Fulltext search in archive

Little is known about the effects of air-drying and freezing on the transformation of phosphorus (P) fractions in soils. It is important that the way in which soils respond to such perturbations is better understood as there are implications for both P availability and loss to surface waters from soils. In this study, the effects of air-drying and freezing were investigated using two soils, one being a forest soil (FS) high in organic matter and the other being a sterile soil (SS) low in organic matter. Soil P was fractionated using a modified Hedley fractionation method to examine the changes of phosphorus fractions induced by air-drying and freezing. Generally, there were no significant differences of total phosphorus among the three treatments (CV% < 10%). Compared with field moist soils, freezing the soil evoked few changes on phosphorus fractions except that the resin-P increased in FS soil. On the contrary, air-drying significantly changed the distribution of phosphors fractions for both soils: increased the labile-P (especially resin-P) and organic-P (NaHCO₃-Po, NaOH-Po and Con.HCl-Po) at the expense of NaOH-Pi and occlude-P (Dil.HCl-P and Con.HCl-Pi). Resin-P significantly increased by 31% for SS soil and by 121% for FS soil upon air-drying. The effect of air-drying seemed to be more pronounced in the FS soil with high organic matter content. These results indicated that drying seem to drive the P transformation form occlude-P to labile-P and organic-P and accelerated the weathering of stable P pool. This potentially could be significant for soil P supply to plants and P losses from soils to surface waters under changing patterns of rainfall and temperature as predicted by some climate change scenarios.

The root system of six-year-old winter jujube (Zizyphus jujuba Mill. cv. Zhanhua) trees were manually pruned at 3, 5 or 7 times trunk diameter distance along both inter-row sides, to study the effects of root pruning on physico-chemical characteristics and biological properties of winter jujube rhizosphere soil. The results showed that the root pruning of 3 and 5 times trunk diameter distance increased the available nitrogen, phosphorus, potassium^[concentrations and pH values in the rhizosphere soil and decreased organic matter concentrations, the contents of amino acids, organic acids and total sugars in the root exudates, the populations of bacteria, actinomyces and fungi, and inhibited the activities of catalase, invertase and urease enzymes in contrast to the control in early stage when root pruning was applied. The determined indexes presented a reverse trend as those in early stage after new roots appeared. Compared to the control, the trees by root pruning had higher pesticides residues of the rhizosphere soil in the whole experiment. No differences were noticed between 7 times trunk diameter distance and the control. It is proposed that root pruning had greater impacts on physico-chemical characteristics and biological properties of the rhizosphere soil depending on root pruning intensity.

Combined application of organic and inorganic amendments was known to play a significant role in improvement of soil properties. A field experiment was conducted to explore the effects of gypsum, farmyard manure and commercial humic acid application on the amelioration of salt affected (saline sodic) soil. During this study, soil pH, electrical conductivity, sodium adsorption ratio, responses of root length and rice paddy yield were examined. Application of gypsum with or without farm manure and commercial humic acid decreased soil pH (8.26%), electrical conductivity (from 6.35 dS/m to 2.65 dS/m) and sodium adsorption ratio (from 26.56 to 11.60), and increased root length (from 9.17 cm to 22.6 cm) and paddy yield (from 695.7 kg/ha to 1644 kg/ha). A negative but significant correlation was observed between root length and electrical conductivity, sodium adsorption ratio (r = -0.93; -0.94, respectively, P ≤ 0.05), whereas positive and significant correlation with paddy yield (r = 0.96; P ≤ 0.05).

Amaranth is a promising C4-crop. However, for a wider spread of the crop a better understanding of factors that are influencing yield formation is crucial for optimizing the plant phenotype and enhancing yield. The present study wanted to clarify the effects of assimilate sources and sinks on yield formation by artificially altering source or sink size. Field experiments were conducted in Eastern Austria during three years with three genotypes, applying source-sink manipulation treatments at mid flowering (control, 50% of inflorescence removed, 50% or 100% of leaves removed). At maturity we measured shoot, inflorescence and grain dry matter, thousand kernel mass and number of seeds per plant. An average grain yield level of about 3.5 t/ha dry matter on control plots indicated favorable growth conditions for amaranth in general. The removal of all leaves had a strong detrimental effect on all parameters, but severity of yield reduction due to defoliation differed between genotypes, ranging from -49% to -73%. Contrastingly, 50% flower reduction did not have any significant effects. Also with 50% defoliation no significant yield reduction was observed. We conclude that source strength of amaranth during flowering is more yield limiting than its sink capacity.

