Rice Straw Content Research Articles

Fermentation by Eco Enzyme on Nutritional Content of Rice Straw, Corn Straw, and Oil Palm Fronds

Novelty statement: This study reveals that fermented agricultural and plantation waste by using different doses of eco enzyme turned out to have a good effect on the quality of the waste. The procedures and parameters standardised in this research can be used for production of ruminant feed.
 Abstract: The low nutrient content of agricultural waste is an obstacle to use as feed. The addition of eco enzyme as biological activators can help the fermentation process. The aim of this research was to determine the effect of three doses of eco enzyme as a starter fermentation of rice straw, corn straw, and palm fronds on changes in the nutritional content of 21 days fermentation. This study used a completely randomized design method with two factorial (three treatments and three replications). Factor D: Doses (D1 = 1%; D2 = 3%; D3 = 5%) and factor L: Forage (L1 = rice straw; L2 = corn straw; L3 = oil palm fronds). The parameters studied were moisture content (MC), dry matter (DM), crude protein (CP), crude fiber (CF). The results of this research showed that addition of eco enzyme dose of 5% on L1, 3% on L2 and 3% L3 can increased water content and crude protein, and reduce levels of dry matter and crude fiber of forage compared without fermentation.

Evaluation of nutrient content andin Vitrogas fermentation of some crop residues as feed supplements for ruminants

The objective of this study was to evaluate the nutritive value of Yam peel (YP), Maize chaff (MC) and Rice straw (RS). Evaluation of the nutrient and anti-nutrient content of the crop residues involved determination of the proximate, mineral and phytochemical contents of YP, MC and RS. In vitro gas production (IVGP) of crop residues was carried out over a period of 24 hr incubation to predict Metabolizable energy (ME), organic matter digestibility (OMD) and short chain fatty acids (SCFA). Methane (CH4) wasmeasured by introducing 10 M NaOH into the inoculums after incubation. Result revealed significant (p<0.05) differences in the values of the proximate composition. The dry matter ranged between 85.55 and 92.18 g/100 g in YP and MC respectively. The highest crude protein (5.01 g/100 g) was obtained in MC, while the lowest (4.00 g/100 g) was recorded for YP. The crude fibre ranged between 25.05 g/100g and 41.49 g/100g (YP). The mineral content of YP, MC and RS were not significantly different from each other, but within acceptable limit for optimum metabolism. YP, MC and RS were implicated for anti-nutrients, though no significant. The IVGP varied significantly (p< 0.05) with the MC recording the highest (30.10ml) value, while the lowest (23.96ml) value was obtained in YP. Same trend was observed for ME, OMD, SCFA and CH4ranging from 5.32–11.12 MJ/Kg DM; 35.13 –64.14 %; 0.50-1.12 μmol and 9.05 –11.00ml respectively.It can be concluded that YP, MC and RShas potential in livestock nutrition. Also the problem associated with disposal of crop residues can be conveniently reduced by incorporating them into ruminant feed.

Association mapping identifies quantitative trait loci (QTL) for digestibility in rice straw

