Growth Dry Weight Research Articles

Exogenous Abscisic Acid Mediated Morphological Characteristics, Photosynthetic Pigments and Antioxidant Metabolism under Drought Stress in Rice (Oryza sativa L.)

Drought stress is one of the major abiotic stresses in agriculture worldwide. Drought also produces Reactive Oxygen Species (ROS), triggering a cascade of antioxidative defense mechanisms, and affects many other metabolic processes. It triggers a wide variety of plant responses ranging from physiological, biochemical to molecular levels. The primary challenge for increasing rice production is overcoming a global water shortage, which can severely limit rice yields. In the present study, response of drought stressed plants to abscisic acid (ABA) on antioxidant activities CAT, POD, APX, SOD were studied. The growth was gradually increased with increasing concentrations of ABA. The growth of plant, fresh weight, dry weight and relative water content was higher in the 200 mM abscisic acid. The photosynthetic pigments such as chlorophyll a, b and carotenoids content were increased in the 200 mM ABA as compared to the treated plants and control. The result indicates that increased growth in the 200 mM abscisic acid treated plants compared to control plants due to enhanced antioxidant activities. .

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The boiled water of Leaves and inflorescences of spiked pepper (Piper aduncum) is one alternative to control the pathogen of anthracnose (Colletotrichum gloeosporioides) in chili. The purpose of this study was to determine the activity of leaves and inflorescences of spiked pepper from different locations in suppressing the growth of C. gloeosporioides in vitro. The research was carried out in Phytopathology Laboratory of Pests and Plant Diseases Department, Faculty of Agriculture, Universitas Andalas from March to May 2017. The study used a Completely Randomized Design (CRD) with 5 treatments and 5 replications. Data from observations were analyzed by ANOVA and LSD at the level of 5%. The parameters observed were the growth of fungal colony area, wet and dry weight, number of conidia/ml of suspension and conidia germination. The results showed that the application of leaves and inflorescences of spiked pepper from different locations could suppress the growth of C. gloeosporioides in chili in vitro. Boiled water of inflorescences of spiked pepper from Bukit Lampu - Bungus - Padang City became the best treatment because it had the highest ability in suppressing C. gloeosporioides colony area with an effective suppression of 73.5% and reducing the highest germination capacity with an effective suppression of 23.28%. Its ability to reduce wet and dry weight were not different from inflorescences boiled water from Limau Manis, then the ability to suppress the number of conidia was not significantly different from leaves and inflorescences boiled water from Bukit Lampu and Limau Manis.

Maximizing the efficacy of Trichoderma to control Cephalosporium maydis, causing maize late wilt disease, using freshwater microalgae extracts

The main goal of this study was enhancing the biocontrol activity of Trichoderma spp. (T. harzianum, T. koningii, T. viride, and T. virens) against Cephalosporium maydis, the cause of late wilt disease in maize. Five isolates of C. maydis were isolated from diseased maize plants, showing late wilt symptoms, and were collected from infected maize fields in Gharbia Governorate, Egypt. Pathogenicity test revealed that all C. maydis isolates were able to attack maize plants (cv. Baladi), which cause late wilt disease. Isolate 3 (Cm3) was the most virulent of them. In in vitro experiments, vegetative growth of the mycelium of C. maydis was highly inhibited after opposite sides’ treatment by Trichoderma species on Potato Dextrose Agar plates amended with Chlorella vulgaris extracts (cool and hot extracts) than unamended one. Formulation of C. vulgaris extracts and Trichoderma spp. were prepared. The formulations maintained the capacity of Trichoderma spp. to inhibit growth of the pathogen for up to 1 year when stored at both room temperature or at 7 °C. These formulations (3-day-old) were examined for biological control activities against late wilt disease of maize. Under greenhouse and field conditions, all treatments reduced late wilt incidence compared to the untreated control. Treatments involved Trichoderma spp., and C. vulgaris extracts were more effective than that used individually. Both of the C. vulgaris extracts, with each of T. virens and T. koningii, were the most effective treatments in this respect. Under greenhouse conditions, formulation treatments (C. vulgaris extracts and Trichoderma spp.) significantly increase the plant growth of maize plants, i.e., plant height and plant dry weight as compared to the non-treated control either in infested or in un-infested soil with C. maydis. Under field conditions, these formulations increased the grain yield as well as ear parameters as compared with either C. vulgaris extracts or Trichoderma spp. alone as well as non-treated control. This study suggests that the efficacy of Trichoderma spp. was enhanced with C. vulgaris extracts and these formulations can be developed as bio-fungicides for minimizing the late wilt disease caused by C. maydis in maize.

