فهرست مطالب m nassiri

Agricultural ecosystems are a type of ecological systems where functions are organized in the direction of agricultural products and the characteristics of their production are determined based on the consumption of external inputs. In agricultural ecosystems, with monoculture of one cultivar and the excessive use of chemical inputs, crop yields are substantially increased. But the main challenge facing agriculture today is the environmental pollution caused by the use of chemicals and reduction of yield stability. Diversity in the selection of crop plant genotypes by farmers reduce production risk and annual yield fluctuations. Increasing genetic diversity through mixed cultivation of different cultivars or species with different morphological and physiological characteristics make possible use of the environment and resources. One of the ways to improve the quality and stability of wheat production is to increase the genetic diversity in the cultivation systems based on the mixed cultivation patterns. In Iran, excessive use of nitrogen fertilizers in agricultural ecosystems, especially in wheat production systems, is a problem, and it seems that increasing the efficiency of using this input is a very effective way to deal with this problem. The purpose of this research was to investigate the effect of increasing genetic diversity through intercropping of wheat cultivars on the efficiency of nitrogen and water use.

In order to evaluate the effect of increasing the genetic diversity of mixed cultivation of wheat cultivars on improving the efficiency of resource use, an experiment was carried out in the form of completely randomized block design with 3 replications in the research farm of Agriculture Faculty of Ferdowsi University of Mashhad in two crop years 2018-2019. Treatments included pure cultivation and double, triple and quadruple mixtures of four varieties of wheat, Heydari, Pishgam, Pishtaz and Falat, which were introduced in the 60s, 70s, 80s and 90s, respectively, and were in the same maturity group. The amount of absorbed nitrogen, absorption efficiency (NUpE), conversion efficiency (NUtE), nitrogen use efficiency (NUE) and water productivity. The data of the two-year test was compiled using Minitab software ver. 18.0 variance analysis was carried out and Excel software was used to draw graphs.

The results of the experiment showed that there was a significant differences in terms of water consumption efficiency, the amount of absorbed nitrogen, consumption efficiency and nitrogen absorption efficiency for pure and mixed cultivation of different wheat cultivars, but no significant difference observed for nitrogen conversion efficiency (p≤ 0.05). The highest amount of absorbed nitrogen, utilization efficiency, absorption efficiency and nitrogen conversion efficiency were observed for mixed cultivation of Pishtaz + Heydari cultivars (99.1 kg/ha, 34.5%, 69.3%, 49.8%), Pishtaz with Heydari and Falat (111.1 kg per hectare, 36.6%, 78.2%). While the highest water consumption efficiency was achieved for pure and mixed cultivars, respectively, Pishtaz (0.9 kg/m3 water), Pishtaz + Heydari (1.4 kg/m3 water), Pishtaz with Pishgam and Heidari (1.3 kg/m3 water). Water productivity showed a positive and significant correlation with absorption efficiency and nitrogen use efficiency (R2= 0.71, R2= 0.68). Thus, with the increase of nitrogen absorption and consumption efficiency, water consumption efficiency also increased, while no significant correlation was observed between water consumption efficiency and nitrogen conversion efficiency. According to the results of this research and the experiments result of other researchers, it can be said that through mixed cultivation and increasing the genetic diversity of wheat cultivars, the amount of absorption, the absorption efficiency and the efficiency of nitrogen consumption can be improved.

The results of this experiment showed that, by increasing genetic diversity through double and triple mixed cultivation of wheat cultivars, nitrogen efficiency and water consumption improved. In terms of water consumption efficiency, the amount of absorbed nitrogen, consumption efficiency and nitrogen absorption efficiency, there was a significant difference for the pure and mixed cultivation of different wheat cultivars, but no significant difference was observed for the nitrogen conversion efficiency. The highest amount of absorbed nitrogen, utilization efficiency, absorption efficiency and nitrogen conversion efficiency were belonged to the mixed cultivation of Pishtaz + Heidari cultivars, Pishtaz + Heidari + Falat. While the mixture of Pishtaz + Heidari, Pishtaz + Pishgam + Heidari had the highest water productivity.

There exists a continuous family of disjoint smooth curves, partitioning the unit square, such that one can choose only one point from each curve to construct a measurable set whose area is equal to 1. This contradicts our intuition which resembles Cavalieri’s principle and Fubini’s theorem! So, what is the problem? In this note, we discuss the theorem (due to A. Katok) and answer this question.

