A Study on the Impacts of Corn cultivation (Zea mays (L.) Family – Poaceae) on the properties of Soil

Maize or Corn (Zea mays L.) is the most important cereal in the world after wheat and rice. It possesses high nutritive value and is important as a coarse grain. In Sri Lanka, this crop has cultivated, around 30,000ha and local consumption is around 200,000mt annually. Further, Maize is an easily grown crop and the cultivation has been popular among farmers as a cost effective crop with limited fertilizers. This Crop earns a reasonable foreign exchange as it is used as infant foods. Maize has a higher leafy mass and higher vegetative growth within shorter period of time than the other monoculture crops. Therefore, like for many other cereal crops, it is worthwhile in studying the environmental impacts due to this plant. Many researchers have shown that soil is the most affected environment due to monoculture plants. But no proper studies on soil quality changes due to this maize crop have been conducted in Sri Lanka. Therefore, it is high time for us to initiate this kind of preliminary study directing relevant authorities to implement suitable extensive research in this area. The objectives of the present study were to find out how soil properties have changed due to corn cultivation, to assess whether soil is under stress or degraded (reduced soil quality) and to suggest suitable measures to restore the soil or improve the soil quality. This study attempted to examine the level of soil deterioration occurred over the time and some impacts on soil quality during different growth stages of maize such as beginning stage, growing stage, blooming stage and after harvesting stage. Some selected soil characteristics (physical, chemical and biological) of maize sites were tested and soil samples of adjacent forest in Anuradhapura district were used as a control. Soil moisture, soil conductivity, soil organic carbon (SOC), soil nitrate and soil microbial biomass were higher in the natural forest than maize plantation. Bulk density, air content, soil permeability, course sand and fine sand content were higher in the maize plantation than the natural forest. It is obvious that maize planted soil is under stress or leading to some soil quality degradation. Therefore, necessary measures should be applied to avoid further damage and restore the soil quality for future generations.