Decrease In Dry Weight Research Articles

Influence of nano-SiO2 on geotechnical properties of fine soils subjected to freeze-thaw cycles

Nanoparticles have been recently used in various applications due to their availability and justified costs. Thus, the effects of such materials on physical, chemical and mechanical properties of soils are of great interest to investigate. In this research, the effects of freeze-thaw cycles on specimens stabilized by nanoparticles are investigated. For this purpose, nano-SiO2 is used as an additive to fine-grained soils subjected up to nine freeze-thaw cycles. Laboratory tests including standard Proctor, Atterberg limits and unconfined compression tests (UCTs) have been conducted on a clayey soil mixed with nano-SiO2. The samples were also cured for up to 42 days. The results show that when the clayey soil is stabilized with nano-SiO2, the optimum moisture content, liquid limit (LL) and plastic limit (PL) increase, while the maximum dry unit weight and PI decrease. An increase of nano-SiO2 up to an optimal of 2% and curing time up to 42 days improves the unconfined compressive strength (UCS) by about 63%. In addition, the increase in nano-SiO2 leads to brittle behavior of the specimens. Moreover, the freeze-thaw cycle decreases the UCS of the specimens. However, a descending trend for strength is observed in nano-SiO2 stabilized specimens compared with untreated clay. After nine freeze-thaw cycles, the strength of untreated and treated soil with 2% nano-SiO2 decrease by about 64% and 42%, respectively. Also, with increasing the freeze-thaw cycles, stabilized specimens exhibit more ductility.

Growth, nutrient uptake and enzyme activity response of Lettuce (Lactuca sativa L.) to excess copper

Copper is an essential element for plants, but its higher concentration can make disruption in plant growth. The current study was conducted to determine the impact of excess copper (Control 0.2, 200 and 400 µM of copper sulfate) on growth, chlorophyll content, nutrient uptake and enzyme activity in lettuce. The results of this study highlighted that chlorophyll content, superoxide dismutase and ascorbate peroxidase activity were higher in the plants exposed to copper treatments. The peroxidase activity (POD) showed a different behavior depending upon the copper concentration; in this respect, 200 and 400 µM of copper sulfate increased POD activity by 59% and 32%, respectively in comparison to the untreated one. Copper application causes a decrease in leaf area (leaf expansion), root and shoot dry weight. Copper sulfate clearly decreased N, K, P, Si, Zn and Mg content in leaves and roots, whereas it increased B content in roots. Based on the outcomes of the current study, it can be concluded that lettuce showed tolerance to copper toxicity by alteration in mineral nutrition uptake, enzyme activity, chlorophyll content and leaf expansion.

Compressibility of Compacted Clays Mixed with a Wide Range of Bentonite for Engineered Barriers

Compacted clay–bentonite mixtures are often used as compacted blocks and landfills in high-level radioactive waste repositories and clay liners, respectively. A better understanding of their compressibility behaviour is essential to guarantee the disposal safety. In this study, mixtures of clays and bentonite are used to investigate the compressibility and compaction behaviour. Three natural clays were selected with different physical characteristics, and clay–bentonite mixtures were prepared by mixing the bentonite content up to 50%. A series of standard compaction tests and consolidation tests were performed in the laboratory; the samples for the consolidation test were prepared at the optimum moisture contents and maximum dry unit weights. With increasing bentonite content, the liquid limit, plasticity index, optimum moisture content, initial void ratio and compression index of natural clays increase and maximum dry unit weight and yield stress decrease. It was observed that the effect of bentonite on geotechnical characteristics pronounced when bentonite content exceeded 10%. Correlations were also proposed to estimate the compression characteristics and compression curves of compacted clays using three physical parameters such as the initial void ratio, optimum moisture content and maximum dry unit weight.

