Treatment Of Barley Straw Research Articles

Effect of supplementing urea-treated barley straw with lucerne or vetch hays on feed intake, digestibility and growth of Arsi Bale Sheep

The study was conducted at Sinana Agricultural Research Center, Ethiopia to assess the supplementation of graded levels of vetch (Vicia dasycarpa 'lana') and lucerne (Medicago sativa,' Hunter river') hay on feed intake, digestibility and body weight (BW) change of Arsi-Bale sheep fed urea treated barley straw (UTBS). A 7 day- digestibility and a 90 day- feed intake trials were conducted using 28 and 35 sheep, respectively. The experimental design was a randomized complete block design with seven dietary treatments that consisted of feeding UTBS (T1) as the control treatment, UTBS plus 150, 250 and 350 g dry matter (DM) per day of vetch for T2, T3, T4, respectively and UTBS plus 150, 250 and 350 g DM per day of lucerne for T5, T6 and T7, respectively. Intake of UTBS was not affected (P > 0.05) by inclusion of lucerne hay at 25-35% of daily DM intake. The supplements increased daily intake of total DM, organic matter (OM), neutral detergent fiber (NDF), acid detergent fiber (ADF) and metabolizable energy (ME) (P < 0.001) as well as apparent digestibility of DM, OM (P < 0.001), NDF (P < 0.01), ADF, crude protein (CP) (P < 0.05) and daily BW gain (P < 0.001). Supplementation with lucerne than vetch hay promoted higher (P < 0.001) CP and ME intakes and daily BW gain. Feeding with the UTBS without supplementation was enough to meet the maintenance requirements of the sheep and allow small BW gain. The results of the study showed that urea treatment of barley straw in conjunction with supplementation of lucerne or vetch hay could serve as a useful strategy in improving smallholder sheep production in the tropics.

Evaluation of Barley Straw and a Commercial Probiotic for Controlling Prymnesium parvum in Fish Production Ponds

AbstractSince 2001, the ichthyotoxic microalga Prymnesium parvum has caused major fish kills in 13 U.S. states, including Texas, raising concerns about its impacts on hatchery fish production, sport fisheries, and local economies. We investigated the efficacy of two natural products, barley Hordeum vulgare straw and the probiotic Liquid Live Micro‐Organisms (LLMO) System in controlling P. parvum and its ichthyotoxicity. Their effects on factors essential for successful production of fingerling fish (i.e., water quality, nutrient levels, phytoplankton biomass and composition, zooplankton density and composition, and fingerling fish production) were also evaluated. Barley straw and LLMO were individually tested during summer and fall 2004 in hatchery ponds for 140 d (experiment 1). Four ponds were treated with barley straw applied once at the beginning of the study at 252 kg/ha, and four ponds received LLMO at a rate of 1 L/56,718 L of pond water at 2‐week intervals throughout the study. Another four ponds were untreated and served as the control. Barley straw was further tested at 280 kg/ha in winter 2005 for 93 d (experiment 2). These barley straw treatment rates were similar to those used in other studies, and the LLMO rate was recommended by the supplier. In both experiments, P. parvum blooms did occur. Neither barley straw nor LLMO had a significant effect on P. parvum density, toxin levels, or ichthyotoxicity at the rates used in this study. Similarly, neither barley straw nor LLMO affected any of the other variables investigated. Our results do not support reports that barley straw and LLMO can control planktonic algae.

Relative fibrolytic activities of anaerobic rumen fungi on untreated and sodium hydroxide treated barley straw in in vitro culture

The fibrolytic activities of rumen fungi were studied in terms of dry matter loss, plant cell wall degradation and enzyme (cellulase and xylanase) activities, when grown in vitro on either untreated or sodium hydroxide treated stems of barley straw over a 12 day period. Changes in fungal growth, development and overall biomass were followed using chitin assay and scanning electron microscopy. Treatment with sodium hydroxide resulted in a decrease in the NDF content together with the disruption of cuticle and the loosening and separation of the plant cells within the straw fragments. The enzyme activities of the anaerobic fungi have a high positive correlation ( R 2 = 0.99 ) with their biomass concentration assessed by chitin assay indicating that chitin is a valuable index for the estimation of the fungal biomass in vitro. The anaeobic fungi produced very extensive rhizoidal systems in these in vitro cultures. After incubation with rumen fungi, dry matter losses were, respectively, 35% and 38% for the untreated and treated straw samples and the overall fungal biomass, determined by chitin assay, was significantly higher in the treated samples. In vitro degradation of cellulose and hemicellulose was also higher in the treated than that of untreated cultures. Although, comparatively, xylanase activity was higher than that of cellulase, the cellulose fraction of the straw was degraded more than hemicellulose in both treated and untreated straw.

