Reaction of Three Strawberry Cultivars to the Salinity: Vegetative Parameters

The study aimed at analysing the reaction of three strawberry Fragaria x ananassa Duch. cultivars to the salinity (0-control, 0.5, 1.0, 2.0, 3.0 and 4.0 g of NaCl L-1) in the irrigation water: equivalent of the following EC values: (0.73, 1.65, 2.66, 4.37, 5.93 and 7.81 mS cm-1). Vegetative trial was carried out at the Faculty of Agriculture in Zagreb during 1997 and 1998. Following parameters were tested: degrees of damage of shoots, number of leaves, number of runners (stolons), yield of fresh biomass and dry matter of shoots and roots, and percentage of dry matter of shoots and roots. Tested cultivars showed significant differences of the level of damage (necrosis and decay of plants due to high NaCl concentration). The highest degree of damage was shown by ‘Elsanta’ in both trial years, followed by ‘Marmolada’ and ‘Miranda’ respectively. The analysis of the number of leaves and stolons confirmed the same trend. The yield of fresh biomass and dry matter of shoots and roots was significantly reduced with the application of NaCl. ‘Miranda’ was characterised by the highest fresh biomass and dry matter yield, followed by ‘Marmolada’ and ‘Elsanta’. Average decrease of fresh biomass yield of shoots in comparison to the control was 45, 33 and 22% in ‘Elsanta’, ‘Marmolada’ and ‘Miranda’. Dry matter yield of shoots decreased correspondingly for 34, 28 and 18%. Total dry matter yield (shoots + roots) of ‘Elsanta’ was significantly reduced at 0.5 g NaCl L-1 and of ‘Marmolada’ and ‘Miranda’ at 1.0 and 2.0 g L-1 respectively

Reaction of Three Strawberry Cultivars to the Salinity: Vegetative Parameters

The study aimed at analysing the reaction of three strawberry Fragaria x ananassa Duch. cultivars to the salinity (0-control, 0.5, 1.0, 2.0, 3.0 and 4.0 g of NaCl L-1) in the irrigation water: equivalent of the following EC values: (0.73, 1.65, 2.66, 4.37, 5.93 and 7.81 mS cm-1). Vegetative trial was carried out at the Faculty of Agriculture in Zagreb during 1997 and 1998. Following parameters were tested: degrees of damage of shoots, number of leaves, number of runners (stolons), yield of fresh biomass and dry matter of shoots and roots, and percentage of dry matter of shoots and roots. Tested cultivars showed significant differences of the level of damage (necrosis and decay of plants due to high NaCl concentration). The highest degree of damage was shown by ‘Elsanta’ in both trial years, followed by ‘Marmolada’ and ‘Miranda’ respectively. The analysis of the number of leaves and stolons confirmed the same trend. The yield of fresh biomass and dry matter of shoots and roots was significantly reduced with the application of NaCl. ‘Miranda’ was characterised by the highest fresh biomass and dry matter yield, followed by ‘Marmolada’ and ‘Elsanta’. Average decrease of fresh biomass yield of shoots in comparison to the control was 45, 33 and 22% in ‘Elsanta’, ‘Marmolada’ and ‘Miranda’. Dry matter yield of shoots decreased correspondingly for 34, 28 and 18%. Total dry matter yield (shoots + roots) of ‘Elsanta’ was significantly reduced at 0.5 g NaCl L-1 and of ‘Marmolada’ and ‘Miranda’ at 1.0 and 2.0 g L-1 respectively

Evaluation of Soil and Plant Nitrogen Tests in Potato (Solanum tuberosum L.) Production

Nitrogen (N) management is critical in optimizing potato (Solanum tuberosum L.) yield and reducing environmental pollution. Several plant and soil based tests were proposed for assessment of N status in crop plants. Aim of this study was to evaluate the convenience of plant based tests (leaf chlorophyll content index (CCI) and petiole nitrate-nitrogen (NO3-N) concentrations) and soil based test (soil nitrogen (Nmin) content) for estimating potato N status. Experiment was conducted in North West region of Croatia in 2011 growing season as randomized complete block design with four replications. Treatments were four N rates, 50, 100, 150 and 200 kg N ha-1. At pre-plant 50 kg N ha-1 was applied as NPK 7:20:30. Four side-dressed N rates, 0, 50, 100 and 150 kg N ha-1 were applied 45 days after planting (DAP). CCI and petiole NO3-N concentrations were measured at 58 and 98 (DAP), while soil Nmin content was measured before planting, 58 DAP, 98 DAP and after harvest. No significant differences in total tuber yield were determined between 100, 150 and 200 kg N ha-1 treatments. Significantly highest residual Nmin content (33.25 kg ha-1) after harvest was determined on plots fertilized with 200 kg N ha-1, indicating potential N leaching during fall and winter. Significant linear relationship between petiole N-NO3 and N treatments were determined at 58 DAP (R2=0.32) and 98 DAP (R2=0.75) and between CCI and N treatments at 98 DAP (R2=0.62). Significant linear relationship between soil Nmin content and N treatments were determined at 58 (R2=0.57) and 98 DAP (R2=0.56). Plant based tests are better correlated with N treatments at later growth stages in which applied N could be utilized by the crop

Evaluation of Soil and Plant Nitrogen Tests in Potato (Solanum tuberosum L.) Production