BackgroundThe conversion of lignocellulosic biomass from agricultural waste into biofuels and chemicals is considered a promising way to provide sustainable low carbon products without compromising food security. However, the use of lignocellulosic biomass for biofuel and chemical production is limited by the cost-effectiveness of the production process due to its recalcitrance to enzymatic hydrolysis and fermentable sugar release (i.e., saccharification). Rice straw is a particularly attractive feedstock because millions of tons are currently burned in the field each year for disposal. The aim of this study was to explore the underlying natural genetic variation that impacts the recalcitrance of rice (Oryza sativa) straw to enzymatic saccharification. Ultimately, we wanted to investigate whether we could identify genetic markers that could be used in rice breeding to improve commercial cultivars for this trait. Here, we describe the development and characterization of a Vietnamese rice genome-wide association panel, high-throughput analysis of rice straw saccharification and lignin content, and the results from preliminary genome-wide association studies (GWAS) of the combined data sets. We identify both QTL and plausible candidate genes that may have an impact on the saccharification of rice straw.ResultsWe assembled a diversity panel comprising 151 rice genotypes (Indica and Japonica types) from commercial, historical elite cultivars, and traditional landraces grown in Vietnam. The diversity panel was genotyped using genotype by sequencing (GBS) methods yielding a total of 328,915 single nucleotide polymorphisms (SNPs). We collected phenotypic data from stems of these 151 genotypes for biomass saccharification and lignin content. Using GWAS on the indica genotypes over 2 years we identified ten significant QTL for saccharification (digestibility) and seven significant QTL for lignin. One QTL on chromosome 11 occurred in both GWAS for digestibility and for lignin. Seven QTL for digestibility, on CH2, CH6, CH7, CH8, and CH11, were observed in both years of the study. The QTL regions for saccharification include three potential candidate genes that have been previously reported to influence digestibility: OsAT10; OsIRX9; and OsMYB58/63-L.ConclusionsDespite the difficulties associated with multi-phasic analysis of complex traits in novel germplasm, a moderate resolution GWAS successfully identified genetic associations encompassing both known and/or novel genes involved in determining the saccharification potential and lignin content of rice straw. Plausible candidates within QTL regions, in particular those with roles in cell wall biosynthesis, were identified but will require validation to confirm their value for application in rice breeding.

Biological pretreatment of rice straw with cellulase-free xylanolytic enzyme-producing Bacillus firmus K-1: Structural modification and biomass digestibility

Biological pretreatment using microorganisms or enzymes offers an eco-friendly process for biomass processing. Herein, the efficiency of pretreatment of rice straw with the cellulase-free xylanolytic enzyme-producing Bacillus firmus K-1 and its enzymes was assessed. After pretreatment with strain K-1 (BRS), the xylan content in rice straw reduced significantly (21% removal), thus increasing exposure of the cellulose crystal structure (Crystallinity index (CrI) = 40.2%) and creating biomass porosity. Subsequent treatment of BRS with the in-house xylanase preparation (BRS-E) slightly increased xylan removal (30% removal). The reduction of xylan thus led to larger pore size and increased crystallinity (CrI = 42.8%). Compared to untreated rice straw (24% glucan conversion), hydrolysis of BRS and BRS-E with the commercial cellulase preparation Accellerase 1500 at 100 g/L substrate load showed comparable glucose yield, giving about 74% glucan conversion. The results indicate that the removal of xylan can enhance accessibility of cellulose to cellulases, although the lignin content was not reduced (24% for BRS and 25% for BRS-E). This work demonstrates a new insight into the improvement of pretreatment efficiency using a xylan-degrading microorganism, which is an alternative to conventional lignin removal by fungal pretreatment.

Effects of different organic amendments on soil organic carbon and its labile fractions in the paddy soil of a double rice cropping system

Application of organic amendments is an effective approach for improving soil organic carbon and soil fertility. To investigate the effects of different organic amendments on soil organic carbon and its labile fraction content, a batch of incubation experiments was conducted on the fluvo-aquic soil in Dongting Lake region, Hunan Province. There were six treatments, including soil amended with rice straw, soil amended with Chinese milk vetch, soil amended with bio-organic fertilizer, soil amended with pig manure, and soil amended with rice straw-derived biochar, with unamended soil as control. Each treatment had the same amount of carbon input. After 180 days of incubation, application of organic amendments increased soil labile organic carbon content. Application of bio-organic fertilizer, pig manure and rice straw-derived biochar significantly increased soil organic carbon content by 26.1%, 9.7% and 30.7%, respectively. There was no significant change in soil organic carbon content in rice straw and Chinese milk vetch treatments which were more favourable to the accumulation of soil dissolved organic carbon and microbial biomass carbon. Pig manure was more favourable to the accumulation of soil dissolved organic carbon. Bio-organic fertili-zer could benefit the accumulation of soil microbial biomass carbon and readily oxidizable organic carbon. Rice straw-derived biochar could promote the accumulation of soil microbial biomass carbon and light fraction organic carbon. Compared with rice straw, soil carbon pool management index was increased by 31.8%, 111.6%, 62.2% and 50.7% in Chinese milk vetch, bio-organic fertilizer, pig manure and rice straw-derived biochar treatments, respectively. The performance of bio-organic fertilizer, pig manure, and rice straw biochar was better than rice straw and Chinese milk vetch from the perspective of soil carbon sequestration and soil carbon pool management index.

