Effect Of Rice Straw Research Articles

The Effect of Rice Straw and Tall Fescue Hay for Holstein Dairy Heifers on Growth, Age at First Calving and Feed Cost

The Effect of Rice Straw and Tall Fescue Hay for Holstein Dairy Heifers on Growth, Age at First Calving and Feed Cost

Linking the potential activities of methanogens and methanotrophs to their communities under different fertilization regimes in coastal saline paddy soils

Methane (CH4) emissions are primarily dependent on the net balance between the activities of methanogens and methanotrophs. Straw returning (straw residue incorporation) and nitrogen (N) fertilizer applications are two of the most frequent agronomic practices applied to ensure rice yield, and they also profoundly affect the behavior of methanogens and methanotrophs. However, the effect of rice straw or its biochar combined with N fertilizer on the activities and compositions of methanogens and methanotrophs is still not well understood, especially in rice root zone soil in coastal saline paddy fields. Moreover, only few studies linking communities and functions of methanogens and methanotrophs are available, resulting in a lack of adequate indicators to predict methane production potential (MPP) or methane oxidation potential (MOP), for improving fertilizer strategies. Here, through quantitative PCR (qPCR), high-throughput sequencing, network analysis and linear regression model, we investigated the response of the abundances, compositions and activities of methanogens and methanotrophs to rice straw or its biochar combined with N fertilizer in rice root zone soil in coastal regions, and explored the relationships between MPP and methanogenic compositions as well as MOP between methanotrophic compositions, respectively. Therefore, a combination of pot and mesocosm experiment was conducted including seven fertilizer treatments: CK, without N fertilizer and rice straw return; SN100, 100 % N plus straw return; SN80, 80 % N plus straw return; SN60, 60 % N plus straw return; BN100, 100 % N plus rice biochar return; BN80, 80 % N plus biochar return; and BN60, 60 % N plus biochar return. Results showed that irrespective of MPP, MOP, or methanogenic and methanotrophic abundance, they all decreased significantly (P < 0.05), with the reduction of N application under the condition of combined straw or biochar with N fertilizer in coastal saline paddy soils. Moreover, compared with straw, biochar could significantly (P < 0.05) reduce MPP and methanogenic abundances, whereas improve MOP and methanotrophic abundances under the same N application rate. The models incorporating mcrA gene copy and soil dissolved organic carbon (DOC) could accurately predict MPP, while MOP was best predicted by a model incorporating pmoA gene copy and NO3−-N. The family Methanobacteriaceae and Methanosarcinaceae were dominant in the methanogenic co-occurrence and keystone patterns. Correspondingly, the genera Methylocystis and Metilomonas were dominant in the methanotrophic co-occurrence pattern, and genus Methylocystis was also the keystone members in coastal saline root zone soil of rice. Soil DOC and salinity were the key factors in shaping the methanogenic co-occurrence and keystone patterns, whereas the methanotrophic co-occurrence and keystone patterns were mainly regulated by NO3−-N. Furthermore, methanogenic keystone taxa were more suitable for predicting MPP than their co-occurrence pattern. Our findings provide insights into the possibility of key microbial taxa for predicting MPP or MOP for low-carbon production fertilizer application strategies in coastal saline paddy soils.

Effect of Rice Straw and Stubble Burning on Soil Physicochemical Properties and Bacterial Communities in Central Thailand.

Rice straw and stubble burning is widely practiced to clear fields for new crops. However, questions remain about the effects of fire on soil bacterial communities and soil properties in paddy fields. Here, five adjacent farmed fields were investigated in central Thailand to assess changes in soil bacterial communities and soil properties after burning. Samples of soil prior to burning, immediately after burning, and 1 year after burning were obtained from depths of 0 to 5 cm. The results showed that the pH, electrical conductivity, NH4-N, total nitrogen, and soil nutrients (available P, K, Ca, and Mg) significantly increased immediately after burning due to an increased ash content in the soil, whereas NO3-N decreased significantly. However, these values returned to the initial values. Chloroflexi were the dominant bacteria, followed by Actinobacteria and Proteobacteria. At 1 year after burning, Chloroflexi abundance decreased remarkably, whereas Actinobacteria, Proteobacteria, Verrucomicrobia, and Gemmatimonadetes abundances significantly increased. Bacillus, HSB OF53-F07, Conexibacter, and Acidothermus abundances increased immediately after burning, but were lower 1 year after burning. These bacteria may be highly resistant to heat, but grow slowly. Anaeromyxobacter and Candidatus Udaeobacter dominated 1 year after burning, most likely because of their rapid growth and the fact that they occupy areas with increased soil nutrient levels after fires. Amidase, cellulase, and chitinase levels increased with increased organic matter levels, whereas β-glucosidase, chitinase, and urease levels positively correlated with the soil total nitrogen level. Although clay and soil moisture strongly correlated with the soil bacterial community's composition, negative correlations were found for β-glucosidase, chitinase, and urease. In this study, rice straw and standing stubble were burnt under high soil moisture and within a very short time, suggesting that the fire was not severe enough to raise the soil temperature and change the soil microbial community immediately after burning. However, changes in soil properties due to ash significantly increased the diversity indices, which was noticeable 1 year after burning.

