Effect of nitrogen rate and forecrop on nitrogen use efficiency in winter wheat (Triticum aestivum)

ArticleApplication of plant nutrient is one of the most important measures increasing grain yield and yield quality. Excessive application of nitrogen fertilizers leads to nitrogen leaching and it affects the quality of groundwater and surface water. The objective of this research was to evaluate the effect of nitrogen fertilizer rate on nitrogen use efficiency in winter wheat after two forecrops. The experiment was conducted at the Research and Study farm ‘Pēterlauki’ of Latvia University of Life Sciences and Technologies (56° 30.658’ N and 23° 41.580’ E) in four growing seasons: 2014/2015, 2015/2016, 2016/2017 and 2017/2018. Researched factors were crop rotation (wheat/wheat and oilseed rape (Brassica napus ssp. oleifera/wheat) and five nitrogen fertilizer rates (kg ha-1 ): N0 or control, N60, N120(90+30), N180(90+60+30) and N240(120+60+60). Nitrogen fertilizer affected winter wheat grain yield significantly (P < 0.001) and average grain yield increased significantly (P < 0.049) until nitrogen rate N180. But analyzing it after each forecrop separately, yield increased significantly (P < 0.05) until N120 after both forecrops. Nitrogen fertilizer affected nitrogen use efficiency (NUE), nitrogen uptake efficiency (NUpE), nitrogen utilization efficiency (NUtE) and protein content significantly (P < 0.001). When increasing nitrogen fertilizer rate NUE, NUpE and NUtE decreased, and higher results were observed at the lowest nitrogen rates. Increased nitrogen fertilizer rate also increased crude protein content in grain, and for bread baking suitable grain was obtained only with the highest N rate: N 240. Forecrop did not affect winter wheat grain yield, however, it affected NUtE (P < 0.01), NUE (P < 0.001) and nitrogen harvesting index (P < 0.001) significantly; higher results were observed when wheat was grown after wheat

Impact of faba bean (Vicia faba L.) cultivation on soil microbiological activity

ArticleFaba bean (Vicia faba L.) is widely grown not only as an important protein source for food and feed, but as a component in different cropping systems to improve soil quality. Beans are grown using different soil management practices, moreover, legume seeds often are inoculated before sowing. Microorganisms, introduced in the soil as an inoculum, affect not only inoculated plants, but these microorganisms can remain in the soil for the next growing season and can also affect the subsequent crops. Seed inoculation can stimulate production of root exudates as well as change microbial diversity and structure. The aim of the present study was to estimate the soil microbiological activity in soils where faba beans were cultivated with different rhizobia inoculants obtained from collection of Latvia University of Life Sciences and Technologies. Another trial was established where faba beans were included in different crop rotations under two tillage systems. During both trials, soil microbiological activity was analysed. Soil respiration intensity was measured by changes of carbon dioxide. Soil enzymatic activity was assessed by dehydrogenase activity and fluorescein diacetate (FDA) hydrolysis intensity. The total number of bacteria, fungi and rhizobia was expressed as colony forming units (CFU) g-1 dry soil. Soil microbiological activity depended on the cultivated crop and the crop rotation. Faba bean inoculation method had less impact on the ratio between analysed microorganism groups than on the activity of soil enzymes

Nitrogen Fertilizer Use Efficiency in Winter Wheat Trials

The field experiments with ten diverse varieties of winter wheat were laid down according to uniform scheme during 2001 – 2002 at three locations having different soils and agroclimatic conditions: study and research farm “Pēterlauki” of the Latvia University of Agriculture on sod – calcareous medium loam soils, humus content 19 – 21 g kg-1 of soil; at the Stende Plant Breeding Station on sod – podzolio soils, humus content 18 - 19 g kg-1 of soil and at Latgale Science Centre in Viļāni on humus – podzolic gley soils, humus content 65 – 95 g kg-1 of soil. There was observed sharp variation in meteorological conditions during experimental years and quite variable weather conditions between the trial sites. The average results obtained in the experiments suggest that stable increase of winter wheat grain yield was reached increasing fertilizer N rates from N90 to N120 (split application) thus ensuring grain yield increase 1 to 20 kg per 1 kg N applied. The crude protein yield 2,8 – 3,47 kg per 1 kg N applied was obtained from trial plots at the study and research farm “Pēterlauki” and at the Stende Plant Breeding Station. The mineral N use efficiency was considerably lower in humus – rich soils in Viļāni. The increase of fertilizer N rate up to N180 (split application) resulted in gradual decrease of nitrogen use efficiency, and utilization coefficient was to a great extent depended on meteorological conditions during vegetation period

