The first chapter of the monograph analyses the effect of precipitation and fertilization on yields and sugar content of sugar beet in the south of Poland. The data were obtained from the Station of Cultivar Evaluation in the south of Poland. Sugar beet was grown on soils of a very good and good wheat complex in the years of 1989-2005. Using the regression method, variation in the roots and foliage of the beet was studied, and so was the percentage content of sugar in the roots as dependent on the following factors: rainfall in the period of April-June, rainfall in July-September, fertilization with nitrogen, phosphorus and potassium, year of cultivation. The variation in sugar beet root yield caused by precipitation in April-June (in 140-240 mm range) was 30 dt ha^–1, the optimum value being 223 mm. Precipitation from July to September (in 150-310 mm range) modified the yield by 29 dt ha^–1. The highest yields were achieved with 310 mm rainfall. Fertilization with nitrogen and potassium in the range studied, i.e. 110-160 and 120-180 kg ha^–1 respectively, affected the beet root yield positively. Phosphorus doses in excess of 60 kg ha^–1 caused a decrease in sugar beet root yield. The yield of foliage increased with increasing precipitation both in the April-June and July-September periods, while precipitation in the first period modified the yield by 45 dt ha^-1 and by 130 dt ha^–1 in the second period. An increase in nitrogen and potassium fertilization caused a decrease in yield, while increased phosphorous fertilization induced increased yield of beet foliage. Sugar content in beet roots expressed in percentage reacted strongly to the increased precipitation. The increased precipitation in April-June resulted in 2.8 pp. fall in sugar content, and in the July-September period the fall was even 5.5 p.p. Sugar content increased as a result of potassium fertilization, and no changes could be found in the content caused by the increased nitrogen and phosphorus fertilization. In second chapter the analysis of sugar beet yields was continued but for the data from the eastern Poland. In this region sugar beet was cultivated on soils of a very good, good and faulty complex in the years 1991-2005. For the highest yields of roots and leaves the optimum set was as follows: rainfall April-June 119 mm (the lowest recorded) and rainfall July-September 266 mm (the highest recorded). The least favorable for root yield was the set with the highest rainfall in IV-VI (215 mm) accompanied by the lowest rainfall in VII-IX (124 mm), and for leaves - the lowest rainfall of both periods (119 mm and 124 mm). Sugar content was the highest when rainfall in the two periods was minimum, and the lowest when the rainfall approached maximum quantity. Next chapter characterizes frost occurrence space variability in two spring months, April and May, in the eastern Poland, in the period of 1988-2007. The analysis is based on the air temperature measurements at the height of 200 cm a.g.l., which were made in 17 meteorological stations. Average number of days with spring frosts in the eastern Poland increased towards the north (besides the area between Rzeszów and Zamość). In April there were six times more such days in Podlaska Lowland than in Sandomierz Hollow and the surroundings of Przemyśl (in May almost 2 days). In all meteorological stations 1-day frosts dominated. Most frequently mild frosts occurred (–2.0°C <= t_min <= 0.0°C), on average from 2.8 days in Tarnów to 6.0 days in Białystok. Since the end of the 80 s of the 20^th century, frosts most often have occurred in April with advanced high pressure system over the Central Europe and during arctic air masses advection from the northern sector. In May, frosts occurred often enough during a strong high appearance over the Scandinavian Peninsula, which determines arctic air masses advection from the north-east. The content of chapter four investigates the spatial patterns of Sum of Active Temperatures (SAT) and Growing Degree Days (GDD) in Poland, in the context of the general, thermal suitability of the region for vine cultivation. The warmest and the coldest years of the 1999-2008 period are spatially analyzed, and changes in spatial extend and location of areas with SAT and GDD conditions favorable for vine cultivation are discussed. The changes in spatial extend of the areas with favorable conditions in Poland are compared with other in the countries of Central Europe: Czech Republic, Slovakia and Hungary. In the most favorable years prevailing areas of Poland are suitable for vine growing (in terms of GDD; 57% of the country area) and sufficient for cultivation of very late ripening varieties (in terms of SAT). However, if the least favorable year is analyzed, when not enough heat can be cumulated, there are extensive areas which are of questionable suitability (63% of the country area) for vine cultivation or suitable only for frost and disease resistant varieties. The aim of the study in the next chapter was to evaluate the impact of weather conditions on the cultivation of maize grain in Poland. An analysis into the yield of maize was performed using statistical data from the Central Statistical Office