Open Field Soil Research Articles

Dissipation and Residues of the Herbicide Mesotrione in Maize and Soil in Open Field

The purpose of this article was to establish a simple residue analysis method for mesotrione in maize using high performance liquid chromatography tandem mass spectrometry. The method was then used to study the dissipation and residues in maize seedling and soil. The half-lives of mesotrione in maize plants and soil were 1.37, 4.31 days in Beijing, and 0.97, 1.80 days in Shandong, respectively. The ultimate residues of mesotrione were undetected in soil, maize grain and stem at the harvest time, suggesting that mesotrione could be safely used in maize crops with an appropriate dosage and application.

Characterization of Greenhouse Soil Properties Using Mid-infrared Photoacoustic Spectroscopy

ABSTRACT Evaluation of soil fertility is required for the sustainable production in greenhouses; however, routine agrochemical analytical methods are not practical since most of them are too time consuming and costly. In this study, Fourier transform midinfrared photoacoustic spectroscopy (FTIR-PAS) was applied as an alternative technique in the fast characterization of greenhouse soils. Nine source clays and 235 soil samples were obtained from different greenhouses in China, and their counterpart open-field soils were also sampled for comparison. The FTIR-PAS spectra of soil clays and soils were recorded with the wave-number range of 600–4000 cm−1, and clear differences were observed among the spectra; soil organic matter (SOM) and soil clay played the main role in the spectral absorption. Partial least square regression (PLSR) models coupled to optimized spectral pretreatment were used to predict greenhouse soil properties, and FTIR-PAS spectra were closely related to SOM (R2 = 0.94) and soil total nitrogen (R2 = 0.90). For the other soil properties—such as pH, EC, water extractable P, K, Fe, and Cu—the calibration results were excellent or acceptable. These results suggested that FTIR-PAS could be used to determine most of greenhouse soil properties. Since the technique of FTIR-PAS is rapid and inexpensive, and it requires no sample pretreatment and little sample mass, it can be used in fast characterization of greenhouse soil and is a promising method for the management of greenhouse soil.

The decline and residues of hexaconazole in tomato and soil

The decline and terminal residues of hexaconazole in tomato and soil in open field were studied. Hexaconazole residues were determined by gas chromatography coupled with an electron capture detector. Recoveries were between 89% and 110% with RSD of 2.99-5.88% in tomato and 90-119% with RSD of 1.15-5.76% in soil at spiked levels of 0.01, 0.1, and 1 mg/kg, respectively. The limit of detection of hexaconazole was 6.3 × 10(-12) g. The decline rates of hexaconazole were described using first-order kinetics and the mean half-lives of hexaconazole in tomato and soil were 4.3 and 18.1 days, respectively. The terminal residues in tomato at interval of 7 days at the dosage of 150 g.a.i./hm(2) for three or four times were all below 0.1 mg/kg. This work would be the guidance of establishing the maximum residue limit of hexaconazole in tomato in China.

Soluble organic nitrogen pools in greenhouse and open field horticultural soils under organic and conventional management: A case study

The aim of this study was to investigate the influence of four different horticultural management practices in open field and in greenhouse conditions under organic and conventional cultivation on the amount of soluble organic nitrogen (SON) present in the soil. Soils used in greenhouses and open field cultivation were sampled in Shanghai, China, where organic farming has been conducted for 3 years or conventional faming has been continued in the same area. The amounts of SON, nitrate (NO 3 −) and ammonium (NH 4 +) were greater in the greenhouse soils than those under open field cultivation, which indicated a higher degree of soil management was imposed under greenhouse conditions. Greenhouse cultivation is also known to accelerate the turnover of SON in the soils, which may explain the significantly higher amounts of SON present in these soils. Organic farming, which does not use artificial fertilizers and pesticides, also resulted in significantly higher amounts of SON (average 42.10 mg kg −1) compared with soils under conventional faming (24.59 mg kg −1). The reasons for the observed differences in pool sizes of soluble inorganic nitrogen (SIN) and NO 3 − in the greenhouse soils and the open fields include (a) the heavy application of both complex fertilizer and organic fertilizer that exceeded crop requirements and (b) warmer temperatures and moist soils in the greenhouses, which are likely to lead to greater rates of N cycling compared with the open field soils. These results suggest that SON may be an important source of N in all horticultural systems, representing a pool of labile N readily available for plant growth. However, its concentration is less sensitive to different management practices than SIN. In contrast to SON, the total soluble nitrogen and inorganic N (SIN) pools varied widely with the different management practices although they were dominated by NO 3 − in all treatments. Soil organic N was positively related to dissolved organic carbon and NO 3 − contents. This relationship indicates that NO 3 − and dissolved organic matter play a key role in the retention of SON in soil.

