Preconditions for Including the Effects of Urease and Nitrification Inhibitors in Emission Inventories.

Urease and nitrification inhibitors can reduce ammonia and greenhouse gas emissions from fertilizers and manure but their effectiveness depends on the conditions under which they are used. Consequently, it is essential for the credibility of emission reductions reported in regulatory emission inventories that their effectiveness is assessed under real-world conditions and not just in the laboratory. Here, we specify the criteria we consider necessary before the effects of inhibitors are included in regulatory emission inventories.

Soil NO emission from organic and conventional cotton farming in Northern Tanzania.

The effort to increase the sustainable supply of food and fibre is challenged by the potential for increased greenhouse gas (GHG) emissions from farming systems with intensified production systems. This study aimed at quantifying soil NO emissions from smallholder organic and conventional cotton production practices in a semi-arid area, Meatu, Northern Tanzania. Field experiments were conducted to quantify NO emissions under (i) current practices with organic (3 Mg ha farmyard manure (FYM)) and conventional (30 kg mineral N ha) cultivation; (ii) a high input practice with organic (5 Mg ha FYM) and conventional (60 kg mineral N ha) cultivation; and (iii) an integrated practice with organic (3 Mg FYM + legume intercropping) and conventional (30 kg N + 3 Mg ha FYM) cultivation.

Effect of feeding practices and manure quality on CH and NO emissions from uncovered cattle manure heaps in Kenya.

Countries in sub-Saharan Africa (SSA) rely on IPCC emission factors (EF) for GHG emission reporting. However, these were derived for industrialized livestock farms and do not represent conditions of smallholder farms (small, low-producing livestock breeds, poor feed quality, feed scarcity). Here, we present the first measurements of CH and NO emissions from cattle-manure heaps representing feeding practices typical for smallholder farms in the highlands of East Africa: 1) cattle fed below maintenance energy requirements to represent feed scarcity, and 2) cattle fed tropical forage grasses (Napier, Rhodes, Brachiaria).

Interactive effects of dung deposited onto urine patches on greenhouse gas fluxes from tropical pastures in Kenya.

Dung and urine patches on grasslands are hotspots of greenhouse gas (GHG) emissions in temperate regions, while its importance remains controversial for tropical regions as emissions seem to be lower. Here we investigated NO, CH and CO emissions from urine and dung patches on tropical pastures in Kenya, thereby disentangling interactive and pure water, dung or urine effects. GHG fluxes were monitored with automated chambers for 42-59 days covering three seasons (short rainy season, long rainy season, dry season) for six treatments (Control; +1 L water; +1 kg dung; 1 L urine; 1 L water +1 kg dung; 1 L urine +1 kg dung).

Severe below-maintenance feed intake increases methane yield from enteric fermentation in cattle.

The relationship between feed intake at production levels and enteric CH4 production in ruminants consuming forage-based diets is well described and considered to be strongly linear. Unlike temperate grazing systems, the intake of ruminants in rain-fed tropical systems is typically below maintenance requirements for part of the year (dry seasons). The relationship between CH4 production and feed intake in animals fed well below maintenance is unexplored, but changes in key digestive parameters in animals fed at low levels suggest that this relationship may be altered.