http://gisgeography.com/agriculture-maps-global-farming/

Food and Agriculture Organization of the United Nations- AQUASAT- global water information system:
http://www.fao.org/nr/water/aquastat/main/index.stm 

Nat. Geo. Global Water Footprint of Key Crops (+ other resources):
http://environment.nationalgeographic.com/environment/freshwater/global-water-footprint/

Interesting point: "Soil water is the limiting factor for photosynthesis"
http://drought.unl.edu/ranchplan/DroughtBasics/GrassesDrought/SoilMoisturePlantGrowth.aspx 

The Importance of Water in Plants & Crop Agriculture: A Climatic Factor:
http://www.cropsreview.com/importance-of-water.html 
     (Some key words- mesophytes, hydrophytes, xerophytes, resurrection plants)

Article: "Plants have unexpected response to climate change"
(mentioned downhill movements in relation to water availability and uphill movements in relation to temperature)
http://www.sciencemag.org/news/2014/08/plants-have-unexpected-response-climate-change

Water holding capacity of soils activity... see Activity 3 with soda bottle/mayo jar
 http://edis.ifas.ufl.edu/pdffiles/4h/4H36000.pdf 

Climate & Crop Growth Lesson: 
http://nationalgeographic.org/activity/climate-crop-growth/ 
     Interactive activity- http://authoring.concord.org/sequences/50/activities/295?show_index=true 

Article: "How do weather and climate influence cropping area and intensity?"
http://www.sciencedirect.com/science/article/pii/S2211912414000583 

GREAT video from a corn farmer: http://www.myamericanfarm.org/videos/video_player.php?vurl=AH808_corn_crop_champions_HulaFamilyFarm.mp4   (talks about drip irrigation, etc.)

Which biomes are able to produce food?
https://www.oxfam.org.au/get-involved/how-schools-can-get-involved/classroom-resources/food-4-thought-2/food-4-thought-geography/worksheet-2-which-biomes-are-able-to-produce-food/ 

Agroecological production zones, probable geographic origin of some crops, environmental factors that affect plant growth, crop adaptations (Oregon State University: CSS 330 World Food Crops):
http://oregonstate.edu/instruct/css/330/two/ 

In-depth Corn Information (Oregon State University): http://oregonstate.edu/instruct/css/330/six/index.htm