id	keyword
aesr-1634	plant
aesr-1634	ha-1
aesr-1634	density
aesr-1634	fertilizer
aesr-1634	yield
aesr-1634	population
aesr-1634	maize
aesr-1634	plant population
aesr-1634	population density
aesr-1634	grain
aesr-1634	growth
aesr-1634	soil
aesr-1634	p2o5
aesr-1634	journal