Pertumbuhan Tanaman Kacang Tanah (Arachis hypogea L. Merril) Setelah Aplikasi Azotobacter chroococcum Dan Pupuk NPK

The combination of biological fertilizers and chemical fertilizers can support the concept of sustainable integrated farming and minimize the adverse impacts of chemical fertilizers. Azotobacter sp. is a soil microbe that used as a biological fertilizer because it can fix N and produce phytohormones which are crucial for plant growth. This research aims to study the growth of peanut plants after Azotobacter chroococcum and NPK fertilizer application. This research was conducted on July-November 2016 in field trials of PT. Pupuk Kujang, Cikampek, West Java with a height of 25 m above sea level. The experiments were performed using a randomized block design with three treatments, 2 L / ha Azotobacter chroococcum, 300 kg / ha of NPK and 2 L / ha Azotobacter chroococcum + 150 kg / ha of NPK with four replications. The results showed treatment with a dose of 2 L / ha Azotobacter chroococcum + 150 kg / ha of NPK fertilizer can increase the growth of plant height and root dry weight, whereas treatment with a dose of 300 kg / ha of NPK most improve plant shoot dry weight. Keywords: Azotobacter chroococcum, NPK, Plant Growth.

Pengaruh Takaran dan Frekuensi Aplikasi PGPR terhadap Pertumbuhan dan Hasil Tanaman Selada (Lactuca sativa L.).

Penelitian ini bertujuan untuk mengetahui dan membuktikan pengaruh takaran dan frekuensi aplikasi PGPR terhadap pertumbuhan dan hasil tanaman selada dan juga mengetahui takaran dan frekuensi aplikasi PGPR yang tepat untuk mendapatkan pertumbuhan dan hasil tanaman selada yang terbaik. Rancangan yang digunakan adalah rancangan acak kelompok (RAK) faktorial dengan tiga kali ulangan. Faktor pertama adalah takaran PGPR yang terdiri dari tiga aras yakni 25 g, 50 g dan, 75 g. Faktor yang kedua adalah frekuensi aplikasi yang terdiri dari tiga aras yakni tanpa penyiraman (kontrol), satu kali penyiraman dan, dua kali penyiraman. Hasil penelitian menunjukkan interaksi antara takaran dan frekuensi aplikasi PGPR terjadi pada semua parameter pertumbuhan dan hasil selada yakni tinggi tanaman, jumlah daun, luas daun, berat trubus baik segar maupun kering, berat akar baik segar maupun kering, berat tanaman baik segar maupun kering, berat tanaman per petak baik segar maupun kering dan indeks panen. Aplikasi PGPR sebanyak dua kali dengan takaran 25 g memberikan pertumbuhan dan hasil tanaman selada yang terbaik. ©2018 dipublikasikan oleh Savana Cendana.

Effects of cultivation period on catch crop chemical composition and potential for bioenergy production