Nutrient Budget and Soil Nutrient Status in Greenhouse System

This paper is based on nutrient budget and its effects on soil nutrient status in typical greenhouse system in China to provide a basis for raising the utilization rate of fertilizers and maintaining the sustainable development of agriculture in the greenhouse. By investigating the management of 18 representative greenhouses in Shouguang, Shandong Province, China, and analyzing both the greenhouse and open field soil samples, the soil nutrient budget and the trend of nutrient accumulation and translocation in soils were thus studied. The results under greenhouse system showed that the average annual inputs of N, P 2O 5 and K 2O were 4 088, 3 655 and 3 437 kg ha −1, respectively. The total inputs of N, P 2O 5 and K 2O provided by chemical fertilizers which are the main source of soil nutrient were 63, 61 and 66%, respectively. The utilization rates of N, P 2O 5 and K 2O were only 24, 8, 46% and the input ratio among N, P 2O 5 and K 2O (1:0.9:0.8) was quite different from the uptake ratio (1:0.3:1.4). It had caused the excess of N, P 2O 5 and K 2O in the soil, and the theoretical surpluses were 3 214, 3 401 and 2 322 kg ha −1, respectively, for N, P 2O 5 and K 2O. The level of the organic matter, total nitrogen, nitrate nitrogen, available phosphorus, and available potassium was increased substantially, and their maximum level was observed in the topsoil (0–20 cm) with an average value being 1.4, 1.9, 21.2, 5.4, and 3.7 times higher than that of the open field soil, respectively. The greenhouse soils showed leaching of the nutrients, especially NO 3 − which would cause a potential risk to the quality of groundwater in the area. It is necessary to apply more organic manure and provide nutrients according to the crop requirements and soil fertility as it could not only produce high crop yield, but also be beneficial to balance the soil nutrient and improve the utilization rate of fertilizers. Further, there would be no significant surplus of nutrients which may leach out of soil to contaminate the environment.

Linking principles of soil formation and flow regimes

Summary Preferential flow (PF) is a fundamentally important soil hydrologic process that controls a variety of soil physical, chemical, and biological functions. However, the lack of theory in this field and the existence of conceptual and technological bottlenecks continue to hinder the advancement of PF modeling and prediction. This paper explores three theoretical perspectives on the relationships between pedogenesis and flow regimes in field soils. First, we examine non-equilibrium thermodynamics as applied to open dissipative field soils with continuous energy inputs and mass exchanges with the surrounding environment. The dual-partitioning of pedogenesis (dissipating and organizing processes) is consistent with the theory of dissipative structure, which explains the genesis and evolution of soil architecture (structure + matrix) and organized heterogeneity found in various soils. Such organized heterogeneity leads to widespread potential for PF occurrence. Second, we investigate constructal theory to explain the tendency for dual-flow regimes in soils – one with high resistivity (Darcy flow) and the other with low resistivity (PF) – together, they form PF configuration that provides the least global flow resistance. This theory is applied to explain some general characteristics of weathering processes and related flow regime changes, which are supported by limited chronologic data from the literature on subsoil’s saturated hydraulic conductivity decrease after a soil reaches a certain age. Third, the theory of evolving networks sheds light on a variety of PF networks observed in field soils, which increase the effectiveness of energy and mass transfer in the subsurface. This is because networks are a part of the organization resulting from the minimum energy dissipation principle and far-from-equilibrium thermodynamics. All the three theories discussed support the notion that the potential for PF occurrence in field soils is likely universal. However, controversies and challenges associated with these theories require further efforts to rigorously test their applicability in natural soils and to formulate explicit quantitative relationships between PF occurrence and its controls. The principle of soil formation and evolution provides a useful guide to this endeavor.

