I am providing a link of paper. The main focus is on the quantification of greenhouse gas emissions arising from the cultivation phase in crop production. The study focuses on 5 main crops: maize, wheat, barley, cassava and soybean. The assessment covers the major GHG emissions: CO2, N2O and CH4 and includes all major processes from raw material production through to on-farm cultivation to the field-gate.
For fodder crops, especially grasses, what is most recommended is that it be associated with crops of luguminosas, as these can be used in human food, or also leguminous forage for animal feed. All of them contribute to decrease the emission of GHGs. You can use Ranunculus, Gliricidia sepium, among others.