Mineral fertilizers prevented the hunger in the world

W referacie przypomniano historie chemii rolniczej jako działu chemii zajmującego się żywieniem roślin i żyznością gleby wraz z jej regulacją poprzez stosowanie nawozów. Omówiono związek pomiędzy ilością stosowanych nawozów i wielkością produkcji rolniczej służącej wyżywieniu człowieka. Z siły tego związku wynika, że nawożenie wraz z postępem biologicznym i ograniczaniem strat i ubytków plonów umożliwia przyrost produkcji żywności w tempie wyprzedzającym dynamiczny wzrost populacji ludzkiej. Tym samym czynnik ten może wyeliminować widmo głodu na ziemi. Dopływ składników mineralnych w formie nawozów powoduje jednak zaburzenia w cyklu obiegu tych składników z ujemnymi konsekwencjami dla wód podziemnych i nadziemnych oraz dla atmosfery.In this paper the history of agricultural chemistry, as a branch of chemistry dealing with plant nutrition and control of soil fertility by fertilizer application, has been briefly reminded. The relation between the amount of fertilizers and agricultural production, focused on human nutrition was discussed. This relation is very close and therefore fertilization along with plant breeding and plant protection makes possible increasing food production at a faster rate than the population growth and hence eliminates the spectre of hunger on the earth. However the huge input of nutrients upsets their natural cycles and poses the potential threats for waters and the atmosphere

Fertilization of plants in specialistic crop rotations and in the monoculture

В статье приводятся обсуждения по специфике удобрения в специализованных севооборотах и монокультурах. Основывались по необходимости на результатах исследований проводимых к классических севооборотах из-за скудости других данных. Специалистические удобрения и монокультуры создают больше затруднений в хозяйствовании ортью азотного удобрения в сравнении с класическими севооборотами. С другой стороны, гораздо проще в рассматриваемых севооборотах было известковение, а также фосфорное и калийное удобрение.Considerations on the fertilization specificity in specialistic crop rotations and in the monoculture are presented in the paper. The considerations were based necessarily, in view of insufficiency of other data, on the results of investigations carried out in classical crop rotations. Specialistic crop rotations and monocultures create great difficulties in the organic matter management. Also less is in them the nitrogen fertilization efficiency as compared with classical crop rotations. On the other hand, much simpler in the crop rotations under study are liming and fertilization with phosphorus and potassium

The perspectives for introduction of the method with 0,01 mol CaCl2 for pH determination in Poland

The investigations on possibility of soil testing in universal extract 0,01 mol/dm³ CaCl₂ have been conducted in 1995 - 1997 in Poland, Czech Republic. The Netherlands and Hungary in a frame of international project Copernicus. One of a basic parameter of soil fertility, which can be determined in calcium chloride extract is hydrogen cation concentration expressed as pH value. The purpose of investigations was to compare pH value determined in 0,01 mol/dm³ CaCl₂ and in 1 mol/dm³ KCl extract, used as a standard method in agrochemical investigations in most countries, as well as determination of critical values (the method calibration) of soil acidity ranges for „universal” method. In Poland about 1300 soil samples were analyzed by both methods. The pH values obtained in both compared extracts were highly correlated. Nevertheless pH values in 0,01 mol/dm³ CaCl₂ were significantly higher then in 1 mol/dm³ KCl in samples from very acidic, acidic and slightly acidic soils. In alkaline soils pH values by „universal” method are lower then by „standard” one. In neutral soils the results of both methods are equal. For the practical purposes the quadratic regression equation can be used for comparison of pH values determined by the both methods: pHCaCl₂ = 1.339 pHKCl- 0.051 pHKCl^2. As the practical purposes we understand calibration of the method with CaCl₂ and determination of optimal doses of lime on the basis of existing calibration for the method with potassium chloride

Measurement validation of numerical analysis of chosen EMC problem of low frequency

W artykule przedstawiono wyniki eksperymentalnej weryfikacji własnych procedur obliczeniowych do analizy trójwymiarowych pól elektrycznych niskiej częstotliwości generowanych w środowisku człowieka przez obiekty elektroenergetyczne. Powyższe procedury wykorzystują technikę hybrydową łączącą metodę elementów brzegowych z wariantem metody ładunków symulowanych zwanym tutaj metodą elementów liniowych. Uzyskano zadawalającą zgodność obliczeń z pomiarami.In the paper, the experimental validation of own software package for the 3D analysis of low - frequency electric field that is generated in human environment by power engineering objects is presented. In the above program, the hybrid technique combining the boundary element method and a version of charge simulation method named here the linear element method has been employed. Good convergence of numerical and measurement results has been observed

Potential role of phosphate buffering capacity of soils in fertilizer management strategies fitted to environmental goals

Sorption behavior and buffering of phosphorus (P) are important, both from an agricultural and an environmental point of view. The objectives of this study were to investigate: (1) the kinetics of the transfer of P from soil to soil solution and assessing P buffering capacity of soils (PBC), as a function of soil solution P; (2) the effect of PBC on soil P status fitted to environmental targets for water quality; (3) the effect of PBC on crop response. PBC was derived from the non-linear Q-I curve describing the time-dependent relationship between plant-available reserve of soil P (Q) versus soil solution P (I). The Q-I curve was determined in soil suspension using sorption and isotopic dilution methods for soil samples from French, Swedish, and Dutch field trials. Soils with low PBC values were more sensitive to the loss of P to the environment, required higher critical value in soil solution P to comply with P demand of maize, and had higher change in soil solution P per unit of P budget. In different soils, both the critical soil solution P for maize and the change in soil solution P per unit of P balance varied inversely with PBC. It is concluded that (1) PBC plays a key role in determining the agronomic and environmental threshold levels of available P content in the soils, and (2) PBC is a prerequisite for the development of more environmentally oriented fertilization recommendation systems