samaneh hasanzadeh

This study was performed to investigate the effect of nitrogen fertilizer levels and pre-planting of cover crops on some vegetative traits and yield of rice plants.

This was conducted over 2017-2018 and 2018-2019, at the research farm of Sari University of Agricultural Sciences and Natural Resources. The experimental design employed a three-replicated split-plot arrangement within a randomized complete block design. The main plots involved five nitrogen consumption levels (0, 120, 240, 320, and 400 kg ha-1). The sub-plots included four types of pre-planted cover crops (no cover crop, canola, bersim clover, and rye).

Based on the findings, employing berseem clover as a cover crop in pre-sowing resulted in a significantly more favorable rice yield than others. Nitrogen fertilizer at rates of 320- 400 kg ha-1 led to enhanced vegetative traits, yield, and various yield components, including leaf area index and tiller number, ultimately resulting in increased overall yield. Results revealed that planting bersim clover cover crop before planting rice, along with 320 kg ha-1 of urea fertilizer, leads to 41.5% higher yield compared to no fertilizer).).

Bersim clover stood out among the pre-planting cover crops, significantly enhancing many rice traits. Additionally, no significant difference was observed between urea fertilizer levels of 320 and 400 kg ha-1 in several measured traits. Thus, the integrated treatment of bersim clover cover crop and 320 kg ha-1 of urea fertilizer is recommended before planting rice.

The field experiment was conducted in order to study the interaction of velvetleaf densities and Imazethapyr doses on yield and yield components of red bean in factorial randomized complete block design with four replications in 2013. The factors were included four levels of velvetleaf densities (0، 5، 10، and 15 plant. m-2) and five levels of Imazethapyr doses (0، 0. 25، 0. 5، 0. 75، and 1 lit. ha-1). Grain yield at weed-free plots with increasing herbicide dose did not change، but it is increased at other velvetleaf densities with increasing doses of herbicide. Grain yield at 4، 8، and 12 velvetleaf plant. m-2 densities at the recommended dose compared to no-herbicide plots increased by 43، 92، and 127%، respectively. The number of pods per plant at no-herbicide plots and 4، 8 and 12 velvetleaf plant. m-2 than velvetleaf weed-free plots reduced by 29، 44 and 48%، respectively. The number of grains per pod at densities of 4، 8 and 12 velvetleaf plant. m-2 than weed-free conditions reduced to 8، 12 and 4%، but the hundred grain weight did not affected by levels of weed densities and herbicide doses.

The past decade has witnessed a rapid development of social networks.Community detection is a very important problem in social network analysis. Finding a community in a social network is to identify a set of nodes such that they interact with each other more frequently than with the nodes outside the group. Classical clustering approach, K-means, has been shown to be very efficient to detection community. However it is sensitive to the initial seeds.To solve this problem, in this study, we first find K seeds using PageRank and second extract community structure of the network using heat diffusion similarity and K-means. Using heat diffusion similarity, we can get the network’s global information about any pair of vertices. The empirical study on real networks show that our algorithm in most social networks studied is better than algorithms including K-rank, K-means, BGLL, OSLOM ,LPA , Infomap and is efficient to be used for sparse large networks.

Importance of reduced consumption of herbicides has been clear for many farmers and experts، and this is because the increased research done today in reducing consumption herbicides and optimizing their applications. To evaluate the efficiency of 2،4-D، Glyphosate and Lontrel at recommended doses (1، 4. 1 and 0. 36 kg ai ha-1، respectively)، half the above values of these herbicides and a mixture of 2،4-D+ Glyphosate (0. 67+ 3. 3 and 0. 51+ 2. 05 kg ai ha-1) each with and without adjuvant application (Cytovit or industrial oil No. 10 + detergent both at 1% v/v) for controlling field bindweed، field experiment was conducted. The results were significant differences between treatments (P=0. 01). Among between applied treatments، the tank-mixed of 2،4-D+ Glyphosate+ adjuvant (Cytovit) at 0. 67+ 3. 3 Kg ai ha-1 with 98% control and Lontrel with the average control of 2% represented the highest and lowest the percentage of control، respectively. Addition of adjuvant to 2،4-D at both rate (whole doses and half-doses) enhanced level of control، but with whole doses of Glyphosate (4. 1 kg ai ha-1) reduced level of control significantly; in other treatments no significant effects were observed. Just for Glyphosate application of reduced doses markedly decreased level of control، but with other herbicides whole doses and half-doses differed not significantly. Without the addition of adjuvant، Glyphosate alone at whole dose (4. 1 kg ai ha-1) controlled field bindweed 79% and in other cases control did not exceed 46%. Overall، the best results with average control of 91%، were achieved by applying tank-mixed of 2،4-D+ Glyphosate (regardless of applied rate and adjuvant).