The effect of a diet based on rice straw co-fermented with probiotics and enzymes versus a fresh corn Stover-based diet on the rumen bacterial community and metabolites\xa0of beef cattle

Improvement of the food value of rice straw is urgently required in rice crop growing areas to mitigate pollution caused by rice straw burning and enhance the supply of high-quality forages for ruminants. The aims of the present study were to compare the effects of fresh corn Stover and rice straw co-fermented with probiotics and enzymes on rumen fermentation and establish the feasibility of increasing the rice straw content in ruminant diets and, by extension, reducing air pollution caused by burning rice straw. Twenty Simmental hybrid beef cattle were randomly allotted to two groups with ten cattle per group. They were fed diets based either on rice straw co-fermented with probiotics and enzymes or fresh corn Stover for 90 days. Rumen fluid was sampled with an esophageal tube vacuum pump device from each animal on the mornings of days 30, 60, and 90. Bacterial diversity was evaluated by sequencing the V4–V5 region of the 16S rRNA gene. Metabolomes were analyzed by gas chromatography/time-of-flight mass spectrometry (GC–TOF/MS). Compared to cattle fed fresh corn Stover, those fed rice straw co-fermented with probiotics and enzymes had higher (P < 0.05) levels of acetic acid and propionate in rumen liquid at d 60 and d 90 respectively, higher (P < 0.05) abundances of the phyla Bacteroidetes and Fibrobacteres and the genera Ruminococcus, Saccharofermentans, Pseudobutyrivibrio, Treponema, Lachnoclostridium, and Ruminobacter, and higher (P < 0.05) concentrations of metabolites involved in metabolisms of amino acid, carbohydrate, and cofactors and vitamins. Relative to fresh corn Stover, rice straw co-fermented with probiotics and enzymes resulted in higher VFA concentrations, numbers of complex carbohydrate-decomposing and H2-utilizing bacteria, and feed energy conversion efficiency in the rumen.

Isolation of High Lignolytic Bacteria from Termites’s Gut as Potential Booster in for Enhanced Biogas Production

Bacteria strain capable of degrading lignin, cellulose and hemicellulose were isolated from wood Feeding termite gut using spread plate technique. The 16S rRNA gene sequencing methodology was adopted in the identification of the isolate. The isolate’s Morganella morganii (strain S4L2C (MH745964) were found to have a high lignin degradation potential. The organism was able to reduce the lignin content of rice straw from 17.43% to 7.29% after 30 days of pretreatment with 53.27% reduction of the lignin content. This study revealed that termite’s gut bacteria are Potential sources of lignocellulose degrading bacteria for the biological conversion of biomass to biogas production.

The effects of fermentation using gamma-irradiated Aspergillus niger and adding rice bran on rice straw digestibility: in vitro study

This study aimed to evaluate the in vitro digestibility of rice straw fermented with gamma-irradiated Aspergillus niger. This study was also determined to evaluate the in vitro digestibility of the combination fermented rice straw and rice bran as ruminant rations. A 500 Gy gamma-irradiated A. niger was used for the fermentation process in rice straw by 21 days. Completely randomized design with six treatments and four replications was applied in this study. The treatments were: JNF (rice straw), JF (fermented rice straw), JNF 85 (85% rice straw + 15% rice bran), JF 85 (85% fermented rice straw + 15% rice bran), JNF 70 (70% rice straw + 30% rice bran), JF 70 (70% fermented rice straw + 30% rice bran). The observed variables were the nutrient content, in vitro gas production and in vitro true digestibility (IVTD). The results showed that fermentation treatment by gamma-irradiated A. niger could reduce ADF content of rice straw (P<0.05). however, there was no significant difference in NDF content. JF 70 treatment produced the highest in vitro gas production (P<0.05). JF 70 also produced the highest IVTD (P<0.05). in conclusion, fermentation treatment by gamma-irradiated A. niger could reduce ADF content and increase IVTD. Adding rice bran in ruminant rations was also increase the availability of soluble nutrients for rumen microbes.

