INFLUENCE OF AGROTECHNOLOGICAL TECHNIQUES ON THE NITROGEN REGIME OF TYPICAL BLACK-SOIL

In the conditions of a southwest part of CBR Russian Federation increase in content of alkaline-hydrolyzable and nitric nitrogen and also strengthening of nitrification ability of the soil in the black-soil typical is caused, mainly, by application of the increasing doses of mineral fertilizers, a manure after-action, use of long-term herbs in a crop rotation as predecessors of a winter wheat, and application, mostly, of plowing in the system of the main processing of the soil. The most noticeable variation of contents in the soil of alkaline-hydrolyzable nitrogen is noted for a layer of earth 20-50 cm, and nitrification ability of the soil – in a layer of 0-20 cm. The most significant increase in its contents in a layer of earth of 0-20 cm at a combination of mineral fertilizers and a manure is characteristic of nitric nitrogen, especially on plowing. The tendency to increase in content of nitrates in underlying layers is caused by application of the raised dose of mineral fertilizers under a winter wheat – N120P120K120 N60 (saturation of 1 hectare of the crop rotation area in a grain-grass-tilled crop rotation of N84P124K124 and in a grain-tilled crop rotation of N120P124K124) and an after-action for the fourth year of 40 and 80 ton/hectare of a manure (saturation of 8 and 16 ton/hectare).

Ammonia loss from protected urea in soil under different irrigation depths

This study presents an evaluation of the viability of using protected urea under different irrigation depths to reduce nitrogen losses caused by the volatilization of ammonia (NH3) under the conditions of the Southwestern Amazon. The study was carried out at the Experimental Station of Embrapa Rondônia, in the municipality of Porto Velho, Rondônia State, Brazil. The experiment was conducted in a Red-Yellow Latosol and arranged in a 5 x 6 factorial design consisting of a combination of five treatments (N sources) with six irrigation depths. The sources of N were as follows: 1) urea (45.5% N); 2) urea (44.3% N) + 0.15% copper and 0.4% boron; 3) urea (45% N) + NBPT; 4) urea (43% N) + sulfur (1%); and 5) control (without N). The irrigation depths were 0, 5, 10, 15, 20, and 25 mm. The results showed that, regardless of the use of urease inhibitors, an irrigation depth of 10 mm is suitable for incorporating urea into the soil and stabilizing N losses from NH3 volatilization. NBPT is the most efficient inhibitor under nonirrigated conditions. All N sources promote increases in the concentrations of nitric and ammonia nitrogen in the soil. In the first 15 days after fertilizer application, the highest concentrations of ammonium were in the 0 - 10 cm and 10 - 20 cm soil layers, and NBPT showed the highest ammonium content compared to that of the other sources in the 0 - 10 cm layer. The nitric nitrogen content in the soil was slightly influenced by the irrigation depth in the first 15 days after fertilizer application. However, the ammonia nitrogen content decreased exponentially with the increase in irrigation depth due to the movement of ammonia in the soil.

Water Quality Development in the Semíč Stream

The aims of the work were to analyse selected quality indicators of a small water stream called Semíč and evaluate the results based on the valid legislation. Eight sampling profiles (SP) were selected and water was sampled four times a year in the period May 2013–April 2014. PH, conductivity, oxygen content and temperature were measured directly in the field. Subsequently, ferrum, nitric nitrogen, ammoniacal nitrogen, sulphates, chlorides, chemical oxygen demand tested using dichromate, total phosphorus, total nitrogen and manganese were analysed in the laboratory. Analyses of selected heavy metals – zinc, copper and aluminum – were carried out in spring 2014. The results were classified in compliance with Government Decree (GD) No. 61/2003 Coll., as amended, and Czech standard ČSN 75 7221. The results of the period 2013–2014 were compared with the results from 2002–2003 and 1992. The resulting concentrations of substances manifest considerable instability during the year, which can most likely be attributed to large changes in flow rates in different seasons. When comparing the values to older results, it can be concluded that the concentrations of a number of substances have decreased; by contrast, others have increased. An extreme increase in copper was detected, where the concentration exceeded the environmental quality standard several times.

Influence of Film Hole Diameter on Soil Water and Nitrogen Transport and Distribution Characteristic under Facilities Conditions

Through the facilities imitating experiment of film hole irrigation with nitric acid potassium solution under different film hole diameter, the content of soil water and nitric nitrogen was determined and analyzed in the different time after irrigation. The result shows: the content of soil water and nitric nitrogen under different film hole diameter reduced with time and achieved the maximum at the center while it is reverse away from film hole; soil water content decreased with the increase of film hole diameter at the same position while the nitric nitrogen content was opposite. The influence of the increase of film hole diameter on soil water and nitric nitrogen distribution is harm for plant to absorb water and nitric nitrogen, so it will be better to reduce the film hole diameter in the agriculture production. The result provided the proof for the sustainable development of facilities agriculture and evaluating the effect of nitrogen on environment.