Survival of outborns with congenital diaphragmatic hernia: the role of protective ventilation, early presentation and transport distance: a retrospective cohort study

BACKGROUND: Congenital diaphragmatic hernia (CDH) is a congenital malformation associated with life-threatening pulmonary dysfunction and high neonatal mortality. Outcomes are improved with protective ventilation, less severe pulmonary pathology, and the proximity of the treating center to the site of delivery. The major CDH treatment center in Croatia lacks a maternity ward, thus all CDH patients are transferred from local Zagreb hospitals or remote areas (outborns). In 2000 this center adopted protective ventilation for CDH management. In the present study we assess the roles of protective ventilation, transport distance, and severity of pulmonary pathology on survival of neonates with CDH. ----- METHODS: The study was divided into Epoch I, (1990-1999, traditional ventilation to achieve normocapnia), and Epoch II, (2000-2014, protective ventilation with permissive hypercapnia). Patients were categorized by transfer distance (local hospital or remote locations) and by acuity of respiratory distress after delivery (early presentation-occurring at birth, or late presentation, ≥ 6 h after delivery). Survival between epochs, types of transfers, and acuity of presentation were assessed. An additional analysis was assessed for the potential association between survival and end-capillary blood CO2 (PcCO2), an indirect measure of pulmonary pathology. ----- RESULTS: There were 83 neonates, 26 in Epoch I, and 57 in Epoch II. In Epoch I 11 patients (42%) survived, and in Epoch II 38 (67%) (P = 0.039). Survival with early presentation (N = 63) was 48 % and with late presentation 95% (P <0.001). Among early presentation, survival was higher in Epoch II vs. Epoch I (57% vs. 26%, P = 0.031). From multiple logistic regression analysis restricted to neonates with early presentation and adjusting for severity of disease, survival was improved in Epoch II (OR 4.8, 95%CI 1.3-18.0, P = 0.019). Survival was unrelated to distance of transfer but improved with lower partial pressure of PcCO2 on admission (OR 1.16, 95%CI 1.01-1.33 per 5 mmHg decrease, P = 0.031). ----- CONCLUSIONS: The introduction of protective ventilation was associated with improved survival in neonates with early presentation. Survival did not differ between local and remote transfers, but primarily depended on severity of pulmonary pathology as inferred from admission capillary PcCO2

Effect of nitrogen fertilization on winter wheat yield and yield quality

ArticleWheat ( Triticum aestivum L.) is the most common cereal, which is grown in Latvia. Nowadays, farmers are trying to get high grain yields in line with food quality, at the same time trying to minimize production cos ts and to use environmentally friendly technologies. The objective of this experiment was to clarify the impact of nitrogen fertilization on winter wheat yield and yield quality under two soil tillage systems and after two forecrops. Trials were conducted at the Research and Study farm ‘Peterlauki’ of Latvia University of Agriculture (56 ° 30.658 ’ N and 23 ° 41.580 ’ E). Researched factors were (1) crop rotation (wheat/wheat and oilseed rape ( Brassica napus ssp. oleifera )/wheat), (2) soil tillage (traditional soil tillage with mould - board ploughing at a depth of 22 – 24 cm and reduced soil tillage with disc harrowing at a depth below 10 cm ), (3) nitrogen fertilizer rate (altogether eight rates: N0 or control, N60, N90, N120(90+30), N15 0 (90+60) , N180 (90+60+30) , N210 (90+70+50) , and N240 (120+60+60)), and (4) conditions of the growing seasons 2014/2015, 2015/2016 and 2016/2017. The results indicate that winter wheat yield has been significantly affected by soil tillage, nitrogen fertilizer rate ( p < 0.001) and forecrop ( p < 0.05). Three - year research confirmed significant yield increase until the nitrogen fertilizer rate N180. Significantly higher average grain yield was obtained under traditional soil tillage. Nitrogen fertilizer affected significantly all tested yield quality indicators ( p < 0.001) . Increase of nitrogen fertilizer rate secured significant increase of winter wheat grain quality indices, except starch content, after both forecrops and in both soil tillage variants. Values of yield quality indicators increased significantly enhancing N - rate from N150 up to N 210

Intracranial tumors in adult population of the Varaždin County (Croatia) 1996-2004: a population-based retrospective incidence study