The first step in biofuel and/or bio-based bulk chemical material production is assessing the amounts of useful substances in a potential biomass. Sugar, nutrients, ash, and functional ingredients (such as antioxidant compounds) in premature dent corn biomass cultivated as a catch crop (plant density; 60shootsm−2) over different cultivation periods (29 days, 49 days, 83 days) were investigated. The sugar recovery amount was estimated by multiplying two regression curves (saccharification efficiency curve, quadratic regression curve; dry weight growth curve, Gompertz curve). A simple economic analysis for ethanol production from the catch crop biomass was also carried out using previously reported process costs and the estimated sugar recovery amount. High plant density led to accumulation of plant biomass providing high amounts of plant dry weight and derived sugars per unit area. About 2700gDWm−2 (about 1400gsugarm−2) was harvested in the 49-day cultivation. The amount is significant compared with biomass yields of other candidates for energy crops. The estimated sugar recovery amount reached its maximum value near the end of experimental period (79-day cultivation). The longer cultivation period was better for sugar recovery although there was a slight decrease in saccharification efficiency with cultivation time. Based on the economic analysis, a higher ethanol price (about 200% higher than the current wholesale price) would be required for catch crop financial independence with around 50-day cultivation. Production of ethanol from catch crop biomass would not be feasible in the current situation. However, condensed biomass production through catch crops is still attractive and requires further research.

Influencia de vitaminas y aminoácidos en el creci­miento y esporulación de Mycena citricolor, Phoma costarricensis, Cercospora coffeicola y Ceratostomella fimbriata

The four most important pathogens of coffee trees in Costa Rica, Mycella citricolor, Phoma costarricensis, Cercospora coffeicola, and Ce­ratostomella fimbriata were grown in liquid cultures and on agar plates to test their responses to eleven different vitamins and to thirteen aminoacids separately and combined, in terms of growth (expressed as oven dry weight and diametral growth on plates) and of spoculation. None of the vitamins used improved growth significantly of Mycella citricolor, Phoma costarricensis or Cercospora coffeicola. Ce­ratostomella fimbriata grew best in thiamine and nucleic acid. Mycella citricolor and Ce­ratostomella fimbriata sporulated in thiamine only. Phoma costarricensis spoculated in five of the eleven vitamins used. The four organisms were favored in their growth by the presence of amino acids. L-tryptophane, L-valine and asparagin were the only amino acids that induced spoculation on the three fungi, Mycella citricolor, Phoma costarricensis and Ce­ratostomella fimbriata. Ce­ratostomella fimbriata did not grow in a mixture of amino acids.

Biofertilizer effect of free living nitrogen fixing bacterium on the growth and water quality properties of Penaeid prawn culture system

The role of phytoplankton is significant in improving the yield of prawn culture. The growth of phytoplankton will be effected various factors viz. dissolved oxygen, production of natural food to shrimp larvae in control of ammonia. The growth of phytoplankton can be enhanced by application of nitrogeneous fertilizers to improve water quality and growth performance of Penaeus indicus. The present research work is focussed on a free-living nitrogen fixing bacterium Azotobacter chroococcum supplemented by nitrogeneous fertilizers to increase the content of proteins, carbohydrates and wet weight of P. indicus. Ten animals of juveniles of P. indicus were collected and grown in controlled conditions for fifteen days. The liquid suspension of free living nitrogen fixing bacteria A. chroococcum has been inoculated for experimental treatment purpose. The inoculum has been introduced to four treatments and for findings of water quality analysis andphytoplankton growth analysis by Strickland and Parsons method and biochemical analysis by Raymont et al., method. The research findings revealed that A. chroococcum supplemented with fertilizers will affect the growth of phytoplankton which is vital in prawn culture and enhance the growth of hormones and dry weight for improvement of the yield.

Impact of Dairy Industrial Effluent of Punjab (India) on Seed Germination and Early Growth of Triticum aestivum

