As we approach mid-July, the tillage season in Burkina Faso is drawing to a close. The rainy season runs from mid-June through September, so crops that are planted after today will not have enough rain to reach maturity. The two exceptions to this rule are super early maturing varieties of corn (72 days) which require lots of fertilizer, and sesame. We will continue tilling fields in preparation for sesame until July 25th, but then we will switch over to cultivating and spraying for weed and insect control.
Now for the science. On Tuesday, I surveyed a field near the village of Koulga and measured plots for a tillage study. Our goal is to compare the effects of four types of tillage (tractor + plow, tractor + disk, cattle-drawn plow, and hand hoeing) on yields and soil bulk density. I designed a randomized block trial with three replications of each treatment. Before tilling, I took two soil samples from each plot (24 in all) at depths of 0 cm and 10 cm. The villagers were bewildered. Gerard asked me “what on earth do you plan to do with that soil?!” Good pun Gerard. We’re going to test it for density before and after each type of tillage. Then, we can see which types of tillage effectively lower bulk density to the level needed for optimal root growth. Science! The villagers seemed to like the idea of the first-ever study conducted in their village, and Justin and I will be keeping tabs on the plot and its management throughout the season.