Responses of Dry Bean to 2,4-D Ester Applied Preplant and Preemergence

Six field studies were completed in Ontario (during 2016 to 2018) to assess the tolerance of adzuki, kidney, small red and navy bean to 2,4-D ester at 528 or 1056 g·ai·ha-1 applied 14, 7 and 1 day before seeding (PP) and 3 days after seeding (PRE). 2,4-D applied PP or PRE caused as much as 4%, 6%, 7% and 8% injury in adzuki, kidney, small red and navy (white) bean, respectively. There was an increase in bean injury as the preplant interval decreased. At 1 WAE, 2,4-D applied at 1056 g·ai·ha-1 14, 7 and 1 day PP and 3 days after seeding caused up to 6%, 10%, 18% and 5% visible bean injury, respectively. The level of injury decreased over time with minimal bean injury (0 to 3%) at 8 WAE. Bean stand counts were similar to the non-treated control with 2,4-D applied at various timings except at 1 day PP when 2,4-D at the 2X rate decreased bean stand 13%. There was up to 23% and 43% decrease in bean dry weight with 2,4-D applied PP at 528 and 1056 g·ai·ha-1 7 and 1 day PP, respectively. Bean height (6 WAE) was not affected by 2,4-D applied at various timings except at 1 day PP when 2,4-D (1056 g·ai·ha-1) decreased bean height 10%. Additionally, there was no effect of 2,4-D treatments on bean maturity or yield. Based on these results, the safest times to apply 2,4-D are 14 days before seeding or PRE. Injury was higher when 2,4-D was applied 7 and 1 day PP. Injury was lower in adzuki bean compared to kidney, small red or navy bean.

Grazing impact on forage quality and macronutrient content of rangelands in Qilian Mountains, NW China

An important indicator of the rangeland health, associated with land degradation, is the ability of semi-natural rangelands to provide forage of sufficient quality for livestock production. In Qilian Mountains (Gansu Province, NW China) biomass production and forage quality are dependent on the seasonality of precipitation and temperature; most of the precipitation falls during summer season, when sheep, goats and yaks graze mountain rangelands. To sustain the rangelands and to improve the management strategies, the assessment of the forage quality should be implemented. The purpose of this research was to study the response of biomass, forage quality and macronutrient content different levels of grazing intensity in Qilian rangelands. We sampled aboveground biomass in the growing seasons in 2012 and 2013 within spring/autumn or summer grazing regimes in two altitudinal zones below and above 3000 m a.s.l. (montane-subalpine and subalpine-alpine respectively). In order to estimate forage quality, biomass was sampled in 1 m × 1 m plots, assigned to the center of 10 ×10 m sites, from which we collected different indicator parameters of rangeland health. Mineral and fiber content of forage biomass was estimated under different levels of grazing intensity with regard to the growing period. It was found that an increase in grazing intensity led to a decrease in dry matter weight. No linearity was observed in the relationship between nutritive value and grazing intensity. The highest fiber content (59.20 %) was found in plots mostly disturbed by grazing. The highest protein (16.30 %) and the lowest fiber (51.30 %) contents were associated with slightly grazing intensity. Concentrations of the mineral elements, such as Zn, P, K and S varied significantly and showed maximum values under low grazing intensity.

Uticaj suše na fiziološke odgovore biljaka kukuruza dobijenih iz semena različite starosti

Drought is one of the main consequences of climate change that negatively affects plant growth and development, which in turn leads to a reduction in yield. The objective of this study was to investigate the effects of the physiological responses to the drought stress of maize plants (population IP3722), obtained from seeds of different ages (originating from 2012. and 2016) and different previous experience (the seeds formed in 2012. were more exposed to drought than in 2016.). Two populations responded to drought treatment by a significant decrease of shoot fresh and dry weight, this was followed with decrease leaf area and transpiration rate. Drought treatments enabled induction and differentiation of chemical signals of drought (abscisic acid-ABA and xylem pH) and hydraulic signals (leaf water potential), and monitoring of their activity on stomatal conductance. The data showed that hydraulic signals have the same impact on stomatal reactions in the D2012 and D2016 treatments. They also indicated that the chemical signal of ABA works toward stomatal closure, but that the effect depends on whether it originates from the leaf or the root. Leaf-originating ABA had more effect on the closure of D2012 stomata, while root-originating ABA and pH was more active in the D2016.

