Large Amounts Of Fertilizers Research Articles

Experimental and modeling study on Cr(VI) transfer from soil into surface runoff

With the development of modern agriculture, large amount of fertilizer and pesticide outflow from farming land causes great waste and serious pollution to surface water and groundwater, and threatens ecological environment and even human life. In this paper, laboratory experiments are conducted to simulate adsorbed Cr(VI) transfer from soil into runoff. A two-layer in-mixing analytical model is applied to analyze laboratory experimental results. A data assimilation (DA) method via the ensemble Kalman filter (EnKF) is used to update parameters and improve modeling results. In comparison with the experimental data, DA updated modeling results are much better than those without the updating. To make predictions better, the inflation method with a constant inflation factor via DA method was used to compensate the fast decrease of ensemble spread partially related to filter inbreeding. Based on the used rainfall and relevant physical principles, the updated value of the incomplete mixing coefficient γ is about 14.0 times of the value of the incomplete mixing coefficient α in experiment 1 and about 7.4 times in experiment 2, while the difference between the flow rate of runoff and infiltration is not so large even after reaching stable infiltration condition. The results indicate the loss of Cr(VI) in soil solute is mainly due to infiltration, rather than surface runoff. With the increase of mixing layer depth, soil adsorption capacity will increase and the loss of soil solute will decrease. The study results provide information for reducing and even preventing the agricultural nonpoint source pollution.

Nitrate percolation and discharge in cropped Andosols and Gray lowland soils of Japan

Contamination of groundwater with nitrate (NO3) derived from agricultural activity is serious problem in many countries worldwide. We investigated the annual (growing and non-growing seasons) behavior of NO3–N in the soil pore water of cropped Andosols and Gray lowland soils under eight crop groups (Type A: paddy rice, Type B: winter crops, Type C: vegetables 1, Type D: vegetables 2, Type E: vegetables and forages, Type F: legume crops, Type G: orchard, and Type H: grass). In the vegetable group (Type C) and the orchard group (Type G), which required large amounts of fertilizer and frequent top-dressing, NO3–N concentrations in the soil pore water were extremely high. In these agricultural lands, it was clear that the inorganic nitrogen produced by nitrification in surface soil was dominantly discharged from a depth of 90 cm in July to September. The descending order of the amount of discharge of NO3–N (N-discharge) was Type C > G > D > E > F > B > H > A for the Andosol, and Type G > C > F > D > E > B > H > A for the Gray lowland soil. If fertilization of the vegetables and orchard was performed based on the standard application amount, the annual average NO3–N concentration at a depth of 90 cm exceeds 10 mg L−1. To reduce the risk of groundwater contamination by NO3–N, we calculated the annual cumulative water flux density and annual cumulative NO3–N flux density. We examined the calculated fertilizer amount and proposed reduced fertilizer application amounts so that the annual average concentration of NO3–N in soil pore water would not exceed 10 mg L−1. The standard application amount of nitrogen fertilizer for vegetables should be reduced by 65.8 and 30.8 kg ha−1 in the Andosol and the Gray lowland soil, respectively. We also proposed that the standard application amount of nitrogen fertilizer be reduced by 59.9 and 40.7 kg ha−1 in Andosol orchards and Gray lowland soil orchards, respectively.

Productivity and fertility of soils in the Indo-Gangetic Plains of South Asia

Fertile soils are a fundamental asset for a sustainable rice–wheat cropping systems followed in 13 Mha in the Indo-Gangetic plains (IGP). Managing practices for the rice–wheat cropping system are changing and in turn influencing soil fertility parameters. In long-term rice–wheat cropping, soil organic carbon content declined only in soils having high initial organic carbon content. Otherwise, soil organic carbon content tends to remain unchanged or increase with continuous cropping and fertilizer/manure applications. Available P content of the soil also increased with P additions through fertilizers or manures. Soil quality deterioration with respect to K supplying power is being largely overlooked. Deficiency of zinc is widespread in the IGP, but with the extensive use of zinc sulfate, it has reduced in some areas. Deficiency of Fe, Mn, and B is also increasing. The western transects of the IGP are more productive not only because radiation decreases and minimum temperature increases from eastern to western IGP but also due to the application of large amounts of fertilizers and availability of assured irrigation in western transects. Since more nutrients are being removed than added through fertilizers, farmers have to apply increasing doses of fertilizers to sustain the productivity levels.

