Crop production,nitrogen recovery and water use efficiency in rice–wheat rotation as affected by non-flooded mulching cultivation (NFMC)

Non-flooded mulching cultivation (NFMC) for lowland rice, as a novel water-saving technique, has been practiced in many areas of China since the 1990s. However, the information on NFMC effects on crop production, nitrogen and water use in rice–wheat rotations is still limited. A field experiment using ¹⁵N-labeled urea was conducted to evaluate the impacts of NFMC on crop yield, fertilizer N recovery and water use efficiency in rice–wheat rotations. Plastic film mulching (PM), and wheat straw and plastic film double mulching (SPM) resulted in the same rice grain yield (7.2 t ha^–1) while wheat straw mulching (SM) and no mulching (NM) led to 5 and 10% yield reduction, compared with rice under traditional flooding (TF). In the rice–wheat rotation, crop productivity in PM, SM or SPM was comparable to that in TF but greater than in NM. Weed growth and its competition with rice for nitrogen were considered the main reason that led to yield decline in NM. Compared with TF, NFMC treatments did not obviously affect fertilizer N recoveries in plant and soil in both rice and wheat seasons. The total fertilizer N recoveries in crop, weed and soil in all treatments were only 39–44% in R–W rotations, suggesting that large N losses occurred following one basal N application for each growing season. Water use efficiency, however, was 56–75% greater in NFMC treatments than in TF treatment in the R–W rotation. The results revealed that NFMC (except NM) can produce comparable rice and wheat yields and obtain similar fertilizer N recovery as TF with much less water consumption.     

Rational firing cycle for converter lining

Conclusions The firing of linings in converters made from tar-bonded refractories should be done with portion loading of coke in amounts of 200 kg, with careful control of the oxygen consumption. The temperature relationship with the rate of discharge of volatiles from the tar should be taken into account.The rational temperature cycle for firing tarred dolomite linings in converters is: raising the temperature to 300–350°C at a rate of 30–40 deg/min, from 300–350 to 700–800°C at a rate of 1.5–2.0 deg/min, and from 700–800° to 1000°C at a rate of 15–20 deg/min. The total firing time is 4.5 h, the coke consumption 2.8 ton, and the oxygen consumption about 4500 m³. The use of this cycle allows excellent preparation of the lining for service, practically excluding loss of brick due to spalling, and increasing the resistance of the lining.Translated from Ogneupory, No. 6, pp. 21–27, June, 1971.     

Thermal operating conditions of an RKZ-4-0-Il furnace in melting corundum

Conclusions Investigations were conducted of the thermal operating conditions of an RKZ-4-0-ll furnace, and complete energy balances of its operation were calculated. The primary energy losses occur through the gas exhaust system (9–17%), the furnace roof (14–25%), and the side walls and bottom of the furnace (13–36%).To increase the efficiency of the installation it is necessary to optimize the gas exhaust conditions and the cooling water consumption with simultaneous solution of the problem of utilization of the thermal losses and to convert the furnace to single tappings of larger volumes of molten material (or to increase the rate of tappings).Translated from Ogneupory, No. 1, pp. 48–53, January, 1984.     

Some features of spinning viscose fibre and yarns into zinc-free precipitation baths

Conclusions The use of low-acid, bicomponent precipitation baths with additions of urea to the viscose, or also of baths containing such polyvalent metals as aluminum or magnesium, which permits one to obtain a fibre with improved physico-mechanical indices and fatigue properties at the spinning speeds which have been adopted in manufacturing is very promising in spinning viscose fibres and yarns into zinc-free precipitation baths.Replacement of the expensive zinc sulfate by cheaper reagents and the reduction in sulfuric acid consumption upon use of less concentrated precipitation baths permit one to obtain an economical advantage and eliminate the possibility of contaminating the water basin with toxic zinc.Translated from Khimicheskie Volokna, No. 2, pp. 51–53, March–April, 1988.     