Opium poppy (Papaver somniferum L.) is currently an important agricultural commodity, with the product being used in the food industry (seed) as well as in the pharmaceutical industry (morphine and other alkaloids). Intensive production of poppy leads to a specific direction of breeding with the aim to obtain highly productive cultivars of the so-called food industry or industrial type. The paper evaluates 57 genetic resources (mostly cultivars), comparing the groups of values representing the indicators of production-significant morphologic and agricultural characters (capsule size; morphine content in poppy straw; weight of dry, empty capsule) and content of morphine in the poppy straw, in relation to the ideotype of poppy, which in these indicators represents 100% of the value. On average lower values in the above indicators were achieved by cultivars with white-coloured seed, including morphine content; concrete data are specified in three cultivars with morphine content in the poppy straw above 0.40%. In blue-seed to grey-seed cultivars, except for the high-morphine cultivar Buddha (1.85% of morphine), we found only six materials with a minimum morphine content of 0.8% in the poppy straw (maximum of 0.92%). These genetic resources also achieved very good values in the morphological indicator and average value in the economic indicator. The results will be used in the selection and classification of suitable genetic resources of poppy in breeding of industrial forms.

Declining water is a great concern in production of rice, because rice is more sensitive to water deficiency which restricts normal rice growth resulting in enormous economic loss. A field experiment was conducted to study the effect of hydrogel in different sowing techniques of aerobic rice viz. flat, ridge, and bed sowing. Observations on soil moisture percentage before every irrigation, yield, and yield components of rice were recorded. Application of hydrogel improved soil moisture contents in all the three sowing techniques as compared to soil without hydrogel. More soil moisture contents met the crop water needs and increased the number of germinated seeds. As a consequence of more emergence and better stand establishment, the yield components were also improved increasing the yield of rice in hydrogel amended soil in all sowing techniques. However, sowing of rice on beds with hydrogel amendment was found the most effective; it not only improved the performance of aerobic rice but also enhanced growth and yield of aerobic rice more than other sowing techniques.

Soil tillage practices involving various depth, intensity, and different methods of loosening the soil and treating plant residues have changed significantly in recent years and have spread also due to technical advance. The reasons are not only in expected benefits for crop production economics but also in preserving and increasing soil fertility. Although the practices were known for decades, their greatest development and use was seen only in the last 15 years, when decreasing production costs, efficient technology and effective herbicides were the main reasons for their development. At present, they are regarded as important alternatives to conventional management practices with moldboard plowing. Minimum soil tillage practices can contribute to effective soil management, however, risks associated with using these practices in various farming conditions shall be regarded. For cereals, these risks also include disease severity that is conditioned by several circumstances, which change along with the crop management practice, variety assortment or weather in individual years. Diseases that can be of greater importance in relation to the conservation soil tillage practice are stem-base diseases, root diseases and Fusarium head blight. Our experiments did not demonstrate an increased demand for protection against Fusarium head blight, foot diseases and take-all in the given system (three-crop rotation where wheat followed white mustard). Individual years were an important factor.

Two osmoprotectants (proline - Pro; trehalose - Tre) were exogenously supplied to seedlings of rice cvs. Pokkali (PK - salt-tolerant) and Khao Dawk Mali 105 (KDML105 - salt-sensitive) to investigate their effects on plants exposed to 200 mmol/L NaCl for 6 days and 5 days after recovery from stress. The reduction of growth, increase in Na⁺ to K⁺ ratio, high level of hydrogen peroxide (H₂O₂) content, enhanced activity of antioxidant enzymes (superoxide dismutase - SOD, peroxidase - POX, catalase - CAT and ascorbate peroxidase - APX) were observed in both rice cultivars under NaCl treatments. Exogenous Pro and Tre supplement to NaCl-stressed plants did not mitigate the reduction of growth during salt-stress. Nevertheless, during recovery plants previously supplied with Tre showed markedly higher percentage of growth recovery than those treated with NaCl alone or supplied with Pro. The beneficial effect of Tre on growth recovery was clearly demonstrated in KDML105 in which growth enhancement was related to reduction in Na⁺ to K⁺ ratio. Exogenous Pro was able to reduce H₂O₂ in both cultivars during salt stress whereas Tre could reduce it only in KDML105. Exogenous Tre did not enhance any antioxidant enzymes during stress but enhanced APX activity in KDML105 during recovery. Exogenous Pro enhanced the activity of APX in PK, and POX, CAT and APX in KDML105 during both stress and recovery period.