Structural and physico-chemical characterization of lignins solubilized during alkaline peroxide treatment of barley straw

In this paper, the seven acid-insoluble lignin preparations from barley straw were first extracted with alkaline hydrogen peroxide in order to study how the delignification and degradation of the lignin is influenced by aqueous 1.5% H 2O 2 extractant to straw ratios. The results showed that treatment of dewaxed barley straw with 1.5% H 2O 2 at 45 ° C for 14 h (pH 12.0) under the extractant to straw ratios of 10:1, 13:1, 15:1, 18:1, 20:1, 25:1, and 30:1 resulted in dissolution of 65.8%, 68.4%, 68.4%, 69.0%, 69.7%, 71.6%, and 72.3% of the original lignin and 78.7%, 79.8%, 82.3%, 83.4%, 84.8%, 85.3%, and 85.3% of the original hemicelluloses, respectively. The degraded seven lignin samples were analyzed with respect to their chemical compositions, content of chemically linked polysaccharides, molecular weights and structural changes. It was found that the alkaline peroxide treatment under the conditions given led to a noticeable increase in a amount of carboxyl groups due to the oxidation. The results from 13 C-NMR analyses showed that the treatment was extremely effective for isolation of highly pure lignins from the straw, and the treatment under the conditions used did not affect the overall structure of lignin. The β- O-4 ether bond and β–β carbon–carbon linkage were found to be the major linkages between lignin units. Hydroxycinnamic acids, such as p-coumaric and ferulic acids, appeared to be strongly linked to lignin molecules, in which p-coumaric acid was found to be bonded to lignin by ester linkage, while ferulic acid was linked by its phenolic group via ether bond to lignin and also principally linked by its carboxyl group via ester bond to lignin and/or hemicelluloses.

Nutritional metabolism of hydrogen peroxide/anhydrous ammonia-treated barley straw in ewe lambs

A control and three treatments of barley straw were compared: NH 3 (3% of dry matter (DM)), 3% NH 3 after rehydration of the straw to 15% moisture with water, and 3% NH 3 after rehy- dration to 15% moisture with a H 2 O 2 solution (0.32% of DM). Forages were fed to fistulated ewe lambs, with a supplement, at two levels of intake (ad libitum and 75% ad libitum). At the ad libitum intake, the treatments mainly improved the intake; and digestible DM intake was 336, 455, 501, and 552 grams per head per day for untreated, NH 3 , NH 3 + H 2 O, and NH 3 + H 2 O 2 -treated straws, respec- tively. The first, second, and fourth values were different from each other ( P < 0.01), but the third one was not different from the fourth ( P = 0.09). A similar trend was observed in most other nutrient uti- lization parameters and fermentation characteristics. Intake restriction raised DM digestibility from 56.9% to 58.2% (P = 0.04). Anhydrous ammonia cannot provide alkalinity for the optimal action of hydrogen peroxide.

Aggregation and organic matter fractions of three Nigerian soils as affected by soil disturbance and incorporation of plant material

Soil management involving organic matter incorporation and reduced tillage intensity has often been reported to improve soil structure. However, the mechanisms and roles of soil organic matter (SOM) fractions in the process of soil structural stabilisation are not well documented. Furthermore, documentation of their positive effects on soils in the tropics is scarce. This study examined the changes in soil structure in response to SOM fractions dynamics in an incubation experiment. Three Nigerian soils: Iwo series (Oxic Tropudalf), Itagunmodi series (Tropeptic Euthrothox) and Owode series (Oxisol) were incubated with ground barley straw ( Hordeum vulgare L.) or green ryegrass ( Lolium perenne L.) with and without disturbance of the soil during incubation. The incorporation of plant material significantly increased the light fraction organic matter (LFOM) with density <1.7 g cm −3 but had no effects on the heavy fraction polysaccharides (HFPS), i.e. polysaccharides attached to heavy fraction soil minerals with density >1.7 g cm −3. A significant decline of LFOM was recorded with time of incubation (0–41 days: 21%, 30% and 36% decrease for the no plant material treatment, the barley straw treatment, and the green ryegrass treatment, respectively). This was associated with a significant rise of HFPS. Furthermore, the added plant material clearly decreased the soils' fraction of dispersible clay even before incubation, which was interpreted as a direct effect of the LFOM on the clay. Therefore, the use of dispersible clay as an indicator of macro-aggregate stability is questioned. After 41 days of incubation the concentration of water-stable aggregates was on an average 9% higher for soils with added plant material relative to soils not receiving plant material. When packing the post-incubation soil in metal cores, the volume of pores with equivalent neck diameter >10 μm was from 0.024 to 0.033 m 3 m −3 higher and the saturated hydraulic conductivity 18–24% higher for soils with added plant material than for soils without. Disturbance of the soil during incubation reduced the concentration of water-stable aggregates by 7% relative to undisturbed. Also the volume of pores with a neck diameter >10 μm and the saturated hydraulic conductivity were significantly reduced (by 6% and 19% relative, respectively) when the soil was disturbed during incubation. The results demonstrate that rapid changes of SOM fractions can occur over a short incubation period and that these changes have a pronounced positive effect on the structure of these tropical soils. It also suggests that incorporated plant material may correct tillage induced degradation of soil physical properties over a relatively short time.