Effect of Cadmium Repartition on Nitrogen Metabolism in Tobacco Seedlings

Thirty-day-old tobacco seedlings (Nicotiana tabaccum, Bureley v) were subjected during one week to increasing cadmium (Cd) concentrations (0, 10, 20, 50 and 100 μM CdCl2). Increasing Cd stress led to a gradual decrease of dry weight (DW) production, water and nitrate contents. More than the half of Cd accumulated per plant was sequestered in the oldest leaf stage (S1 leaves). Leaves from S1 were the least affected by Cd stress. The activities of nitrate reductase (NR, EC 1.6.1.6), nitrite reductase (NiR, EC 1.7.7.1) were the least reduced in S1 leaves despite of the high presence of Cd ions. At 100 μM Cd, glutamine synthetase activity (GS, EC 6.3.1.2) from S1 leaves rose to become 2 times more important than control. Western Blot analysis showed that S1 GS activity induction was correlated to the GS1 and GS2 protein accumulation. Young leaves (S3 leaves) were more affected by Cd stress than old leaves. The GS activity reduction in S3 leaves was correlated to GS2 protein decrease detected by western-blot analysis. So, tobacco plant accumulated Cd ions in old leaves (S1 leaves) to protect younger leaves which are more sensitive to Cd effects. Leaves from S1 are a target organ to verify an eventual soil contamination per cadmium. This leaves may evolve adaptive process to partially inactivate Cd ions and maintain stable rate of nitrogen metabolism.

Aktivitas Ekstrak Metanol Daun Akasia (Acacia mangium Wild) Terhadap Perkecambahan Dan Pertumbuhan Maman Ungu (Cleome rutidospermaeD.C) Dan Rumput Grinting (Cynodon dactylon L. Pers)

Acacia (Acacia mangium Wild.) have alelokimia compound that can suppress the growth of the plants that it can be used as bioherbicide. This aimto study determined the concentration of the methanol extract of leaf of acacia capable of inhibit the germination and growth of weed, purple maman (Cleome rutidospermae DC.) and grass grinting(Cynodon dactylon L.). This study use a completely randomized design (CRD) with five replication and five treatment consist of control, concentrationmethanolextract0.2; 0.4; 0.6 and 0.8 g mlˉ1.Resultshowed that the methanol extract of leafacacia with a concentration of 0.4 g mlˉ1able to inhibit germinationpurple maman and grass grinting. Concentration of 0.2 g mlˉ1extract acacia can inhibit the growth of plant height, root length, and a decrease in wet weight and dry weight in weed purple maman andgrass grinting

Influence of nano-zinc oxide on tropane alkaloid production, h6h gene transcription and antioxidant enzyme activity in Hyoscyamus reticulatus L. hairy roots.

The use of nanotechnology and biotechnology to improve the production of plant bioactive compounds is growing. Hyoscyamus reticulatus L. is a major source of tropane alkaloids with a wide therapeutic use, including treatment of Parkinson's disease and to calm schizoid patients. In the present study, hairy roots were obtained from two-week-old cotyledon explants of H. reticulatus L. using the A7 strain of Agrobacterium rhizogenes. The effects of different concentrations of the signaling molecule nano-zinc oxide (ZnO) (0, 50, 100 and 200mg/L), with three exposure times (24, 48 and 72 h), on the growth rate, antioxidant enzyme activity, total phenol contents (TPC), tropane alkaloid contents and hyoscyamine-6-beta-hydroxylase (h6h) gene expression levels were investigated. Growth curve analysis revealed a decrease in fresh and dry weight of ZnO-treated hairy roots compared to the control. ANOVA results showed that the antioxidant activity of the enzymes catalase, guaiacol peroxidase and ascorbate peroxidase was significantly higher in the ZnO-treated hairy roots than in the control, as was the TPC. The highest levels of hyoscyamine (37%) and scopolamine (37.63%) were obtained in hairy roots treated with 100mg/L of ZnO after 48 and 72 h, respectively. Semi-quantitative RT-PCR analysis revealed the highest h6h gene expression was in hairy roots treated with 100mg/L of ZnO after 24 h. It can be concluded that ZnO is as an effective elicitor of tropane alkaloids such as hyoscyamine and scopolamine due to its enhancing effect on expression levels of the biosynthetic h6h gene.