One of the factors frequently affecting yields is topography. Topographic data can be obtained from various sources with different precision. This work evaluates suitability of airborne laser scanning data for use as another source of topographical characteristics creation in a smaller scale in regards to precision agriculture needs. Simple models of elevation, slope and flow accumulation were created and the correlation between yield and topography was determined over a seven-year period in relation to precipitations and temperature. The suitability of airborne laser scanning data was proved with certain limitations. Flow accumulation model derived from original airborne laser scanning data indicated the right trend of flow accumulation but not as clearly compared to other models. In drier years the correlation coefficients between flow accumulation and yield reached up to 60-70%.

We have tested the effect of water, methanol and dichloromethane extracts from the leaves of several species of Impatiens (I. noli-tangere, I. parviflora, I. glandulifera) on germination of seeds Leucosinapis alba and Brassica napus. All of the tested extracts had inhibitory effects to seeds of all studied plants (except the dichloromethane extracts). The highest activity revealed methanol extract and extract from I. glandulifera.

Organic manure is considered as a beneficial fertilizer on soil quality and an excellent alternative resource of chemical fertilizer (CF). However, organic manure from intensive farms may have a negative impact on soil quality because of containing some harmful components, such as heavy metal and antibiotics. The aim of this study was to determine the influence of poultry litter (PL) and livestock manure (LM) from intensive farming on soil physical and biological indicators of soil quality. Results showed that PL and LM amendment increased soil macropore and mesopore volumes and decreased soil micropore volumes. Tensile strength in PL and LM treatment were lower than those in CF, while soil aggregate wet stability index were greater than those in CF. Compared with CF treatment, the microbial biomass C and N contents (+89%, +74%), soil basal respiration rate (+49%) and soil microbial quotient (+45%) in PL and LM treatment were significantly greater. Significant linear correlations were found between soil organic carbon and most soil physical and biological properties (P < 0.01). The results suggested that modern intensive farm manures can be alternate chemical fertilizers as a main fertilizer to improve soil physical and biological indicators in a rice-wheat system.

To investigate the environmental advantages of using grass-clover binary mixtures over pure stands as winter cover crops, a serial of five field experiments (each designed as randomized complete blocks with four replicates) was carried out in eastern Slovenia. Trifolium incarnatum L. and Lolium multiflorum Lam. were sown in late summer as pure stands and binary mixtures. Pooled data calculated from all the experiments revealed that the soil mineral N in spring and accumulation of N by plants decreased with decreasing proportion of T. incarnatum in the binary mixtures, while the C:N ratio of cover crop organic matter increased. C accumulation was the highest when the seeding ratio of the binary mixture of T. incarnatum and L. multiflorum was 50:50. In the C and N environmentally sustainable management efficiency coefficients, three important traits of winter cover crops for environmental pro-tection were given equal importance (low soil mineral N content in spring, high C accumulation in plants, and high N accumulation in plants). The coefficient was higher for binary mixtures of T. incarnatum and L. multiflorum than for pure stands of these crops, proving the complex environmental advantages of binary mixtures over pure stands.

In 2004-2006 an influence of various plantation row spacings on yield and quality of hops was observed in field trials. A hybrid variety Agnus was selected for this purpose. The common space between the rows remained (300 cm). The tested distances of individual hop plants within each row amounted to 114 and 133 cm. We compared the standard kind of four trained bines from each hill with a new one (five bines per hill). The yield of hops was the highest if row spacing 300 × 114 cm was used (2.80 tons of dry hops per hectare). If spacing 300 × 133 cm was tested, the yield amounted to 2.69 t/ha. The lowest yield of hops was obtained when the common row spacing 300 × 100 cm was used (2.58 t/ha). Yield increase in the plots with new spacing was at the limit of significance. Weather was the main factor influencing hop crop in 2006. Statistically significant differences in the yield of hop cones were proved in the year with very good growing conditions (2005) as well as in the year with relatively bad weather conditions (2006). If average conditions prevailed (2004) no significant differences between experimental and control plots were observed. Alpha acid contents were the highest (12.45%) in the perspective row spacing (300 × 114 cm); a slight decrease was found when the spacing of 300 × 133 cm was used (11.92%). In the case of the control variant with the common row spacing 300 × 100 cm, alpha acid contents amounted to 12.29%.