Establishing the Ecological Circulation Circle in the Water Source Areas of the South–to–North Water Diversion Middle Routes Project

The South–to–North Water Diversion project provides water mainly for Henan and Hebei province , Beijing and Tianjin city . So the ecological environment protection in the water source areas is very important. But the ecological environment of water source areas of the middle route project is damaged becsuse a large amount of fertilizer and pesticide are used in the field, the pollution is heavy, and some lakes are turned into fields at some area. The systematic ecological circulation circles have not been established. This paper puts forward the countermeasures and methods of establishing the ecological circulation circle in the water rource areas of the middle route project after it illustrates the importance of establishing the ecological circulation circle in the water source areas , and analyzes the problems of the ecological circulation circle in the water source areas.

Interaction of local and landscape features in the conservation of Hungarian arable weed diversity

Question: How do local and landscape management contribute to weed diversity in Hungarian winter cereal fields? Location: Central Hungary. Methods: Vascular plants were sampled in 18 winter cereal fields along an intensification gradient according to nitrogen fertilization, in the first cereal rows (edge) and in the interior part of the fields. Weed species were divided into groups according to their residence time in Central Europe (native species, archaeophytes, neophytes) and nitrogen preference (low to medium, LMNP, and high, HNP species). The percentage of semi-natural habitats was calculated in the 500 m radius circle. Effects of fertilizer use, transect position and semi-natural habitats were estimated by general linear mixed models. Results: We recorded 149 weed species. Fertilizer had a negative impact on the species richness of archaeophytes and LMNP species, and on the cover of native weeds. There was greater species richness and weed cover at the edge of the fields than in the centre. A higher percentage of seminatural habitats around the arable fields resulted in greater total species richness, especially of archaeophytes and LMNP species. We found an interaction between the percentage of semi-natural habitats and transect position for species richness of archaeophytes and LMNP species. Conclusions: Reduced use of fertilizers and a high percentage of semi-natural habitats would support native and archaeophyte weed diversity even in winter cereal fields, while large amounts of fertilizer may promote invasion of neophytes. However, the beneficial effect of the semi-natural habitats and greater species pool on the arable flora may prevail only in the crop edges.

Reversing agriculture from intensive to sustainable improves soil quality in a semiarid South Italian soil

Intensive agriculture (IA) is widespread in South Italy, although it requires frequent tillage, large amounts of fertilizers and irrigation water. We have assessed the efficacy of reversing IA to sustainable agriculture (SA) in recovering quality of a typical South Italy soil (Lithic Haploxeralf). This reversion, lasting from 2000 to 2007, replaced 75% of nutrients formerly supplied inorganically by farmyard manuring and reduced the tillage frequency. Several chemical and biochemical properties, functionally related to C and N mineralisation–immobilisation processes and to P and S nutrient cycles, were monitored annually from 2005 to 2007 in the spring. Reversing IA to SA decreased soil bulk density, almost doubled the soil organic matter (SOM) as favoured the immobilisation of C and N, increased most soil microbial indicators but decreased contents of nitrate, mineral N and K2SO4-extractable C. The K2SO4-extractable C/K2SO4-extractable organic N ratio suggested that substrate quality rather than the mass of readily available C and N affected biomass and activity of soil microflora. Also, the largely higher 10-day-evolved CO2–C-to-inorganic N ratio under SA than IA indicated that higher C mineralisation, associated with higher microbial biomass N immobilisation, occurred under SA than IA. Decreases in most soil enzyme activities under IA, compared to SA, were much higher than concomitant decreases in SOM content. Soil salinity and sodicity were always higher in IA than SA soil, although not critically high, likely due to the intensive inorganic fertilisation as irrigation waters were qualitatively and quantitatively the same between the two soils. Thus, we suggest that the cumulative small but long-term saline (osmotic) and sodic (dispersing) effects in IA soil decreased the microbial variables more than total organic C and increased soil bulk density.

