Maize is increasingly used for energy production in agricultural biogas plants. The first biogas production project in agriculture is realized in the Research and Study Farm (RSF) Vecauce of the Latvia University of Agriculture in 2008 and animal manure together with plant biomass are planned to be used as substrate. The paper aimed to evaluate ten maize hybrids possibly suitable for biomass production at three different harvesting times. Field trial was carried out in Research and Study farm Vecauce of the Latvia University of Agriculture in 2008. Ten maize hybrids with different maturity rating according FAO numbers (FAO 180 - 270) were harvested at three different times beginning on 5 September at fourteen days intervals. Results showed that harvest time effect on maize yield was substantial (p is less than 0.05), but hybrid influence on the average yield per all harvest dates was not substantial (p is greater than 0.05). The highest organic dry matter yield was obtained harvesting maize on October 3. The Total N, crude ash, protein, fibre, cellulose, lignin, neutral detergent fibre (NDF) and acid detergent fibre (ADF) concentration decreased, but crude fat concentration increased during plant development. Relevance was not noticed between harvest dates and total carbon and hemi - cellulose content. The C : N ration rose from 34.76 at first, early harvest on 5 September to 37.97 at the last harvest on 3 October.

Two studies were conducted: the first study evaluated the production potential of indigenous (Tswana) chickens under an extensive free-range management system in the Gaborone agricultural region of Botswanal; and the second study was a survey of 25 randomly selected, commercial small-scale broiler farms in the Southern region of Botswana. Data were obtained using a structured questionnaire, interviews and direct observations of the birds and their management in the two systems. Study 1 involved 85 farmers. Ten different common supplementary feeds fed to the free-range chickens together with soil samples from where the chickens roost were collected. The feeds were: sorghum grain (Sorghum bicolor), maize grain (Zea mays), jugo bean, also known as bambara groundnut (Vigna subterranea), tepary bean (Phaseolus acutifolius), millet grain (Pennisetum glaucum), melon seeds (Colocynthis citrullus [Citrullus lanatus]), Tswana water melon fruit (whole), sorghum milo, maize bran and sorghum beer residue (moroko). Mean adult body weight of the birds (n=713) was 2.2 and 2.0 kg for cocks and hens respectively. Average egg weight (n=188) was 48 g with an annual production of 34 eggs laid in 2 to 3 clutches. Production varied little among flocks. Sexual maturity was attained at about 6 months for females. The crude protein content of the feeds (as-fed basis) given as supplements was: maize grain 9.8%, millet 6.5%, sorghum 11.1%, tepary bean 18.5% and jugo bean 15.8%. All the feeds had a low level of calcium, for example 0.22% for melon seeds. The farmers kept the chickens for home consumption and occasional sales. In study 2, all the farmers practiced intensive housing on deep litter. The number and size of the poultry houses ranged from one to eight, with floor area of less than 100m2 to 1000m2. Numbers of chickens in each batch ranged from less than 1000 to 10000 with about 4 batches in a year. The broiler strains were Ross hybrid, Indian River and Cobb with 56% of the farmers keeping Ross hybrid. Various heating methods were used for brooding with more than 40% using gas as a source of heat. Vaccinations for either gumboro and/or Newcastle were used by 76% of the farmers. Feed was provided ad libitum in all instances.

Maize yield and quality are affected by many factors, including production practices, diseases, pests, and differences in the climate. Usually it is not possible to do much to change the effect of temperature, but it is important to grow better adapted or characterized with right maturity rating hybrids. The paper is aimed to determine the impact of accumulated growing degree days (GDD) on maize development, organic dry matter yield, ODM and chemical composition of maize hybrids. A field trial was carried out in the Research and Study farm ’’Vecauce’’ of the Latvia University of Agriculture (LLU) from 2008 till 2010. Ten (in 2008), eleven (in 2009) and fifteen (2010) maize hybrids with different maturity ratings according to FAO numbers (FAO 180-340) were harvested at three different times beginning on 5 September at fourteen-day intervals. GDD were calculated when maize reached a certain growth stage (full emergence, first tassels, full tassels, first ears, full ears, specific harvest date) to characterize conditions for maize growing in a specific year. Composition of fresh maize was analyzed for all hybrids using standard methods. Results were statistically processed using methods of correlation and regression analysis. Our results presented evidence that ODM yield in 2008 and 2009 on last harvest dates was lower than that on the first harvest date in 2010. Organic dry matter yield was higher in years when more GDD were accumulated. Results also showed that GDD negatively correlated with the total N, protein, fibre cellulose, hemi-cellulose, NDF, and ADF concentration.

Renewable energy resources have been developing very fast due to negative effects and finite reserves of the fossil fuels. Biomass is ranked among the most promising renewable energy resources within the Central Europe. Corn (Zea mays L.) is currently the most widely grown crop in the Czech Republic; nevertheless, the cultivation of corn provokes soil erosion by water. Perennial energy grass called tall wheatgrass (Elymus elongatus subsp. Ponticus cv. Szarvasi-1) is supposed to be a good and environment-friendly alternative to corn. Field trials including these two crops were established in the experimental locality of South Bohemia. Their yield potential was monitored during spring harvest periods (use for combustion). Dry phytomass was fundamentally analysed (N, C, H, S) and higher heating value was determined too. Universal Soil Loss Equation was calculated for both crop species. Corn provided much higher average yield in a three-year interval; corn phytomass reached higher heating value as well. The area of Elymus elongatus should enlarge considerably, if we wanted to get the identical amount of energy from corn and Elymus elongatus. However, we found that, compared to Zea mays L., water erosion theoretical land losses would be several times less serious for Elymus elongatus.

The purpose of this study was to predict and compare salt accumulation in the soil profile under drained and undrained conditions. The water management simulation model, Drainmod (Ver. 6.1) was used to determine the optimal drainage system design parameters, which will decrease soil profile salinity and provide maximum crop yields in Ankara-Bala Basin of Turkey. Soil sampling points were coordinated with the Global Positioning System (GPS). Soil, crop and site parameters were obtained as an input. The model was run for 5 years from 2005 to 2010 to simulate optimum drainage design parameters (drain depth, drain spacing) while controlling soil salinity in the root zone. Soil water conditions and soil salinity level were simulated for crop rotation of corn (Zea mays) and winter wheat (Triticum). Yield of individual crops was predicted for each growing season. The results of the simulations were analyzed to identify alternatives of subsurface drainage system that would satisfy maximum crop productions. According to the simulation results, the drain spacing of 130 m and drain depth at 160 cm are recommended for Bala Basin. Soil salinity maps were created for undrained and drained conditions. Results showed that the soil salinity level and salinity stress can be reduced and yield increased by installing a drainage system.