Objectives: The aim of the present research was to study the impact of dairy industry effluent fertigation on agronomical characteristics of wheat (Triticum aestivum). Methods/Statistical Analysis: The treatments of such effluent, namely 0%, 25%, 50%, 75% and 100% were used for the cultivation of wheat. The effluent of such industry had significant amounts of nitrogen (28mg/l), phosphorous (13.10mg/l), potassium (168.2mg/l), copper (0.75mg/l), iron (<1mg/l) and nitrate (11.9mg/l) that may support plant growth. The effluent had no heavy metals like Cd, Co, Ni and Pb. Findings: The studies exposed that effluent at dilution of 50% showed the significant effect on seed germination percentage of 94.10 after seven days of irrigation. The shoot length (33.20cm), root length (12.90cm), total growth of plant (46.10cm), dry weight (0.57g), chlorophyll content (0.60) and nitrogen content (2.70%) were increased after one month of treatment with 50% concentration at lab scale. Significantly increased shoot length (48.35cm), root length (9.20cm), total growth of plant (57.55cm) and dry weight (0.71g) were observed maximum at concentration of 50% at pilot scale. The maximum agronomic performance of wheat was noticed with 50% concentration of dairy industry effluent. Application: The treated effluent of dairy industry had potential to be used as liquid fertilizer by mixing it with soil after appropriate dilution.

Responses of Eucalyptus benthamii seedlings to the application of the organic fertilizer Bacsol

Eucalyptus benthamii is a tree species commonly planted in subtropical areas, including the Southern Brazil, due to its tolerance to low temperatures and frosts. The success of E. benthamii plantation depends on the seedlings vigor during transplantation. We hypothesized that improvement of chemical and biological properties of growth substrate would produce more vigorous E. benthamii seedlings. Thus, we applied increasing doses (0, 0.5, 1.0, 1.5 and 2.0 g per seedling) of the organic fertilizer Bacsol, which carries a consortium of potential plant growth promoting microorganisms, on the substrate, and measured the growth and development of E. benthamii seedlings. Two experiments were performed in 2011 and 2012. The first experiment included measurements in four growth stages to estimate the relative growth rates. The second one ended at the time that seedlings reached standard heights for transplantation (about ± 20 cm). Measurements on plant height, stem diameter, shoot dry weight and relative growth rates indicated that the application of Bacsol improved E. benthamii seedlings vigor and decreased the time needed in nursery, from 150 days to 90 days. The best responses occurred at doses from 1.3 g to 1.5 g per seedling. The data demonstrated that application of Bacsol in substrate is a promising technology to increase E. benthamii seedlings vigor.

Effect of Different Time of Sowing and Weed Management Methods on Weed Interference, Productivity and Profitability of Bt Cotton in Western Zone of Tamil Nadu

A field experiment was conducted at Tamil Nadu Agricultural University; Coimbatore during winter season of 2015-16 and 2016-17 to evaluates the influence of time of sowing and weed management on weed interference and productivity, profitability of Bt cotton hybrid. Result reveled that, Distinctive time of sowing in cotton impact the weeds and cotton growth. Advance sowing of cotton (1st August) with pre-emergence application of pendimethalin 38.7% CS followed by post-emergence pyrithiobac sodium 5% EC 62.5 g/ha significantly recorded lower total weed density and dry weight and better crop growth, higher seed cotton yield, net return and B: C ratio in both years of the experiment.

Enhance Growth and Biochemical Composition of Nannochloropsis oceanica, Cultured under Nutrient Limitation, Using Commercial Agricultural Fertilizers

Microalgae culture media should be economic, allow for high growth, satisfy the needs of microalgal cells and easy to prepare. In this study, we evaluate the effect of different media formula prepared from commercial agricultural fertilizers (CAGF), comparing to F/2 Guillard standard medium as a control medium, on growth (cell density, CD; dry weight, DW and specific growth rate, μ) and biochemical composition (lipid, protein, and carbohydrate) of Nannochloropsis oceanica. Comparing to N/P ratio (9.6) and actually quantity (12.36 g/l and 1.29 g/l, respectively) of F/2 standard medium, six N/P ratios (19.2, 9.6, 9.6, 4.8, 3.2 and 1.6) were prepared from Nitric Acid (N-Nt) or Ammonium Sulphate (N-Am), as a nitrogen source, with phosphoric acid (P), as a phosphorus source, for culturing media of N. oceanica. The results investigated that some CAGF media achieved significant (P ≤ 0.05) growth and biochemical composition higher than F/2. Comparing to lipid percentage (30.70 %) of F/2, the lipid percentage of N. oceanica cultured on different CAGF media were ranging from 18.40% to 46.12%, depending on nutrient limitation, nitrogen source, N/P ratios and actually atom concentrations. Finally, the use of CAGF constitutes a viable alternative of F/2 medium to reduce the production costs N. oceanica, the commonly used in marine hatcheries and also other biotechnological applications.

