GHG emission reduction in the nonETS (emission trading system) sector is a relevant component of environmental policies for the next programming period. Specific policy matters of the next programming period are unclear, yet in general, it is clear that the reduction of emissions or at least the introduction of emission abatement measures are binding on agriculture. A popular way how to analyse GHG emission abatement measures is to use a marginal abatement cost curve (MACC) that ranges the measures according to their costs and emission reduction potential. Such a research study has been done and the measures have been analysed in Latvia. A MACC, however, gives a relative notion of the effects of GHG emission abatement measures on sustainable development in Latvia. The research aim is to analyse the effects of GHG emission abatement measures on sustainable development in Latvia. The key instrument of the present research is Integrated Impact Assessment; according to it, experts from various fields identify the effects of GHG emission abatement measures on the economy, the environment and social development, determining its vector (positive/negative) as well as effect intensity (on a scale from 1 to 3). The results showed that some measures, e.g. promotion of biogas production, could have a negative effect in some sustainability sub-dimensions, yet overall the GHG emission abatement measures make positive and significant effects not only on the environment but also on sustainability at large. At the same time, it has to be taken into consideration that the effects identified by the experts are indicative and more research has to be done to make a more accurate assessment.

An tons Ru ža*, Dzid ra Kreiš ma ne, Dzin tra Krei ta, Sil vi ja Stri kaus ka LLU Agrobiotehnoloģijas institūts Institute of Agrobiotechnology, LLU Ab stract. A three-year field study (2005)(2006)(2007) of winter wheat was conducted on lessive brown soil, silt loam at the Study and research farm "Peterlauki". The study covered three genetically different winter wheat cultivars ('Cubus', 'Tarso', and 'Zentos'). Wheat was sown on 4 different dates with a 10-day interval in the period from the end of August until the end of September by using three sowing rates (300, 400, and 500 fertile seeds per 1 m 2 ) in four replications. Samples for identification of sugar content were taken from all cultivars in autumn at the end of vegetation period and in spring at the beginning of vegetation by cutting the surface part of the plant. During overwintering -end of January and beginning of February -samples were taken from all wheat varieties sown on all sowing times with the sowing rate of 400 fertile seeds per 1 m 2 . The study revealed that sugar content in autumn, prior to the end of vegetation, was the highest for early sown winter wheat, but slightly decreased with each succeeding date of sowing. However, prior to overwintering, differences in sugar content among plants sown on different dates depended on the length of autumn season and on fluctuations in temperature during that period. Sugar content was different among different varieties, and changes that were identified during the vegetation period depended mainly on wintering conditions. If varieties with rich tillering and intensive growth in autumn were sown early, they lost greater amounts of sugar during overwintering. Although sugar content in plants in spring differed considerably year after year, differences in sugar content among the plants sown on different dates within one year almost completely leveled out and were slight. Plants rich in above-ground biomass utilised considerably more sugars to support their life function in the period of wintering. In the spring with comparatively early beginning of vegetation, relatively more sugar had remained in plants out of the amounts accumulated in autumn period in comparison to the spring with late beginning of vegetation. No impact of the sowing rate on sugar content and its changes during the vegetation period was identified.

One of the largest producers of GHG emissions in agriculture is the dairy and meat livestock sector. Grassland is the main feed base for dairy and meat cattle. Managed grasslands can become a major contributor to and leverage of GHG gas exchange. High quality information with studies on the flow of the three main GHG gases and concentration linked to different management strategies is important for the development of good management practices, as well as for the development of climateresilient landscapes and the reduction of climate impacts on agricultural lands. The aim of this study is to identify the impacts of the composition of grassland plants on GHG emissions on clay soils, as well as to clarify the impact of fertiliser on these gases. The pilot research used a field of 45 m wide and 34 m long, which was divided into 64 squares. The squares of field were divided into 2 parts � fertilised and non-fertilised, creating four repetitions. Each of the groups consisted of eight fields, each of which was filled with herbaceous grasslands in accordance with Latvian climate conditions. Measurements of GHG emissions were carried out weekly from 5 June to 16 September. N2O, CH4, CO2, gases were measured with CRDS gas measurement device PICARO G2508. Each field was measured for four minutes, a minute pause was withheld between the measurements, for measurement accuracy. Grass composition has an impact on GHG emissions, as the results have revealed a significant difference between the selected grass mixtures. The lowest N2O emissions, as well as one of the largest CH4 sequestration, but CO2 emissions are among the average. Additional an analysis of the data, it was found that the fertiliser had not affected GHG emissions, this is due to the correct selection of the fertiliser.

