Agricultural Fertilizer Application Research Articles

Sedimentary geochemical evidence for recent eutrophication of Lake Chenghai, Yunnan, China

Geochemical anomalies and stable isotope ratios (δ18O, δ13C) in authigenic carbonates and organic matter (δ13C) from a 660-year sediment core from Lake Chenghai, southern China, provide a continuous history of recent lake eutrophication. The multi-proxy geochemical and isotopic record can be divided into a three-part history of contrasting limnological development, including: (1) a clear-water, oligotrophic open lake system (1340 and 1690 AD); (2) an environmentally unstable, hydrologically closed, oligotrophic lake system (1690–1940 AD); and (3) an increasingly eutrophic, closed lake system marked by higher organic matter, nitrogen, CaCO3, and pigment concentrations, and lower δ18O and δ13C values in authigenic calcite (1940–1999 AD). The unanticipated lowering of δ18O and δ13C of authigenic calcite during eutrophication is thought to be the result of disequilibrium water–carbonate fractionation of oxygen and carbon isotopes during periods of elevated primary production, pH, and [CO3 2−] activities in the water column. The recent eutrophication of Lake Chenghai indicated by these geochemical proxies is essentially simultaneous with large-scale human migration and the application of agricultural fertilizers in the catchment area during the 20th century.

Spatial evaluation of alternative nonpoint nutrient regulatory instruments

Recent work has shown that because of differences in the physical environment across an area the choice of an instrument for regulation of nonpoint source agricultural pollution is an empirical question. The objective of this study is an empirical comparison of an economic incentive policy (an input tax) for reduction of agricultural fertilizer application with a command and control policy. Although a “first‐best” policy would be administered at the farm level, transactions costs practically require a single policy for the whole area. In an application to the Columbia plateau, a 300% input tax is shown to be preferred to a mandated 25% reduction in nitrogen fertilizer on financial and policy efficiency grounds.

Modeling the impact of hydrological changes on nitrate transport in the Mississippi River Basin from 1955 to 1994

The export of nitrate by the Mississippi River to the Gulf of Mexico has tripled since the 1950s primarily due to an increase in agricultural fertilizer application and hydrological changes. Here we have adapted two physically based models, the Integrated Biosphere Simulator (IBIS) terrestrial ecosystem model and the Hydrological Routing Algorithm (HYDRA) hydrological transport model, to simulate the nitrate export in the Mississippi River system and isolate the role of hydrological processes in the observed increase and interannual variability in nitrate export. Using an empirical nitrate input algorithm based on constant land cover and variability in runoff, the modeling system is able to represent much of the spatial and interannual variability in aquatic nitrate export. The results indicate that about a quarter of the sharp increase in nitrate export from 1966 to 1994 was due to an increase in runoff across the basin. This illustrates the pivotal role of hydrology and climate in the balance between storage of nitrate in the terrestrial system and leaching.

Application of Microbial Fertilizers in Sustainable Agriculture

Summary This paper summarizes the conception and development of microbial fertilizers and inoculants in China that are used to improve soil quality and the growth, yield and protection of crops. The results presented show the relative effects of these microbial products applied singly or with chemical fertilizers on soil fertility, crop yield and protection. The paper discusses current trends in the development and use of microbial fertilizers in China and suggests areas of high priority research.

Radium and uranium in phosphate fertilizers and their impact on the radioactivity of waters