Effect of Rice Straw- and Bamboo-Derived Biochar on Pollution Controlling and Health Risks of Heavy Metals in a Rice-Rape-Corn Rotation Area of Eastern China

Effect of Rice Straw- and Bamboo-Derived Biochar on Pollution Controlling and Health Risks of Heavy Metals in a Rice-Rape-Corn Rotation Area of Eastern China

The effects of co-utilizing green manure and rice straw on soil aggregates and soil carbon stability in a paddy soil in southern China

The co-utilization of green manure (GM) and rice straw (RS) in paddy fields has been widely applied as an effective practice in southern China. However, its effects on soil aggregate and soil organic carbon (SOC) stability remain unclear. In the present study, the effect of GM, RS, and co-utilization of GM and RS on particle size distribution of soil aggregates and SOC density fractions were measured in a field experiment. The experiment included six treatments, i.e., winter fallow (WF) without RS return (Ctrl), WF with 50% RS return (1/2RS), WF with 100% RS return (RS), GM without RS return (GM), GM with 50% RS return (GM1/2RS) and GM with 100% RS return (GMRS). The results showed that the proportion of small macro-aggregates (0.25–2 mm) and the mean weight diameter (MWD) of aggregates in the GMRS treatment was greater (by 18.9 and 3.41%, respectively) than in the RS treatment, while the proportion of silt+clay particles (<0.053 mm) was lower (by 14.4%). The concentration of SOC in microaggregates (0.053–0.25 mm) and silt+clay particles was higher in the GMRS treatment than in GM and RS treatments individually. The concentration and proportion of free light organic carbon (fLOC) in aggregates of various particle sizes and bulk soil was greater in the GMRS treatment than the RS treatment, whereas the concentration and proportion of mineral-associated organic carbon in small macroaggregates, microaggregates, and bulk was lower in the GMRS treatment than in the RS treatment. The proportion of intra-aggregate particulate organic carbon (iPOC) was greater in the GMRS treatment than in GM treatment. The GMRS treatment had strong positive effects on iPOC in small macroaggregates, suggesting that SOC was transferred from fLOC to iPOC. In conclusion, co-utilizing green manure and rice straw cultivated the SOC pool by increasing the concentration of fLOC and improved soil carbon stability by promoting the sequestration of organic carbon in iPOC as a form of physical protection.

Effects of straw and straw-derived biochar on bacterial diversity in soda saline-alkaline paddy soil