Elimination of the Effect of Some Herbicides on the Growth of Zea mays and Accumulation in the Soil Using Urea

ABSTRACT: This study evaluates the effect of urea on growth of herbicide-treated maize and its accumulation in the soil. When the seedlings were 15 days old, the plots were divided into five groups. One group served as control, two received treatments with metolachlor and isoproturon at the dose of 1.5 kg ha-1 and 2.5 L ha-1, respectively. The two remaining groups received the same dose of herbicide along with urea added at a rate of 129 kg ha-1. The application of the two herbicides appeared to cause a significant decrease in shoot dry weight, photosynthetic pigments, d-aminolevulinate dehydratase enzyme [ALA-D, EC 4.2.1.24] and total soluble carbohydrates of the maize plants. The application of urea appeared to alleviate the effects of both herbicides on maize growth. A statistical analysis demonstrated a significant association between the soil criteria and the accumulation of herbicides in it. This study clearly highlights the urgent need for use of urea to retract the effects of herbicides on maize growth.

Effect of carbon-to-nitrogen ratio on eco-friendly mycoherbicide activity from Lasiodiplodia pseudotheobromae C1136 for sustainable weeds management in organic agriculture

The utilization of bioherbicides in place of chemical herbicides has been described as one of the sustainable eco-friendly technologies that can improve agricultural outputs. This work investigated the impact of different carbon and nitrogen sources on the bioherbicidal efficiency of Lasiodiplodia pseudotheobromae (C1136). The preliminary screening of various carbon and nitrogen sources was carried out, out of which sucrose and peptone were selected for further C:N ratio investigations using strain C1136. The fungus produces a different quantity of mycelium biomass and spores in varied ratios of C:N when compared to the basal medium. Also, the effect of C:N ratio was tested by evaluating for leaf necrosis assay, mortality rate and the dry-matter biomass from the aerial parts of Chromolaena odoratum and Echinochloa crus-galli under guided laboratory and screen house conditions. Both the 7.5:1 and 10:1 ratios produced optimal spores count of 6.1 × 107 and 5.9 × 107 CFU/mL, respectively (p = 0.05) when compared to the control containing potatoes dextrose broth without any carbon or nitrogen amendment produced a spores count of 1.1 × 107 CFU/mL. Also, the phytotoxic metabolite amended with C:N of 10:1 showed a strong herbicidal, high mortality and a significant decrease in dry weight on the seedling on the tested weeds. This demonstrated hypothetically the optimization influence of carbon (sucrose)–nitrogen (peptone) manipulations either in variable combination or as single nutrient based on the cultural development of strain C1136. Spores, mycelium biomass and biocontrol efficacy of the fungus all experienced accretion in sucrose and peptone nutrient environment and likewise support their use as an attractive alternative in the optimization of mycoherbicidal assays.

Bioherbicidal potential of rhizosphere bacteria for management of Phalaris minor weed

Phalaris minor is a problematic weed of wheat (Triticum aestivum L.). Repeated application of herbicides to control this weed causes environmental pollution and some of the weeds even develop herbicide resistance. Recently, phytohormones and allelochemicals produced by rhizosphere microorganisms have been found to suppress the growth of different weeds. Therefore, 32 bacterial isolates obtained from the rhizosphere of wheat were screened for the production of phytohormones indole-3-acetic acid (IAA) and 5-aminolevulinic acid (ALA). Rhizobacterial isolates, having variation in IAA and ALA production ability, were tested for their effect on seedling growth of P. minor on 0.8% water agar plates and four rhizobacterial isolates i. e. HWM 7, HWM 11, HWM 17 and CP 43 caused significant retardation of P. minor seedling growth on 5th and 10th day of seed germination. Under pot house conditions, seed inoculation with Bacillus subtilis strain SYB 101 caused 70.8 and 80.7% decrease in root and shoot dry weight of P. minor and its inoculation showed 136.8 and 316.6% increase in root and shoot dry weight of wheat at 75 days of wheat growth. P. minor growth was also suppressed in the pot house by inoculation of Providentia rettgeri strain CPS 67 and Pseudomonas isolate HWM 11. Maximum growth stimulation of wheat was observed by inoculation with rhizobacterial isolates SYB 101 and HWM 11. Maximum growth retardation of weed was observed by inoculation of B. subtilis strain SYB 101 having moderate level of IAA and ALA production, followed by high IAA and ALA producing P. rettgeri strain CPS 67, suggesting that besides phytohormones, some other metabolite was also involved in growth retardation of P. minor. These rhizobacterial isolates could be further tested for suppression of weed growth under field conditions for their subsequent application as bioherbicide.