In Europe, Rumex obtusifolius L. is the most problematic grassland weed species, especially under the conditions of organic farming. The aims of this study were (1) to investigate the effectiveness of repeated mechanical weeding of R. obtusifolius from the permanent sward, cut two or three times per year, by digging the plants out from 5 cm below the soil surface, and (2) to test the effect of nutrient availability on the effectiveness of mechanical weeding. In 2007, the manipulative experiment was established on permanent grassland infested by R. obtusifolius using the following fertilizer treatments: control, P, N, NP and NPK. Plants of R. obtusifolius were removed eight times during three vegetation seasons. No significant decrease in the density of R. obtusifolius was recorded after three vegetation seasons and density was not significantly affected by fertilizer treatment. The cover of R. obtusifolius decreased slightly, but significantly, over the study period from 7.5% to 4.5%. The cover of R. obtusifolius was only marginally affected by fertilizer treatment. Mechanical weeding by digging the plants out from 5 cm below the ground is not a sufficient method of control for R. obtusifolius in infested fertile grasslands, even when applied eight times during three vegetation seasons.

Pea (Pisum sativum L.), sunflower (Helianthus annuus L.) and maize (Zea mays L.) plants were cultivated for 10 days in hydroponics at 1mM and 7mM nitrate or ammonium concentrations at regulated pH 6 and ambient CO2 level. Plant growth, content of total N and both ions in plant tissues, uptake of water and both N ions were evaluated, N uptake related to transpiration mass flow and to diffusion supply was calculated. Pea and sunflower preferred nitrate nutrition while maize plants used both N ions. The content of total N as well as of both N ions in plant tissues increased with N level with some exceptions. The uptake of both N ions related to transpiration mass flow was dependent on transpiration rate and N ion concentration. At a 1mM N concentration the uptake of N ions related to transpiration mass flow was low and reached in maize up to 16 times, in sunflower 11 times and in pea 2-3 times lower values in comparison with diffusion supply. At a 7mM N concentration N uptake in pea plants was totally supplied by transpiration mass flow, in sunflower plants the ratio of N supply related to transpiration mass flow amounted to 50% and in maize plants N supply through diffusion prevailed, amounting to 70-80%. These results explicate N starvation at low N supply that can intensify at elevated CO2 causing decreased stomatal diffusion.

Influence of growth regulators chlormequat chloride, ethephon, trinexapac-ethyl, and a combination of chlormequat chloride and ethephon on decreasing sunflower height was examined in the years 2006-2009. Height was reduced by as much as 63 cm by double application of chlormequat chloride (915 g/ha) + ethephon (465 g/ha) at early and later growth stage (BBCH 32 and 50). Trinexapac-ethyl (375 g/ha) did not affect the height. One-time application of chlormequat chloride (1440-2160 g/ha), chlormequat chloride (458 g/ha) + ethephon (233 g/ha) (BBCH 30 or 50), or ethephon (480 g/ha) (BBCH 30) was sufficient for a ca 30 cm reduction during flowering, but this effect did not last until harvest. With double application (BBCH 30 and 50), reduction lasted until harvest. For ethephon (480 g/ha), application at BBCH 50 reduced height by as much as 35 cm and lasted until harvest. Combining a lower rate of ethephon with ammonium sulfate was effectively equivalent to using a full rate. Flower head diameter at maturity showed no significant negative influence compared to the control. In 2008 and 2009, a delay in flowering onset was observed after applying growth regulators.

The present investigation was conducted to know the impact of bio-inoculants in low input field conditions on the magnitude and direction of gene effects and mean performance of some morphological and productivity traits in three wheat cultivars WH 147 (medium mineral input), WH 533 (drought tolerant), Raj 3077 (drought tolerant) and six generations namely P₁, P₂, F₁, F₂, BC₁ and BC₂ of three crosses i.e. WH 147 × WH 533, WH 533 × Raj 3077 and WH 147 × Raj 3077. The experiment was conducted in randomised block design with three replications and three treatments i.e. control (C, without inoculation), inoculation with arbuscular mycorrhiza fungi (AMF, Glomus fasciculatum), and AMF + Azotobacter chroococcum (Azc). Mineral fertilizer (80 kg N/ha + 40 kg P/ha + 18 kg ZnSO₄/ha) was applied in all the three treatments. The application of bio-inoculants, AMF and AMF + Azc had a positive effect on plant height, peduncle length, grain yield, biological yield and harvest index in various populations of all the crosses. However, in some of the generations the impact of bio-inoculants was insignificant. The joint scaling test revealed that additive-dominance gene effects were mainly operative in governing expression of peduncle length, tillers per plant, plant height, grains/spike, grain yield and all traits except days to flowering and harvest index in crosses WH 147 × WH 533 and WH 533 × Raj 3077. The application of bioinoculants influenced gene effects for days to flowering, days to maturity, flag leaf area, spike length, grains/spike, 1000 grain weight and harvest index where complex genetic interactions were changed to simple additive-dominance gene effects in the cross WH 147 × Raj 3077. Likewise, additive-dominance gene effects were altered and digenic interactions exhibited for days to maturity, flag leaf area in WH 147 × WH 533 and days to flowering, plant height, flag leaf area in WH 533 × Raj 3077. Flag leaf area and plant height were governed by additive gene effects while for days to maturity and 1000-grain weight both additive and dominance gene effect were important. Duplicate epistasis was important in all the three crosses for days to flowering and harvest index and in the cross WH 147 × Raj 3077 for grain weight grains per spike and flag leaf area.