Aim: To estimate the incidence of intracranial tumors in the adult population of the Varazdin County, Croatia, for the 1996-2004 period. - - - - - Methods: Setting: Varazdin County General Hospital and four university hospitals in Zagreb, the capital of Croatia. Study period: January 1, 1996 to December 31, 2004. Incident patients: county residents admitted for newly diagnosed intracranial tumors according to the WHO diagnostic criteria. Demographic data were extracted from the 2001 Croatian census. Incidence rates (IRs) per 100,000 person-years (p-y) and annual IRs (per 100,000 persons) were determined and compared as incidence rate ratios (IRRs) with 95% CI. - - - - - Results: For primary intracranial tumors (PITs), IR was 12.1/100,000 p-y (95% CI: 10.3-14.2), comparable in men and women. The highest incidence was recorded for glioblastoma (IR 4.8, 3.7-6.2) and meningioma (IR 3.1, 2.2-4.2). The incidence of PIT was somewhat greater than that of metastatic tumors (IRR 1.58, 95% CI: 1.22-2.05, P = 40 vs. population aged <= 39 (all IRRs with 95% CI greater than 1, P < 0.05 or < 0.001), comparable in men and women. Women were somewhat older than men at the time of diagnosis of PIT: median difference -6 years (95.1% CI: -10 to -1, P < 0.05). Annual IRs for all these tumor categories showed increasing trends over the study period. - - - - - Conclusion: Overall, there was an increasing trend in the incidence of primary intracranial tumors in the Varazdin County. Data did not allow estimation for most of the specific tumor types

Evaluation of effective nucleon-nucleon potential and description of α-cluster type nuclei in restricted dynamics approach

The application of the Restricted Dynamics Approach in nuclear theory, based on the approximate solution of many-particle Schrödinger equation, which accounts for all conservation laws in many-nucleon system, is discussed. The Strictly Restricted Dynamics Model is used for the evaluation of binding energies, level schemes, E2 and Ml transition probabilities as well as the electric quadrupole and magnetic dipole momenta of light a-cluster type nuclei in the region 4 ≤ A ≤ 40. The parameters of effective nucleonnucleon interaction potential are evaluated from the ground state binding energies of doubly magic nuclei 4He, 16O and 40Ca

Research Activities of the Latest Decades in the Faculty of Agriculture

Abstract. Research activities in the Faculty of Agriculture comprise three main specialisation lines: Field Crops, Horticulture and Animal Science which are associated with other subjects like Soil Science and Management, Grassland, Crops Breeding, Plant and Animal Biology, Plant Protection, Weed Science and Fertiliser Use etc. Traditionally our research strategy is to be engaged in two directions: 1) to provide intellectual services and sound scientific basis for Latvia primary agricultural sector and 2) to incorporate into the interdisciplinary research sector on Latvia, the EU and global scale. Brief overview of activities and results within these spheres is given related to the period starting from 1990 up to now with relevant ideas and propositions for the future prospects. Interinstitutional and international research cooperation and possibility to provide knowledge and services for society are the main pillars of our future development. Key words: Latvia agriculture, research priorities, agricultural research. Introduction In 1992, two faculties -Faculty of Agronomy and Faculty of Zootechnics -were merged and Faculty of Agriculture was established. Three main specialisation lines Field Crops, Horticulture and Animal Science which are associated with other subjects like Soil Science and Management, Plant Biology, Plant Protection, Weed Science, Fertiliser Use were organised within the Faculty. Therefore the main field of research and education was to provide students with competence in the primary agricultural production sectorcrop and animal farming. At the same time some part of research activities were related to the environmental aspects, forestry and other sectors through cooperation with other faculties of Latvia University of Agriculture (LLU), research institutions in Latvia and abroad as well. This time was also very important due to the active start of international cooperation. Number of our staff and post-graduate students has a possibility to be involved in different workshops, to attend conferences, and to participate in study courses and short-term on-site training programmes. Besides a number of foreign researchers have visited the Faculty and contributed to our research and teaching activities, and promoted establishment of good professional relationship. It has stimulated our research activities, staff involvement in international research programmes, and expert groups, and has given a good basis for long-term cooperation with international partners. Our research strategy is to follow the two lines: 1) to provide intellectual services and sound scientific basis for Latvia agricultural sector and 2) to incorporate into the interdisciplinary research sector on Latvia, the EU and global scale. Therefore our contribution and achievements may vary and sometimes it is not easy to determine where our efforts have been more effective either for implementation of small and very practice-oriented tasks or participation in large scale international projects. In general, the latter is good for knowledge and capacity building but the first one -for acknowledgement of our mission and importance for Latvian society. The period starting from 1990 up to now has been rich in many research-related activities; still it also reflected radical changes going on in economy and social sphere of this country. In the present article we would like to summarise only the main activities and changes, and also to discuss the results that could be important for future developments. The layout of article reflects the main research lines traditionally existing in our Faculty