Mercury degassing from forested and open field soils in Rondônia, Western Amazon, Brazil

A Teflon ® dynamic flux chamber was used to characterize Gaseous Elemental Mercury (GEM) flux from forested and open field soils in a highly changing environment in Rondônia State, western Amazon. We simultaneously analyzed meteorological parameters at the soil level relating GEM fluxes to soil temperature, air humidity, soil moisture, solar radiation, and speed and wind direction. We also examined variations of atmospheric GEM concentration. GEM fluxes during the day and night in the open field site were significantly different (17 ± 14 ng m −2 h −1 and 0.9 ± 1.9 ng m −2 h −1, for day and night, respectively), but were similar within the forest site (4.8 ± 1.4 ng m −2 h −1 and 4.4 ± 1.8 ng m −2 h −1 for day and night periods, respectively). A comparison between 24-h periods averages in the two sites showed much larger emission from the open field site. GEM fluxes at the open field site were positively correlated with soil moisture, solar irradiation and soil temperature and inversely correlated with air humidity. At the forest site GEM fluxes showed no correlation with meteorological variables. At the open field site GEM concentrations significantly correlated with GEM flux, at least during the day. At night in the open field site and during the day and night at the forest site no correlation was found between GEM fluxes and GEM concentrations in the ambient air. Higher emissions from the open field site support earlier studies showing larger Hg remobilization following forest conversion to pasture.

Effects of continuous cucumber cropping and alternative rotations under protected cultivation on soil microbial community diversity

The diversity of soil microbial communities as affected by continuous cucumber cropping and alternative rotations under protected cultivation were evaluated using community level physiological profiles (CLPP) and random amplified polymorphic DNA (RAPD) analysis. The soils were selected from six cucumber cropping systems, which cover two cropping practices (rotation and continuous cropping) and a wide spectrum for cucumber cropping history under protected cultivation. Shannon–Weaver index and multivariate analysis were performed to characterize variations in soil microbial communities. Both CLPP and RAPD techniques demonstrated that cropping systems and plastic-greenhouse cultivation could considerably affect soil microbial functional diversity and DNA sequence diversity. The open-field soil had the highest Shannon–Weaver index (3.27 for CLPP and 1.50 for RAPD), whereas the lowest value occurred in the 7-year continuous protected cultivation soil (3.27 for CLPP and 1.50 for RAPD). The results demonstrated that continuous plastic-greenhouse cultivation and management can cause the reduction in the species diversity of the biota. Higher Shannon–Weaver index and coefficients of DNA sequence similarity were found in soils under rotation than those under continuous cropping. Cluster analysis also indicated that microbial community profiles of continuous cultivation soils were different from profiles of rotation soils. The reduction in diversity of microbial communities found in continuous cultivation soils as compared with rotation soils might be due to the differences in the quantity, quality and distribution of soil organic matter.

Occurrence of Pasteuria spp. Associated with Plant-parasitic Nematodes in Korea

A survey was conducted on the occurrence of Pasteuria spp. associated with plant-parasitic nematodes in greenhouse and open field soils in Korea from 1996 to 2000. Among the 372 soil samples assayed, 20 samples had plant-parasitic nematodes attached with Pasteuria spp. endospores. The nematodes found with Pasteuria endospores and their collection sites were Meloidogyne spp. in Sungju, Cheju, and Yeoju and Helicotylenchus sp., Pratylenchus sp., Heterodera sp., and Aphelenchus sp. in Cheju. Morphological characteristics of the endospores on Meloidogyne incognita juveniles observed under light, scanning and transmission electron microscopes were same as the previous description of Pasteuria penetrans Sayre & Starr 1988.