Leaching is one of the most practical methods for improvement of saline soils and both the quality and the quantity of leaching water play an important role in desalinization of these soils. To determine the effects of different qualities and quantities of leaching water on salinity of drainage water during the growing season of wheat, pot experiments were conducted with a silty clay loam soil, a typical salt-affected soil in an arid region of central part of Iran. The experiment comprised the treatments of three irrigation water salinities (4, 9 and 12 dS/m) and four leaching levels (3, 20, 29 and 37%), using a factorial design with seven replications for each treatment. The results showed that at the beginning of the growing season the drainage water salinity was highest for all treatments. Then it started to decrease and depending on the quality and quantity of leaching water it became nearly constant or continued to decrease until the end of the growing season. The leaching of salts from the soil profile was more efficient during the first few irrigations and thereafter became less efficient. The increase of leaching level had a significant effect on the decrease of drainage water salinity. The comparison with steady-state mass balance of soil salt, sodium and chloride showed that the simple ratio of chloride in irrigation water to chloride in drainage water can be used to estimate the leaching fraction of saline soils with high accuracy.

The objectives of present study were to determine the residual and cumulative effects of zinc (Zn) fertilizer on cotton (Gossypium hirsutum L.) and wheat (Triticum aestivum L.) in a silt loam Typic Haplocambid soil (< 0.05 mg/kg diethylenetriaminepentaacetic acid (DTPA)-Zn). The study comprised of two years field experiments where first cotton crop received zinc sulphate (ZnSO₄∙H₂O) at five rates (0, 5, 7.5, 10, 12.5 kg Zn/ha) in a randomized complete block design with four replications. After harvest, each plot was divided into two sub-plots. To study the residual effect, one sub-plot of all plots did not receive Zn fertilizer for the subsequent crops; however, the other sub-plot received all Zn rates for 2005-06 wheat, 2006 cotton, and 2006-07 wheat. Fresh applied, residual as well as cumulative Zn application significantly (P ≤ 0.05) increased crops production for both experimental years. Residual effect of 5.0 kg Zn/ha optimized the 2006 cotton yield; however, wheat productivity was optimized with residual effect of 7.5 kg Zn/ha in 2005-06 and of 10.0 kg Zn/ha in 2006-07. Optimum yield of both crops was attained with a lesser fresh-applied and residual Zn rate than cumulative Zn rate. Total Zn uptake by wheat (134.9-289.6 g/ha) was much greater than by cotton (92.3-192.5 g/ha). It is concluded that one application of 7.5 kg Zn/ha proved adequate for optimizing two cycles of the cotton-wheat production system. Two-year repeated use of 5.0-7.5 kg Zn/ha did not depress crop yields.

The effects of three tillage systems: no-tillage (NT), reduced tillage (RT) and conventional tillage (CT), and three levels of fertilization (0, 258 and 516 kg/ha NPK (58:18:24)), on the maize yield during ten years (1999-2008) were analyzed on the chernozem soil type in Zemun Polje, Serbia. Statistical analyses showed significant effects of all three factors i.e., year, soil tillage and amount of fertilizers, and their interactions on the maize yield. The ten-year averages showed that the highest yields were observed with CT (10.61 t/ha), while the averages with RT and NT were lower (8.99 t/ha and 6.85 t/ha, respectively). The results of the influence of the amount of the applied fertilizers on maize yield showed that the lowest yield was in the zero level of fertilization 7.71 t/ha, while the yield was raised when the 258 kg/ha and 516 kg/ha NPK were applied (9.18 t/ha and 9.56 t/ha, respectively). Analyzing the influence of the soil tillage systems on maize production with respect to the amounts of applied fertilizers, this research revealed the benefits of CT under the presented agroecological conditions, irrespective of the level of applied fertilizer.

