Dagnija Lazdina - Academia.edu (original) (raw)

Papers by Dagnija Lazdina

Biofuels, Bioproducts and Biorefining, Sep 22, 2022

Engineering for Rural Development, May 20, 2020

Choosing the most suitable soil preparation method is not only important in aspects of seedling g... more Choosing the most suitable soil preparation method is not only important in aspects of seedling growth conditions, but it is also a question about costs of forest regeneration. Most popular soil preparation methods in Latvia are either furrows with disc trenching or spot mounds with an excavator on soils with unfavourable water regime for optimal seedling environment. As modern technology evolves, mounders installed on forwarders become more sophisticated and well adapted to difficult conditions. The main advantage of mounders installed on forwarders is better productivity and lower costs for forest renewal compared to spot mounds made with the excavator bucket. The aim of this study is to asses a two arm UOT MOUNDER M22 compliance with the established quality standards in the Latvia State Forests and compare the soil preparation quality with LSFRI Silava elaborated excavator bucket MPV600 and a mounding/planting device M-planter. The study of UOT MOUNDER M22 was done in the eastern part of Latvia, where in 5 clear cuts soil was prepared with the two arm UOT MOUNDER M22 in 2017 and reforested in 2018, and 5 clear cuts, where soil was freshly prepared in spring of 2018, collecting data with the mound dimensions and count of planting spots prepared in clear cut. The results of this study show that with UOT MOUNDER M22 it is possible to make 3822 ± 106 planting spots per hectare in typical clear cuts in Latvia, total compliance with soil preparation quality requirements is 50.6 %.

Research for Rural Development, Dec 10, 2018

In 2016 more then 40,300 ha of forest was regenerated in Latvia, where 13,000 ha were seeded or p... more In 2016 more then 40,300 ha of forest was regenerated in Latvia, where 13,000 ha were seeded or planted and 30,300 ha were left in natural regeneration. Before planting, usually one of two soil preparation methods are usedmounding or disc trenching. In areas with optimal water regime, disc trenching is used, while in wet areas mounding is used. Tree planting and after planting tending is done manually by hand tools. The aim of the study was to compare planting and tending productivity in different soil preparation methods (mounding and disc trenching) by planting different stocktypes (containerized and bareroot seedlings). Planting time studies were done in 12 sites and tending time studies in 8 sites. In planting time studies, different planting operations were measured and compared. In tending time studies, GPS devices were used, where area, distance and working time (productive and rest) was counted from GPS data. Average planting time for containerized seedlings in disc trenches was 10.3 seconds, while in mounds 9.2 seconds per seedling, an 11% improvement. Average planting time for bareroot seedlings in mounds was 28.3 seconds, while in trenches-18.2 seconds, a 35% improvement. Tending in trenches was done faster than in mounds. On average, one hectare tending time in mounds was 8.4 hours, while in trenches 7.4 hours, an 11% improvement. Walked distance for 1 hectare tending in mounds was 5.4 km, 7% shorter than the distance of 5.0 km in trenches. Factors that influence planting and tending productivity are soil preparation quality, logging residue, and water level on the site. Data from planting and tending time studies could be used for better plan work activities and select suitable planting material for a particular soil preparation method.

Engineering for Rural Development, May 22, 2019

Soil preparation method-mounding (with varying depth of the pit and the mound height)-may be the ... more Soil preparation method-mounding (with varying depth of the pit and the mound height)-may be the solution for establishing new forests when the soil water regime is unfavourable, since the pit serves as a reservoir for water during rainy periods and can retain water for the dry season. Thus, seedlings planted on mounds may obtain water through the soil capillary system when needed. During the last decades extreme weather conditions have occurred more often. And as there is a labour shortage for simple forest management tasks and increased hourly labour cost mechanized planting on mounds could be a promising solution to advance tree planting practices in Latvia. The aim of this study was to compare the productivity, quality and cost of mechanized planting and manual planting in Latvian conditions, where planting density of 2-2.5 thousand seedlings per ha is used. The M-planter was selected for the mechanized establishment of forest sites on mounded soils. During field trials, when 2000 trees per ha were planted, the productivity of the M-planter was 11.2 h ha on drained peat soils, 11.6 h per ha on drained mineral soils and 14.1 h per ha on wet mineral soils. Average mechanized planting time per 1 ha was 11.9 h, while making mounds and manual planting together took 11.2 h per ha. The cost of mechanized planting experiments in Latvian conditions, depending on the number of seedlings planted and planting conditions varied between 450 and 550 EUR per ha. Tree establishment success did not differ between the sites with mechanized or manually planted seedling, but depended more on the local site conditions.