Sedimentary Records of Heavy Metal Pollution in Fuxian Lake, Yunnan Province, China: Intensity, History, and Sources

This study focused on the concentration change of heavy metals of sediment cores in heavily polluted north area and less polluted middle area of Fuxian Lake in Southwest China. On the basis of the analysis of Cu, Ni, Ti, V, Pb, Cd, and Zn concentration-depth profiles, the pollution history of heavy metals was studied using 137cesium ( 137Cs) dating. The sources of heavy metals were distinguished by normalization of their profiles to aluminum and analysis of heavy metal concentrations of potential source materials. Geoaccumulation index ( I geo) was used to quantify their contamination intensity. The results showed that all the heavy metals found in the Fuxian Lake sediments originated naturally before 1980s. Cu, Ni, Ti, and V were still mainly natural in the north lake after 1980s, Cu, Ni, Ti, V, and Pb were mainly natural in the middle lake at all time, but the concentrations of Pb and Zn in the north lake were influenced by industrial wastes from the phosphorus fertilizer factory and cement plants. In all the lake, the contaminations of Cd and Zn were the results of agricultural cultivation using a large amount of fertilizers and the atmospheric fallouts of dusts from cement plants. At present, the geoaccumulation indices showed that the Fuxian Lake sediments were moderately to strongly polluted by Cd in the middle lake, and unpolluted to moderately polluted by Pb and Zn and strongly polluted by Cd in the north lake. Moreover, the pollution intensities of Cd, Zn, and Pb have been increased since 1980s.

Climate change and agricultural pollution effects on the trophic status of a Mediterranean lake

AbstractTrichonis Lake is the largest natural freshwater body in Greece with a surface area of 97 km2. It receives pollutants from numerous anthropogenic activities, especially from intensive agricultural practices, urban sewages, stock grazing land and small industries. In this study, hydrologic and chemical parameters are assessed during two periods (1990–1991) and (2001–2002) to evaluate the effects of the climatic changes on phosphorous trends and consequently on the trophic status of Trichonis Lake. Even though large quantities of fertilizers are applied in the lake's catchment, phosphorus loads are still in the permissible level as estimated according to Vollenweider's relationship based on total phosphorus concentration. Due to relatively higher rainfall precipitation during the last years, an increased amount of the phosphorus entering into the lake system is flushed out, thus keeping the trophic status of the lake in oligotrophic levels. In contrast, lower rainfall rates during the first period (1990–1991) have led to the decrease in phosphorus flush out and its detainment into the lake water and sediment resulting to mesotrophic conditions. As the trophic status of the lake is mainly hydrologically dependent and thus unpredictable, effective management plans targeting the elimination of nutrient pollution loadings are necessary.

Natural Protection Against Groundwater Pollution by Nitrates in the Central Valley of Chile/Protection Naturelle Contre la Pollution des Eaux Souterraines par les Nitrates Dans la Vallée Centrale du Chili

The Central Valley of Chile is a zone of intensive agricultural activity. Historically, in this zone, large amounts of fertilizers have been applied and low technological level irrigation methods have been used. Contrary to what might be expected, the existing aquifers in the Central Valley do not contain significant nitrate that could be associated with agricultural activity. This situation leads one to infer the existence of favourable conditions for the occurrence of natural attenuating processes such as denitrification. Favourable conditions may be related to the particular soil and climatic conditions, and/or the structure and dynamics of the existing aquifers.

Natural Protection Against Groundwater Pollution by Nitrates in the Central Valley of Chile/Protection Naturelle Contre la Pollution des Eaux Souterraines par les Nitrates Dans la Vall�e Centrale du Chili

Abstract The Central Valley of Chile is a zone of intensive agricultural activity. Historically, in this zone, large amounts of fertilizers have been applied and low technological level irrigation methods have been used. Contrary to what might be expected, the existing aquifers in the Central Valley do not contain significant nitrate that could be associated with agricultural activity. This situation leads one to infer the existence of favourable conditions for the occurrence of natural attenuating processes such as denitrification. Favourable conditions may be related to the particular soil and climatic conditions, and/or the structure and dynamics of the existing aquifers.

Effects of Large Scale Irrigation on Drinking Water Quality in the Bukhara and Kashkadarya Provinces of Uzbekistan

This article presents the results of a study on the effects of farm practices on drinking water quality in the Bukhara and Kashkadarya provinces of Uzbekistan. These two provinces are the largest irrigation districts in Uzbekistan and, in 1999, withdrew more than 10 cubic kilometers (km3) of irrigation water from the Amu Darya River. Cotton is the major irrigated crop grown in these districts and has required the application of large quantities of fertilizers and pesticides. These irrigation practices resulted in 2 km3 of discharge water draining directly into the Amu Darya River and an equal amount of discharge water draining into natural lowlands in the region. Drinking water quality has worsened dramatically because of these discharges. The main pollutant components originated from mineral fertilizers and chemicals, which were applied on the irrigated lands. The amount and type of chemicals present in the drainage water can be linked to the agricultural production systems in the region.

