Closing yield gaps in Colombian direct seeding rice systems: a stochastic frontier analysis

Rice is one of the most important crops in terms of harvested area
and food security both globally and for Colombia. Improvement of
technical efficiency levels in rice production in order to close yield
gaps in a context in which rice demand increases, natural resources are
depleted, and where there are growing expectations about both climate
changes and trade agreements is likely the most important challenge
that farmers confront. This research assessed the main management
factors that limit both rice crop productivity and the likely drivers of
non-optimal technical efficiency levels (a proxy for yield gaps). This
study focused on both upland and irrigated direct seeding systems
across a variety of environments in Colombia. Stochastic frontier
models were used to integrate microeconomic theory and empirical
regression analysis in conjunction with a large commercial rice production
database developed by the Colombian rice growers’ federation
(Fedearroz). A large variation was found in technical efficiency (from
40 to 95%) levels for both upland and irrigated systems, and major differences
were obtained in the limiting factors of the two systems (e.g.
seed availability, variety type, market accessibility, fertilizer type, and
use rate). This suggests both substantial and varied opportunities for
improvements in current technical efficiency levels. Across systems,
the correct choice of variety was identified as a common key factor
for maximizing yield for a particular environment. For upland systems
optimal choices were F174 and F2000, whereas for irrigated rice
F473 was found to produce the highest yield. Additionally, numerical
analysis suggests a yield impact of ca. 0.18% for each 1% increase in
the nitrogen application rate for upland systems. For irrigated rice,
phosphorous rather than nitrogen application rates were found to be
more important. Since our analysis is based on farm-scale commercial
production data, we argue that once our results are brought to
consensus with local extension agents, technicians and agronomists,
then management recommendations for closing yield gaps can be
used to improve rice productivity.