Response of contrasting root genotypes of castor (Ricinus communis L.) to water stress

Two contrasting genotypes for root biomass i.e. RG-111 with good root, RG-1520 with poor root were studied for root, shoot growth till 90 DAS in root structures and also in field for seed yield by imposing water stress (30-90 DAS) during late rabi (2011-12). The reduction in root length was less due to stress. But root volume, dry weight and shoot growth reduced with stress and the per cent reduction was less in poorer root genotype (RG-1520) compared to good root genotype (RG-111). With drought stress in field, the growth before relieving stress, seed yield of different order branches and total seed yield reduced significantly in both genotypes. RG-1520 showed adaptation to survive drought stress in root structure and in field by increasing chlorophyll content (SCMR), less reduction in relative water content (RWC), decrease in specific leaf area (SLA) and increase in bloomcontent as that of good root genotype RG-111. But, seed yield reduction was more in poor root genotype (RG-1520) and also recorded high drought susceptibility index (DSI) as its photo assimilates were spent for its survival in stress and assimilate translocation was less for seed growth. Hence good root is important for crop survival, growth and seed yield especially in drought conditions.

Growth and physiological response of Arundo donax L. to controlled drought stress and recovery

Soil water deficit constrains crop growth more than any other abiotic stress, both per se and in combination with other factors, making drought resistance a key element for the successful exploitation of marginal areas. Arundo donax (Poaceae), is a mesophyte that can adapt to a wide variety of ecological conditions, although its growth can be retarded by a shortage of water. The objective of the present research is to draw a comprehensive picture of the integrated response mechanisms of A. donax to controlled drought conditions, and characterize its ability to recover upon rewatering in terms of photochemical efficiency. Plants were subjected to a gradually applied drought stress for a period of three weeks, after which they were returned to fully hydrated soil conditions for one week. Overall, plant dry weight and key growth parameters were not significantly affected. However, detrimental effects were visible in the form of impaired leaf gas exchange, which influences the performance of photosynthesis, and pre-dawn leaf water potential (pdΨW), −92.1% of net CO2 assimilation rate and −0.36 MPa, respectively at the cessation of stress. Nonetheless, a rapid restoration of A. donax physiological functions was observed upon rewatering, testifying to the environmental plasticity of this species.

Formation of ‘Crioula’ guava rootstock under saline water irrigation and nitrogen doses

ABSTRACT The objective of this research was to evaluate the growth and formation of fresh and dry weight of ‘Crioula’ guava rootstock irrigated with waters of different saline levels and nitrogen (N) doses, in an experiment conducted in plastic tubes under greenhouse conditions. The experimental design was randomized blocks, in a 5 x 4 factorial scheme with four replicates, and the treatments consisted of five levels of water electrical conductivity - ECw (0.3, 1.1, 1.9, 2.7 and 3.5 dS m-1) and four N doses (70, 100, 130 and 160% of the N dose recommended for the cultivation of guava seedlings, cv. ‘Paluma’). The dose referring to 100% corresponds to 773 mg of N dm-3. The highest growth of ‘Crioula’ guava rootstock was obtained with ECw of 0.3 dS m-1 and fertilization of 541.1 mg N dm-3 of soil; increasing N doses did not reduce the deleterious effect of the salt stress on the growth and phytomass formation of ‘Crioula’ guava rootstock; irrigation with water of up to 1.75 dS m-1, in the production of guava rootstocks, promotes acceptable reduction of 10% in growth and quality of the seedlings.

Recovery of terrestrial plants in vegetative vigor and seedling emergence tests from exposure to atrazine.