The study of radioactivity in the phosphate fertilizers and waters of the Kanovci area was performed in order to determine the influence of the application of phosphate fertilizers on the radioactivity of waters. The activity of 226Ra, 228Ra, 235U and 238U was measured in different types of phosphate fertilizers and waters by means of γ-ray spectrometry. Surface water, water from drainage channels, shallow groundwater and deep groundwater samples were collected from the Kanovci agricultural and well field area in Eastern Slavonia, where phosphate fertilizers have been used for the past 15 years. 137Cs was also measured in water samples. The typical phosphate fertilizer used in the Kanovci area contains 75 Bq kg −1 of 226Ra, 9 Bq kg −1 of 228Ra, 52 Bq kg −1 of 235U and 1120 Bq kg −1 of 238U. The estimated annual deposition of uranium and radium in soils of the agricultural and well field area in Kanovci is: 4.5 Bq m −2 for 226Ra, 0.5 Bq m −2 for 228Ra, 3.1 Bq m −2 for 235U and 67 Bq m −2 for 238U. The greatest concentrations of both uranium isotopes are measured in water from drainage channels with a mean value of 120 Bq m −3 for 238U and 5.5 Bq m −3 for 235U. The concentrations of both radium isotopes generally increase with depth of water as distinct from uranium, whose concentrations in deep groundwater are much lower. The highest concentrations of 137Cs were measured in water from drainage channels; it was not detected in deep groundwater. The 238U/ 226Ra activity ratio (AR) is the highest in water from drainage channels and the Bosut River, while in deep groundwater the ratio is only 1.6. Results indicate that high uranium concentrations in surface water, shallow groundwater and water from drainage channels are caused by phosphate fertilizer application in agriculture on the Kanovci area.

Overview of a Large-Scale Bioremediation Soil Treatment Project

How long does it take to remediate 290,000 yd{sup 3} of impacted soil containing an average total petroleum hydrocarbon concentration of 3,000 ppm Approximately 15 months from start to end of treatment using bioremediation. Mittelhauser was retained by the seller of the property (a major oil company) as technical manager to supervise remediation of a 45-ac parcel in the Los Angeles basin. Mittelhauser completed site characterization, negotiated clean-up levels with the regulatory agencies, and prepared the remedial action plan (RAP) with which the treatment approach was approved and permitted. The RAP outlined the excavation, treatment, and recompaction procedures for the impacted soil resulting from leakage of bunker fuel oil from a large surface impoundment. The impacted soil was treated on site in unline Land Treatment Units (LTUs) in 18-in.-thick lifts. Due to space restraints, multiple lifts site. The native microbial population was cultivated using soil stabilization mixing equipment with the application of water and agricultural grade fertilizers. Costs on this multimillion dollar project are broken down as follows: general contractor cost (47%), bioremediation subcontractor cost (35%), site characterization (10%), technical management (7%), analytical services (3%), RAP preparation and permitting (1%), and civil engineering subcontractor cost (1%). Start-up of field workmore » could have been severely impacted by the existence of Red Fox habitation. The foxes were successfully relocated prior to start of field work.« less

Lake M�ggelsee ?the use of lake water and its consequences

Lake Muggelsee (Groβer Muggelsee) — the largest lake in the area of Berlin — is the main drinking water reservoir for Berlin (East), but also a center of numerous recreational activities and fishing. The use of the lake and its catchment area has continuously increase during the past decase and has caused a substantail deterioration of the lake water quality. Mass development of algae has become a limiting factor to all future utilizations of the lake. Since the beginning of this century up to the seventies the lake water has shown signs of a permanently growing eutrophication, e.g. the content of particulate matter in the lake water has nearly doubled. During and after World War II the lake quality (Secchi depth and seston content) improved remarkably due to a reduced input of nutrients. According to time series analyses of buoyant seston and meterologica elements the development of blue-green algae seems to depend more on weather conditions than on the nutrient content of the lake water. Therefore, a certain probability of blue-green algae blooms will remain, also in the case of reduced nutrient input. Phosphorous is the main cause for eutrophication. It was responsible for distinctly higher mass developments of algae during spring and autumn in the past two decades. As a consequence, comprehensive measures are to be taken to reduce phosphorus inputs into the Spree river and lake Muggelsee, e.g. by the substitution of P in detergents, construction of tertiary sewage treatment plants and a substantially reduced application of fertilizers in agriculture.

ENHANCEMENT OF THE NATURAL BIODEGRADATION OF CONDENSATE AND CRUDE OIL ON BEACHES OF ATLANTIC CANADA

ABSTRACT Low-energy coastal systems are considered among the most sensitive of marine ecosystems to oil spills because of their vulnerability to oil stranding and the difficulty in cleanup. Field experiments, in an aerobic intertidal sand-beach environment, demonstrated that the biodegradation of Scotian Shelf condensate and Hibernia crude oil can be substantially accelerated by periodic application of agricultural fertilizers. Due to the diauxic growth response of microorganisms, similar applications of an oleophilic nutrient mixture were found to be less effective.