between 1992 and 2008. An assessment of the impact of meteorological conditions on maize cultivation was performed using the weather-yield statistical model, with a weather yield index WI and partial weather index evaluating conditions during the vegetation of maize. For this analysis, meteorological data from Puławy (central Poland) between 1921 and 2009 were used. The result shows that the lowest variation in yield occurs in the south-eastern part of Poland, where there is more suitable climatic condition for maize cultivation than in the northern regions. This indicates that in the northern regions, a lack of heat is still a limiting factor for maize production. The analysis of weather maize yield index (WI) for Puławy between 1921 and 2009 shows an improved tendency of climatic condition for maize cultivation. There is an increase in the frequency of years with favorable conditions for maize cultivation with WI> 105, along with a decreasing number of years with adverse conditions with WI< 95. At the same time, years such as 2006 and 1994 were observed when a drought occurred in the spring and summer causing very low yields. An analysis of partial weather maize yield indexes shows that in recent years, weather changeability during June and July (WIJJ) has been increasing, whilst WIMJ and WIJA have had more stable and higher values than in previous years. The aim of the next chapter is to present the application of low-altitude remote sensing, used in order to assess the impact of drought on the state of crops in different regions of Poland. The chapter describes the elaborated methodology and analysis of aerial photographs. Spatial analysis was carried out using geographical information systems (GIS). The result of the study is the assessment of drought impact on crops in different regions of Poland. The analysis was carried out in areas affected by drought as well as the areas outside which have been designated on the basis of climatic water balance (CWB). The Drought Monitoring System for Poland (ADMS) is provided by the Institute of Soil Science and Plant Cultivation - National Research Institute (IUNG-PIB) on behalf of the Ministry of Agriculture and Rural Development. Chapter seven is devoted to the impact of climate changes on agriculture and possible adaptation activities in this field. Addressing the above problem 11 research teams established a consortium and prepared the project called ADAGIO. The purpose of the project was to gather information on potential threats to agriculture then, to determine adaptation activities and their diffusion. The main threats to agriculture in the future climatic conditions were identified as follows: - increase of frequency and intensity of occurrence of extreme climatic events; - intensification of problems connected with proper water supply for plants (increase of frequency of drought occurrences, bigger water drainage, decrease of ground water supply, etc.); - more intense development of native phyto pathogens and the expansion of thermophilic species. Considering the above mentioned threats the experts engaged in the implementation of the project in Poland proposed various adaptation activities. In their opinion climate changes will influence mainly water supplies and hydrological cycle therefore, the following measures should be taken: - increasing water supply available for farming; - increasing the efficiency of using water in agriculture; - decreasing the intake of water by plants. In the case of occurrence of new agrophages or intensification of the incidence of the native ones the following steps should be taken : - adapting the farming technology in order to limit the incidence of agrophages; - introducing efficient methods of preventing the development of new agrophages. In the case of extreme meteorological phenomena the most effective preventive measure seems to be the development of special insurances for farmers. Chapter eight addresses the problem of using weather derivatives in agriculture insurance. Progressing climate changes carry the risk of bad weather conditions. One might expect that in the future the number of disasters will increase together with the weather changeability in our country. Currently, when unfavorable weather conditions occur in a larger scale farmers usually expect support from the government. Usually in Polish conditions such help is granted however, it does not compensate for all losses. In the case of weather changes, in turn, the insurance seems of little efficiency. Modern economic instruments could help to avoid such situations. Polish traditional agriculture economy uses simple insurance systems with difficulty, can more complex solutions be applied here then? It may seem that implementing modern insurance solutions requires the engagement of people from banking or para-banking sector only. Surely the economist is the most important person in the process of management and development however, the estimate of weather risk and results of harmful phenomena belongs to agrometeorology. The following work is one of the few publications dealing with this problem and aims at explaining some basic issues at the same time emphasizing the necessity of undertaking