Ten species of terrestrial plants, including 6 dicotyledonous and 4 monocotyledonous species, were exposed to a direct overspray of atrazine according to US Environmental Protection Agency seedling emergence and vegetative vigor study guidelines and subsequently evaluated for potential recovery. For each species, no-observed-effect rate (NOER), 10% effect rate, 25% effect rate, and 50% effect rate values were calculated (where possible) for a variety of guideline-required endpoints (but focusing on growth rate) for both the standard experimental phase and a recovery phase; and the rates subsequently were compared. For the seedling emergence study, the standard experimental (designated test 1) and recovery (designated test 2) phases encompassed days 0 to 14 and days 14 to 28, respectively. Similarly, for the vegetative vigor study, test 1 and test 2 encompassed days 0 to 21 and days 21 to 42, respectively. Plants were exposed to atrazine at nominal application rates ranging from 1.1 g active ingredient (a.i.)/ha (0.0010 lb a.i./A) to 28,000 g a.i./ha (25 lb a.i./A), depending on the species; the 28,000 g a.i./ha rate is greater than 12 times the maximum application rate of 2250 g a.i./ha (2 lb a.i./A) registered on corn. For seedling emergence, only 2 of 10 species tested, cabbage and tomato, provided clear rate responses in the initial 14 d of exposure (test 1). Based on a comparison of x% effect rate (ERx) and NOER values for growth rates of shoot length and shoot dry weight for days 0 to 14 relative to days 14 to 28, recovery was apparent for cabbage shoot length growth rate and tomato shoot length and shoot dry weight growth rates. Test application rates selected for the remaining 8 species showed either a weak response that did not allow a clear assessment of recovery or no response at all. For the vegetative vigor study, 9 of the 10 species tested provided clear rate responses in test 1 (days 0-21); corn did not demonstrate any herbicidal response up to the highest rate tested, 28,000 g a.i./ha. Based on comparison of day 0 to 21 (test 1) relative to day 21 to 42 (test 2) ERx and NOER values for shoot length, average growth rates indicated that 8 of 9 species clearly demonstrated an increase in 2 or more metrics (cabbage did not demonstrate a response based on shoot length). Clear recovery was also indicated by an increase in ERx and/or NOER values from test 1 to test 2 for shoot dry weight average growth rates for 7 of the 9 species (corn did not show a response, and oat and soybean showed variable responses). Thus, in most species, where initial herbicidal effects were observed, the effects are largely ameliorated over time.

Effects of supplementation of decapod zoea toArtemiabasal diet on fatty acid composition and digestive gland histology in common octopus (Octopus vulgaris) paralarvae

The present study aimed to evaluate the effect of the supplementation of different crab zoeas to enriched Artemia basal diet for Octopus vulgaris paralarvae during the first month of life. Paralarvae were fed using enriched Artemia nauplii alone and Artemia co-fed either first zoea stages of Grapsus adscensionis or Plagusia depressa. The experiment was carried out over a period of 28 days, in 0.12 m3 tanks with a flow-through rearing system. Growth in dry weight as well as mantle length and width were assessed weekly. Additionally, prey and paralarvae fatty acid composition and digestive gland (DG) histology were evaluated. Addition of low amounts of crab zoeas (approx. 100 indv. L−1 day−1) provided during critical life stages of O. vulgaris proved to be good enough to improve paralarvae growth and survival in comparison with those fed exclusively on enriched Artemia. These results were supported by the finding of a higher number of glycoprotein absorption vacuoles in the DG from paralarvae co-fed crab zoeas, suggesting a higher feeding activity. In addition, fatty acid analysis of crab zoea showed that these are good sources of dietary arachidonic and eicosapentaenoic acids during the octopus planktonic life stage, whereas the low docosahexaenoic (DHA) content suggests the use of additional DHA sources or higher zoea densities to meet paralarvae nutritional demand to carry out a successful metamorphosis to benthic life.