PurposeIn order to provide a scientific basis for the improvement of soda saline-alkaline paddy soil, the pot experiment was performed to explore the effects of rice straw and straw-derived biochar on the diversity of soil bacteria and community structure in soda saline-alkaline soil.MethodsThe experiment was four gradients of straw return (3 (RS1), 7.5 (RS2), 12 (RS3), and 16.5 (RS4) t/hm2) and four gradients of biochar return (3 (RB1), 7.5 (RB2), 12 (RB3), and 16.5 (RB4) t/hm2), using 0 t/hm2 as a control (CK). After 5 consecutive years of measuring straw returns, high-throughput sequencing was used to determine the relative abundance, alpha diversity, and changes in the community structure of soil bacteria.ResultOur results demonstrated that straw return significantly increased the relative abundance of Bacteroidetes, Firmicutes, and Sphingomonas and significantly reduced the relative abundance of Acidobacteria, Actinobacteria, Gemmatimonadetes, Parcubacteria, Anaeromyxobacter, Pontibacter, uncultured_bacterium_f_Draconibacteriaceae, and Bryobacter. Straw-derived biochar return significantly increased the relative abundance of uncultured_bacterium_f_Draconibacteriaceae and significantly reduced the relative abundances of Actinobacteria, Gemmatimonadetes, Thiobacillus, and Anaeromyxobacter, indicating that both straw and its associated biochar return changed the relative abundance of the phyla and genera of some bacteria. Straw return affected bacteria phylum and genus more than straw-derived biochar. With the exception of the 16.5 t/hm2 straw return, which reduced bacterial richness, the treatments did not significantly impact alpha diversity. Compared with straw-derived biochar return, straw return significantly changed the bacterial community structure, and the higher the straw return, the higher the impact on the bacterial community structure. Redundancy analysis (RDA) demonstrated that there was a significant correlation between the physicochemical properties of the soil and the community structure of its bacteria. A Mantel test demonstrated that the content of available phosphorus, available potassium, and organic matter was all important environmental factors affecting community structure.ConclusionWe speculate that straw return regulates the physicochemical properties of the soil, which affects the bacterial community structure.

Effects of king grass and rice straw hay on apparent digestibility and ruminal microorganisms of buffalo

The purpose of this study was to explore the effects of Rice straw and King grass on apparent digestibility, ruminal bacterial, and fungus composition in buffaloes. Three ruminal fistulated buffaloes were used in a 3 × 2 Latin square design. The dietary treatments were king grass and straw hay. Experimental animals were kept in individual pens and concentrate was offered at 1 kg/d while roughage was fed ad libitum. Each period lasted for 15d, with the first 12d for an adaptation period, followed by a 3-day formal trial period. King grass has higher digestibility of protein. Rice straw has higher digestibility to cellulose. The results showed that when buffaloes were fed king grass and straw, Bacteroidetes were dominant in the rumen normal flora, but firmicutes were not. In addition, the results of this experiment suggest that increasing protein content in diets may be beneficial to increase the relative abundance of Proteobacteria. Similarly, higher dietary fiber content may be beneficial for increasing relative abundance of Prevotella and Staphylococcus. The dominant fungi in ruminal fluid 2 h after ingestion were aerobic fungi. These aerobic fungi most likely entered the rumen with food. Whether and how long aerobic fungi can survive in the rumen needs more research.

Effect of Rice Straw on Tensile Properties of Tailings Cemented Paste Backfill

It is important and difficult to improve the tensile strength of backfill material to ensure the stability of goafs. In this study, rice straw (RS) in fiber form is used to improve the tensile properties of cemented paste backfill (CPB). An orthogonal experiment was designed, Brazilian indirect tensile strength tests were conducted to test the tensile performance of RS fiber-reinforced cemented paste backfill (RSCPB) under different fiber content (1, 2, 3 kg/m3) and fiber length (0.8~1, 1~3, 3~5 cm), and the microstructure of RSCPB was analyzed with scanning electron microscopy (SEM). The results showed that, compared with the conventional cemented paste backfill (CCPB), the increase in tensile strength of RSCPB ranged from 115.38% to 300.00% at 3 days curing age, 40.91% to 346.15% at 7 days, and −38.10% to 28.00% at 28 days, and the strain was slightly reduced during the curing period. The tensile strength, strain, and percentage increase of the RSCPB compared to the CCBP did not show a monotonic pattern of variation with the RS fiber content and length during the curing period. The RSCPB samples fractured under peak stress, showing obvious brittle failure. In addition, sulfate generated from S2− in the tailings inhibits the hydration reaction, and generates swelling products that form weak structural surfaces, which, in turn, lead to a 28-day tensile strength and strain of RSCPB lower than those at 7 days.

Effects of rice straw fermented with spent Pleurotus sajor-caju mushroom substrates on milking performance in Alpine dairy goats.

