Although this is not an article, it is extremely helpful in clearly explaining terms such as bulk density. According to, The Cooperative Soil Survey??"the combined influence of soil texture and structure may best be described by the term??"soil bulk density". Soils are composed of solids (minerals and organic matter), and pores which hold air and water. The bulk density of a soil sample of known volume is the mass (or weight) of that sample divided by the bulk volume". ??Because I do not have a lot of time to pour over tech manuals or become engrossed in horticultural terminology, its easier receive clear, straight forward explanation of various technical terms such as bulk density if those terms are stripped to their basic rudiments.The article was also able to clearly explain why this is extremely important. In fact due to its explanation of bulk density, it wasn't until cleaning up the garbage around my building's bottle brush tree and pouring marble aggregates over it to prevent debris from being tossed into it that I was able to vividly see how macro/micro-pores are essential to water infiltration and why. This was due to witnessing unwanted debris fail to be able to fit through the pores of the marble aggregates; while water from my building's water hose was quite capable of doing so.To further illustrate this point the fact that my Lysol which I did not want to enter into the same soil as it was filled with Styrofoam particles could now be compared to a colloid possessing various particles such as micro-nutrients. If the marble aggregates, which I compared to sand,?? where clay, it would possibly lack macro pores and prevent certain micro-nutrients and water from passing through and reaching the plant's root hairs; thus it is better if a soil is composed of 50%?? organic matter and 50% micro-nutrients/minerals which allow it to be composed equally of?? air and water. In soils possessing a heavy bulk density these percentages are extremely limited due to such soils possessing the micro/macro-pores possessed by soils that have lighter soil bulk densities.This is exactly what "The Cooperative Soil Survey" site does in its explanation of technical terms such as bulk density. Because it's a tutorial, it enables me to review material without relying strictly upon notes, or reading passages over and over again in order to understand the material that is being presented in class.?? Cooperative Soil Survey??is a Cares Website dedicated to??continuing??developing science-based soil system information, customized to meet user needs for natural resource management". The site enables individuals that may be struggling with understanding Horticultural?? terminology and concepts a chance to study these things in-depth; while having time to arrive at their own personal understanding of them without slowing down formal classroom instruction which may decrease an instructors ability to keep the class moving forward. The strength of this site is that it is a reliable site that can be easily reached through the internet, yet is hosted by Mizzou, University of Missouri's division of Applied Social Sciences and can be reached by phone Tel: 573.882.7458/Fax 573.884.2199. Based upon this information the site can be credited as a reliable horticultural information site.In terms of this site possessing weak points, its single weak point would be that its only available on the Internet; thus for those lacking either computer access or basic computer skills the site is not easily reached. What impressed me most about the site is that you are also able to ask questions and be immediately referred to information dealing with it that is clear and easy to understand.