Fertilizer facts Fertilizers are crucial for closing the ‘yield gap’ Why are some farmers less productive than others?
How big are yield gaps?
Farmers may achieve very different yield levels under similar agroecological conditions. The ‘yield gap’ represents the difference between farmers’ actual and attainable yields and is often caused by poor access to agricultural inputs and to knowledge. Environmental differences & non-transferable factors. Cannot be narrowed.
Yield gaps may be substantial. For instance, in Sub-Saharan Africa the average maize yield is only one fifth of the attainable yield. OCEANIA NORTH AMERICA
Differences in crop management. Can be narrowed.
EUROPE SOUTH AMERICA EAST & SOUTH ASIA NORTH AFRICA & WEST ASIA SUB-SAHARAN AFRICA
Potential yields
Attainable farmers’ yields
Actual farmers’ yields
0,0
0,2
0,4
0,6
0,8
Illustration of the yield gap
Ratio between actual yields and attainable yields for maize
Why do yield gaps matter?
How can we narrow the yield gap?
High yield gaps are clearly correlated with increases in hunger prevalence.
Yield gaps can be narrowed through adoption of existing best Nutrient stewardship approach management techniques and technologies, and improved access to Nutrient stewardship approach Right Source and finance. 2013Match fertilizerinputs type
Cereal yield • t/ha 6 5
Right Source Match fertilizer type 4 Source Right to crop needs Match fertilizer type to crop needs 3
SUB-SAHARAN AFRICA
2 1
1990
0 35
1,0
30
Right Source Match fertilizer type EAST ASIA to crop Source needs Right Nutrient stewardship approach to crop Source needs Farmers’ yields are often limited by nutrient availability, making mineral Right Match fertilizer type Match fertilizer type to crop needs fertilizer is a bulky Nutrient stewardship approach Right to cropRate needs fertilizers crucial for bridging yield gaps. Because Right1990 Source N P Match amount ofproduct and its efficient use is knowledge-intensive, improving market Match fertilizer type K fertilizer to crop needs Right Rate Right to crop Source needs N are infrastructures and access to best practices priorities. P Match amount of Match fertilizer type K Right fertilizerTime to crop needs to cropRate needs Right 2013 N P Make nutrients available Match amount of N K P K when need them Rightcrops Time Right Source Right Rate Right Rate fertilizer to crop needs N Make nutrients availableP Match fertilizer type Match amount of 2013 Match amount of N K P K Right Place when crops need them fertilizerTime to cropSOUTH needs ASIA Right t o crop needs fertilizer to crop needs Keep nutrients where 1990 Make nutrients available crops use themN K P Rightcan Place Rightcrops Time when need them Keep nutrients where Make nutrients available crops can use themN K P when crops need them Right Place Right Time Right Place Keep nutrients where 25 20 15 10 Make nutrients Keep nutrients where Rightcan Place crops use them Hunger prevalence % available when crops Keep nutrients where crops can use them crops can use them need them
Relation between prevalence of hunger and cereal yield, 1990-92 and 2011-13
www.fertilizer.org
Nutrient stewardship approach
May 2014