Establishment of Transplants on Machine‐Graded Ski Runs Above Timberline in the Swiss Alps

AbstractThe suitability of 24 native species for restoration above the timberline in Switzerland was assessed with demographic monitoring of their populations after transplanting. The plots were laid out in 1985–1986 and 1995–1996 on machine‐graded ski runs using a total of 8,603 transplants of native grasses, legumes and forbs. Establishment conditions were improved with biodegradable wood‐fiber mats and a small addition of garden soil. Transplant survival rates were generally good after 12 years. The regeneration of mixed stands was clearly recognizable because some transplants successfully reproduced by seed, and colonizers immigrated from the adjacent natural vegetation and neighboring restoration plots. Comparative studies of reproductive parameters in transplants and their donor population revealed that differences in seed production may become nonsignificant within a short time span. These fitness features have important diagnostic value for assessing restoration success and provide information on the performance of the same or closely related genotypes in their natural populations and in the restoration site. The plants studied showed species‐specific traits in establishment after transplanting. Most species can be recommended for restoration in the alpine vegetation belt. The risk of restoration failure can be considerably reduced by using species with different life‐history characteristics. From an ecological point of view, this method is a valid alternative to commercial revegetation using seed mixtures of non‐native species and large amounts of fertilizers.

Effect of potassium fertilizer on the yield, quality and potassium offtake of sugar beet crops grown on soils of different potassium status

The effect of different rates of potassium (K) fertilizer on the yield and quality of sugar beet was studied in a series of 26 trials on soils of different type and K index between 1992 and 1997. There were few yield responses even though the majority of trials were on soils of low K index, and large quantities of fertilizer were applied (0–600 kg K/ha). Potassium offtakes (kg/ha) in the harvested beet increased asymptotically, not linearly, with yield and were much larger for a given yield on high K index soils than on low index soils. Commercially acceptable concentrations of beet K for processing are in the range 700 to 1000 mg K/100 g sugar. Concentrations in excess of this decrease the amount of sugar crystallized from the extracted juice. They were not greatly affected by large applications of fertilizer K but were strongly influenced by long-established differences in soil exchangeable K (Kex) due to soil type, previous cropping or manuring history.The asymptotic nature of the K offtake[ratio ]yield relationship was confirmed by factory tarehouse measurements relating to the national sugar beet crop delivered during the 1993–97 UK processing campaigns. Potassium offtakes generally increased linearly with yield up to 60–70 adjusted t of clean beet/ha, but increased little beyond that. The amount of K removed by a 60–70 t/ha crop of beet varied from 70 kg K/ha on low K index sandy loams to 120 kg K/ha on clay soils of K index 3 and above. Further increases in yield decreased the amount of K in fresh beet from 1·7 to 1·4 kg K/t on low K index soils, and from 3·6 to 2·5 kg K/t on high K index soils.An analysis of data from individual fields of commercially grown sugar beet showed that much of the site and season variation in the K content of beet was due to differences in K uptake driven by Kex, and to differential effects of nitrogen (N) supply on K uptake and sugar yield. Regressions on Kex and total crop N (kg/ha) accounted for c. 30 and 50% of the variance in beet K content, respectively, and the two together for over 60%. Total N uptake by the crops ranged from 100 to 550 kg N/ha. The total K content of the crop and the amounts of K in the beet (kg/ha) both increased linearly with crop N over the whole of this range, whereas sugar yield increased asymptotically with total uptakes of N up to 250–300 kg N/ha. Consequently, low yielding crops grown on soils in which N and K were freely available produced beet of poor K quality. However, the asymptotic relationship between beet K (kg/ha) and yield implies that, in many situations, the processing quality of the beet could be improved by increasing yield through better agronomy.