ObjectiveTo improve the feeding value of rice straw (RS), this study evaluated the potential of rice straw fermented with Pleurotus sajor-caju (FRS) as dairy goat feed.MethodsSpent Pleurotus sajor-caju mushroom substrate was used as fungi inoculum to break the lignocellulose linkage of rice straw, which was solid-fermented at 25°C to 30°C for 8 weeks. The ruminal degradation of pangolagrass hay (PG), FRS, and RS were measured in situ for 96 hours in three dry Holstein cows, respectively. Effect of fungi fermented RS on milking performance was studied in feeding trials. A total of 21 Alpine goats a trial were divided into 3 groups: a control group in which PG accounted for 15% of the diet dry matter, and FRS or RS was used to replace the PG in the control group. Goats were fed twice a day under two 28-day trial in individual pens. Meanwhile, a 3×3 Latin square trial (14 days/period) was conducted to study the rumen digestion of three diets by using three fistulated dry goats. Rumen contents were collected for metabolite analyses every one to three hours on the last two days.ResultsIn situ study showed that fermentation could elevate the rumen degradable fraction and effective degradability of RS (p<0.05). Effective degradability of FRS dry matter was significantly increased from 29.5% of RS to 41.7%. Lactating trial results showed that dry matter intake and milk yield in the PG group and FRS group were similar and higher than those in RS group (p<0.05). The concentration of propionic acid and total volatile fatty acid in the RS group tended to be lower than those in PG group (p<0.10). There were no differences in rumen pH value and ammonia nitrogen level among the groups tested.ConclusionFermentation of rice straw by spent Pleurotus sajor-caju mushroom substrate could substantially enhance its feeding value to be equivalent to PG as an effective fiber source for dairy goat. The fermented rice straw is recommended to account for 15% in diet dry matter.

Allelopathic Potential of Rice Straw Incorporation on Weed Emergence in Rice Cultivars

Laboratory experiment was conducted to evaluate the effect of in corporation of rice straw on the germination of different rice cultivars viz: ADT 36,ADT 38,ADT49,CO43.Further the allelopathic impact of crop residues on weed count and weed biomass was also registered. Different rates of incorporation was tried and higher the rate of incorporation, higher the inhibitions on rice and weed observations. Reduction in the performance of rice seed germination and growth parameters was observed with increased rice straw incorporation in all the four rice cultivars tried. Perhaps the rice straw incorporation had an influence on the biomass of rice cultivars too. Supporting research evidences also reveals that allelopathic effect of rice straw on rice and weed performance can stand as a remarkable achievement for recycling rice straw in rice producing countries.

Impact of Organic Matter, Inorganic, and Biofertilizer Combination on Soybean Yield in Entisol Soil of Indonesia

The study aimed to investigate an effect of organic fertilizer applied to rice in the first planting season for unfertilized soybean as second crop followed by inorganic and biofertilizer applied in the third season on soybean growth and yield under the rice-soybean-soybean cropping pattern in 2016/2017. The main plot was organic: (1) without organic amendment, (2) 10 t·ha−1 of chicken manure, and (3) 10 t·ha−1 precomposted rice straw. The subplot was inorganic N and P fertilizers and commercial biofertilizer (consisting of Rhizobium, nitrogen-fixing bacteria, and P-solubilizing bacteria) applied at planting of soybeans in the second dry season: (1) control (no inorganic and biofertilizer), (2) 50 kg urea ha−1, (3) 100 kg SP36·ha−1, (4) 50 kg urea + 100 kg SP36 ha−1, (5) biofertilizer, (6) biofertilizer + 25 kg urea ha−1, (7) biofertilizer + 75 kg SP36 ha 1, and (8) biofertilizer + 25 kg urea + 75 kg SP36 ha−1. Soybean planted on the first dry season after rice harvested was not fertilized (untreated). The results showed that the chicken manure amendment increased grain yield of soybean in the second season, i.e., from 1.03 t·ha−1 (without organic amendment) to 1.27 t·ha−1, an increase of 23%. There was no effect of rice straw on soybean grain yield. In the third season, however, the residual effect of straw compost or chicken manure increased soybean grain yield by 8% and 20%, respectively. Both straw compost and chicken manure also showed a positive effect on the use of inorganic and biofertilizers in increasing soybean productivity.