Evaluation of current fertilizer practice and soil fertility in vegetable production in the Beijing region

A survey on current fertilizer practices and their effects on soil fertility and soil salinity was conducted from 1996 to 2000 in Beijing Province, a major vegetable production area in the North China Plain. Inputs of the major nutrients (NPK) and fertilizer application methods and sources for different vegetable species and field conditions were evaluated. Excessive N and P fertilizer application, often up to about 5 times the crop requirement in the case of N, was very common, especially for high-value crops. Potassium supply may have been inadequate for some crops such as leafy vegetables. Urea, diammonium orthophosphate ((NH4)2HPO4) and chicken manure were the major nutrient sources for vegetable production in the region. Over 50% of N, 60% of P and nearly 90% of K applied originated from organic manure. Total N application rate for open-field Chinese cabbage from organic manure and inorganic fertilizers ranged from 300 to 900 kg N ha–1 on 78% of the farms surveyed. More than 35% of the surveyed greenhouse-grown tomato crops received > 1000 kg N ha–1 from organic and inorganic sources. A negative K balance (applied K minus K removed by the crop) was found in two-thirds of the surveyed fields of open-field Chinese cabbage and half of the surveyed fields of greenhouse-grown tomato. Plant-available N, P and K increased with increasing length of the period the greenhouse soils had been used for vegetable production. Similarly, soil salinity increased more in greenhouse soils than in open-field soils. The results indicate that balanced NPK fertilizer use and maintenance of soil quality are important for the development of sustainable vegetable production systems in this region.

Modelling of mercury emissions from background soils

Emissions of volatile mercury species from natural soils are believed to be a significant contributor to the atmospheric burden of mercury, but only order-of-magnitude estimates of emissions from these sources are available. The scaling-up of mercury flux measurements to regional or global scales is confounded by a limited understanding of the physical, chemical and biochemical processes that occur in the soil, a complex environmental matrix. This study is a first step toward the development of an air–surface exchange model for mercury (known as the mercury emission model (MEM)). The objective of the study is to model the partitioning and movement of inorganic Hg(II) and Hg(0) in open field soils, and to use MEM to interpret published data on mercury emissions to the atmosphere. MEM is a multi-layered, dynamic finite-element soil and atmospheric surface-layer model that simulates the exchange of heat, moisture and mercury between soils and the atmosphere. The model includes a simple formulation of the reduction of inorganic Hg(II) to Hg(0). Good agreement was found between the meteorological dependence of observed mercury emission fluxes, and hourly modelled fluxes, and it is concluded that MEM is able to simulate well the soil and atmospheric processes influencing the emission of Hg(0) to the atmosphere. The heretofore unexplained close correlation between soil temperature and mercury emission flux is fully modelled by MEM and is attributed to the temperature dependence of the Hg(0) Henry's Law coefficient and the control of the volumetric soil-air fraction on the diffusion of Hg(0) near the surface. The observed correlation between solar radiation intensity and mercury flux, appears in part to be due to the surface-energy balance between radiation, and sensible and latent heat fluxes which determines the soil temperature. The modelled results imply that empirical correlations that are based only on flux chamber data, may not extend to the open atmosphere for all weather scenarios.

Strontium as a tracer of weathering processes in a silicate catchment polluted by acid atmospheric inputs, Strengbach, France

This paper determines the weathering and atmospheric contributions of Ca in surface water from a small spruce forested silicate catchment (N–E France) receiving acid atmospheric inputs. The bedrock is a granite with K-feldspar and albite as dominant phases. The calcium content in plagioclase is low and the Ca/Na ratio in surface water is high, reflecting other sources of calcium from those expected from the weathering of major mineral phases. The biotite content is low. Only traces of apatite were detected while no calcite was found in spite of a major hydrothermal event having affected the granite. The strontium isotopic ratio 87Sr/ 86Sr and Sr content was used as a tracer of weathering and was determined in minerals and bulk bedrock, open field precipitation, throughfall, soil solution, spring and stream water. The Sr isotopic ratio of the reacting weathering end-member was predicted by simulating the alteration of the granite minerals by incorporating strontium into the water–rock interaction kinetic code KINDIS. In the early stages of water–rock interaction, K-feldspar and biotite strongly influence the isotopic composition of the weathering solution whereas, the Na-rich plagioclase appears to be the main long-term reactive weathering end-member. Approximately 50% of dissolved Sr in streamwater are atmospherically derived. The 87Sr/ 86Sr ratios of exchangeable Sr in the fine fraction at 1-m depth from a soil profile indicate that the amount of exchangeable Sr seems essentially controlled by atmospheric inputs. The exception is the deep saprolite where weathering processes could supply the Sr (and Ca). Na-Plagioclase weathering obviously control the chemistry and the isotopic composition of surface waters. The weathering of trace mineral plays a secondary role, the exception is for apatite when plagioclase is absent. Our hydrochemical, mineralogical and isotopic investigations show that a major part of the strong Ca losses detected in catchment hydrochemical budgets that result from the neutralization of acid precipitation has an atmospheric origin. Consequently, in the long term, in such areas, the availability of such an exchangeable base cation might be strongly limited and surface waters consequently acidified.