Effects of sodic water irrigation on growth, physiological relations and ion uptake in two Ziziphus rootstocks

We studied the effects of sodic irrigation on growth, physiological parameters and mineral partitioning in Zizyphus rotundifolia (ZR) and Z. spina-christi (ZS) seedlings used as rootstocks for Indian jujube scion cultivars. Plants grown in normal soils were irrigated with fresh (control) and three kinds of sodic waters having residual sodium carbonate (RSC) levels of 3, 6 and 9 meq/l. Both the species displayed appreciable decreases in fresh and dry weights of shoots and roots at RSCiw level of 9 meq/l. Leaf chlorophyll and chlorophyll fluorescence also decreased with increasing sodicity. While leaf proline content remained unchanged up to RSCiw 3 meq/l, plants treated with 9 meq/l sodic water had nearly twofold higher leaf proline than control indicating that it could play a major role in osmotic adjustment in salt stressed plants. Na+ and Cl- contents increased while K+ and Ca2+ declined in different plant parts with increase in RSCiw. Na+: K+ ratio was higher at a given RSCiw in leaves and roots of ZS and in stems and roots of ZR reflecting better Na+ exclusion by ZR. ZR leaves also had less Cl- than ZS at a given RSCiw. Owing to these adaptive traits, both the species could tolerate RSCiw up to 6 meq/l.

Screening of jute and kenaf varieties for salinity tolerance

A study was conducted in the Department of Agronomy, Bangladesh Agricultural University (BAU), Mymensingh from April to August 2012 to examine the salinity tolerance of eight jute varieties (CVE-3, C-83, CVL-1, BJC-7370, O-795, O-9897, OM-1, O-72) and two kenaf varieties (HC-95 and HC-2). Initially germination of these varieties were evaluated under six salinity levels viz. 0mM, 20mM, 40mM, 60mM, 80mM, and 100mM NaCl in the seed laboratory of the Department of Agronomy. Afterwards, all the varieties was grown in pots in the net house under four salinity levels viz. 0mM, 25mM, 50mM, and 75mM. The results from the germination study revealed that under control condition (0mM NaCl) all the jute varieties showed germination more than 80% both at 7 and at 14 days after seed sowing, whereas kenaf varieties had germination a little less than 80%. Among the jute varieties, O-72 showed the highest germination (92%), which was statistically similar with those of OM-1(91%), O-795 (90%), and C-83(87%). Salinity stress decreased germination drastically in all of the jute and kenaf varieties. A salinity level of 100mM caused the highest germination inhibition (74.70%) in jute variety CVL-1, which was very close to those of BJC-7370 and O-72. On the other hand, the lowest germination inhibition (51.11%) was recorded in jute variety O-795. The results of the pot trail showed that the plant characters of jute and kenaf varieties were affected significantly by salinity stress. All the varieties produced their respective plant height, number of leaves per plant, and plant dry weight under control condition (no salinity). Among these varieties, CVE-3 produced the highest plant height (145.2cm), and total dry weight (22.55g), whereas O-72 produced the highest number of leaves per plant (24.67). All these plant characters decreased sharply due to salinity stress irrespective of variety. However, the rate of decrease of plant characters occurred differentially in the jute and kenaf varieties. The highest rate of decrease in number of leaves (74.22%) was found from the variety CVE-3, whereas the lowest one was recorded from the variety HC-2 (51.68%). Salinity stress caused the highest decrease in total plant dry weight (73.68%) in the variety CVL-1 and plant height (73.64%) also in the variety CVL-1. On the contrary, the lowest decrease in plant dry weight (50.99%) was found in the variety O-9897 and plant height also in variety O-9897 (50.88%). Based on the results from germination test and pot trail, it can be inferred that jute variety O-9897 appeared to be the most salt tolerant followed by O-795, HC-2, HC-95, CVE-3, O-72, C-83, BJC-7370, OM-1, and CVL-1.