Effect of Rice Straw on Potassium Availability in Illite Containing Soils of Central Plain, Thailand

Soil potassium (K) in various forms and the effect of rice straw on soil K release were studied in lowland soils containing illite clay minerals. Surface soils of 2 Inceptisols and 2 Alfisols were collected to study. Soil samples were incubated for 120 days with rice straw incorporation at different rates (0, 3,125, 6,250, and 9,375 kg/ha), and various forms of K in soils were determined at various times during the period of incubation. The results showed that the readily available K content (water-soluble K + exchangeable K) of the studied soils increased with the increasing rate of rice straw incorporation. In addition, non-exchangeable K content also increased with the increasing rate of rice straw incorporation by fixation process for all soils. The maximum increase of water-soluble K content of the studied soils was observed on the 4th day of incubation for all treatments, corresponding to the decrease of exchangeable K content at the same time. This result indicated that water-soluble K and exchangeable K were in equilibrium. Changes of non-exchangeable K content during the period of incubation through alternate release and fixation processes were observed monthly. This result suggested that most of the readily available K enhanced by rice straw incorporation would be beneficial for K uptake by the plant.

Physiochemical properties and pyrolysis behavior evaluations of hydrochar from co-hydrothermal treatment of rice straw and sewage sludge

Co-hydrothermal treatment is an effective approach to recovery the energy and fuels from organic matter in rice straw (RS) and sewage sludge (SS). In this study, the basic fuel characteristics, ash composition, the subsequent pyrolysis behavior and relevant reaction kinetic parameters of obtained hydrochar were evaluated. The results indicated that co-hydrothermal treatment improved the fuel characteristics of hydrochar with high HHV and low N and S contents. FTIR analysis indicated that the presence of the synergy between RS and SS during co-hydrothermal treatment that the organic acids from hydrolysis of hemicellulose promoted the degradation of N-containing functional groups. In addition, the ash composition analyses showed that the obtained hydrochar had high ash fusion temperature as a result of the high removal efficiency of alkali metals during co-hydrothermal treatment. Moreover, co-hydrothermal treatment can promote the pyrolysis reaction by reducing the activation energy with the synthetic effect of RS and SS during co-hydrothermal treatment process. In summary, co-hydrothermal treatment improved the physiochemical properties and promoted the pyrolysis behavior of obtained hydrochar from RS and SS.

Effects of rice straw and rice straw ash on rice growth and \u03b1-diversity of bacterial community in rare-earth mining soils

Pot experiments were carried out to study the effects of rice straw (RS) and rice straw ash (RSA) on the growth of early rice and α-diversity of bacterial community in soils around rare earth mining areas of Xunwu and Xinfeng counties in South Jiangxi of China. The results showed that the exploitation of rare earth resources leads to soil pollution around rare earth mining areas and affects the growth of rice, and the content of rare earth elements (REEs) in rice was positively correlated with that in soils and negative correlated with dry weight of rice; The addition of RS to soils around REE mining area can inhibit growth of early rice, and the dry weight of rice grains, shoots, roots is lower when compared with the controls, while the content of REEs is higher. The α-diversity of soil bacterial decreases, which promotes the growth of Pseudorhodoferax, Phenylobacterium and other bacteria of the same kind, and inhibits the growth of beneficial bacteria. The addition of RSA to soils had no significant effect on α-diversity of soil bacterial but promoted the growth of Azospira and other beneficial bacteria, inhibited the growth of Bryobacter and other bacteria of the same kind, significantly improved the dry weight of grains, shoots and roots of early rice, and reduced the content of REEs in these parts of rice. It can be concluded that RS is unsuitable to be added to the planting soil of early rice in REE mining area, while RSA is suitable.

Determination of mechanical, flowability, and microstructural properties of cemented tailings backfill containing rice straw

China is the world’s major producer of tailings and straw, and they lead to serious environmental and economic problems. This work was conducted to study sustainable rice straw (RS) and tailings utilization for cemented tailings backfill (CTB), and the effect of RS on the properties of CTB was evaluated. The RS fiber of the RS content (0.08, 0.16 and 0.24 wt%) and RS length (0.9, 2 and 4 cm) were used to prepare CTB. RS fibers show slight side effects of a decrease of 5% in the flowability of the fresh CTB slurry because the natural RS fibers with high water absorption cause viscous increases in the fresh CTB slurry. This decrease further decreases with increasing RS fiber content and length. The impact of the RS fibers on the unconfined compressive strength (UCS) and the elastic modulus of the CTB is significant. A UCS of more than 85% CTB and an elastic modulus of more than 74% CTB have been increased more than twice. The RS fiber reinforcement improves the ductility of the CTB and maintains the integrity of the CTB matrix when failure occurs. Scanning electron microscopy (SEM) observations analyses revealed that much hydration gel was generated in the RSCTB matrix, and these hydration gels became trapped on the surface of the RS fibers, which established a physical skeleton structure and enhanced the strength of the CTB. Additionally, the RSCTB method can reduce the backfill cost by 24.76% by reducing the consumption of cement, increasing the comprehensive utilization of the RS and tailings, and reducing the environmental pollution caused by industrial and agricultural waste.

