Reference:

 Book:

•  M. L Jackson, "Soil Chemical Analysis", Prentice-Hall, Inc. (1956).

Webliography:

• http://www.buzzle.com/articles/soil-ph-levels.html
• http://megapib.nic.in/soil%20testing.htm
• http://passel.unl.edu/pages/informationmodule.php?idinformationmodule=1130447043&topicorder=3&maxto=15&minto=1
• http://mykitchenbythelake.blogspot.in/2011/05/hydrangeasblue-or-pink.html
• http://homeguides.sfgate.com/reduce-alkalinity-soil-20955.html
• edis.ifas.ufl.edu/ss118

Image References:

• http://liveconsciouslynow.files.wordpress.com/2012/01/plant_roots.jpg
• http://theveggielady.com/wp-content/uploads/2010/07/startuphorizontal.png
• http://www.justfoodnow.com/wp-content/uploads/2010/08/potato-plant-image-from-agro.basf_.com_.jpg
• http://www.sophisticatededge.com/assets/images/Gardening/Vegetables/How-to-Plant-pumpkin.jpg
• http://www.theinnovationdiaries.com/wp-content/uploads/2011/07/planting-cucumbers.jpg
• http://par-edc.org/images/cauliflower.jpg
• http://dmt-sbi3u.wikispaces.com/file/view/Tomatoes-on-vine2.PNG.png/187613895/Tomatoes-on-vine2.PNG.png
• http://4.bp.blogspot.com/-nQSBKPk5eoc/TafwVku_VBI/AAAAAAAAALo/BHTEPtsQoQs/s1600/onion+for+diabetic.jpg
• http://4.bp.blogspot.com/-Stu8VZDiyYQ/TZ4lvhhJMkI/AAAAAAAAA98/95U4nPpGnfk/s320/lettuce.jpg
• http://www.magazine.ayurvediccure.com/wp-content/uploads/2008/12/cabbage.jpg
• http://t2.gstatic.com/images?q=tbn:ANd9GcTTieGIrBHOjUVZrAbnnav2PLHp85yCkq3Ko64Ld0aG9QmmhuBkP9BtgJ_n9g
• http://images.flowers.vg/1024x768/beans_green_group.jpg
• http://periodicnetwork2011.pbworks.com/f/1321128578/phosphorus%202.gif
• http://peer.tamu.edu/curriculum_modules/Environ_Hazard/images/nitrogencyclesmall.jpg
• http://www.lrss.co.nz/ESW/Images/childrens_guide_to_vermicomposting_img_41.jpg
• http://www.enchantedlearning.com/geology/soil/soillayers.GIF
• http://www.swac.umn.edu/classes/soil2125/img/10hms.jpg
• http://www.organicagriculture.co/resources/soil%20organic%20matter.jpg