Biofuels, Bioproducts and Biorefining

Results of success of afforestation or establishment of plantation forests on abandoned agricultu... more Results of success of afforestation or establishment of plantation forests on abandoned agricultural land are described in the current book edition. The book gives a short introduction into the history of the afforestation program in Latvia made in the Republic of Latvia period before the Second World War, statistics for that time period and for following time periods. Analysis of measurements, ground vegetation and soil surveys in experimental plantings established in 1983 through 2011 cover a 20 years worth of data. Information is given for each experimental object, increments and yield data for different species depending on growing conditions and agrotechnology used are described and analyzed. The plantations established on marginal lands are included in the list of demonstration objects for the HORIZON 2020 project No 727698 "Marginal lands for cultivating industrial crops: turning a burden into an opportunity (MAGIC)" book published in hard copies which will used for...

Agronomy

Cutaway peatland is a marginal land, which without further management is an unfavourable environm... more Cutaway peatland is a marginal land, which without further management is an unfavourable environment for plant growth due to low bearing capacity, high acidity and unbalanced nutrient composition of the soil. After wood-ash application, the soil becomes enriched with P and K, creating better conditions for tree growth. In addition to being economically viable, tree plantations ensure long-term carbon storage and promote habitat restoration. In a three-year term, we studied how distance from a drainage ditch and three different doses of wood-ash—5, 10, and 15 tons per hectare—affect the diversity of vascular plants in a tree plantation on a cutaway peatland. Plant species richness, vegetation cover and composition were positively affected by the distance from the drainage ditch and application with fertiliser, but in most cases, fertiliser dose had no significant effect. Both cover and species diversity were not affected by the planted tree species. In a tree plantation, herbaceous p...

21st International Scientific Conference Engineering for Rural Development Proceedings

In order to achieve the goals, set within the EU Green Course, it is necessary to increase the sh... more In order to achieve the goals, set within the EU Green Course, it is necessary to increase the share of renewable resources, as well as to change the resource use habits, including greater emphasis on the re-use of plant nutrients. Taking into consideration political objectives, it can be expected that energy production from plant biomass obtained from agricultural land will increase in the near future. Perennial grasses are more perspective for bioenergy production in temperate climate conditions, taking into account their growing conditions, productivity, biomass quality, and productive longevity. In order to facilitate the achievement of these objectives, a research was carried out to study the possibilities of the cultivation of reed canary grass (RCG) (Phalaris arundinacea L.) and festulolium (×Festulolium) by using the waste products from bioenergy productionbiogas fermentation digestate and wood ashas fertilisers. A field experiment was set up where an equivalent amount of plant nutrients (100 N; 80 P2O5; 160 K2O, kg•ha-1) by different fertilisers was provided, compensating for the missing elements with mineral fertilisers. Two mowing regimes for grass harvesting were used: two-cut and one-cut. The results obtained showed that in this way, partial re-use of plant nutrients can be ensured: waste products provided a significant increase in grass dry matter yield (DMY) for both species. Furthermore, harvest analyses showed that when mowing at plant senescence, part of nutrients had already been transformed from the above-ground parts to the roots, ensuring plant nutrient re-use in the following seasons. Nutrient removal by yield using the two-cut mowing regime, especially for RCG, was significantly higher, compared to the one-cut regime. The highest removal was obtained for potassium: in the two-cut mowing regime, the removal with RCG was two times higher (202.3 kg•ha-1 K2O) compared with the one-cut regime (92.5 kg•ha-1 K2O). Similar tendencies were observed also for nitrogen and phosphorus, showing the ability of grasses to efficiently transfer the plant nutrients from aboveground biomass to roots during plant senescence, especially for RCG.

In Latvia there is agroforestry, but it is not mentioned in local legislation. There are two main... more In Latvia there is agroforestry, but it is not mentioned in local legislation. There are two main farming methods which could be also be classified as agroforestry, they are short rotation coppices and silvopastoral systems.

