The most important aim of sustainable agriculture is to ensure our natural resources – such as soils – protection, which includes fertility preservation and the use of appropriate methods of cultivation.
If we want to get accurate information about the occurred changes, way and danger of changes, we should track the resupply and eff...ect of the mineral nutrients and the removed quantity of nutrients with the harvest.
Nitrogen is an essential element for living organisms and it is present in the soil mainly in organic form. In general only a low percentage of the total nitrogen content can be used directly by plants in the soil. The mineral nitrogen is incorporate by plants into our bodies. This inorganic nitrogen is produced by the transformation of organic contents through mineralization processes and it gets into the soil by fertilization. This is how nitrogen turnover occurs when mineral forms become organic and organic forms become mineral.
The objective of this publication was to introduce – through some element s of nitrogen turnover- how changing the properties of soil in a long term fertilization experiment.
We established that the fertilization is influenced the soil pH. With the increase of fertilization levels increased the acidity of the soil, maybe it is related with the number of nitrification bacteria. The fertilization and the rotation affected to the quantity of nitrate.
For crop production and agricultural production, the most important natural resource is the soil that can optionally renew. Paralelly with this, soil plays a major role in the geological and biological cycle of elements. As a result of the big (geological) and small (biological) element cycles, the elements and combines neccessary for organisms... can accumulate in the soil creating suitable living conditions for plants and other organisms. Soil is a heterogenous system both horizontally and vertically, and soil constituents show great variety in all the three dimensions, in addition, most of the parameters can also change between two examination dates. When talking about the factors influencing plant production, one should take into account this variation and heterogenity in time and space. When making fertilization recommendations, these factors should all be considered. In any consultation system, most of the mistakes and errors made are due to the unsatisfying soil testing and the negligence of soil heterogenity. In the practice of fertilization the biggest mistake is the improper soil sampling, then comes the methodical mistake of soil testing, which is followed by the inaccuracy of instrumental analysis and the subjectivity of result evaluation, but the latter two are negligible compared to the others. Under normal, i.e. production conditions, the quantity and distribution of nutrients in the soil are greatly dependent upon the applied technology, the amount and form of the applied natural and artificial fertilizers and the quality of fertilization.
Fertilization recommendations are needed because in the layer which is accessible for plant roots only a part of the nutrient content is available for plants in a specific production cycle. An illustration of this is that though the upper 1 m layer of an average chernozem soil contains more than 5000 kg N, 12000 kg K2O and 1500 kg P2O5 (form of expression mostly used in Hungary), the application of fertilizer doses which are just fractions of these quantities is essential. This is due to the fact that the available amount of the total nutrient content depends from the quality of soil, the environmental factors (the physical and chemical qualities of the soil) and the specific nutrient’s qualities (solubility, adsorption). Knowledge of these processes and the examination of the factors influencing the actual nutrient content are vital for working out a fertilization practice, which does not put more strain on the environment than neccessary.
All of the above mentioned should be considered when applying inputs in the fields. In a well-functioning practice that considers the economic and environmental conditions (unfortunately the present production and economic conditions do not enable an appropriate level and degree), three nutrients are supplemented generally (and were supplemented in the last decades): nitrogen, phosphorus, potassium.
Studying the nutrient balance of the Hungarian field production’s last hundred years, we can draw some interesting conclusions.
The nutrient balance became positive for nitrogen and potassium in the second half of the 1960’s, while for phosphorus it was positive from the first half of the 1960’s and this period lasted until the end of the 1980’s.
Neither before the 1960’s, nor since the 1990’s has the amount of nutrients supplemented in a specific year reached the amount of the nutrient uptake of the same year.
The level of nitrogen supply of a plant population can be quickly measured with non-destructive optical measurement devices and the differentiated determination of nitrogen shortage and the replenishment of nitrogen can also be carried out. The level of nitrogen supply is based on the fact that the chlorophyll content of crops is in close corre...lation with nitrogen content and that the amount of chlorophyll can be easily measured on the basis of the light absorption of chlorophyll molecules. The successfulness of optical measurements can be influenced by the change of weather parameters; therefore, it is important to know the correlations between measurement results and weather parameters when it comes to practical use.
The GreenSeeker Model 505 measurement device determines the relative chlorophyll content in the form of the Normalized Difference
Vegetation Index (NDVI) calculated on the basis of the intensity of the reflected red and infrared rays of light from the crop population. The measurements were performed in alfalfa population with 10 replications at five measurement heights and four measurement times. The weather parameters were measured by a weather station located in the middle of the alfalfa population and the correlations between the meteorological data and the NDVI values were examined. During the statistical evaluation of the results, it was established that the NDVI measurement is primarily influenced by the relative humidity of the air, secondly by air temperature and thirdly by wind speed. Relative humidity was in strong correlation with the NDVI values which were also influenced by the measurement height and time. Regression was not significant in the case of 20 cm measurement height, but the measurements above 40 cm height showed significant correlations. The correlation was shown to be strong at each measurement time, but the influence of humidity was the lowest at 11:00 and 14:00.