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.

A function of Bioslurry Organic for Solid Fertilizer

Indonesia is an agricultural country in which people mostly work as farmers and produce abundant farming outcomes. On one hand, the use of chemical fertilizer supports the plants growing well. On the other hand, it decreases the soil fertility and farming product quality. The alternative way to reduce or substitute the chemical fertilizer is by using organic fertilizer which can be made through composting method for 2 months mixing the leaf waste and rice straw. Before mixing both materials, the values of C, N, P, K and the water content of Bioslurry were respectively 15.17%, 0.27%, 0.3%, 0.05%, and 67.07%. Meanwhile, the values of C, N, P, K and the water content of leaf waste were consecutively 41.12%; 1.22%; 1.16%; 8.94%; and 28.77%. Moreover, the values of C, N, P, K, and the water content of rice straw were sequentially 39.42%; 1.20%; 1.05%; 10.07%; and 31.23%. After mixing both materials through composting method, the results of rice straw fertilizer got C-Organic 20.87%; N 2.01%; P 0.16%; K 5.64%; water 22.31%, and C/N ratio 16.38%. Meanwhile, the composting process of leaf waste yielded C-Organic 25.44%; N 1.18%; P 0.18%; K 7.95%; water 11.85%, and C/N ratio 21.55%.

Compressive behavior of rice straw-reinforced concrete for rigid pavements

Micro-shrinkage cracking in concrete is normally observed at early stages. The cracking increases with the passage of time and affects the serviceability. The micro-shrinkage cracking can be avoided if its initiation is controlled by use of fibers. The utilization of natural fibers gains popularity in developing countries, including Pakistan, where vast resources of natural fibers are available as by-products with a low economic use. This paper primarily focuses on the utilization of locally available rice straw in concrete for rigid pavement application. The compressive behavior of rice straw-reinforced concrete (RSRC) is explored as per ASTM standard. The mix proportion of 1:2:4:0.6 (cement, sand, aggregate, and water, respectively by their weight) is considered for plain cement concrete (PCC) which is taken as reference. For RSRC, the length and content of rice straw are 25 mm and 1% (by wet volume weight), respectively. In addition to compressive strength, elastic modulus, absorbed energy, and toughness index of PCC and RSRC are experimentally determined and compared. The modulus of rupture is determined through empirical relation. Rigid pavements for PCC and RSRC are designed and compared using these parameters. The proposed rigid pavement design is discussed in detail.

English

The study investigated the effects of probiotic treatment on nutrient content of rice straw and its impact on blood parameters and gut microbes of heifers. Eight Holstein crossbred heifers with initial average body weight (BW) of 180.25&plusmn;21 kg were used in this study. The experimental period lasted for 33 days of feeding, of which 5 days were adjustment period. The treatments included feeding of untreated rice straw (Control) and probiotic treated rice straw. In each treatment, four animals were randomly assigned. Feed were offered twice daily and ensured ad libitum water supply. Probiotic treatment improved crude protein (CP) level from 4.35 to 6.37%. Crude fiber content (acid detergent fiber, ADF) was decreased from 64.83 to 61.30% after treatment of straw using probiotic. Blood glucose, albumin and high density lipoprotein (HDL) level were significantly (P&lt;0.05) increased from 65.62 to 125.08 mg/dl; 3.70 to 4.18 g/dl, and 106.28 to 165.28 mg/dl, respectively in probiotic treated straw fed animals. Low density lipoprotein (LDL) level was significantly (P&lt;0.05) decreased from 8.77 to 0.79 mg/dl and 247.6 to 162.2 mg/dl in probiotic treated rice straw fed animals which are worthy for animal health. Probiotic treated group had a normal range of microbial community in the intestine. In conclusion, probiotic treated straw improves nutrient content of rice straw and maintains normal blood parameters and microbial gut flora of heifers. Key words: Probiotic, rice straw, crude fiber, crude protein, acid detergent fiber, blood parameters, fecal microbiota. &nbsp

Structural and behavior changes of herbaceous and hardwood biomass during steam explosion pretreatment and enzymatic hydrolysis