The importance of dietary HUFA for meagre larvae (Argyrosomus regius; Asso, 1801) and its relation with antioxidant vitamins E and C

Despite the interest of meagre (Argyrosomus regius) as a fast-growing candidate for Mediterranean aquaculture diversification, there is a lack of information on nutrition along larval development. Importance of highly unsaturated fatty acids (HUFA) and the antioxidant vitamins E and vitamin C has not been investigated yet in this species. Six diets with two levels of HUFA (0.4% and 3% dw), two of vitamin E (1500 and 3000 mg kg−1) and two of vitamin C (1800 and 3600 mg kg−1) were fed to 15 dah meagre larvae. Larval growth in total length and dry body weight was significantly lowest in larvae fed diet 0.4/150/180 and showed few lipid droplets in enterocytes and hepatocytes and lower HUFA contents than the initial larvae. Increase in dietary HUFA up to 3%, significantly improved larval growth and lipid absorption and deposition. Besides, among fish fed 3% HUFA, increase in vitamin E and vitamin C significantly improved body weight, as well as total lipid, 22:6n-3 and n-3 fatty acids contents in the larvae. Thus, the results showed that 0.4% dietary HUFA is not enough to cover the essential fatty acid requirements of larval meagre and a high HUFA requirement in weaning diets is foreseen for this species. Besides, the results also pointed out the importance of dietary vitamin E and C to protect these essential fatty acids from oxidation, increase their contents in the larvae and promote growth, suggesting high vitamin E and C requirements in meagre larvae (higher than 1500 and 1800 mg kg−1 for vitamin E and vitamin C respectively).

Allelopathic potential of Alnus nitida (Spach) Endl. Against two crop species.

Allelopathic studies were conducted by using aqueous extracts from leaves, stem twigs of Alnus nitida (Spach) Endl., litter and mulching in various experiments. It was seen that the germination, plumule growth, radical growth, no. and growth of seminal roots, fresh weight and dry weight of Triticum aestivum L and Brassica campestris L. were invariably significantly reduce in various bioassays. The aqueous extracts from leaves powdered were more inhibitory than stem twigs for test species Triticum aestivum Aqueous extract obtained at room temperature was more inhibitory than hot water extract. Litter and mulching experiments also proved to be inhibitory. It is suggested that various assayed parts of Alnus nitida (Spach) Endl., has strong allelopathic potential at least against the tested species. Further studies are required to see its allelopathic behavior under field condition against its associated species, to identify the toxic principle, and to evalvate as biocontrol agents for weeds, insect and disease control.

Effects of Rice Straw Amendment and Nitrogen Fertilization on Rice Growth and Soil Properties in Reclaimed Tidal Paddy Field

Farmers with forage barley (Hordeum vulgare L.)-rice (Oryza sativa L.) cropping system at reclaimed tidal lands burn crop residues to facilitate seedbed preparation or remove them for feed stock. This study was conducted to investigate the effect of rice straw amendment and N fertilization on soil properties and N uptake of rice under forage barely?rice cropping system at reclaimed tidal paddy field. Rice straw was applied at the rates of 0, 2.5 and 5.0 ton ha -1 and N was fertilized at 0, 100, 200 and 400 kg ha -1 . Although there was no significant difference in the growth and yield of rice, fresh and dry weight of forage barely increased with increasing the amount of rice straw. The amount of N uptake of rice at harvesting stage was 65.8-69.2 kg ha -1 by the amount of rice straw amendment, but there were no significant differences among rice straw amendment levels. After harvesting the rice, the soil salinity decreased with rice straw amendment compared to the control. After forage barely and rice cultivation, soil organic matter contents increased to 2.6-2.8 g kg -1 and 3.2-3.5 g kg -1 , respectively. The amount of N uptake of rice at harvesting stage increased up to 82 kg ha -1 in 400 kg ha -1 N applied plots which were 37.8 kg ha -1 higher than the control. Nitrogen fertilization decreased N recovery efficiency. The highest yield of rice was observed at 244 kg ha -1 N fertilization level, but the optimum N level was estimated at 168 kg ha -1 in order to keep the protein content of rice under 6.5%. Further researches on N uptake and application of organic matter according to soil salinity will be necessary to increase N use efficiency at reclaimed tidal paddy field.