Maize water requirement during the growing period is calculated by Kc * ET0, per FAO's method.
In order to help farmers to choose an appropriate planting date, we estimated the rainfall received in 2022 long rain season if choosing different planting date by calculating the average of historial analog years. For a 120-day maize the results are shown below. Different colors represent 10 counties in Kenya. X-axis is the planting date ranging from March 1st to May 31st. Y-axis is the rainfall received during a growth period of 120 days. In most counties, the later you plant, the fewer rainfall you will receive. The constant horizontal yellow line is the water requirement of 120-day maize.
Furthermore, we break down the total rainfall received to rainfall received in each of 4 maize growth stages. Different colors represent 10 counties in Kenya. X-axis is the planting date ranging from March 1st to May 31st. Y-axis is the rainfall received during a particular growing stage. The constant horizontal yellow line is the water requirement of 120-day maize.
A good way to use the above diagrams is to see how predicted rainfall received in the growing season will change with planting date and compare that with maize water requirement in order to decide a planting date. Please bear in mind that not all rainfall received can be used by maize. The percent of effective rainfall can be as low as 50% or lower.
A superset dashboard has been established for easy view (that link might not work, we are trying to make it public)http://superset.plantvillage.psu.edu/r/36
http://superset.plantvillage.psu.edu/r/36