Evaluation of the Associative Effects of Rice Straw with Timothy Hay and Corn Grain Using an In Vitro Ruminal Gas Production Technique.

Simple SummaryRice straw is a widely used forage source for ruminants in most Asian countries; thus, it is important to accurately estimate its nutritional value. Rice straw is typically fed to the animals along with other ingredients, and the associative effects of the combined ingredients may alter the nutritional value of rice straw. We found associative effects on the ruminal fermentability (gas production kinetics and rumen parameters), especially when rice straw was co-fermented with timothy hay and corn grain. We conclude that the nutritional value of rice straw increases when used with timothy hay and corn grain, due to the associative effects among feeds, which should be considered in diet formulations.The objective of this study was to evaluate the associative effects of rice straw with timothy hay and corn grain. Using an automated gas production system, in vitro ruminal fermentation was studied for six substrates: 100% rice straw, 100% timothy hay, 100% corn grain, 50% rice straw and 50% timothy hay, 50% rice straw and 50% corn grain, and 50% rice straw, 25% timothy hay, and 25% corn grain. Incubation was performed in three batches with different rumen fluids to assess the in vitro ruminal gas production kinetics and rumen parameters (pH, NH3-N, volatile fatty acid (VFA), and true dry matter digestibility (TDMD)). The associated effects were tested by comparing the observed values of the composited feeds and the weighted means of individual feeds. There was a significant increase in NH3-N when rice straw was fermented with timothy hay, corn grain, or both (p < 0.05). TDMD increased when corn grain was co-fermented, and the total gas and VFA production increased when all three feeds were co-fermented. We conclude that the feed value of rice straw increases when fed to animals along with timothy hay and corn grain.

Co-incorporation of green manure and rice straw improves rice production, soil chemical, biochemical and microbiological properties in a typical paddy field in southern China

The cultivation of green manure or rice straw returns in southern China increases crop yields and soil fertility. Few studies have reported the effects of combining both management techniques on rice performance and soil fertility. A 3-year field study was carried out to analyse the impacts of the co-incorporation practice on soil microbial and biochemical parameters as well as crop yield. Five treatments were tested: (i) no-fertilizer (CK); (ii) chemical fertilizer (F); (iii) F plus green manure (FM); (iv) F plus rice straw (FS); (v) F plus green manure plus rice straw (FMS). The results showed that incorporation of green manure and/or rice straw increased double rice yields by 4.1% (FM), 4.7% (FS) and 9.6% (FMS) compared with F. The FMS treatment enhanced soil organic C (SOC), total N (TN), mineral N (Nmin), and available K (AK) levels by combining the advantage of FM in increasing TN and Nmin and the advantage of FS in increasing SOC and AK in comparison with F. The incorporation of green manure and/or rice straw stimulated microbial growth (total phospholipid fatty acids, PLFAs) and altered the soil microbial community structure relative to F, in which FMS had the greatest effect. The enzyme activities of β-glucosidase, β-cellobiosidase, N-acetyl-glucosaminidase, L-leucine aminopeptidase and phosphatase were higher in the green manure and/or rice straw application treatments than in the F treatment in the order FM ≈ FS < FMS. The partial least squares path model (PLS-PM) analysis indicated that green manure mainly influenced the abovementioned indices in the early rice season, while the effects of rice straw lasted until the late rice season. Our results suggest that co-incorporation of green manure and rice straw is a more effective practice for improving soil fertility and rice yields.