This study aims to reveal and to compare effects of two different systems of nitrogen (N) nutrition (sidedress application or injection application) on toxicity of NH₄⁺ and mixed nutrition. We investigated whether NH₄⁺ or mixed (NH₄NO₃) application causes significant changes in the endogenous levels of cytokinins (CK), whole plant N and their effects on yield of selected plants. Ammonium sulphate or ammonium nitrate were used as N source in the pot experiment. The yield of Festulolium and Trifolium pratense L. above-ground biomass and roots was more substantially enhanced after sidedress application of both ammonium sources in comparison with injection application. Our results confirmed that the accumulation of CKs in plants is in correlation with their N content (R² = 0.66-0.98). Proportions between individual CK forms remained relatively steady and their dynamics exhibited similar trends after N application. Our results indicate that the negative effect of the application of NH₄⁺ on the growth of Festulolium and clover plants could be effectively modulated by the presence of NO₃^-.

Morinda citrifolia Linn. (family Rubiaceae) is a small tree occurring in tropical areas of the world. The plant contains several medicinally active components that exhibit the therapeutic effects such as antibacterial, antiviral and anticancer activities. Anti-genotoxic effects of aqueous extracts prepared using dried leaves of M. citrifolia was studied. Allium cepa root tip meristem cells treated with 7% hydrogen peroxide were used for eliciting anti-genotoxicity. For this purpose experiments were performed with A. cepa onion bulbs treated for 24 h with different concentrations (15 or 30 g/L) of aqueous extract with or without pre-treatment (1 h) with 7% hydrogen peroxide. A significant reduction in mitotic index was recorded in treatment groups over negative control. Chromosomal aberrations such as breaks, bridges, stickiness and polar deviations were observed in positive control and treatment groups. The highest (21.48) percentage of chromosomal aberrations was noticed in positive control. A significant reduction in chromosomal aberrations (9.39) was recorded in root tips treated with hydrogen peroxide followed by 15 g/L extract. H₂O₂ induced chromosomal aberrations were reduced due to leaf extract treatment indicates anti-mutagenic potential of the M. citrifolia. The observations suggest that M. citrifolia aqueous leaf extracts have anti-mitotic and anti-genotoxic effects; consequently oxidative stress induced aberrations due to H₂O₂ are efficiently restored in the extract treated A. cepa root meristem cells.

Changes in root anatomical structures at successive cycles of selection (cycle 1 to cycle 18, alternating) were observed in the study of maize (Zea mays L. cv. Saracura-BRS 4154) capable to survive and produce in temporarily flooded soils; this cultivars was developed by the Maize and Sorghum National Research Center through stratified phenotypic recurrent selection for cultivation wetland soils. Field trial was carried out and flooding of the soil was initiated at the six-leaf stage; the soil was flooded with water (20-cm deep) three times per week. Root sample was collected, fixed, and selected for observation in photon microscope. A gradual increase in the number of aerenchyma, the proportion of vascular cylinder, smaller metaxylem, and phloem and epidermis width, and a decrease in exodermis and cortex were observed in successive selection cycles. Such phenotypic changes impart the flood tolerance ability to this maize cultivar.

Agricultural practices that reduce soil degradation and improve agriculture sustainability are important particularly for dry hilly land of Chaoyang County in the Liaoning Province, North-east China, where cinnamon soils are widely distributed and mainly for wheat production. The impacts of 10-year cropping systems (wheat-cabbage sequential cropping, wheat-corn intercrop, wheat-sunflower rotation, wheat-soybean rotation) on soil enzyme properties of surface-soil (0-20 cm) were studied. Total carbon, nitrogen, phosphorus and sulfur, and nine soil hydrolases related to nutrient availabilities (β-galactosidase, α-galactosidase, β-glucosidase, α-glucosidase, urease, protease, phosphomonoesterase, phosphodiesterase, arylsulphatase) and five enzymes kinetic characters were examined. Wheat-corn intercrop systems had higher total C, total N, total P and total S concentrations than wheat-soybean and wheat-sunflower rotation systems. Most test enzyme activities (α-galactosidase, β-galactosidase, α-glucosidase, β-glucosidase, urease, protease, phosphomonoesterase and arylsulphatase) showed the highest activities under wheat-corn intercropping system. Urease, protease and phosphodiesterase activities of wheat-cabbage sequential cropping system were significantly higher than two rotation systems. The maximum reaction rates of enzymes (V_max) were higher than apparent enzyme activity, which suggests larger potential activity of enzymes, while not all kinetic parameters were adaptive as soil quality indicators in dry hilly cinnamon soil.