Steam explosion (SE) was used to pretreat rice straw (RS) and Caragana korshinskii Kom. (CKK). Enzymatic hydrolysis of pretreated RS and CKK, and a pure cellulose (bacterial cellulose, BC) were performed and compared. The characteristics and changes of different substrates during pretreatment and enzymatic hydrolysis were observed. After SE pretreatment, the hemicellulose content of RS and CKK was decreased from 21.7% to 4.9% and 17.9% to 6.2%, respectively. The cellulose percent of RS and CKK was increased to 45.1% and 38.4%, and the enzymatic hydrolysis conversion of cellulose was increased 1.1 times and 0.9 times, respectively. Although the composition and enzymatic yield of different substrates varied, their enzymatic hydrolysis rates showed a similar declining trend during enzymatic hydrolysis. The adsorption capacities of substrates on the enzyme were increased by pretreatment. The enzymatic hydrolysis efficiency was closely related to the enzyme adsorption capacities of substrates at the initial stage (1 h). The BC and SE pretreated RS first adsorbed and subsequently desorbed the enzyme, while the untreated RS and CKK had weak adsorption capacity and formed irreversible adsorption with the enzyme. The changes in crystallinity after enzymatic hydrolysis suggested that there was no direct correlation between the crystallinity and digestibility of cellulose.

Nutrient Characteristics and Redox Potential Changes as Affected by Water Management in Rice Paddy Weighing Lysimeter

This study was designed to assess the nutrients characteristics and redox potential changes as affected by water management condition in rice paddy weighing lysimeter. Rice was grown from June to October 2015, and the water management was consisted of two methods: continuously flooding (CF) and alternate wetting and drying (AWD). Under the CF condition, the redox potential (Eh) of 5 cm topsoil began to decrease rapidly and maintained around -260 to -200 mV. The AWD showed the oxidation condition. The changes of soil pH in CF and AWD ranged from 6.0 to 7.0 and 5.7 to 7.1, respectively. Soil pH in the AWD condition indicated up and down patterns by irrigation. In changes in nutrient contents of the soil solutions, nitrate nitrogen (NO3-N) was initially 12.2 to 26.6 mg L-1 at the highest concentration, and the concentration of ammonia nitrogen (NH4-N) and phosphate (PO43-) appeared to be lower than 1 mg L-1 during rice cultivation. The grain yield of rice was significantly higher in the CF than in the AWD. Nitrogen and magnesium content in both rice grain and straw were not significantly different between the water management conditions. Phosphorous, potassium, and calcium content in the rice grain were not statistically different between CF and AWD conditions. However, the nutrient contents in rice straw were higher in the CF, compared with that in the AWD. Although the iron content in rice straw was higher in the CF than in the AWD, the manganese content showed an opposite tendency. Interestingly, soil maximum temperature at the daytime was significantly higher in the AWD than in the CF, whereas the soil minimum temperature at the night time was 0.5-0.9℃ lower in the AWD, compared with that of the CF. Therefore, these results suggest that the decrease in rice yield in AWD condition can be linked to the inhibition of phosphate absorption into rice plants under oxidized-soil condition and/or high temperature difference between day and night in the soil. Changes in the redox potential (Eh) of (A) 5, (B) 10, and (C) 15 cm soil depth under water management conditions of the continuously flooding (CF) and alternate wetting and drying (AWD).

Utilization of rice straw and used paper for the recycle papermaking

Rice Straw is one of the most important materials that has been used for pulp and paper production due to its abundance and cost-effectiveness. However, the pulping and papermaking characteristics of the mixture of rice straw and used paper have rarely been investigated. In this experiment, delignified rice straw was mixed with used paper in order to make recycle papers with acceptable properties. Soda pulping process was carried out to remove out of lignin. The delignification was designed to measure the effects in terms of sodium hydroxide concentration and temperature, on the cellulose and lignin content of rice straw, and its tensile strength and water absorption. The mass ratio of used paper and rice straw was varied and its physical properties was observed and compared to paper from natural rice straw. The delignification was conducted using NaOH concentrations (4-10% w/w) and temperatures (60-90°C) for 1 hour. The ratio of rice straw to used paper was varied (1:1-1:9). An optimum condition was obtained from rice straw delignification at NaOH concentration of 8% and temperature of 90°C. The results of the optimum condition obtained the highest amount of cellulose content and tensile strength while having the lowest amount of lignin content and water absorption.

