No-till methods reduce soil erosion, but is there an increase in nutrient loss due to lack of fertilizer incorporation?
An article published earlier this June by researchers with the USDA Agriculture Research Service (ARS) in the Soil Science Society of America Journal sought to deal with the above (hypothesized) conundrum.
Why does nutrient loss matter? It matters to farmers who want those nutrients to stay on or in their soil and fertilize their crops. Moreover, nutrient loss from agricultural systems can result in harmful algal blooms which damage the ecosystems in watersheds connected to farmland.
What did the researchers find? Lack of fertilizer incorporation in no-till systems, on average, did not result in markedly higher nutrient runoff than in conventional tillage systems. Rather, “Nutrient loss in surface runoff is highly dependent on runoff timing relative to nutrient application.” Thus “losses varied greatly from year-to-year for all tillage practices.” Moreover, “for the soil types investigated and fertilization regimes used, no-till did not have a greater impact on surface water quality than chisel tillage where nutrient stratification should have been less pronounced. This suggests that farmers with properly managed no-till crops should not have to occasionally till to incorporate fertilizers to reduce nutrient losses in surface runoff.”
This study seems to apply most to row crop farmers, so this might not be of great interest to vegetable farmers, orchardists, or livestock farmers. But anyone interested in soil conservation, soil management techniques and the health of ecosystems may want to take note. The researchers compared three different systems, one of which employed significantly less inputs and relied largely on manure and red clover to supply nutrients; thus, this study may be of interest to organic farmers or farmers interested in a low-input approach.
To learn more about this study and to dig into the details, the full article is available here for free. A summary of this research was published at ScienceDaily.com.