Reducing water consumption in washing viscose textile yarn in packages

Conclusions The effect of specific flow rate of soft water on the intensity and extent of wash-out of viscose textile yarn in packages has been studied.A process of washing yarn on OK-I machines with a reduced consumption of soft water — down to 60 m³ per metric ton of yarn — has been developed and carried out in manufacturing.Translated from Khimicheskie Volokna, No. 1, pp. 44–45, January–February, 1987.     

Removal of lubricants from effluents from Capron production

Conclusions 1. The composition of water obtained after removing lubricant by the aluminate method and further softening scarcely differs at all from that of softened water and can be re-used in industry.2. The flowsheet described enables a closed purification cycle to be built and finishing waste waters to be used; it enables the water consumption for fibre washing to be reduced, the discharge of toxic caprolactam to reservoirs to be discontinued and caprolactam to be recycled.Kiev Combine. Translated from Khimicheskie Volokna, No. 4, pp. 76–78, July–August, 1969.     

Optimization of the water preparation regime in water-softening stations of branch plants

Conclusions As a result of following the operation of water-softening stations, recommendations have been developed for increasing their efficiency.Realization of the proposed measures will make it possible to cut down the consumption of reagents and water for inherent needs of the water-softening stations, and to reduce the salt content of the wastewater. Thereupon, the economic benefit will be 25,000–50,000 rubles/year for a typical water-softening station.Translated from Khimicheskie Volokna, No. 1, pp. 44–46, January–February, 1984.     

Expenditure of heat energy in drying viscose textile yarns

Conclusions It has been found that the thermogravimetric analysis method is applicable for determining the expenditure of thermal energy in desorbing moisture from hydrocellulose textile fibres; it gives a quantitative evaluation of the fractional composition of the water sorbed by the yarns and of its bonding energy with the yarn matrix.The change in consumption of heat energy at various extents of drying of freshly-spun viscose textile yarns has been studied.It has been found that extensive drying of yarns, to a moisture content significantly lower than the conditioned values, that is, overdrying, requires elevated, unjustified expenditures of heat energy.Translated from Khimicheskie Volokna, No. 4, pp. 43–44, July–August, 1987.     

Yield,water use and nitrogen uptake for different water and N levels in winter wheat

In an effort to establish an optimum combination of water and nitrogen for winter wheat a field investigation was carried out on a coarse loamy sand soil during 1984–85 and 1985–86 to assess effects of irrigation regime (IR) and N application on yield, water use and N uptake. The treatments compromised all combinations of three irrigation regimes (IR) based on ratios of irrigation water to cumulative pan evaporation viz.1.2 (I-1), 0.9 (I-2) and 0.6 (I-3) and four rates of N, viz. 0, 60, 120 and 180 kg ha^–1. Grain yield increased with increase in frequency of irrigation. In spite of wide differences in weather during the two years, scheduling of irrigation at IW/CPE = 1.2 gave the highest wheat yield on the coarse-textured soil. During 1984–85, the rainless year, grain yield under I-1 was 20 and 32 per cent higher than I-2 and I-3, respectively. With increasing N rate the yield and water use efficiency increased progressively upto 180 kg N under I-1 and upto 120 kg N ha^–1 under I-2 and I-3 regimes. During 1985–86, the wet year, grain yield response to IR was relatively low. Irrespective of IR, yield increased progressively upto 180 kg N ha^–1 during the wet year. Irrigation water regimes and N application also influenced leaf area index and root growth of wheat. The yield of unfertilized wheat was relatively less affected by seasonal rainfall and IR.Both N uptake and grain yield of wheat were found to increase linearly with increase in water use. Water use efficiency was highest under I-1 regime at all levels of N in the dry season of 1984–85 and under I-3 regime in the wet season of 1985–86. Increase in N uptake with increasing N rates was significantly higher under I-1 than I-2 and I-3 regimes. The N use efficiency being maximum at 60 kg N ha^–1, decreased at higher N levels irrespective of IR.     