Cellulase and xylanase activity of the rumen anaerobic fungi grown on untreated and sodium hydroxide treated barley straw

The treatment of straw with sodium hydroxide in order to upgrade its nutritive value and to increase the utilisation of its energy by ruminants has been widely employed in many parts of the world. The aim of the experiment was to assess the fibrolytic activity of the anaerobic fungi in vitro using either untreated or NaOH treated barley straw.Anaerobic fungi were isolated from the rumen of a sheep fed with a diet of hay and lucerne pellets using medium C based on that described by Davies et al. (1993) and as modified by Rezaeian (1996). The Isolates were inoculated into two series of culture media containing either sodium hydroxide treated (TS) or untreated milled straw (US). Five replicate cultures were prepared and incubated at 39 °C over a period of 12 days. The dry matter loss of the substrates and changes in pH of the medium cultures were measured.

Effect of moisture and temperature on the degradability of fiber and on nitrogen fractions in barley straw treated with urea

The effect of the treatment of barley straw with urea (6% of the D.M.) on its chemical composition, digestibility, degradability and nitrogen fractions was studied varying the initial straw-treatment moisture level (20%, 30% and 40%) and storage temperature (25°C and 35°C). The urea treatment fundamentally affected the NDF content of the straw, which decreased as a result of hemicellulose solubilization. The decrease in NDF was greatest when the initial temperature and moisture content of the straw were both high, under which conditions the maximum solubilization of hemicellulose (25%) occurred. In vitro digestibility and degradability also improved with the urea treatment. In this regard, the greatest improvement (up to 20 points in the case of the digestibility results) was seen when hemicellulose solubilization was maximum. The amount of nitrogen retained by the straw (after deducting the residual urea) rose under conditions of increased moisture and temperature, reaching its highest values at moisture levels of 35% and 40%, when the best urea hydrolysis also took place.

Turnover of carbon and nitrogen in a sandy loam soil following incorporation of chopped maize plants, barley straw and blue grass in the field

In a field experiment, chopped maize, barley straw and blue grass were incorporated into a sandy loam soil. Mineral N, soil microbial biomass C and N, extractable organic C and N, as well as C and N in particulate organic matter fractions were measured frequently over 1 y in the upper 15 cm of the soil. Measurements were carried out weekly at the beginning and with decreasing frequency as the experiment progressed. In the early stage of decomposition, the soil surface CO 2-evolution rate and the N mineralization-immobilization rates were influenced primarily by the C-to-N ratio and by the content of easily decomposable substances of the added plant materials. However, during the later stage the lignin contents and the lignin-to-N ratios of the added plant materials were more significant for the intensity of the microbial turnover. N-balances were calculated for the N-turnover during periods with minimal N-leaching. Negative balances indicated that N disappeared into an unknown sink which is considered to be microbial residual products (e.g. empty hyphae, residues of dead microbial cells, cell exudates). The disappearance of N was most obvious in the barley straw treatment. The development of different microbial communities induced by the different qualities of the added plant materials may have been responsible for this substrate dependent effect. The amount of light particulate organic matter (>100 μm, ρ<1.4 g cm −3) and its C-to-N ratio decreased during the experiment. This confirms a previous study which identified light particulate organic matter as an indicator of the portion of added plant material that remains undecomposed in the soil. The total amount of decomposed added plant material C calculated from the light particulate organic matter measurements was more than double that of the plant material C evolved as CO 2 from the soil surface. Our results suggest that a part of the decomposed plant material C was immobilized both in the soil microbial biomass as well as in a considerable amount of microbial residual products. Therefore, it does not appear that soil surface CO 2-flux-measurements are useful for quantitative estimations of the absolute turnover of added plant residues in the soil within the duration of our study. The natural 13C-enrichment of the added maize material was apparently sufficient for the calculation of the maize-derived particulate organic matter in the light particulate organic matter fraction of the soil. However, these measurements seemed to be biased by an uneven distribution of the 13C-abundance in the added maize material.

