and third experimental factors, respectively. According to the results, the larger mother corms significantly resulted in a greater number of flowers per m2, increased fresh flower and dry stigma + style yields. However, the effect of nutrient foliar application was observed to be not significant on these traits. When Iranian mother corms were planted, the number of flowers per m2, fresh flower and dry stigma + style yields were higher, compared with Spanish mother corms. For instance, flower number, fresh flower and dry stigma + style yields increased by 17, 13 and 14%, respectively, when planting Iranian mother corms. Nonetheless, picrocrocin concentration was higher (up to 3.8%) in the Spanish planted corm treatment. Based on the results, beside the optimal nutrient foliar application, the importance of adapting the corms origin with environmental conditions of the site designated for planting is emphasized

Weed Competition Periods Affect Grain Yield and Nutrient Uptake of Black Seed (Nigella Sativa L.)

The combination of the relatively open plant canopy and slow growth, especially at early growth stages, results in lower competitiveness of black seed (Nigella sativa L.) than weeds. Thus, weed interference is known as an important factor affecting black seed yield. Therefore, to determine the critical period of weed control and its effects on nutrients uptake of black seed field experiments were conducted in 2011 and 2012. Two quantitative series of weed removal treatments including weed-infested and weed-free treatments were implemented from black seed emergence to maturity harvest. To determine critical period of weed control, plots were weed-infested or weed-free for 0, 14, 28, 42, 56, 70 days after emergence, in weed-infested and weed-free treatments, respectively. The results revealed that N, P and K contents in weed tissues significantly increased with increasing weed-infested periods during both years of the experiment. The reduction in grain and oil yield due to longer periods of weed-infested conditions or shorter periods of weed-free conditions were accompanied by simultaneous reduction of N, P and K uptake in black seed grains and tissues. Overall, N, P and K contents in weed tissue were found to be 1.8 to 2 times higher than that of black seed. It was concluded that 58 or 49 days weed-free periods are required to avoid yield loss (above 5% or 10%) in black seed

<b>Assessing nitrogen flow in production and utilization cycle of wheat and maize as a tool to monitor N loss in Iran</b> - doi: 10.4025/actascibiolsci.v35i3.16039

<p>Increasing resource use efficiency is crucial for enhancement of agricultural productions and reducing environmental hazards. For this purpose, improvement of Nitrogen use efficiency is an effective approach. Not only N loss occurs in field but also in processing course of food utilization. The objective of this study was to evaluate N loss and efficiency from production to consumption for wheat and maize. For this purpose, data for the amount of applied nitrogen, acreage, yields, amount of returned residue were collected and a proportion of N allocated to different source of food or feed was also traced. Results showed that total N harvested by wheat and maize were 387 and 81.7 kt and N use efficiency for the same crops were 25 and 60%, respectively. Efficiency of N harvested by the crops was different based on the path used. Total N use efficiency in food production cycle for wheat and maize were 14.2 and 7.6%, respectively. Higher efficiency of N was observed in plant food production compared with animal feed. In general, N use efficiency in plant food production system was about 13 times higher than that of feed. For decreasing N loss in food production system, efficiency should be increased in the field and processing courses.</p> <p class="apalavrachave"> </p><br /

The effects of different cattle manure levels and branch management methods on organic production of Cucurbita pepo L.

To study the effects of different manure levels and two branch management methods on organic production of Schneider squash, a field experiment was conducted during 2005 and 2006. Treatments were four manure levels (10, 15, 20, 25 ton ha-1) and two branch management methods (with and without a wood pole), which were allocated to main plots and subplots, respectively. Results showed that the crop performed better in branch management without a wood pole than with a wood pole. Results showed that in the first year, manure level had a significant effect on fruit and seed yields. However, these traits were not significantly affected by manure levels in the second year. For both years, there were no differences in seed numbers due to manure levels. Seed oil content was slightly increased when the manure level was increased from 10 to 25 ton ha-1

Effects of arbuscular mycorrhizal fungi and free-living nitrogen- fixing bacteria on growth characteristics of corn(Zea mays L.) under organic and conventional cropping systems

In recent years, biological fertilizers have received special attention in sustainable agriculture. Inoculation with arbuscular mycorrhizal fungi and free-living nitrogen-fixing bacteria had significant effects on corn photosynthesis and yield; the highest photosynthesis rate and yield were obtained with dual inoculation with fungus plus bacteria. These outcomes were also affected by cropping systems, but to a lesser extent. Therefore in organic and low input cropping systems, a combination of mycorrhiza and free-living bacteria performed satisfactorily