Carbon and nitrate utilization in soils: the effect of long-term fertilization on potential denitrification

Soil samples were taken from plots at 3 different experimental sites that had received different fertilizer applications for more than 20 years. Denitrification capacity (DC) and denitrification potential (DP), defined as the amount of N 2O released from the soils amended with KNO 3 and KNO 3 + glucose, respectively, and incubated anaerobically in the presence of 10 kPa acetylene were measured at 25°C for up to 48 h. Also, CO 2 evolution and microbial biomass were determined. Both DC and DP were significantly influenced by the treatments. Application of manure (40 t ha −1 every 4 yr) and lime (5 t CaCO 3 ha −1 every 4 or 5 yr) alone as well as in combination with moderate amounts of inorganic fertilizers (80 kg N + PK ha −1 yr −1) increased DC and DP. In highly fertilized soils (manuring, liming and 160 kg N + PK ha −1 yr −1), however, DC was further enhanced in one soil only, while DP was significantly decreased in all soils. When no lime was applied but large amounts of fertilizers were (manure and 160 kg N + PK ha −1 yr −1), DC and DP were further significantly decreased, in some cases even below the rates in unfertilized soils. Overall carbon dioxide production from soils followed similar pattern as DC and DP. Fertilization did not significantly affect microbial biomass in limed soils, but decreased it in unlimed soils. Possible indirect influences of long-term fertilization, related to changes in soil chemistry in general and in soil pH in particular, are discussed.

Measurements of natural radioactivity in phosphate fertilizers

The natural radioactivity, mainly due to radium ( 226Ra), in phosphate fertilizers used in north-western Greece has been measured by γ-spectroscopy. Also radioactivity measurements were performed in soil samples and were compared to samples from undisturbed soils. 226Ra belongs to the 238U chain and is the precursor of radon gas ( 222Rn). The radon concentrations in warehouses, where large quantities of fertilizers are kept, were measured with CR-39 SSNTDs. The radium concentrations in the fertilizers ranged from 0 to 4584 Bq kg −1 and the radon concentrations in warchouses were measured 540–3320 Bq m −3. The results are discussed from the radiation protection point of view.

Nutrient emissions from agriculture in the Netherlands, causes and remedies

Agriculture causes 60% of the total nitrogen emissions and 40-50% of the total P emissions to the surface waters in the Netherlands. These high emissions are mainly caused by the large amounts of fertilizers used on Dutch farms. On average, 39 kg P ha−1 and 340 kg N ha−1 are given in excess to the uptake by the crop. The Netherlands follows a strategy of gradual reduction of the nutrient applications to crops. The first two phases were aimedat stabilisation and a gradual reduction of the use of organic manure. The goal of the third phase is to accomplish equilibrium fertilization in the year 2000. This means that the amount of fertilizer given may not exceed the crop uptake, considering an acceptable loss to the environment. The losses are based upon acceptable emissions, mainly to surface waters. With the average excess rainfall in the Netherlands, the water quality standards are met with a loss of 0.4 kg P ha−1 and 6 kg N ha−1, much lower than the present excesses of minerals. The challenge for the future is to close the gap between environmentally acceptable and present losses. Equilibrium fertilization will not solve all problems at short notice. Therefore, additional techniques to reduce nutrient losses are in development. Examples are restoration of buffer strips and wetlands, lowering of groundwater levels, dosing of ferric and aluminum compounds in the soils and several additional measures in eutrophied lakes.

Nutrient emissions from agriculture in the Netherlands, causes and remedies

Agriculture causes 60% of the total nitrogen emissions and 40–50% of the total P emissions to the surface waters in the Netherlands. These high emissions are mainly caused by the large amounts of fertilizers used on Dutch farms. On average, 39 kg P ha−1 and 340 kg N ha−1 are given in excess to the uptake by the crop.The Netherlands follows a strategy of gradual reduction of the nutrient applications to crops. The firsts two phases were aimedat stabilisation and a gradual reduction of the use of organic manure. The goal of the third phase is to accomplish equilibrium fertilization in the year 2000. This means that the amount of fertilizer given may not exceed the crop uptake, considering an acceptable loss to the environment. The losses are based upon acceptable emissions, mainly to surface waters. With the average excess rainfall in the Netherlands, the water quality standards are met with a loss of 0.4 kg P ha−1 and 6 kg N ha−1, much lower than the present excesses of minerals. The challenge for the future is to close the gap between environmentally acceptable and present losses. Equilibrium fertilization will not solve all problems at short notice. Therefore, additional techniques to reduce nutrient losses are in development. Examples are restoration of buffer strips and wetlands, lowering of groundwater levels, dosing of ferric and aluminum compounds in the soils and several additional measures in eutrophied lakes.