The impacts of climate change on crop production are increasingly noticeable. Extreme weather conditions – such as devastating droughts, which occur more often – have serious effects on crop conditions, thus damaging their defence ability against pathogens and pests. Therefore, in order to achieve high-quality and high yielding crops, it is... urgent to elaborate new technologies that improve general condition of crops and prevent development of nutrient diseases. Those crops which suffer from the lack of certain nutrients are more sensitive and their tolerance against diseases are decreased. Nitrogen – as the most influencing macronutrient in yield – is also essential in maintaining crop health. Nevertheless, due to the complicated processes in soil (such as leaching, denitrification), the utilization of nitrogen is not nearly complete, therefore nitrogen stabilizers may be needed to maximize this factor. The use of these stabilizers can be promising where plants with high nitrogen content are grown, although further experiments are needed in which impacts of nitrogen stabilizers on crop protection aspects are examined as well, since there is a close correlation between exaggerated nitrogen fertilizing and sensitivity to pests. During my research I am going to examine the combined effect of foliar fertilizer and nitrogen stabilizer on crop health. Furthermore, my goal is to find clear correlation between pathogens and the different technological variants of nutrition.
The research topic has timeliness, since the rational utilization and protection of the soil, besides the conservation of its diverse functions is part of the sustainable development. Research of the long-term experiments is esentially important, because it can model the term effects in the same place, under the same conditions. If we want to g...et accurate informations about the occured changes, way and danger of changes, we should track the resupply and effect of the mineral nutrients and the removed quantity of nutrients with the harvest. Nitrogen is an essential element for living organisms, it is present in the soil mainly in organic form. In general only only a low percentage of the total nitrogent content can be used directly by plants in the soil. This inorganic nitrogen is produced by the transformation of organic contents through mineralization processes and it get into the soil by the fertilization. The plants incorporote the mineral nitrogen into our bodies. This is how nitrogen turnover is realized when mineral forms become organic and organic forms become mineral.
The purpose of our paper is to make a literature before our research.
A greenhouse pot experiment was conducted to compare the effects of manure with different origin (horse, cattle), various bedding materials (straw, sawdust) and diverse doses (30 t ha-1, 60 t ha-1) and the impact of food waste compost on the plant growth and the available plant nutrient content of soil. The study was condu...cted on humic sandy soil and consisted of 9 treatments in a randomized complete block design with four replications. Spinach (Spinacia oleracea L.) was grown as the test crop. The treatments were: 1. unfertilized control; 2. horse manure with straw (30 t ha-1); 3. horse manure with sawdust (30 t ha-1); 4. cattle manure (30 t ha-1); 5 food waste compost (30 t ha-1); 6. horse manure with straw (60 t ha-1); 7. horse manure with sawdust (60 t ha-1); 8. cattle manure (60 t ha-1); 9. food waste compost (60 t ha-1). Plant growth was monitored for 4 weeks. Shoot and root weights per pot were measured, total biomass weight per pot were counted.
On the basis of the results it can be concluded, that among treatments the application of horse manure with straw enhanced spinach growth most significantly compared to other treatments and to the non-treated control, resulted the highest weights of leaves and roots of spinach. At the same time even small dose (30 t ha-1) of this fertilizer caused increased plant available nitrogen and phosphorus of soil and the higher dosage further increased these values. The horse manure with sawdust applied in lower dose did not alter the leaves and roots weights, but higher portion (60 t ha-1) caused significantly decreased plant biomass. The results proved that the bedding material may significantly alter the composition of manure and may change the plant nutrition effect of organic fertilizer. Cattle manure and food waste compost in both applied doses enhanced plant growth. Both fertilizers increased the plant available nitrogen forms and phosphorus content of soil, but cattle manure caused higher increase.
Plant-production is determined by many production-factors. Each of these factors became subject of research-works through the years, still we state, that studying their interaction is even more important. For studying these interactions we set up a potexperiment, within that the direct effect and the interactions of four factors was inspected:...soil, nitrogen-supply, nickel-loading and liming. Experiments were carried out on two soil types with extremely different characters: one was a chernozem soil with good fertility and buffering capacity, the other was a shifting sand soil with low humus-content and buffering capacity. Nitrogensupply and liming was added on two levels, while nickel on three within 12 combinations on each soil types. Plant production was cut two times within the vegetation period. The amount of production and dry matter was weighted, fractured and their element-content was measured by an ICP-detector.
Ca-content on the shifting sand soil was determined by all three factors, however the interaction between nickel-loading and liming was also significant. Nitrogen and liming increased Cauptake, that is due to appropriate nutrient-supply and improvement of a better pH-value. On the chernozem soil nitrogen and CaCO3 also increased the Ca-content. This is caused by a better nutrient supply and a higher amount of available Ca-ions.
On the shifting sand soil nickel content was increasing parallel to higher nitrogen-dosages. In presence of higher nickelamount the nickel-content of plants was also increasing, still according to liming, this increment was different. On the chernozem soil nitrogen a nickel increased Ni-uptake. However, liming also had a positive effect on Ni-content, that can be explained by the high amount on colloids in the soil, the adsorption of Ni-ions on them and in presence of liming material the replacement of Ca-and Ni-ions.
The potassium-content on the shifting sand soil was different in each liming-combination. In combinations without nickel the potassium-content of limed and not limed combinations was on the same level. In not limed combinations by adding nickel potassiumcontent was increasing, while in limed combinations no change was observed. On the chernozem soil by adding liming material the amount of uptaken potassium was decreasing, that is due to the antagonism between Ca- and K-ions.