Dissolved organic matter contribution to rain water, throughfall and soil solution chemistry

A method is proposed to determine the acid-base properties of natural water samples containing relatively high amounts of dissolved organic matter. The electroneutrality principle as well as titration data are used to estimate the organic anion concentration in open field precipitation, throughfall and soil solutions, and to develop empirical models based on pH and dissolved organic carbon content. The organic acids dissolved in throughfall have a similar acidic site density but are weaker than those dissolved in soil solution, stream and lake waters. This method is usefull to determine the contribution of organic anions to the charge balance and to the buffering capacity of dissolved organic rich waters with low acid neutralizing capacity, if can be used also to determine the respective contribution of natural organics and anthropogenic minerals to the total acidity of throughfall and rain waters.

Application of a teflon™ dynamic flux chamber for quantifying soil mercury flux: Tests and results over background soil

High precision and low blank contamination were achieved with a Teflon™ dynamic chamber for measuring, soil mercury flux. Using this chamber, background soil mercury flux averaged between 2 and 7 ng m −2 h −1 over forest soil, and between 12 and 45 ng m −2 h −1 over open field soil. Spatial heterogeneity of soil mercury flux at duplicate plots co-located within 2 m was small but significant, differing by 20–50%. Elevated mercury emission over field soil occurred in the presence of direct sunlight at the open field sites. Solar radiation, soil temperature and soil moisture were all significant factors effecting mercury emission from soil. Solar radiation affected the reduction of naturally occurring, inorganic soil mercury compounds to volatile elemental mercury (Hg°). We estimate that background soil accounts for the gross emission of ∼ 109 g yr −1 of Hg° to the atmosphere, with approximately two-thirds of this total from sunlight-exposed soil and the remainder from forest and other shaded-soil ecosystems.

Anthropogenic and Lithologic Pb Behaviours in Acid Atmospheric Polluted Catchment (the Strengbach Case Study, Vosges, France)

Two main reasons lead us to study the behaviour of lead in an equiped natural catchment the Strengbach bassin in the Vosges massif, France. (1) Like other radiogenic isotopes, Pb is an interesting tracer to provide insights on the fonctionning the natural system. (2) Lead is also one of the most significant and dangerous polluting agent. Therefore the knowledge of its behaviour in environnmental systems is primordial. In such natural systems Pb has two origins: a natural one and an anthropogenic one. In an interesting way Pb isotopic composition allows to distinguish these two origins. Geochemical characteristics of open field rain water, throughfall, soil solution, spring and streamwaters in the small granitic Strengbach catchment (Vosges, France) have been regulary determined for ten years (Probst et al., 1995; Dambrine et al., 1995) and specifically during hydrological event (Ladouche et a/.,1995). Major elements, dissolved organic carbon (DOC), trace element contents were particulary analysed. The different water fluxes distinguish one another by specific geochemical features. Following these previous studies, a specific analysis of the Pb absolute content and isotopic signature was undertaken in these different water fluxes in order to identify the behaviour of this element in such an acid atmospheric polluted catchment and to distinguish the anthropogenic Pb from the substratum Pb. The following main points were reached: Isotopic compositions of the atmospheric anthropogenic Pb (from the rain) and of the substratum (granite) distinguish clearly one another. The water fluxes display Pb isotopic compositions in between these two extremum values (17.8 < 2~176 < 18.9) (Fig. 1).