Feeding livestock a balanced diet with a differentiated crude protein (CP) content, depending on the lactation phase can reduce nitrogen emissions from livestock excrement and urine. A higher content of non-starch polysaccharides in livestock diets improves feed absorption in the livestock body and, consequently, nitrogen is emitted more from protein present in livestock manure than from urea acid present in livestock urine. The aim of the study is to calculate the ammonia emission reduction potential in Latvia by optimizing the feeding of dairy cows and ensuring life longevity, as well as provide justification for ammonia emission reduction in dairy farms. Calculations made by using the NorFor Model for optimization of dairy cow (Bos primigenius f. taurus) diets revealed that compared with lowyielding cows, a higher CP content diet fed to high-yielding cows at the beginning of lactation increased the amount of nitrogen (N) in their excrement and urine by 90–180 g d-1. Reducing the CP content in the cow diet by an average of 10 g kg-1 dry matter (DM) during mid-lactation resulted in the same trend. Reducing the CP content in the cow diet during late lactation and the dry period by another 20–30 g kg-1 of DM, N emissions from excrement and urine significantly decreased. Increasing the lifespan of dairy cows also means reducing ammonia emissions from the farm. By increasing the number of lactations per cow on dairy farm, it is possible to reduce the number of heifers per cow. The total reduction of ammonia emissions in Latvia was calculated based on a long-term projection of a decrease of 0.1 heifer per dairy cow. Ammonia emissions could be reduced by 0.051 kt by decreasing the number of heifers by 12.54 thou. at the planned increase in the lifespan of dairy cows by 2030.

Perennial ryegrass (Lolium perenne L.) is one of the most important forage grasses, providing high yields with excellent forage quality. The main limiting factor for increasing the cultivation area of perennial ryegrass in the Nordic-Baltic region is insufficient winter hardiness due to unstable climatic conditions as well as insufficient persistence and drought resistance. Currently, the genetic diversity of perennial ryegrass cultivars is relatively limited; therefore, developing new, highly adaptable germplasm is of high importance in the context of changing climatic conditions. In the framework of the Nordic-Baltic Public-Private Partnership (PPP) project in pre-breeding of perennial ryegrass, 250 tetraploid plants (hereinafter genotypes), created by chromosome doubling using colchicine at the Institute of Agriculture, Lithuanian Research Centre for Agriculture and Forestry, were evaluated in open field conditions at the Research Institute of Agronomy of Latvia University of Life Sciences and Technologies. Detailed phenological scoring of all genotypes was performed over a three-year (2016-2018) period. For data analysis, the plants were grouped according to heading time and growth habit. Significant differences among the groups were found in winterhardiness, regrowth rate, development rate of generative shoots, susceptibility to rust, etc. The seed from plants that survived well and showed some promising properties were harvested in the 2 nd ley year-a total of 199 genotypes or 358 individuals (80% and 48% of all, respectively). Results of genotyping of randomly selected genotypes with the highest and lowest winter hardiness showed that the clones were genetically differentiated from the cultivars developed in Baltic countries-unique alleles were found in the tetraploid clones that were not present in the analysed cultivars. This suggests that these developed tetraploid clones or genotypes could provide valuable breeding material to improve the suitability of perennial grass cultivars to local environmental conditions in the future.