J. Appl. Environ. Biol. Sci., 5(6)88-95, 2015 © 2015, TextRoad Publication ISSN: 2090-4274 Journal of Applied Environmental and Biological Sciences www.textroad.com *Corresponding authors: Farid Golzardi, Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran. E-mail: Golzardi@chmail.ir; Mobile: +98 9183510550 Effect of Solarization and Polyethylene Thickness Cover Type on Weeds Seed Bank and Soil Properties Farid Golzardi 1* , Yazdan Vaziritabar 2 , Yavar Vaziritabar 2 , Kamal Sadat Asilan 3 , Mohamad Hasan Jafari Sayadi 4 , Shabnam Sarvaramini 5 1 Seed and Plant Improvement Institute, Agricultural Research, Education and Extension Organization (AREEO), Karaj, Iran 2 Department of Agronomy, Science and Research Branch of Tehran, Islamic Azad University, Tehran, Iran 3 Department of Agricultural Sciences (Agronomy Engineering), Payame Noor University (PNU), Tehran, Iran 4 Department of Agriculture and Natural Resources, Payame Noor University (PNU), Tehran, Iran 5 Department of Agricultural Management and Development, University of Tehran, Karaj, Iran Received: September 28, 2014 Accepted: April 9, 2015 ABSTRACT To investigation the effect of soil solarization and thickness plastic cover on weed seed bank and soil properties, an experiment based on randomized complete block design with three replications was carried out in experimental farm in 2013 were conducted in the research and education of Islamic Azad University of Karaj. Examined factors include solarization period at seven levels (0, 1, 2, 3, 4,5 and 6 weeks) and polyethylene thickness in two levels(100 and 200 microns).According to preliminary result 11 species is ultimately distinguished; the analysis variance result indicated the effect of solarization period, plastic thickness and their interaction on weeds seed bank was significant; So that the highest value of weeds seed bank associated to 6 weeks of solarization, which statistically had no difference with 5, 4 and 3 weeks of solarization. Also the highest value of weed populations pertained to evidence treatment (without plastic cover). By increasing the plastic thickness, the weed seed bank increased through the soil pattern. So that the number of weed seeds per kilogram was 233 and 186 unites when the thickness of the cover was about 200 and 100 micron. The solarization period length on acidity and soil moisture content had no significant effect, but leads a significant effect on soil organic matter at level of 5%. The thickness of the plastic cover had no effect on either of the measured parameters. KEY WORDS: Solarization, polyethylene, weed seed bank, organic matter INTRODUCTION The study of weeds seed bank alternation is a general and novel prospect in the term of weed science, which helps arable management systems to control weeds and especially distinguished as an effective entity in integrated weed management (IWM). Seed bank plays a major role in weeds durability through the time. Not only is the seed bank recognition essential in ecological aspects, but also a pivotal entity of long time weeding management programs. Indeed seed bank is a rather memory, which stores the region revolutions and explains the arable history, earlier regional plant cover and greatly figure the next regions plant canopy [1]. Seed species and density compositions differ greatly in the soil pattern and immensely associated to the earlier cropping in the region [2]. Seed bank perusing makes us able to know valuable information about species, which develop in arable lands. The obtained information from seed bank like diversity and composition of seed bank, anticipating the composition and density of different weed species ease and provided right management in this term [3]. Solarization is one of the non-chemical ways to manage weeds seed bank. The most current way of solarization is to use a plastic layer on the soil surface [4]. In this way along a period soil is covered with plastic sheet to trap the sun waives and ultimately to increase the top soil layer temperature to 40-55°C. Indeed the thermal reaction is the main reason which leads weeds seed bank decrease [4]. Investigation of solarization effect on weeds seed bank showed that the light plastic solarization treatment significantly reduces the weeds seed bank. Increasing soil temperature Known as a main reason of weeds seed bank reduction [5]. Seed bank reduction is essential for two reasons; first, seeds transmission from the beneath soil layers to the top (by agriculture operations) and second for conveying temperature to the subterranean soil layers and weeds seed devastation (by solarization method) [4]. In Ethiopia to investigate the light and darkness plastic covers on controlling seed bank of Orobanche ramose and Orobanch ecernu showed use of these colored covers significantly decreased weeds seed bank; So that this reduction rate in light and dark covers 88