Operational Drought, Desertification and Crop Yield Monitoring data providers

UN > FAO > GIEWS
The Global Information and Early Warning System on Food and Agriculture, provides information in report format.
UN > FAO > SD > METART
Low resolution satellite imagery, meteorological data and derived products, methods and techniques used for environmental monitoring, crop  forecasting, early warning, desert locust control and others
USDA > FAS
The Foreign Agricultural Service (FAS) of the U.S. Department of  Agriculture (USDA) aims to improve foreign market access for U.S. products    
USDA > FAS > PECAD
The Production Estimates & Crop Assessment Division of the Foreign Agricultural Service (FAS)
FANR > SADC
Southern African Development Community (SADC). The SADC established a Food Security Program. Operates under the Food, Agriculture and Natural Resources (FANR) Development Unit in Harare, Zimbabwe.
DMC-GHA
Drought Monitoring Center for Greater Horn of Africa. Countries: Burundi,  Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, Sudan, Tanzania, Uganda . 
USAID > LEWS 
Early warning system for monitoring nutrition and livestock health for food security of humans in east Africa.
USAID > FEWS
Famine Early Warning System of the US Agency for International Development Pronouncement
The water page

An independent initiative dedicated to the promotion of sustainable water resources management and use. Emphasis is placed on the development, utilisation and protection of water in Africa and other developing regions.

plantstress.com

An excellent website addressing plant environmental (abiotic) stress issues in agriculture, plant physiology, breeding, genetics and biotech. Offers news, a bibliographic  database, articles, files, a bulletin board and many links to other relevant sites.

 

Other Institutional Information Services
UN > Reliefweb
News site of the UN with various food/drought related information. Features an early warning list page
FAO > SD

Sustainable Development department of the Food and Agriculture Organization. Various information (e.g. Desertification and Agro-Meteorology etc.)

UN System Network on Rural Development and Food Security
A partnership of various organizations towards tackling rural development challenges at the country level. 
World Resource Institute
 News site of the World Resource Institute. Various information on agricultural resources.
World Meteorological Organization
  Various links: agriculture related, cloud duration, precipitation etc.
CILLS > CENTRE REGIONAL AGRHYMET
SAHEL site, covering Burkina Faso, Cape Verde islands, Gambia, Guinea, Mali, Mauritania, Niger, Senegal, Chad.

 

Drought and Desertification monitoring

Italian Clearing House Mechanism on Desertification

Desertification center of Italy
UN > UNDP > SEED > UNSO
United Nations Office for Combat of Drought and Desertification
UNL (University of Nebraska-Lincoln)
The National Drought Mitigation Center of the University of Nebraska-Lincoln helps people and institutions develop and implement measures to reduce societal vulnerability to drought.
P-CASE (program on changes in arid and sub-humid ecosystems)
Information on Italian institutions operating in the field of applied research in arid and sub-humid ecosystems.