concrete interdisciplinary research in this field. Particularly it explains the following issues: - definition and description of a weather derivative instrument, - instrument parameters; - types of weather indexes which can be applied in creating the instru-ments, - weather models and weather indexes as instrument parameters, - comparison of the insurance with weather derivatives, - policy and strategy of using weather derivatives, and particularly indicating the dangers resulting from using them by people who have little business experience. In the ninth chapter vegetation seasons, as well as spring and autumn ground frosts, were measured on the basis of twenty-four-hour mean and minimum air temperatures recorded from 1966 to 2005 in Mikołajki and Kętrzyn, situated in the Mazurskie Lakeland. Ground frost was defined as the minimum air temperature falling below 0°C in the vegetation season. The frequency of ground frost was established at 5 centimeters above the ground level, in particular spring and autumn months of the vegetation season. After ascertaining the mean dates of final spring ground frosts and initial autumn frosts, the duration of the frost-free period in the locations under analysis was established. The conclusions from the analysis of the data demonstrate that the duration of the vegetation season in the forty years under analysis was 212 days in Kętrzyn and 210 days in Mikołajki. The mean beginning of this season occurred on April 3rd in Kętrzyn, and on April 2nd in Mikołajki, while the end occurred on October 31st in Kętrzyn and October 30th in Mikołajki. The analysis of frequency of ground frost in particular months of the vegetation season showed that spring ground frost accounted for 70%, and autumn ground frost for 30%. The duration of the frost-free period was 135 days in Kętrzyn and 144 days in Mikołajki. The most days with ground frost in spring were recorded in April. With regard to autumn, the most days with ground frost were recorded in October. Next chapter contains research aimed at determining the impact of meteorological factors on the growth, development and yielding of Lupinus angustifolius of the Emir cultivar in 1987-2002. The research material concerning yield and weather conditions originated from three experimental stations for various assessment, located in the north-eastern Poland. The analyses used the multiple regression method, with the application of linear and quadratic functions, with step-wise selection of variables and the created equations were evaluated by means of R2 determination factor, adjusted R2 and a Cross Validation test, by determining R2pred. In the years of research, a clear diversity of weather factors was established, i.e. solar radiation, mean temperature and precipitation in individual periods of growth and development of blue lupine, which significantly affected the rate of yield, dates of phenological stages and the length of interphase periods. Only in the experimental station in Marianowo all created equations passed verification procedures with the application of the Cross Validation tests. Factors significantly affecting the yield of the cultivar included total solar radiation and precipitation in the sowing-germination period; these were quadratic relations, demonstrating the moderate response of the cultivar to these factors. Chapter eleven presents information on the quality verification of decision supporting system in agriculture. Agrometeorological information services are a valuable tool in the hands of farmers who have ample knowledge and experience to interpret the information included in this service properly. This information can help one to determine the dates for performing of the most important agricultural activities, which in turn, can significantly optimize the work of a farmer and at least help to minimize the losses incurred as a result of improperly chosen date of performing the procedure. Wielkopolska Region Internet Agrometeorological Information Service is a valuable source of agrometeorological information for the farmers in the region. It enjoys a growing popularity, which is confirmed by the number of visitors to the website. Since April 2005, more than 195,000 hits have been registered, which gives on average over 3,000 per month. Each day more than 100 users visit the website, which gives the evidence of high usefulness of the service. Chapter twelve confirms the observation that trends in air temperature changes in the north-eastern Poland follow the world pattern. It allowed using non-observational methods to forecast the incidence of pests by means of the so called degree-days which were analyzed considering the changes which occurred in the period of 1951-2005.The rate of these degree-days changes can be estimated to be close to even 205 DD per each 1.0°C average air temperature change when Tlow>0°C and 85 DD, when Tlow>10°C. These changes can have essential influence on the length of growing season, appearance of new plants and invertebrates (e.g. pests) as happened in other parts of Poland, as well as they can have an effect on physiology and phenology of different insects what have already been reported and many others predicted.