Reducing pre-harvest aflatoxin content in groundnuts through soil water management

In Zambia, groundnut (Arachis hypogaea L.) is an important food and market crop. However, the crop has very limited access to international markets due to high concentrations of aflatoxins in kernels, which pose serious health concerns. There exists several promising field intervention measures to minimize pre-harvest aflatoxin incidence. Good agricultural practices that contribute to prudent management of soil moisture have shown potential to reduce aflatoxin incidence. In this study, we investigated the effect of three soil moisture management practices on pre-harvest aflatoxin content in groundnuts. Treatments included controlled irrigation during pod-development, time of planting within a growing season, and application of manure. Soil from experimental sites was sampled from the top 20 cm and characterized using standard laboratory procedures. In each case, a Virginia bunch type groundnut variety was planted and grown to full maturity. The harvested pods were sampled, dried to about 8 % moisture content, shelled and then tested for aflatoxin content using the Reveal Q+ Aflatoxin Testing Kit. To determine the distribution of means, the data collected were subjected to either the Analysis of Variance or the alternative Kruskal Wallis Test at 95 % Confidence Interval. Results indicated up to 10-fold reduction in aflatoxin content with increasing soil moisture status during pod development. Therefore, it can be concluded that maintaining a favorable soil moisture status is a key factor in minimizing pre-harvest aflatoxin risk in groundnuts.