In 1998-2000, in a multi-factorial field experiment established by the method of split blocks and subplots, we studied the effect of three systems of beet tops management, two sowing rates and two levels of N fertilization and the effect of interactions of the factors on production and qualitative indicators of spring barley varieties Amulet and Kompakt. The evaluation shows the dominant effect of the particular year on the variability of all characters. The proportion of the effect of the year on the variability of characters ranged from 2.1 (number of plants per m2) to 80.1% (yield). The variability of quality parameters was also considerably affected by the genetic factor of the variety (grain over2.5 mmsieve 40.4%, TGW 20.5%). The level of characters was greatly variable in relation to the course of climatic conditions of the year. The highest grain yield was achieved in 1999 (7.21 t/ha), the lowest one in 2000 (5.25 t/ha). The best quality parameters were shown by grain from the 1998 harvest (yield 6.20 t/ha) with significantly highest TGW (47.76 g), a high proportion of grain over2.5 mmsieve (92.01%, 5.54 t/ha) and a favourable content of N substances in the grain (10.60%). Ploughed down beet tops supported the creation of the yield, the average differences between variants were, however, minimal being heavily affected by the course of weather in particular years. More favourable conditions for the creation of the yield (6.17 t/ha) and for the formation of mechanical properties of the spring barley grain (TGW45.55 g, grain over2.5 mmsieve 85.86%) were produced by variants with late ploughing down beet tops, the smallest accumulation of N substances occurred in variants with harvested beet tops (11.83%). Sowing rate significantly affected values of all studied characters. Variants sown 4.5 MGS (6.27 t/ha) gave higher average grain yields, grain of better quality was obtained from the stands sown 3.5 MGS (TGW45.22 g, grain over 2.5 sieve 84.41%, N substances 11.93%). Between particular varieties, significant differences were found both in the economic yield and the grain quality. The Kompakt variety showed on average 4.7% higher yield (6.37 t/ha) than the Amulet variety which, however, reached the higher average TGW values as well as the proportion of grain over2.5 mmsieve (45.87 g, 88.24%). The grain quality of the Amulet variety was negatively affected by the increased accumulation of N substances in the grain (12.49%). As compared with control, N fertilization at the rate of 30 kg/ha showed significant increase in the yield in 1998 only (by 7.5%) while in other years, an increase in the yield was not noticed. In all years under investigation, the TGW values and the proportion of grain over2.5 mmsieve decreased and the content of N substances in grain increased after application of N at the rate of 30 kg/ha.

Soil pollution of fluorine is a serious environmental problem in the world, and the fluorine pollution evaluation of spatial and vertical distribution study in the Karst region is quite limited. In this study, the farmland around lead-zinc mine in the Karst region was chosen as the study area. Ninety-one upper layer soil samples and two soil profiles (one in paddy field, the other one in aerated field) samples were taken. The average concentration of total fluorine of topsoil in the paddy fields is 378 mg/kg, whereas in the aerated field it is 508 mg/kg. The concentrations of total fluorine in all paddy soil samples and 97.87% aerated field soils are higher than that of the background value of Guangxi. The total fluorine contaminations in all aerated field soils are much higher than in paddy soil samples, so the aerated field is contaminated severely. The vertical distribution of fluorine is different in paddy field and aerated field. In paddy field, the content of fluorine increases from 20 to 40 cm, then it decreases rapidly from 40 to 60 cm in depth, and then increases gradually. However, in the aerated field, the content of fluorine rises gradually with the depth of the sampling point. The results of relative analysis and regression analysis between fluorine in soil and soil properties show that the spatial distribution and vertical variation of fluorine in this region are mainly affected by parent rock.