Efficient superoxide scavenging and metal immobilization in roots determines the level of tolerance to Vanadium stress in two contrasting Brassica napus genotypes

Brassica napus also known as Rapeseed is a member of the Brassicaceae family which is mainly cultivated for its oil-rich seeds. Indeed, B. napus is ranked the third-largest source of vegetable oil in the world. Brassica napus growth, development and yield are negatively affected by heavy metals. Vanadium is a heavy metal and presence in high concentrations impact plant growth and development negatively. However, the impact of Vanadium on B. napus growth and development is unknown. Therefore, in this study we assessed the effects of Vanadium stress on leaf physiology and biochemistry response of two B. napus cultivars (namely Agamax and AV Garnet). A randomised pot-experiment under controlled conditions was used to grow B. napus cultivars under control (distilled water) and Vanadium (350 μM NaVO3) treatments. Results showed that Vanadium caused yellowing of AV Garnet leaves but not Agamax leaves. Furthermore, Vanadium stress caused a more severe decrease in leaf dry and fresh weight of AV Garnet as compared to the decrease in leaf dry and fresh weight of Agamax. We also observed that Vanadium stress only decreased leaf chlorophyll content (a, b and total) of AV Garnet but had no effect on chlorophyll content of Agamax. In addition, Vanadium stress induced an increase in toxic superoxide (O2-) content in leaves of both AV Garnet and Agamax however; we observed more O2- content in AV Garnet leaves than Agamax leaves. Furthermore, we observed a more drastic increase in leaf lipid peroxidation and leaf cell death (assessed by Evans blue uptake) of AV Garnet when compared to Agamax. In order to investigate whether Vanadium regulates O2- metabolising enzymes we assessed superoxide dismutase (SOD) activity (total SOD enzymatic activity and SOD isoform activity). Vanadium inhibited the total leaf SOD activity of AV Garnet more than the total leaf SOD activity of Agamax. The SOD isoform analyses displayed that Vanadium treatment did not alter the leaf MnSOD as well as leaf Cu/ZnSOD isoforms of both Agamax and AV Garnet. However, we observed that FeSOD 1 and FeSOD 3 activity was upregulated in Agamax leaves in response to Vanadium treatment but decreased in AV Garnet following Vanadium treatment. Furthermore, we observed that the leaf FeSOD 2 activity was inhibited in both Agamax and AV Garnet. In addition, we also analysed the Vanadium contents in the two cultivars following Vanadium treatment and observed more Vanadium content in Agamax roots than in AV Garnet roots. Furthermore, translocation factor (TF) analysis showed that AV Garnet had a higher Vanadium TF from roots to leaves than Agamax following Vanadium treatment. In conclusion, Vanadium stress tolerance in B. napus is possibly controlled by SOD activity and Vanadium content root immobilisation.

Artificial intelligence outperforms experienced nephrologists to assess dry weight in pediatric patients on chronic hemodialysis.

