Effects of hotter, drier conditions on gaseous losses from nitrogen fertilisers.

Global warming is expected to cause hotter, drier summers and more extreme weather events including heat waves and droughts. A little understood aspect of this is its effects on the efficacy of fertilisers and related nutrient losses into the environment. We explored the effects of high soil temperature (>25 °C) and low soil moisture (<40% water filled pore space; WFPS) on emissions of ammonia (NH) and nitrous oxide (NO) following application of urea to soil and the efficacy of urease inhibitors (UI) in slowing N losses.

Striking a balance between N sources: Mitigating soil acidification and accumulation of phosphorous and heavy metals from manure.

Manure amendment has been shown to effectively prevent red soil (Ferralic Cambisol) acidification from chemical nitrogen (N) fertilization. However, information is lacking on how much manure is needed to mitigate acidification and maintain soil productivity while preventing accumulation of other nutrients and heavy metals from long-term inputs. This study determined the effects of various combinations of manure with urea-N on acidification and changes in soil P, K, and heavy metals in a 9-year maize field experiment in southern China.

Changes in soil organic carbon status and microbial community structure following biogas slurry application in a wheat-rice rotation.

Biogas slurry is widely used as a crop fertilizer due to its available nitrogen content. However, it remains unclear how biogas slurry application affects soil organic carbon (SOC) status and soil microbial community under typical agricultural systems. Here, under a wheat-rice field experiment, we examined the responses of SOC and soil bacterial and fungal communities to biogas slurry application, both with (BSS) and without (BS) straw return, relative to chemical nitrogen fertilizer with (CFS) and without (CF) straw return.

Fate and transfer of heavy metals following repeated biogas slurry application in a rice-wheat crop rotation.

The application of biogas slurry, from anaerobic digestion of livestock excreta, to cropland has proven to be an effective mechanism for recycling nutrients within farms. However, the potential pollution of heavy metals from repeated biogas slurry fertilization has not received much attention. Here we present the results of a field experiment under rice-wheat rotation demonstrating the accumulation, speciation distribution and plant uptake of heavy metals (Cu, Zn, Pb and Cd) in soil following biogas slurry application.

Effects of urease and nitrification inhibitors on soil N, nitrifier abundance and activity in a sandy loam soil.

Inhibitors of urease and ammonia monooxygenase can limit the rate of conversion of urea to ammonia and ammonia to nitrate, respectively, potentially improving N fertilizer use efficiency and reducing gaseous losses. Winter wheat grown on a sandy soil in the UK was treated with urea fertilizer with the urease inhibitor N-(n-butyl) thiophosphoric triamide (NBPT), the nitrification inhibitor dicyandiamide (DCD) or a combination of both. The effects on soil microbial community diversity, the abundance of genes involved in nitrification and crop yields and net N recovery were compared.

Land-use type affects NO production pathways in subtropical acidic soils.

The change in land-use from woodland to crop production leads to increased nitrous oxide (NO) emissions. An understanding of the main NO sources in soils under a particular land can be a useful tool in developing mitigation strategies. To better understand the effect of land-use on NO emissions, soils were collected from 5 different land-uses in southeast China: shrub land (SB), eucalyptus plantation (ET), sweet potato farmland (SP), citrus orchard (CO) and vegetable growing farmland (VE).