Departement of Agriculture (DA)
A website full of usefull information! There is for example the agricultural guide map with hazard levels or crop suitability.
Philippine Center for Postharvest Development and Mechanization (Philmech)
I actually have no idea how much useful information you can find here. I think I need to check out this website myself someday.
Bureau of Internal Revenue (BIR)
Here you can find plenty of information about taxes. I know why you would be interested in this. Anyway, you can find here things like zonal values of properties.
Department of Agrarian Reform (DAR)
They will give you a big headache if you want to own some farm land. If you want to find out more, just read the FAQ about CARP on their site.
Department of Science and Technology (DOST)
I never really explored this site. There are plenty of sub-sites. I think I really need to check this out later in a quiet moment.
Local Water Utilities Administration (LWUA)
This site has a decent set of information about water districts, rates, water quality and much more. I had fun checking out all the registered well locations on Google map.
Philippine Atmospheric, Geophysical & Astronomical Services (PAGASA)
PAGASA is actually a sub-site of DOST. They are providing information about the climate. I found, for example a statistic about the rainfall normal values.
Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD)
I’m a bit confused about this site. I just found some information about Agricultural Machinery on that site.
Food and Agriculture Organization of the United Nations (FAO)
You can find literally an incredible amount of information and instruction material about farming on this website.