One of the most difficult parts of organic farming is, obviously, weed and pest control, as very few pesticides and herbicides are all natural.
Links:
[1] http://admin.indiaenvironmentportal.org.in/news/clove-oil-all-herbicide-farmers-need-research-says-no
[2] http://admin.indiaenvironmentportal.org.in/category/newspaper/nature-world-news
[3] http://admin.indiaenvironmentportal.org.in/category/thesaurus/agriculture
[4] http://admin.indiaenvironmentportal.org.in/category/thesaurus/organic-farming
[5] http://admin.indiaenvironmentportal.org.in/category/thesaurus/pesticides
[6] http://admin.indiaenvironmentportal.org.in/category/thesaurus/herbicide
[7] http://admin.indiaenvironmentportal.org.in/category/thesaurus/crop-pests
[8] http://admin.indiaenvironmentportal.org.in/category/thesaurus/weeds