Dry weight is the lowest weight patients on hemodialysis can tolerate; correct dry weight estimation is necessary to minimize morbi-mortality, but is difficult to achieve. Here, we used artificial intelligence to improve the accuracy of dry weight assessment in hemodialysis patients. We designed a neural network which used bio-impedancemetry, blood volume monitoring, and blood pressure values as inputs; output was artificial intelligence dry weight. Fourteen pediatric patients were switched from nephrologist to artificial intelligence dry weight. Artificial intelligence dry weight was higher (28.6%), lower (50%), or identical to nephrologist dry weight. Mean difference between artificial intelligence and nephrologist dry weights was 0.497kg (- 1.33 to + 1.29kg). In patients for whom artificial intelligence dry weight was lower than nephrologist dry weight, systolic blood pressure significantly decreased after dry weight decrease to artificial intelligence dry weight (77th to 60th percentile, p= 0.022); anti-hypertensive treatments were successfully decreased or discontinued in 28.7% of cases. In patients for whom artificial intelligence dry weight was higher than nephrologist dry weight, no hypertension was observed after dry weight increase to artificial intelligence dry weight; when present, symptoms of dry weight underestimation receded. Neural network predictions outperformed those of experienced nephrologists in most cases, proving artificial intelligence is a powerful tool for predicting dry weight in hemodialysis patients.

EFFECT OF NITROGEN FERTILIZER RATES AND WEED CONTROL TREATMENTS ON WEEDS GROWTH AND PRODUCTIVITY, QUALITY, AND ECONOMIC FEASIBILITY OF TARO CROP

Two field experiments for taro vegetable crop were carried out in ElKanater El-Khiria, Horticulture Research Station, Kalubia Governorate, Egypt, in a split plot design during the two successive 2015 and 2016 seasons. This study aimed to investigate the effects of two nitrogen fertilizer rates at 90 or 120 kg/ fed. in main plots and nine weed control treatments in sub plots i.e. Harness at one liter/ fed., Sencor at 300 g/ fed. and Stomp extra at 1.7 liter/ fed. each individual and/ or plus Roundup at one liter/ fed., Roundup individual, hand hoeing twice after 25 and 40 days from sowing and untreated check (control) on weeds growth and vegetative growth, yield, quality and economic feasibility of taro. The main findings of this research revealed that nitrogen fertilizer rate at 90 kg/ fed. gave the highest decrease in dry weight of weed categories i.e. , broadleaf weeds, grassy weeds and total weeds in both seasons and increased diameter and weight of taro corm in the second season. Whereas, taro plant height, taro number of leaves/ plant and uptake of nitrogen by weeds were increased by application of nitrogen rate at 120 than 90 kg/ fed. during the two seasons without any significant differences in the yield of taro, its components, chlorophyll content and chemical analysis characterized. The use of Stomp extra at 1.7 liter/ fed. applied as post-sowing plus Roundup at one liter/ fed. after 25 days from sowing applied as taro pre-emergence above soil surface exhibited significantly decreased in dry weight of total weeds by 96.9 and 95.1 % in first and second seasons, respectively. Application of Seconr at 300g /fed. plus Roundup at rate of one liter/ fed. reduced the previous total weeds by 93.3 and 94.5% and increased taro yield (43.6 and 43.5%) in the first and second seasons, respectively. Thus, these herbicides can broaden weed control weed spectrum with long weed control season, which minimize taro yield by weed competition, consequently eliminated N uptake from soil and improved protein and starch accumulation in favor taro crop yield. Also, it can be advised as alternative hand hoeing to weed control in this crop with economic feasibility and delectable herbicides residues and under permissible levels which accompanied with high quality for taro growth characteristics i.e. plant height, number of leaves/ plant and chlorophyll reading in leaves, corm length, corm diameter, corm weight, corm fresh yield, dry matter % and chemical of taro corms (protein percentage, starch percentage and total nitrogen of corm yield).

Characterization and Utilization of Pulp and Paper Mill Sludge Digesting Thermophilic Bacteria in Composting Process

