The Effect of Biochar on Sweet Corn Production

Biochar is an organic amendment produced by a process called pyrolysis, which is the burning of biomass in a limited oxygen environment. In the recent past, agricultural use of biochar has been steadily increasing and attracting tremendous research interest. This study investigated the effect of biochar in sweet corn (Zea mays ‘Temptation’) production. The study comprised of a randomized complete-block design with following rates of biochar: 0, 6.2, 12.4, or 24.8 t/ha.  Each treatment plot was 81 m² and was replicated four times. Biochar was applied and disked in on 12 April, 2012. On 17 April 2012, sweet corn (‘Temptation’, a bicolor sugar enhanced cultivar) was planted. Herbicide and fertilizer applications were made later in the season based on Midwest Vegetable Production Guide. Sweet corn was harvested on 5 July 2012 and data was collected on marketable and nonmarketable weight and number. Ten ears were randomly collected from each treatment to record husked ear weight, ear length, and diameter. Further, two husked ears were randomly selected and analyzed for sweetness. There was a general trend of increasing soil pH with increasing biochar rates; however, there were no statistically significant differences between treatments. Soil temperature measured 10 cm below the surface during the growing season did not show difference. Biochar significantly affected the number and weight of marketable ears. Higher rates of biochar, 12.4 and 24.8 t/ha, reduced number and weight of marketable ears, however, 6.2 t/ha rate did not reduce yield and was statistically similar to the control treatment (0 t/ha biochar). The effect of biochar on vegetable crop yields are not widely available, however, row crop studies have shown yield reductions in the first year of biochar use followed by increases in subsequent years. Increases in crop yields have been attributed to better water holding capacity, higher cation exchange capacity, increased nutrient retention, and the ability of biochar to reduce bulk density.  In terms of fruit quality, we did not find any significant differences in husked weight, ear length, ear width, or sweetness (°Brix).  This was the first year of the study and it is early to speculate effects of biochar on soil properties, crop growth, and yield. Biochar could be a valuable tool for management of soils that are either degraded or have poor nutrient status; however, it could take time to observe significant changes in soil and crop attributes after biochar addition.