Experience gained in increasing the durability of steel-teeming ladle linings at the West Siberian Metallurgical Works

Conclusions The use of 70–75% of silica artifacts to line steel-teeming ladles, accompanied by routine hot patchings, has permitted an increase in the lining durability by from four to five melts.With an increase in the ladle throughput from 1–2 to 6–7 melts per day, accompanied by hot patchings, the maximal lining durability was 37 melts (average 28 melts) and the refractory consumption was reduced by 2.1 kg/ton of steel.The saving obtained by the use of a silica lining was 332,200 rubles.Translated from Ogneupory, No. 7, pp. 33–35, July, 1980.     

Modifications in the process of preparing polypropylene twine for agriculture

Conclusions A process for preparation of agricultural twine from profiled polypropylene film has been developed and introduced into manufacturing at the Balakovskii Khimvolokno PO. The twine has a linear density of 2200–2400 tex, a breaking load not less than 980 N, and an elongation at break of not over 16%.The use of this twine has made it possible for organizations of the State Committee on Agricultural Technology to reduce the specific consumption of twine in pressing fodder by a factor of two as compared with the consumption of twine having a linear density of 3000 tex.The authors express their thanks to G. D. Litovchenko and E. P. Myasoedov for help in this work.Translated from Khimicheskie Volokna, No. 1, pp. 20–21, January–February, 1986.     

Condensation of caprolactam vapor in the synthesis of polycaproamide under vacuum

Conclusions It is recommended to use a mixture based on caprolactam and benzoic acid, with small amounts of added water, for the low-temperature condensation of CL vapor in the synthesis of PCA under vacuum.Condensation of CL vapor at a temperature below 333°K permits one to return 7–9 kg of CL per ton of polymer to the technological cycle.The use of low-temperature condensation permits one to reduce the concentration factor of lactam in water from the steam-ejector pumps by a factor of more than 30 and to effect water recycling.Translated from Khimicheskie Volokna, No. 5, pp. 23–24, September–October, 1983.     

Global use and trade of feedstuffs and consequences for the nitrogen cycle

This paper presents an estimate of the amount of nitrogen involved in the use and trade of feedstuffs for a number of world regions. Livestock production has shown a steady increase world-wide as a result of an annual increase of 1.4% in developing countries and 0.9% in developed countries during the period 1960–1990. Particularly in developing countries, the strong growth of animal production and a tendency towards decreasing reliance on grazing and increasing importance of fodder crops and feed concentrates, cause a major increase in the consumption of feedstuffs. Cereals form the major feedstuff world-wide. The current global use of cereals for feed is about 30% of the total use (57% in developed countries and 17% in developing countries). Net trade of cereals and other feedstuffs represents 4–8 Tg N per year, which is only 4–7% of the total N consumption by the world's animal population. A strong growth of the per capita food consumption, a relative increase of meat consumption, coupled with a strong population growth, may cause a strong increase of the net trade of cereals. In particular the countries of the Middle East, North Africa and China may become important importers of cereals. In future, the N transport between regions in the form of feedstuffs may become an important component in the global N cycle.     

Electrochemical removal of dissolved oxygen from water

A new electrochemical method of oxygen removal has been developed in which oxygen-rich water flows through the three-dimensional cathode of an electrochemical cell. The cathode removes the dissolved oxygen from the water and the anode releases it as gas into the air. By this technique oxygen levels lower than 3 µmg oxygen per kilogram of water can be reached (starting level: oxygen-saturated water, 8000 µg kg^–1). This result is better than that obtained by physical methods and is equal to those obtained by chemical methods. Compared with conventional methods, the advantages of the electrochemical method are high effIciency, low energy consumption and avoidance of the use of toxic deoxygenation chemicals.     

Production and use of low-fired stopper tubes

Conclusions Fireclay stopper tubes made by semidry pressing and fired at 800–900° C are suitable for service in steel casting ladles in the open-hearth departments of NTMK. Compared with ordinary low-fired stopper tubes they are more spalling resistant and less thermal conducting.The use of low-fired stopper tubes is economical owing to the reduction in loss and fuel consumption in firing.Translated from Ogneupory, No. 5, pp. 8–10, May 1967.     