RURAL DEVELOPMENT 2019, 2022

European Union (EU) aims to increase the share of renewable energy in total energy consumption in... more European Union (EU) aims to increase the share of renewable energy in total energy consumption in the next decades. The main renewable resource, which is mentioned in the policy documents, is biomass, especially wood biomass. Wood biomass for energy purposes could be successfully acquired from fast-growing woody plantations, growing on non-used agricultural lands. In Latvia, in 2019 were around 250 000 ha non-used agriculture land and part of it could be used for plantation growing. In Latvia, suitable woody species for use in plantations are willow, hybrid aspen, and grey alder. For economic calculations plantation site preparation before planting, planting, management, and biomass harvest costs were calculated, as well as revenues from selling biomass. In total 7 different plantation models were evaluated. Comparing the economic indicators for fast-growing woody crop plantation models during their cultivation and applying a discount rate of 7.63%, average service costs and product selling prices for the period 2015-2019, and under the existing plantation support system in 2021, intensively managed willow plantations, extensively managed willow plantations and hybrid aspen agroforestry plantations show positive accumulated cash flow. Hybrid aspen woody plantations and plantation forest, and grey alder energy wood and woody plantations show a negative accumulated cash flow, and their establishment in 2021 does not pay off. Factors that mostly affect plantation cash flow and therefore economic return are the biomass selling price and harvested biomass volume.

Research for Rural Development, 2021

The Northern European countries largely rely on poplars and their hybrids that are transferred no... more The Northern European countries largely rely on poplars and their hybrids that are transferred northward from more southern regions, therefore, facing a trade-off between the use of full growth potential and sufficient tolerance of low temperatures. We characterized frost damage and its link to early growth and survival of 33 poplar genotypes at the age of one, three, and four years in a clonal collection on agricultural land. The survival after the first season varied from 42% to 99%. Half of the clones had autumn frost injuries with a maximum of 20% of trees damaged. The autumn frost-damaged trees were significantly (p < 0.001) higher before the injury than the undamaged trees with site mean 105.3 ± 7.9 and 72.0 ± 2.5 cm, respectively, but, at the clone mean level, the proportion of autumn frost-damaged trees had no link to survival (rho = 0.53, p < 0.001). The observed winter frost damage showed no relation (p < 0.05) regarding the proportion of trees with autumn frost d...

Proccedings of International Scientific Conference "RURAL DEVELOPMENT 2017", 2018

In Latvia one third of the total forest area is regenerated by planting tree seedlings and theref... more In Latvia one third of the total forest area is regenerated by planting tree seedlings and therefore it is important to choose the appropriate soil preparation method and the right type of regeneration material for each forest type. Usually the success of afforestation is evaluated by how high is the average seedling survival rate and growth parameters like height, annual increment, diameter at breast height while the location of the seedling is disregarded. This may be of great importance since in such stands the environmental conditions typically are not entirely homogenous. Micro topography differences impact seedling growth, because it modifies water regime, temperature, micronutrient availability, sun radiation and other factors. Therefore, aim of this work is to improve monitoring methods and determine the most efficient soil preparation and seedling preparation combination to improve the quality of forest regeneration. That could be done using ASTA documentation system origin...

Agronomy research, 2016

Tall growing perennial grasses such as Phalaris arundinacea and Festulolium can be used as an alt... more Tall growing perennial grasses such as Phalaris arundinacea and Festulolium can be used as an alternative source for bioenergy production in northern latitudes as they can be grown in less cultivated areas and can be potentially used as a dual purpose crop (bioenergy and forage). The aim of studies was to investigate the effectiveness of using bioenergy waste products – fermentation residues (digestate) and wood ash as fertilisers for perennial grasses. The field experiment was conducted in the central part of Latvia (56°42' N and 25°08' E) from 2013 to 2015. For all fertiliser treatments (wood ash, digestate once per season; digestate twice per season and mineral fertilisers) the same amount of plant nutrients (N, P, K) was applied annually: N (100), P2O5 (80), K2O (160); and the missing quantities of elements in ash and digestate were compensated by mineral fertilisers. Dry matter yield (DMY) in two harvest regimes (single cut and two cut) and chemical composition (ash con...