Enhanced Soil Chemical Properties and Rice Yield in Acid Sulphate Soil by Application of Rice Straw

Swampland development such as acid sulphate soil for agricultural cultivation has various problem, including high soil acidity, fluctuated and unpredictable water flooding and the presence of toxic elements such as Fe which resulting in low crop yields. The research was conducted at the experimental station Belandean, Barito Kuala regency in dry season 2007. The objective of research was to study the effect of rice straw on the dynamic of soil pH, the concentration of iron and sulphate and yield on tidal land acid sulphate soil at two different water inlet channel. This research was designed in RCBD (Randomized Completely Block Design) with five treatments (0, 2.5, 5.0, 7.5 and 10 Mg ha-1) and four replications. Dolomite as much as 1 Mg ha-1 was also applied. This research was divided into two sub-units experiment i.e. two conditions of different water inlet channel. The first water channels were placed with limestone and the second inlet was planted with Eleocharis dulcis. The results showed that (i) rice straw application did not affect the dynamic of soil pH, concentration of iron and sulphate, and (ii) the highest yield was obtained with 7.5 Mg ha-1 of rice straw.

Effect of rice straw and/or nitrogen fertiliser inputs on methanogenic archaeal and denitrifying communities in a typical rice paddy soil

ABSTRACTTo understand better the microbial functional populations which are involved in methanogenesis and denitrification in paddy soils with rice straw (RS) and/or nitrogen fertiliser (potassium nitrate, N) application, the dynamics of methanogens and the denitrifying community were monitored simultaneously during the incubation period. The results show that the community structure of methanogens remained relatively stable among treatments based on 16S rDNA analysis, but fluctuated based on 16S rRNA. The Methanocellaceae and Methanosarcinaceae dominated all treatments at 16S rDNA and 16S rRNA level, respectively. RS+N increased the relative abundance of Methanosaetaceae at the 16S rRNA level, while there was an increasing trend in that Methanomicrobiaceae following RS addition at the 16S rDNA level. RS and/or N did not significantly change the diversity of methanogens targeting both 16S rDNA and 16S rRNA. RS and RS+N increased copy numbers of methanogens targeting both 16S rDNA and 16S rRNA analyses. The community structure and abundance of nirS and nosZ-containing denitrifiers, and the diversity of nirS-containing denitrifiers was significantly altered only by the N treatment. These results indicate that the community structure, diversity and abundance of methanogens respond differently to RS addition at the 16S rDNA and 16S rRNA levels.

Effect of Rice Straw and Husk Biochar on Vegetative Growth and Yield Attributes of Oryza sativa L

Effect of rice straw and husk biochar on vegetative growth and yield attributes of Oryza sativa L Singanayagam Thavanesan1*, Thayamini H. Seran2 1 Department of Crop Science, Faculty of Agriculture, Eastern University, Chenkalady, Sri Lanka 2 Department of Crop Science, Faculty of Agriculture, Eastern University, Chenkalady, Sri Lanka Abstract: A research was conducted to evaluate the growth and yield of rice as influenced by rich straw and husk biochar along with chemical fertilizer. The experiment was done with six treatments. T1- recommended chemical fertilizer, T2- Rice straw (1.0 t/ha), T3-Rice husk biochar (1.0 t/ha), T4-Rice straw (0.5 t/ha) + Rice husk biochar (0.5 t/ha), T5-Rice straw (1.0 t/ha) + Rice husk biochar (0.5 t/ha) and T6-Rice straw (1.0 t/ha) + Rice husk biochar (1.0 t/ha). Recommended chemical fertilizer was incorporated to all the treatments. During the vegetative periods, the growth parameters were recorded and finally yield analysis was done. Rice plants treated in rice straw (1.0 t/ha) and husk biochar (1.0 t/ha) along with chemical fertilizer had significantly (P&amp;lt;0.05) higher mean values of leaf area (185.93 cm2), number of tillers (4.0), number of roots per plant (105.33) and also dry weights of shoots (5.15 g) and roots (4.27 g) per plant when comparing chemical fertilizer alone. Average number of grains (187.67), number of filled grains (170.33) and filled grain weight per panicle (3.142 g) was also considerably increased in rice straw (1.0 t/ha) and husk biochar (1.0 t/ha) treatment followed by husk biochar (1.0 t/ha) treatment than those in the control. There were no significant difference (P&amp;gt;0.05) in 100 seed weight between them. Hence, it can be concluded that addition of rice straw (1.0 t/ha) and husk biochar (1.0 t/ha) along with chemical fertilizer to rice field is feasible to increase the grain yield under local conditions. Key words: Biochar, Rice straw, Rice husk, Rice, Seed weight [*] Corresponding author: thayaminis@esn.ac.lk, thayasean@yahoo.com