The interaction between types of cover crop residue and digestate application methods affects ammonia volatilization during maize cropping season

Abstract

Organic and mineral fertilizers are important sources of ammonia (NH3) emissions from agricultural fields. The objectives of this study were (a) to evaluate how different cover crop (CC) residues (i.e., rye [Secale cereale L.], white mustard [Sinapis alba L.], and bare soil as control) in combination with different application methods of digestate (surface broadcast vs. shallow injection) affect NH3 volatilization before planting maize (Zea mays L.) and (b) to assess the residual effect of previous CCs on NH3 volatilization after urea top‐dress application at the V5‐V6 phonological stage of maize. Ammonia volatilization was measured using semi‐static chambers for 14 d (335 h) after planting and for 6 d (150 h) at the V5‐V6 stage. Overall, NH3 emissions decreased by 67–77% with digestate injection compared with surface broadcasting. However, the reduction in NH3 volatilization using the injection method was significantly lower with mustard residue (6.72 kg NH3–N ha–1) than with rye residue (14.15 kg NH3–N ha–1), which allowed for more volatilization by increasing the exposure of digestate to the air. Broadcast digestate method did not affect the cumulative NH3–N losses obtained with different CC types. After urea top‐dressing at the V5‐V6 stage of maize, the cumulative losses of NH3 (during 150 h) were 2.99 kg NH3–N ha–1 with rye as previous CC and 2.49 kg NH3–N ha–1 with mustard. Our study shows that digestate injection before maize planting and urea top‐dressing application followed immediately by irrigation (15 mm) could be considered as useful strategies to mitigate NH3 volatilization and increase N use efficiency in maize.

Towards efficient N cycling in intensive maize: role of cover crops and application methods of digestate liquid fraction

“…Ammonia volatilization results during the experiment have already been reported by Maris, Capra, et al (2021). Here, we use the NH 3 data presented in that article in combination with the N 2 O and leaching data reported here to compute cumulative N‐losses and yield‐scaled cumulative N losses.…”

“…This was not the case when rye was used as CC, where NH 3 volatilization represented 58% of total yield‐scaled N‐losses. Although rye residues left over the soil surface acted as a mechanical barrier against DLF infiltration into the soil and increased NH 3 volatilization (Maris, Capra, et al, 2021), the strong reductions in ‐leaching induced by this CC compensated for this effect, leading to generally lower yield‐scaled N‐losses compared with the other treatments.…”

“…Cumulative NH 3 volatilization (kg NH 3 ‐N ha −1 ) was then obtained by simple addition of sampling events. Further details on sampling methodologies and quantification techniques can be found in Maris, Capra, et al (2021).…”

Using highly stabilized digestate and digestate-derived ammonium sulphate to replace synthetic fertilizers: The effects on soil, environment, and crop production

“…The original Hutchinson and Mosier (HM) three-points calculation was used when non-linear accumulation was detected; otherwise, Linear Regression has been used (Bertora et al, 2018;Maris et al, 2021). In order to preserve linear conditions, big volume chambers and short deployment times (0-10-20 mins) were used.…”

Impacts on water quality of producing biogas on pig farms as a function of the associated agricultural practices

“…Several studies have shown that fertilization with digestates has higher NH 3 volatilization than does fertilization with raw livestock waste (Möller and Stinner 2009, Ni et al 2012, Crolla et al 2013, Lili et al 2016, Nicholson et al 2017. However, we used relatively low volatilization factors as compared to these references, considering that volatilization could be reduced through phase separation of the digestate (Svehla et al 2020) and/or less-polluting application techniques, such as injection (Riva et al 2016, Maris et al 2021.…”