Road slope stabilization is one of the most common issues in reducing financial and life risks. Use of efficient and cost effective approaches for stabilizing earth slopes is a crucial matter. Due to Road growth, stabilizing of endanger slopes and insuring its safety is one of the basic concerns for engineers. With regard to regional condition, site importance, economical status, and many other factors, using common methods of stabilizing are diverse. One of these appropriate approaches for reinforcing earth slopes is the use of stone columns. Using stone columns, which, besides its simplicity and comfort implementation, is also very economical. The object of this research is presentation of experimentally and numerically investigates stone column stabilization of earth slopes, and investigates case studies about using stone columns in road slopes stabilization.

The Time Synchronized Channel Hopping (TSCH) mode of IEEE 802.15.4e has been widely used as an access method for the industrial Internet of Things (IoT). It permits to overcome the performance limits of 802.15.4 standard in such networks. It provides bounded latency and increased network capacity while mitigating the effects of interference and multipath fading. In this paper, we tackle two critical concerns of industrial networks, namely end-to-end reliability and delay by proposing two centralized scheduling mechanisms; First, the Height-based Scheduling (HS) that computes the schedule only based on the network topology. Second, T2AS, which takes into account both traffic demand and network topology to calculate the schedule. The later mechanism uses a composite weighting function that allows scheduling links with more load and longer distance from the root in earlier timeslots. This prioritizes the flows with more traffic to be scheduled earlier. Both algorithms provide subsequential scheduling for multi-hop scenarios. Simulation results, obtained from the OpenWSN emulator, particularly confirm the efficiency of T2AS in terms of reliability and end-to-end latency. More precisely, it guarantees a reliability of more than 99% for all network sizes. Furthermore, T2AS provides a noticeable bounded delay by delivering data packets within a single slotframe.

Introduction of high yielding as well as high quality rice cultivars is one of the most important activities at Rice Research Institute of Iran (RRII). In 1991, 210 rice lines introduced from International Rice Research Institute (IRRI) to Rice Research Institute of Iran were evaluated in observational and statistical experiments in Mazandaran for two years, and seven lines were selected. These lines had better performance in morphological characteristics, early maturity and yield than other lines. Results of additional experiments showed that Fajr cultivar was high yielding and stable in different environments of Mazandaran province. This cultivar had medium maturity with average yield of 6.5t th-1. According to agronomic experiments, the best planting space for this cultivar was 20 20 and 14 30 cm for traditional and machinery transplanting, respectively. Based on soil analysis and crop requirements, 115, 50 and 50 kgha-1 N, P2O5 and K2O are recommended, respectively. Results revealed that this cultivar is similar to Nemat and Dasht cultivrs in response to diseases and pests, but it is much more tolerant to lodging. Plant height and 1000-grain weight are about 108 cm and 24g, respectively. Fajr is one of the most superior improved rice cultivars with a high cooking quality, which has ever been introduced to the farmers of Mazadaran province since RRII establishment. Due to high adaptability of this cultivar, its cultivation could be extended to other provinces like Golestan, Fars and Khuzestan.

In recent years most activities of Rice Research Institute, has been focused on introduction of high yielding as well as high quality rice cultivars. In 1994, 185 lines introduced from International Rice Research Institute (IRRI) to Rice Research Institute of Iran (RRII), were evaluated in observational and statistical experiments in RRII for two years, and eight lines were selected. These lines had better performance, morphological characteristics, early maturity and higher yield than other lines. Results of different experiments carried out during next five years, showed that line IR67015- 94-2-3, introduced later as Shafagh cultivar was more high yielding and stable in different environments of Mazandaran province compared to the other lines. This cultivar is medium in maturity with average yield of 7.7 tha-1. The best planting space for Shafagh cultivar is 20 x20 and 18 x 30 cm for traditional and machine transplanting, respectively. Based on different experiments on soil analysis and crop requirements, 115 kg N ha-1, 50 kg P2O5ha-1 and 50 kg K2O ha-1 are recommended. Results revealed that this cultivar has similar responses as Nemat and Dasht cvs to all major diseases and pests, but more tolerant to lodging. Its plant height and thousand-grain weight are around 110 cm and 25g, respectively. (Also see Tables 1 and 2 in Farsi Text).