May 23, 2013 by Jawoo Koo

Where in sub-Saharan Africa is the difference between actual and potential yield of maize most striking? We can answer this question pixel by pixel, region by region, but for the purpose of this brief analysis, let’s talk countries.

May 22, 2012 by Jawoo Koo

While we were brainstorming “big ideas” at a recent working retreat, we stumbled upon the idea of promoting FourSquare as a tool to monitor smallholder farmers’ crop management practices.

Aug 31, 2011 by Jawoo Koo

With limited resources to cope with weather variability, smallholder farmers in Sub-Saharan Africa (SSA) are facing highly unreliable crop production from year to year. In this modeling exercise we quantified how much area is under such condition and what are their production potential under intensification. The simulation result indicates that, without further intensification, only 15% of current maize growing area has the potential to reliably produce more than 3 t/ha, a yield level suggested as being sufficient to sustain the cereal needs of a typical smallholder household. However, with well-managed intensification, 82% of the current maize area showed the potential to reliably produce 3 t/ha or more.

MAIZE AREA WITH > 1 T/HA IN MAJORITY OF YEARS UNDER LOW-INPUT (GREEN AREAS

Feb 16, 2011 by Jawoo Koo

What's the reported level of maize yield in Chad? Or, how about for all Sub-Saharan Countries? What's the time trend of groundnut yield in Ghana? Please be quick; you have one minute to find the answers! OK, good questions.

Question

Dec 6, 2010 by Jawoo Koo

For crop modeling researchers who are in need of finding soil profiles at regional-scale in Sub-Saharan Africa (SSA), this post gives a spatial dataset that delineates SSA into 588 units and corresponding soil profiles, based on the WISE v1.1 and HC27 soil profile databases.

How to find a right soil profile for this grid cell?

Sep 17, 2010 by Jawoo Koo

Many of HarvestChoice spatial datasets are organized and released on 10-km grids. To make spatial analyses easier for researchers (even without having access to GIS platform), we put data layers from multiple themes together in one denormalized big table. This post describes the methodology and presents a prototype.

Layered information on a grid cell

Aug 15, 2010 by Jawoo Koo

Conceptually, in its simplest form, one may liken the cultivation of a crop in the field to a mathematical function.

YIELD RESPONSES TO NITROGEN

Aug 12, 2010 by Jawoo Koo

As a quick demonstration to estimate crop yield levels at regional-scale with various management assumptions, this post describes how crop systems models can be used to assess yield gap of rainfed maize due to the limited supply of soil nitrogen. This methodology can help researchers to find what is the most critical factor that limits crop yield productivity in a given environment condition and how to address the constraint.

Aug 10, 2010 by Jawoo Koo

By modeling the decomposition of soil organic matter dynamics, crop systems models can simulate the effects of soil nutrient depletion under low-input extractive field management practices, as well as soil carbon sequestration under regenerative management practices.

Maize