Pulp and paper mill sludge (PPMS) was found to be poorly colonised with thermophilic microorganisms. However, evidence to support the need for inoculation to facilitate PPMS composting has only been demonstrated in one instance. In this study, we aimed to: screen and identify PPMS digesting thermophilic bacterial strains; investigate effects of the mixture of selected thermophilic bacterial strains on PPMS digestion; and utilize this mixture as start inoculum in PPMS composting and assess the quality of compost product. The results showed that eleven thermophilic bacterial strains were isolated from Bai Bang PPMS by the enrichment culture method. Among these, three strains which reflected high growth rates on the plates of Minimal Media Agar supplemented with Bai Bang PPMS and showed hydrolytic and ligninolytic activities on the agar plates containing appropriate inductive substrates were selected. Based on the morphological, biochemical characteristics and 16S rRNA gene sequencing, they were identified as Bacillus subtilis. The inoculation with the mixture of selected strains enhanced remarkably Bai Bang PPMS digestion. The dry weight decrease, volatile suspended solids removal, dehydrogenase and protease activities in the inoculated sludge were 2.1-, 1.5-, 1.3- and 1.2- fold higher, respectively, compared to the non-inoculated sludge. The assessment of compost quality based on stability using the alkaline trap method and maturity using the germination and root elongation test showed that the inoculated compost was stable and mature while the non-inoculated compost was unstable and immature. These thermophilic bacterial strains therefore have great potential for Bai Bang PPMS composting.

Physical Characterization of a Deep Weathering Profile Over Rhyolite in Humid Tropical Peninsular Malaysia

The weathering profile, exposed at 38.2 km of the Kuala Lumpur—Karak Highway, can be differentiated into three broad zones; the topmost Zone I (pedological soil) comprising A, B and C soil horizons and made up of clayey silty sand with indistinct relict bedrock textures. The intermediate Zone II (saprock) consists of gravelly silty sand with distinct relict bedrock texture and structures, and can be sub-divided based on differences in volumes of litho-relicts. The bottom Zone III (bedrock) is a continuous outcrop of rhyolite with alteration along discontinuity planes; its upper surface marked by an unconfined groundwater table. The weathering zones thin towards valley sides and can be assigned rock mass weathering grades; Zones I and II defining the residual soil over bedrock. Constant volume samples in Zone II show an upward decrease in dry unit weights, porosities and silt contents, but a corresponding increase in clay contents. Constant volume samples in Zone I show it to be distinct from Zone II with large clay contents but low porosities and silt contents. Decreasing fine clay contents with depth and stained quartz grains show pedological processes to have given rise to Zone I. As the silt-sized (sericite) particles mainly originate from alteration of bedrock feldspars and later break-down to clay-sized (illite and kaolinite) particles, a textural weathering index (Iw) based on the ratio of clay to silt and clay contents, is proposed to describe the progress of weathering within the profile. It is concluded that the saprock results from in situ alteration of the rhyolite rock mass due to lowering of an unconfined groundwater table whilst the A, B and C soil horizons have formed by pedological processes acting on saprock.

Perubahan Komposisi Gulma pada Sistem Tumpangsari Padi Gogo dengan Kedelai di Lahan Pasir Pantai

Weeds can reduce upland rice yields in coastal sandy area. Density and growth of weeds can be controlled and reduced by an intercropping system between upland rice with soybeans. The study aimed to determine the weeds composition change and weeds biomass in various crop proportions of upland rice and soybean under intercropping. The research was conducted from December 2016 until March 2017, at coastal sandy soil of Samas, Bantul, Yogyakarta (8°00’03.5”S and 110°15’20.1”E). This study used a complete randomized block design (RCBD) with one factor and three replications. The treatments were crop proportions of upland rice and soybean under intercropping with 6 levels, such as 100:0 (upland rice monoculture), 80:20, 60:40, 40:60, 20:80, and 0: 100 (soybean monoculture). The results showed that there was weeds composition changes due to setting crop proportions of upland rice and soybean under intercropping at coastal sandy soil. Weed of sedges, grass, and broadleaf were found throughout the experimental plots, but varied in number and type of weeds among experimental plots. Weeds condition differed among the soybean proportion treatments < 40% and ≥ 40%. The average community coefficient value was <75% which was dominated by Digitaria nuda and Eragrostis tenella under soybean proportion treatments < 40%, and Ludwigia parviflora and Amaranthus lividus under soybean proportion treatments ≥ 40%. The linear model was established between the increase of soybean proportion to a decrease in dry weight of weeds as Y = -0.6624X + 67.699; R2 = 0.7224).<br /><br />Keywords: crops proportion, intercropping, weeds community<br /><br />