Tests of a filter with a filtering layer of synthetic fibre waste

Conclusions A fibre filter ensures thorough clean-up of wastewater from viscose fibre manufacturing from suspended particles and dispersed sulfur.The high rate of filtration of the fibre filter (27 m/h), reduction in water consumption, and 30% reduction in time for washing the filter show that economy can be achieved by replacing the quartz filter with a fibre one in the scheme of wastewater clean-up.Translated from Khimicheskie Volokna, No. 5, pp. 49–50, September–October, 1983.     

Electrolytic manganese metal from chloride electrolytes. I. Study of deposition conditions

Results of beaker scale and large laboratory scale experiments on the deposition of manganese from chloride electrolytes are reported for conditions where chlorine is the secondary anode product.Manganese concentration in the catholyte was found to be the most significant variable, with higher manganese levels (to 33 g Mn l^–1) resulting in higher current efficiency (65–70%) and lower power consumption (5.5 kWh kg^–1). Temperature (30–60°C) and current density (1.0–2.0 kAm^–2) had opposing effects on current efficiency and power consumption. In the ranges studied, lower temperatures and higher current densities gave rise to increases in current efficiency and power consumption.The literature on the electrowinning of manganese from chloride electrolytes is reviewed and the anomalies in previous reports discussed.     

Effect of surfactant concentration on the stacking modes of organo-silylated layered double hydroxides

The effects of the surfactant concentration on the structure, morphology and thermal property of silylated hydrotalcites have been investigated. By in-situ coprecipitation, the surfaces of layered double hydroxides (LDHs) have been modified by using 3-aminopropyltriethoxysilane (APTS) and anionic surfactant, Na-dodecylsulfate (SDS). Two different stacking modes in the resultant materials were detected by X-ray diffraction (XRD). One has an identical structure of LDHs, in which the SDS and APTS only bond to the outside surfaces and plate edges of LDH. The other is with enlarged interlayer distance, in which SDS and APTS combined with the inside surfaces of LDH. With the increased loading of SDS and APTS, the surface of the modified LDH appeared rough as observed in the transmission electron microscopy (TEM) images. The attenuated total reflection Fourier-transform infrared (ATR FTIR) spectra of the silylated hydrotalcites showed a series of bands attributed to –NH₂ and Si–O–M (M = Mg and Al), proving that APTS has successfully been grafted onto LDH. The thermogravimetric curves (TG) showed that the silane grafted samples have less –OH concentration and less interlayer water, as a result of the –OH consumption during the condensation reaction between Si–OH and –OH on LDH surface. These nanomaterials are of potential applications including clay-based nanocomposites, adsorbents for removal of organic contaminants from water and flame retardant materials.     

Guniting of the lining of furnaces for heating of steel billets

Conclusions A method of guniting of the rolling mill heating furnaces during shutdown for cold repairs and with a lining surface temperature of 900–1200°C was developed with the use of guniting powders produced by industry of aluminosilicate and basic compositions with hydraulic and silicate binders. The introduction of composite guniting of the lining in the cold and hot conditions makes it possible to reduce the volume of lining repair work by 10–15 m³ per furnace and the consumption of brick refractories by 0.1 kg per ton of steel rolled and to increase the life of the lining by 1.5–2.0 times.Translated from Ogneupory, No. 4, pp. 48–51, April, 1988.     

Application of a solid polymer electrolyte reactor to remove nitrate ions from wastewater

The application of a zero gap solid polymer electrolyte (ZGSPE) reactor to deminealise nitrate ions in aqueous wastewater is described. The following performance data for the reduction of a simulated alkaline solution with 16.1 mM nitrate ions under galvanostatic operation were achieved: percentage of nitrate removal up to 100%, rates of nitrate removal up to 0.057 mol cm^–2 h^–1, space–time yields up to 5.4 kg m^–3 h^–1, current efficiencies up to 24.5% and energy consumption between 40.1 and 63.3 kW h kg^–1. The beneficial effects of higher temperatures and nitrate ion concentrations and using a suitable electrolyte flow rate on the activity, selectivity and efficiency is reported. PdRh_1.5/Ti mini-mesh electrode used in the study was stable after a cumulative use of 1000 h.