Comparison of paddy soil fertility under conventional rice straw application versus cow dung compost application in mixed crop–livestock systems in a cold temperate region of Japan

ABSTRACT After the rice harvest in Japan, rice straw (RS) is usually cut by combine harvester and incorporated into the soil to improve its fertility. In mixed crop–livestock systems, however, RS is collected and used as livestock feed, and cow dung compost (CDC) is then applied to the soil. This system utilizes the residual organic matter from both rice production and livestock husbandry to make each product. CDC application is also considered to improve the fertility of paddy soil. However, the nutrient input from CDC and the effect of CDC application on soil fertility vary among regions and/or soil types. We compared soil fertility between RS application (RS treatment, avg. 32 years) and RS removal plus CDC application (CDC treatment, avg. 21 years) in 79 paddy fields in Mamurogawa town, Yamagata Prefecture, a cold temperate region of Japan, and measured the nutrient contents in the applied RS and CDC. The total C content of RS was significantly higher than that of CDC, whereas the N, P, K, and Si contents of CDC were significantly higher than those of RS. However, there was no significant difference in paddy soil fertility – as measured by soil organic C, total N, CEC, available N, P, and Si, exchangeable K, Ca, and Mg, base saturation percentage, pH, and bulk density – between the treatments. The soil fertility of most fields was adequate by RS or CDC treatment. Thus, leaving RS in paddy fields or removing it and then adding CDC to the paddy fields has a similar effect in maintaining adequate soil fertility for single rice production or rice–livestock production systems.

Investigation of fifteen popular and widely grown Indian rice varieties for variations in straw fodder traits and grain-straw relationships

Fifteen 15 popular rice cultivars were investigated over two years for grain yield (GY) and straw yield (SY), harvest indices (HI), straw nitrogen content (N), neutral (NDF) and acid (ADF) detergent fiber, acid detergent lignin (ADL), Silica, in vitro organic matter digestibility (IVOMD) and metabolizable energy (ME) content. Except for ADL (P = 0.06) highly significant (P < 0.0001) differences were observed for all traits. The observed cultivar-depend variations were substantial with GY varying by 1.8-fold and SY by 2.3-fold and HI by 1.6-fold. Important straw fodder quality traits such straw N varied by 1.5-fold and the cultivar with the highest IVOMD differed from the poorest one by 6.1 percentage points. With the exceptions of N and ADL, year had a significant effect on traits. Broad sense heritability (H2) for SY and IVOMD were substantial (>0.73) and intermediate (>0.49) for GY, NDF, ADF and ME and poor (<0.17) for Silica, N and ADL.Possible trade-offs between traits were investigated. GY and SY were unrelated (P = 0.52). Nitrogen content of rice straw tended (P = 0.08) to be inversely related with GY but not with SY (P = 0.89). NDF content was unrelated to GY (P = 0.52) but was significantly (P = 0.01) positively correlated with SY. The reverse was observed for ADF, which was significantly (P = 0.02) positively correlated with GY but unrelated to SY (P = 0.48). ADL was not correlated (P = 0.79) with GY but was positively associated (P = 0.01) with SY. Silica content was also unrelated (P = 0.17) to GY but was inversely (P = 0.03) associated with SY. IVOMD and GY were inversely associated (P = 0.07) as was ME and GY (P = 0.09. IVOMD tended (P = 0.1) to also inversely related to SY but ME and SY were not related (P = 0.24). To summarize, considerable cultivars-dependent variations in food and fodder traits exist among released cultivars, though key positive straw quality traits could inversely (P < 0.10) associated with GY. Straw storage influenced straw quality, though an unexpected one since quality tended to improve. Key straw quality traits at harvest and after storage were still significantly correlated but the correlation coefficients could fall substantially below 1.

