Loading...
3 results
Search Results
Now showing 1 - 3 of 3
- Can dairy slurry application to stubble, without Incorporation into the soil, be sustainable?Publication . Silva, Arejacy; Carvalho, Mario; Coutinho, João; Vasconcelos, Ernesto; Fangueiro, DavidIn many countries, livestock slurry must be injected or incorporated into the soil to reduce nitrogen losses. However, when the injection is not feasible, farmers adopting conservation practices discard the use of slurry as fertilizer. New approaches related to slurry treatment or application management can stimulate the use of slurry in conservation agriculture (CA). This study aimed to evaluate the agronomic effects of some new management strategies to use dairy slurry for fertilization of ryegrass grown on stubble-covered soil, using as reference standard practices (slurry injection and mineral fertilizer application). The following treatments were considered: (i) bare soil: control (CB), mineral fertilizer (MB), injection (IN); (ii) stubble: control (CS), acidified dairy slurry (ADS), raw dairy slurry (RDS), irrigation following RDS (IR), mineral fertilizer (MS), RDS placed under the stubble (US), raw slurry applied 16 days after sowing (RDS T16). Effects on ryegrass yield, apparent nutrient recovery (ANR) and soil chemical properties were assessed. ADS reached 94% equivalence to MS and performed similarly to IN for productivity, ANR and soil parameters showing to be a sustainable alternative to replace mineral nitrogen and a potential solution to enable dairy slurry application in CA without injection or incorporation into the soil.
- Slurry Acidification as a Solution to Minimize Ammonia Emissions from the Combined Application of Animal Manure and Synthetic Fertilizer in No-TillagePublication . Silva, A.A.; Fangueiro, David; Carvalho, M.The combined application of manure/slurry and synthetic fertilizer (SF) might be a solution to decrease transport and application costs involving those by-products as well as enable access to them in regions where availability is low. Moreover, their joint application can potentially reduce environmental pollution, enlarge the manure benefits to more areas, and enhance the SF efficiency. However, such a strategy might result in increased ammonia emissions when applied to crop residues. Two experiments were implemented to assess ammonia emissions from stubble-covered soil fertilized with manure amended with SF. In Experiment 1 (E1), urea (U) and calcium ammonium nitrate (AN) were applied combined with dairy manure (MAN). In Experiment 2 (E2), urea was combined with acidified pig slurry (APS) and applied just after sowing (T0) or eight days later (T8). The combinations U + MAN and AN + MAN increased the ammonia emissions, while APS decreased the emissions from U, in APS + U combination, by more than 75%. Therefore, manure combined with SF applied on stubble-covered soil should not be recommended. T8 reduced ammonia emissions from U. APS enhanced the efficiency of U, being then an interesting strategy to mitigate ammonia emissions when applied on stubble-covered soil, as in no-tillage
- Dairy Slurry Application to Stubble-Covered Soil: A Study on Sustainable Alternatives to Minimize Gaseous EmissionsPublication . Silva, Arejacy António; Carvalho, Mário; Coutinho, João; Vasconcelos, Ernesto; Fangueiro, DavidThe development of sustainable application practices, which do not demand incorporation into the soil, is necessary to encourage slurry use in conservation agriculture (CA). Incorporation is the most common practice to reduce nitrogen losses from the applied slurry. However, in CA, soil disturbance must be avoided. Two experiments were conducted to evaluate strategies to reduce gaseous emissions from dairy slurry applied to stubble-covered soil without incorporation. We evaluated (1) effects on ammonia (NH3) emissions of pretreatment by acidification (ADS), irrigation (IR) and placement under the stubble (US); and (2) effects of ADS, IR, US and delayed fertilization (RDS T16) on greenhouse gases (GHG). The results of the evaluated strategies were compared to raw slurry (RDS) and ammonium sulphate (MS). Additionally, in experiment 2, the results were compared to ammonium sulphate (MB) and slurry injection (IN), both in bare soil. ADS, US and IR decreased NH3 emissions by 66%, 60% and 32.5%, respectively, with total N emissions NH3 emissions accounting for more than 79% of N losses in slurry-based treatments. Late application reduced N2O emissions by 48%. GHG emissions from ADS, US and IR were similar to those from MS, MB and IN. ADS, US and IR are the most suitable strategies for slurry application in CA