Research on the Influence of Irrigation Amount on Dynamic Changes and Accumulation of Soil Nitric Nitrogen under Film Hole Irrigation

Through the experiment of different Irrigation Amounts with urea applied, the paper studied the influence of Irrigation Amounts on soil nitric nitrogen dynamical changes under film hole irrigation and the nitric nitrogen content of the growing period was determined. The result showed: different irrigation amount in the profiles being 3cm and 8cm away from the film hole center, it appeared nitric nitrogen accumulation peaks, increased the irrigation amount promoted the transformation of urea, increased the transformed nitric nitrogen content and distribution of nitric nitrate and the risk of nitric nitrate leaching. In the profiles being 3cm away from the film hole center, the nitric nitrogen accumulation peak significantly reduced at harvest stage, but it reduced in the profiles being 8cm away from the film hole center at milky stage. The milky stage was the maximum period when the corn uptook nitrogen at different irrigation amount. Increased irrigation amount lower the accumulation content of nitric nitrogen near the film hole center after harvest, and higher the accumulation content of nitric nitrogen far away from the film hole center. Above researches could provide the basis for rational fertilization of farmland and nitrate environmental impacts on assessment.

The Detection of Soil Parameters by Portable near Infrared Spectrometer

Soil test is the key-point for formulated fertilization. The traditional chemical analysis methods for estimating soil nutritional parameters were time-consuming. The present aims to use portable acousto-optic tunable filter (AOTF) near-infrared (NIR) spectrometer to measure soil parameters, thus provide basis for field analysis of soil quality. A total of 231 soil samples were collected, Partial least squares (PLS) was used to construct the calibration model between the NIR spectra and the reference values measure by standard chemical methods, including organic matter, pH, ammonium nitrogen, nitric nitrogen, and total kalium content. Results showed that the prediction of organic matter and pH had high correlation (R=0.8745, R=0.8594, respectively), the prediction of ammonium nitrogen and total kalium content were acceptable (SEP%=23.2595%, 10.1516%), and the calibration model for nitric nitrogen had the worst performance. The present study indicated that portable AOTF-NIR spectrometer could be used to measure the nutrient parameters of soil.

The Effects of Summer Green Manures on the ammonia and Nitrate Contents of soils Cropped for Winter Wheat. An Examination of the Woburn Green Manure Plots

1. The Woburn field experiments on wheat after green manures are briefly reviewed. Contrary to the original expectations the wheat was less good after two summer crops of tares than after two mustard crops. This result was obtained many times and in recent years the wheat yields were extremely low after both green manures.2. Regular soil analyses for nitrate and ammonia through 1928 and 1929 showed that the mean nitrate content was extremely low (1·2 parts of nitric nitrogen per million of soil). During the cold dry winter of 1928–9 the ammonia nitrogen was several times greater than the nitrate nitrogen.3. Further evidence of an acute nitrogen deficiency during the critical period for the wheat plant in May and June was afforded by the large responses to top dressings of sodium nitrate both in the 1929 and the 1930 wheat crop.

Biochemistry of water-logged soils: Part I. The effect of water-logging on the different forms of nitrogen, on the reaction, on the gaseous relationships, and on the bacterial flora

Rothamsted and Indian soils were water-logged in the absence of freshly decomposing organic matter.Nitrogen changes: Water-logging resulted in:(1) A distinct increase in the free and saline ammonia content.(2) A significant though only slight diminution in the nitric nitrogen.(3) No marked loss of ammonia by volatilisation or otherwise in the gaseous form: nor considerable variation in the nitrites: nor any observable diminution in the total nitrogen.Reaction: Water-logging resulted in an increase in alkalinity; the increase in pH value was closely correlated with the corresponding increase in ammonia.Gaseous relations: Water-logging resulted in:(1) No release of any soluble reducing matter capable of absorbing dissolved oxygen.(2) No appreciable carbon dioxide production.(3) An absorption of dissolved oxygen from the surface water. An equation has been worked out expressing the concentration gradient of dissolved oxygen with depth.Bacterial numbers:From bacterial counts on water-logged soils it was found that:(1) There was significant though slight decrease in bacterial numbers on Thornton's Agar.(2) Very few colonies were obtained by plating aerobically (and fewer still anaerobically) on Giltay's Agar. None of the organisms appearing on the plates brought about any nitrate reduction in soils.(3) The total counts on gelatine plates also showed some decrease. The numbers of gelatine-liquefiers on the other hand did not vary. There was no evidence to suggest that the increased production of ammonia was due to the activity of the gelatine-liquefiers.Agency responsible for ammonia formation:The results indicate that the formation of ammonia in water-logged soils is not due to biological action. It is suggested that the action is due to an enzyme.

Estimation of nitric nitrogen and total nitrogen in plant tissue extracts

Several methods for estimating nitrates by reduction to ammonia were examined. The error involved in the use of acid reducing agents in presence of amino groups was emphasised.A method based on the use of Devarda's alloy and magnesia is recommended.In the estimation of nitrates in plant extracts, etc., by this method an equal volume of rectified spirit is first added to the solution to precipitate colloidal matter. The precipitate is filtered off and an aliquot part of the filtrate containing the equivalent in nitrate nitrogen of about 0.1 gm. of KNO3 is distilled with steam for 45 minutes with 1 gm. of Devarda's alloy and ½ gm. of freshly ignited magnesia. A blank determination is essential, in which the same volume of filtrate is distilled for the same length of time with ½ gm. of magnesia.In Kjeldahl estimations in presence of nitrates, where the separate estimation of nitrates is not required, 2 c.c. of 25 per cent. NaOH may be substituted for the magnesia. Relatively this is very much less soda than Devarda recommends. The mixture in this case may be distilled directly for half-an-hour. The nitrates are thus reduced and the ammonia produced is collected before beginning the digestion with sulphuric acid.This work was carried out under the supervision of Mr F. W. Foreman to whom the author's best thanks are due for much valuable criticism and advice.