Nitrogen (N) management is critical in optimizing potato (Solanum tuberosum L.) yield and reducing environmental pollution. Several plant and soil based tests were proposed for assessment of N status in crop plants. Aim of this study was to evaluate the convenience of plant based tests (leaf chlorophyll content index (CCI) and petiole nitrate-nitrogen (NO3-N) concentrations) and soil based test (soil nitrogen (Nmin) content) for estimating potato N status. Experiment was conducted in North West region of Croatia in 2011 growing season as randomized complete block design with four replications. Treatments were four N rates, 50, 100, 150 and 200 kg N ha-1. At pre-plant 50 kg N ha-1 was applied as NPK 7:20:30. Four side-dressed N rates, 0, 50, 100 and 150 kg N ha-1 were applied 45 days after planting (DAP). CCI and petiole NO3-N concentrations were measured at 58 and 98 (DAP), while soil Nmin content was measured before planting, 58 DAP, 98 DAP and after harvest. No significant differences in total tuber yield were determined between 100, 150 and 200 kg N ha-1 treatments. Significantly highest residual Nmin content (33.25 kg ha-1) after harvest was determined on plots fertilized with 200 kg N ha-1, indicating potential N leaching during fall and winter. Significant linear relationship between petiole N-NO3 and N treatments were determined at 58 DAP (R2=0.32) and 98 DAP (R2=0.75) and between CCI and N treatments at 98 DAP (R2=0.62). Significant linear relationship between soil Nmin content and N treatments were determined at 58 (R2=0.57) and 98 DAP (R2=0.56). Plant based tests are better correlated with N treatments at later growth stages in which applied N could be utilized by the crop

Static Sensitivity of the Aerial Load Transport by Two Rotocopter Unmanned Aerial Vehicles

Aerial load transport by Unmanned Aerial Vehicles (UAVs) can be performed either using a single UAV or using a group of cooperative UAVs. The latter option is assumed more reliable, yet more demanding regarding the control and required power, than the former one. This article theoretically evaluates power consumption for aerial load transport by the use of two UAVs and compares it with the power consumption in case of a single UAV. In all treated cases, we assume a stationary level flight. For the stated comparison the theoretical model for aerial load transport by two identical UAVs is formulated. Generic flight characteristics and UAVs characteristics are prescribed, and corresponding solutions of the model evaluated. Independent parameters of the model are masses of the UAVs and the load, as well as flight velocity. Variables in the model are vertical and horizontal distances between the UAVs. The emphasis is put on the available instantaneous power and sensitivity to occasional wind gusts. We extract intervals of the model parameters for which each of the two UAVs is less loaded than a UAV which solitary carries a load. The sensitivity to wind gusts is lesser in configurations in which one UAV carries most of the load while the other provides the additionally needed instantaneous power

The quality of digested residue after anaerobic digestion of chicken manure

Cilj ovog rada je utvrditi kakvoću digestiranog ostatka nakon anaerobne digestije pilećeg gnoja. Istraživanja su provedena na postrojenju za proizvodnju bioplina u Republici Austriji anaerobnom digestijom pri 35°C. Istraživanja su obuhvatila kemijske analize (pH, elektroprovodljivost, suha tvar, žareni ostatak i gubitak žarenjem, organska tvar, C, N, P, K, Ca, Mg, Na, Mn, Zn, Cu, Fe, Pb, Cd) i bakteriološke pretrage uzoraka. Utvrđeno je da digestirani ostatak u svim uzorcima, koji su blago alkalni, sadrži niski udio suhe tvari od koje je oko 75% organska tvar. Biogeni elementi su u svim istraživanim uzorcima u umjerenoj koncentraciji, vrijednost teških metala nalazi se u dopuštenim granicama. Analizom N:P:K, vrijednosti biogenih elemenata i teških metala može se zaključiti da se digestirani ostatak nakon anaerobne digestije pilećeg gnoja može primijeniti u poljoprivrednoj proizvodnji, posebice u ratarstvu i travnjaštvu. U digestiranom ostatku su pronađeni mezofilni i termofilni mikroorganizmi, dok kriofilnih nije bilo. Ni u jednom uzorku nisu pronađene patogene bakterije. Sve izolirane bakterije potpuno su uništene nakon sterilizacije.The aim of this paper is to determine the quality of the digested residue after the process of anaerobic digestion by using chicken manure as a raw material. The research was conducted in the Republic of Austria in a plant for biogas production by means of anaerobic digestion at 35°C. The research comprised chemical analysis (pH, electrical conductivity, dry matter, burning residue, burning loss, organic matter, C, N, P, K, Ca, Mg, Na, Mn, Zn, Cu, Fe, Pb, Cd) and bacteriological tests of samples. .It was found that the digested residue in all of the samples, all of which were mildly alkaline, contained a low level of dry matter, 75% of which was organic matter. Biogenic elements in all investigated samples were present in moderate concentration; the values of heavy metals were within approved limits. The analysis of the N:P:K ratio, values of the biogenic elements and heavy metals, leads to the conclusion that the digested residues of chicken manure can be used in agricultural production, especially in plant production and grassland cultivation. Mesophilic and thermophilic microorganisms were found in the digested residue samples, but there were no criophilic microorganisms. Not one sample showed proof of pathogenic bacteria. All isolated bacteria were destroyed in the process of sterilization