The effect of 24-epibrassinolide and 28-homobrassinolide on seed germination and seedling growth of radish (Raphanus sativus L.) was studied under cadmium toxicity. The impact of brassinosteroids (BRs) on free proline levels and the activity of antioxidant enzymes catalase (CAT; EC 1.11.1.6), peroxidase (POD; EC 1.11.1.7), superoxide dismutase (SOD; EC 1.15.1.1), ascorbic peroxidase (APOX; EC 1.11.1.11) and guaiacol peroxidase (GPX; EC 1.11.1.7) in radish seedlings under Cd toxicity was evaluated. The effect of BRs on the activity of ascorbic acid oxidase (AAO; EC 1.10.3.3) and lipid peroxidation in radish seedlings challenged with Cd stress was also investigated. BRs supplementation alleviated the toxic effect of the heavy metal and increased the percentage of seed germination and seedling growth. Out of the two substances, HBL was found to be more effective than EBL in stress alleviation. HBL (3µM) alleviated the toxic effect of the heavy metal and increased the percentage of seed germination by 57% over Cd and 20% over unstressed control. Similarly supplementation of HBL (3µM) caused an increase of 156%, 78% and 91% in length, fresh weight and dry weight of seedling, respectively, over Cd treatment alone. The amelioration of seedling growth by BRs under metal toxicity was associated with enhanced levels of free proline. The activities of antioxidant enzymes CAT, SOD, APOX and GPX were increased in the seedlings from treatments with Cd along with BRs. Brassinosteroid treatment reduced the activity of POD and AAO in heavy metal stressed seedlings. Lipid peroxidation induced by Cd was found reduced with the supplementation of BRs. The results obtained in the study clearly indicated the ameliorative influence of brassinosteroids on the inhibitory effect of Cd toxicity.

Limited water resources restrict winter wheat grain yield and quality in the Huang-Huai-Hai Plain of North China, and establishing optimal planting patterns according to crop water requirements is the key factor for achieving rational water use. In this paper, 4 planting patterns were applied, namely, uniform row (30 cm; traditional pattern), wide (40 cm)-narrow (20 cm) row, furrow (double lines in the furrow with 20 cm spacing, and 40 cm between furrows), and seed bed (double lines on the bed with 20 cm spacing, and 40 cm between beds). Each planting pattern was irrigated twice during the jointing and heading stages, and total irrigation water was controlled at 120 mm. Grain yield was significantly (LSD, P < 0.05) higher in the furrow planting pattern than in the uniform row, wide-narrow row, and seed bed planting patterns, by 73.4, 64.3, and 53.4 g/m², respectively, in 2004-2005 and by 54.3, 42.6, and 30.2 g/m², respectively, in 2005-2006, mainly because of a significant (LSD, P < 0.05) increase in the spike and kernel numbers. These results were caused by changes in the contribution of dry matter remobilization to grain yield (CDMRG); the CDMRG was higher in the furrow planting pattern than in the uniform row, wide-narrow row, and seed bed planting patterns by 5.1%, 4.3%, and 2.9%, respectively. Gliadin and glutenin contents in the furrow planting pattern were 4.67% and 5.85%, respectively, and were significantly (LSD, P < 0.05) higher than those in the uniform row, wide-narrow row, and seed bed planting patterns; however, the furrow planting pattern had no significant (LSD, P < 0.05) effect on albumin and globulin contents. Dough development time (DDT) and dough stable time (DST) in the furrow planting pattern were 5.6 min and 8.8 min, respectively; they were significantly (LSD, P < 0.05) improved compared to those in the uniform row, wide-narrow row, and seed bed planting patterns; however, there were no significant (LSD, P < 0.05) differences in dough breakdown time (DBT) between any of the planting patterns. These results suggest that the furrow planting pattern combined with deficit irrigation during the jointing and heading stages can be applied to winter wheat production in the Huang-Huai-Hai Plain of North China.

A field experiment was conducted to illustrate the different degree and dynamics of microbial community structure and function in the rhizosphere across four growing stages (before plantation and three growth stages) using a combination of biochemical (enzyme assay and microbial biomass carbon) and molecular approaches of qPCR and PCR-DGGE (polymerase chain reaction-denaturing gradient gel electrophoresis). Rice plant cultivation promoted higher enzyme activities (invertase and urease), microbial biomass carbon (C_mic), bacterial (16S rRNA) and fungal (ITS rRNA) genes abundances in the rhizosphere compared to unplanted soil. Principal component analyses of PCR-DGGE profile also revealed that structures of bacterial and fungal communities of rice planted soil were well distinct from unplanted soil. Moreover, enzyme activities showed a significant positive correlation with the total microbial biomass in the rhizosphere throughout growth stages of rice plant. Relative fungal: bacterial ratios were significantly higher in rice planted soil compared to unplanted soil, suggesting rice plantation enhanced the fungal community in the rice rhizosphere environment. These results further suggest a significant linkage between the microbial community dynamics and function in the rhizosphere associated with rice plant over time.

he study was undertaken to determine a possible role of polyamines (putrescine, spermidine, spermine) as antioxidants in salt tolerance of Chamomilla recutita and Origanum majorana. Salinity generally induced variable changes in growth, contents of oil and flavonoids of both plants; foliar application of any polyamines counterbalanced the effects of salinity. In general, the degree of stimulation differed according to the type and concentration of the used additive and the type of the plant.