Leaf-Mining Insects and Fluctuating Asymmetry in Elm Ulmus glabra Leaves

Fluctuating asymmetry, which represents small, random deviations from bilateral symmetry, arises as a result of an inability to control development under genetically and environmentally stressful conditions. Herbivory is also particularly common in plants growing under stressful conditions. It was hypothesized that herbivory would be particularly prevalent in plants with leaves demonstrating high degrees of fluctuating asymmetry. This prediction was tested for the leaf-mining insect, Rhynchaenus rufus, which commonly attacks elm Ulmus glabra. Leaves with mines were significantly more asymmetrical in the width of their two halves and the distance between side-ribs, than the nearest neighbouring leaf without a mine. Elm trees with a high incidence of leaf mines had significantly more asymmetric leaves than the nearest neighbouring elm tree with a low incidence of leaf mines. This was the case regardless of whether affected or unaffected leaves were compared. The incidence of leaf mines across trees was positively related to the degree of leaf asymmetry of the tree. Developmental stability of leaves, as measured by fluctuating asymmetry, was therefore associated with susceptibility to one kind of herbivory in elm trees. Leaves of elm trees watered with a large amount of fertilizer were more asymmetric than leaves of trees just provided with water, suggesting that one kind of stress increased the level of leaf asymmetry. The relationship between foliar asymmetry and herbivory appeared to be causal since increased asymmetry caused by the fertilizer treatment gave rise to an increased abundance of leaf miners.

Systems

Abstract The unique climatic and soil conditions in west‐central Florida require specific nutrition and water management methods for cole crops. High day and night temperatures in spring and early fall and rapidly fluctuating temperatures in the winter, create stress conditions for the plants. Soil is an EauGallie fine sand (sandy, silicaceous, hypothermic Alfic haplaquod) with a spodic horizon at 86 cm and a native pH of 3.9–4.2. With the conventional full‐bed polyethylene mulch and seepage (modified furrow) sub‐irrigation system, large amounts of fertilizer and water are applied for the crops. Cabbage and cauliflower yields were highest with banded fertilizer placement and 256 N, 37 P and 296 K kg‐ha‐1. Broccoli yields increased with increasing N rates but were not affected by K rates. With the trickle irrigation system, fertilizer placement, source and rate were studied to reduce production input. High fertilizer rates were required for high yields, but irrigation was reduced by 50–60% compared to the seepage system.

NPK-fertilizer efficiency — a situation analysis for the tropics

This paper examines the efficiency of applied N, P, and K fertilizers under tropical conditions. To meet their food demands, tropical countries are importing large quantities of fertilizers at an enormous cost. There is a need for improving crop yields at a reduced cost and a better understanding of the factors that contribute to the overall efficiency of applied fertilizers. It is estimated that under tropical condition, the efficiency of applied N is less than 50%, less than 10% for P and for K it is somewhere around 40%. Losses of N are mainly due to leaching, runoff and volatile losses of ammonia. Under flooding and in alternate wetting and drying conditions of rice lands and low lands, dentrification and volatile ammonia losses are considerable. The N losses from these soil could be minimized by proper management such as rate, methods and time of application. The coating of urea with S has shown some improvement in increasing efficiency. Nitrification and urea hydrolysis inhibitors can improve fertilizer efficiency in certain situations provided they are properly used. The efficiencies of these inhibitors depend on the nature of the chemical compounds, soil properties, and method of application. Low efficiency of applied P fertilizer is mainly due to retention of P by soil clay fractions and iron and aluminum hydroxides. Even though retained P is not available to the first crop, it is made available to a certain extent to the succeeding crops. The rate and methods of P applications and forms of P determine the efficiency of applied P fertilizers. The use of native rock phosphate along with P fertilizers on acid soils appears to be an attractive alternative in reducing the fertilizer cost. The loss of K in tropical soils is largely attributed to leaching and runoff. To reduce K loss by leaching, it is more advisible to apply K in split doses than a single dose. Liming has a beneficial effect in retention of K and reducing P fixation in acid soils.