Effects of biochar amendment on the soil silicon cycle in a soil-rice ecosystem

For the soil-plant ecosystem, knowledge about the effects of biochars on the soil silicon (Si) cycle is still tenuous. In this study, the effect of biochars on the yield, Si uptake and Si distribution within different tissues of rice plants and the soil Si cycles in a soil-plant system were investigated. Si-rich (RH300-700) and Si-deficient (WB300-700) biochars prepared from rice husk and wood sawdust were applied to high-Si soil (HSS) and low-Si soil (LSS). Biochar addition increased the yield of grain and straw and had no effect on the yield of root, and the increase in the yield with Si-rich biochars was obvious; this effect had a high response to LSS. Si-rich biochars increased the plant Si content of grain and root and had no effect on straw. RH300 amendment increased the Si concentration in grains, compared to RH500 and RH700. The addition of Si-deficient biochar to HSS had little effect on the Si content, while Si-deficient biochar-amended LSS had a great impact on the reduced Si content in rice straw and root, and WB700 decreased the Si concentration in grains, compared to WB300 and WB500. Finally, the Si-rich biochars increased the total Si uptake within rice, while Si-deficient biochars decreased the total Si uptake in LSS. According to the FTIR and SEM-EDX spectra of biochars before and after rice harvest, a new band of SiOSi at 471 cm−1 was found after aged WB700, and the minerals of iron and Si were found on the surface of aged WB700; biochars can fix the dissolved Si on its surface as a temporary store to prevent Si loss. Therefore, biochars can be considered reservoirs of soil Si, which is a slow release source of available Si, to impact the speed of biogeochemical cycling of soil Si in agricultural paddy soil.

Investigating effects of temperature on fuel properties of torrefied biomass for bio-energy systems

ABSTRACTTorrefaction of selected agro-residues (rice straw and cotton stalk) was successfully carried out on indirectly heated, batch-type fixed-bed reactor under different reactor temperatures (200–300°C) at a fixed heating rate of 10°C/min. Our preliminary results demonstrated that the rice straw, torrefied at 275°C, exhibited higher mass yield (64%) and energy yield (84%) with better fuel properties, i.e. lower moisture content (1.2%), volatile matters (54.7%), higher fixed carbon (24.8%), and higher heating value (HHV) 18.7 MJ/kg. On the other hand, cotton stalk showed a slightly lower mass yield (56.3%) and energy yield (74.4%) compared to rice star with very high HHV 22.5 MJ/kg torrefied at a relatively lower temperature of 250°C. Interestingly, the lignocellulosic composition showed a drastic increase in the lignin content of rice straw and cotton stalk, torrefied at 275°C and 250°C, respectively, which indicates good binding ability of bio-fuel leading to improved energy density. Our present work gives an insight that the torrefied rice straw and cotton stalk could be a promising biomass feedstock for bio-energy based systems such as biomass pyrolsyis and gasification.

Designing of Straw Chopper Machine for Compost Production

Amount of straw wastes in Ciparay, Bandung, West Java Indonesia reaches 10-12 tons.ha-1 but its has not been well managed, after harvested, the remaining unused straw is abandoned on the ground and is eventually burned. In the long run, this straw burning will be very disadvantageous to farmers, especially in terms of the environmental impacts on rice paddy including decreasing soil fertility, killing soil biota, damaging soil physical properties and wasting energy. One of alternatives to utilize rice straw able to provide added value is utilizing its waste as a material to make compost on the condition that the straw is already chopped into a size of 5-10 cm according to SNI standards. Therefore, a study on rice straw chopping technology based on the composting requirements is required. The aim of this study is to design a prototype of rice straw chopper with capacity 100 kg.hr-1. The method used in this research is engineering design with observation of the reasearch, design criteria, functional and structural design, figure design, technical analysis, prototyping of rice straw chopper, machine functional and performance test. The measurement results of rice straw characteristics show that the average length, diameter, bulk density and moisture content of rice straw are 708 mm, 4 mm, 160.6 kg.m-3 and 34.6% wet basis. This straw chopper design were produces a prototype with a dimension of 1040 mm (length) x 1000 mm (height) x 465 mm (width) with a power source generator using 5.5 HP gasoline motor. The result of functional test of the straw chopper shows that the actual capacity of this straw chopper is 100.32 kg.hr-1.