Details

Autor(en) / Beteiligte

• Ma, B. L.
• Liang, B. C.
• Biswas, Dilip K.
• Morrison, Malcolm J.
• McLaughlin, Neil B.

Titel

The carbon footprint of maize production as affected by nitrogen fertilizer and maize-legume rotations

Ist Teil von

• Nutrient cycling in agroecosystems, 2012-09, Vol.94 (1), p.15-31

Ort / Verlag

Dordrecht: Springer Netherlands

Erscheinungsjahr

2012

Quelle

Springer Journals

Beschreibungen/Notizen

• Studies on the sustainability of crop production systems should consider both the carbon (C) footprint and the crop yield. Knowledge is urgently needed to estimate the C cost of maize ( Zea mays L.) production in a continuous monoculture or in rotation with a leguminous crop, the popular rotation system in North America. In this study, we used a 19-year field experiment with maize under different levels of synthetic N treatments in a continuous culture or rotation with forage legume (Alfalfa or red clover; Medicago sativa L./ Trifolium pratense L.) or soybean ( Glycine max L. Merr) to assess the sustainability of maize production systems by estimating total greenhouse gas (GHG) emissions (kg CO 2 eq ha −1 ) and the equivalent C cost of yield or C footprint (kg CO 2  eq kg −1  grain). High N application increased both total GHG emissions and the C footprint across all the rotation systems. Compared to continuous maize monoculture (MM), maize following forage (alfalfa or red clover; FM) or grain (soybean; SM) legumes was estimated to generate greater total GHG emissions, however both FM and SM had a lower C footprint across all N levels due to increased productivity. When compared to MM treated with 100 kg N ha −1 , maize treated with 100 kg N ha −1 , following a forage legume resulted in a 5 % increase in total GHG emissions while reducing the C footprint by 17 %. Similarly, in 18 out of the 19-year period, maize treated with 100 kg N ha −1 , following soybean (SM) had a minimal effect on total GHG emissions (1 %), but reduced the C footprint by 8 %. Compared to the conventional MM with the 200 kg N ha −1 treatment, FM with the 100 kg N ha −1 treatment had 40 % lower total GHG emissions and 46 % lower C footprint. Maize with 100 kg N ha −1 following soybean had a 42 % lower total GHG emissions and 41 % lower C footprint than MM treated with 200 kg N ha −1 . Clearly, there was a trade-off among total GHG emissions, C footprint and yield, and yield and GHG emissions or C footprint not linearly related. Our data indicate that maize production with 100 kg N ha −1 in rotation with forage or grain legumes can maintain high productivity while reducing GHG emissions and the C footprint when compared to a continuous maize cropping system with 200 kg N ha −1 .