Fractionation of zinc in greenhouse soils

Abstract The Zn content in 8 soil chemical fractions was determined for 21 greenhouse soils and for 8 reference (open field) soils from Kochi Prefecture, Japan to investigate the forms of spontaneously accumulated Zn in the greenhouse soils associated with heavy application of fertilizers and manures. Sequential extraction method was applied to every soil and each Zn fraction was designated as exchangeable (Ex-Zn), Pb-displaceable (Pb-Zn), acid soluble (Aci-Zn), Mn oxide-occluded (MnO-Zn), organically bound (OM-Zn), amorphous Fe oxide-occluded (AFeO-Zn), crystalline Fe oxide-occluded (CFeO-Zn), and residual (Res-Zn) fractions. The Zn content of the greenhouse soils was significantly higher than that of the reference soils in every fraction, except for the CFeO-Zn, and Res-Zn fractions. The Pb-Zn, Aci-Zn, and MnO-Zn fractions showed a difference of more than 60% in the total Zn content between the two soil groups. The amounts of Zn extracted in the Pb-Zn, Aci-Zn, MnO-Zn, AFeO-Zn, and CFeO-Zn fractions of t...

Influence of acid atmospheric inputs on surface water chemistry and mineral fluxes in a declining spruce stand within a small granitic catchment (Vosges Massif, France)

The characteristics of surface and soil waters draining an old declining spruce stand, and their chemical behaviour under acid input influence within a small catchment are described using open field precipitations, throughfalls, soil solutions, spring and streamwater data. Element fluxes are calculated in the different ecosystem compartments, and the proton mass balance has been assessed. The results show the importance of acid occult deposits and, more generally, of acid atmospheric inputs, in explaining present soil acidification. This acidification is characterized by the base cation deficiencies observed in spruce thereby showing symptoms of decline. However, stream waters and spring waters are not yet acidified owing to the neutralization of acid inputs by weathering in the regolith. Nevertheless, streamwater chemistry is dominated by strong acid anions which are not characteristic of waters draining granitic bedrock in pristine areas.

Negative allelopathic effects of rutin and quercetin on fourteen soil and enteric microbes

The flavonoids rutin and quercetin were assayed separately and in combination for antimicrobial activity againts 14 soil and enteric microbes. Microbial inhibition was observed when rutin and quercetin (pH 5.7 and 5.8 respectively) solutions were not adjusted to pH 7.0. At neutral pH no antimicrobial activity was observed. The addition of flavonoids at neutral pH did not effect the bacterial growth curve of Agrobacterium tumefaciens or the exponential growth of Escherichia coli. Both bacteria grew to turbidity from a loop-inoculum in medium containing rutin or quercetin as the sole carbon source. Furthermore, medium containing rutin and/or quercetin did not decrease either the number or relative frequency of several microbes from open field and forest floor soil samples. It is concluded that microbial inhibition has not played a major evolutionary role in the production of flavonoids in plants.

Four bacterial soil populations characterized and compared by a factor analytical method.

Bacterial populations from four adjacent sites with different soils were compared. The sites sampled were acid forest humus, grassland soil, and adjacent duplicates of open field soil. About a hundred random isolates from each of the four soil samples, 467 in all, were submitted to 44 two-state tests. The correlations between the tests were computed in terms of the test results obtained with all the isolates. Forty-two of the tests were accepted for further consideration. Their correlation matrix was factorized, and the first nine principal factors, covering 99% of the total estimated communality, were taken into account after varimax rotation.With the aid of within/between population variance, the ecologically discriminating efficiency of the factors was determined. For qualitative description of the populations six significantly discriminating factors (P &lt; 0.1%) were used. These factors covered 56% of the total factor variance considered. The populations were characterized by the position in the 6-factor space of the point centroids (population means or "centers of gravity") of all the item points making up a population.The six factors of ecologically discriminating efficiency were dominated by attributes on (1) oxidase, and nitrate reductase, (2) Bacillus characteristics, (3) protocatechuic acid utilization, (4) pH tolerance, (5) nutritional demands, and (6) pigment-correlated hydrolytic abilities.The similarity or difference between the populations was expressed as the squared distance (d2) between the population means in the selected discriminating 6-factor space. This parameter varied from 10 for the pair of duplicate field soil populations, to 172 between one of the field soil populations and the forest humus population.