Ammoniation of barley straw. Effect on cellulose crystallinity and water-holding capacity

The X-ray diffraction patterns of untreated and ammonia-treated barley ( Hordeum vulgare L. cv. Klaxon) straws showed spectra typical of cellulosic materials, having the major peak at a diffraction angle (2θ) of 23° and a broader, secondary peak at 16°. Two measures of cellulose crystallinity calculated from the X-ray diffraction pattern indicated that treatment of barley straw with 30 g NH 3 kg −1 straw produced a reduction in cyrstallinity index values of 14–24%. The water retention of ammonia-treated barley straw was approximately 25% greater than that of the untreated straw following centrifugation at 300 g and 3000 g. A slightly higher swollen volume was also observed for water-saturated ammonia-treated barley straw, although the difference was not significant. It is suggested that two major consequences of treatment, the effect of ammonia as a weak base on ester bonding within the cell wall and the ability of ammonia in an undissociated form to affect cellulose cystallinity, combine to increase the degradability of the treated straw.

Techniques for trapping ammonia generated from urea treatment of barley straw

Three step-wise experiments were conducted to determine the ability of feeds in trapping excess ammonia from urea treated barley straw. In the first experiment, shredded barley straw was treated with urea (60 g kg −1 DM) at 300 and 400 g moisture kg −1 in laboratory silos. They were stored in incubator at 26 °C for 7, 14, 21 and 28 days. This was used to estimate the extent of urea hydrolysis and nitrogen retention. The second experiment measured the outflow rate of ammonia by blowing in air through treated straw into dilute H 2SO 4. The third experiment assessed the ability of grass and citrus pulp silages in holding ammonia. Urea hydrolysis was extensive (90–100%) but independent of moisture and treatment period ( P > 0.05). About 74% of nitrogen added in the form of urea in treated straw was lost during aeration. Fermentation enhanced the ammonia holding capacity of citrus pulp. This was further improved with time and addition of molasses. It's nitrogen content was increased from 11.7 to 21.2 g kg −1 DM. This decreased to 16.0 g kg −1 DM about 5 h after gassing. Improvement in the nitrogen content of feeds with gassing suggest that dry matter and nitrogen intake by ruminants can be enhanced.

The effect of calcium hydroxide and urea treatment of barley straw on chemical composition and digestibility in vitro

An experiment was conducted to investigate the effectiveness of calcium hydroxide (Ca(OH) 2) and urea treatment of straw. Chopped barley straw was treated with mixtures of Ca(OH) 2 (0, 30 and 60 g kg −1 straw dry matter, DM) and urea (0, 30 and 60 g kg −1 straw DM) dissolved in 0.81 water kg −1 straw DM and ‘ensiled’ in a polythene bag (1.0 kg per bag) at 15°C or 25°C for 60 days. Control treatment at each temperature involved untreated straw and treatment with 30 or 60 g NaOH kg −1 straw DM dissolved in 0.81 water kg −1 straw DM. Ensiled straws were examined for mould, chemically analysed and assessed for organic matter digestibility (OMD) in vitro. Mould occurred in Ca(OH) 2-alone and water-alone ensiled straw, but other ensiled straws were apparently mould free. In the presence of Ca(OH) 2 with urea treatment, the nitrogen content of ensiled straw increased more than urea-alone treatment. Analysis of variance of OMD in vitro results showed that Ca(OH) 2, urea and temperature interact significantly ( P < 0.01). Interactions were found to be non-significant for other parameters (nitrogen, acid detergent fibre and hemicellulose). However, straw ensiled at 15°C with 30 g urea +60 g Ca(OH) 2 kg −1 straw DM, 60 g urea +60 g Ca(OH) 2 kg −1 straw DM or 30 g NaOH kg −1 straw DM had similar OMD in vitro (67%). Untreated straw OMD was 48.5%. It can be concluded that mixtures of Ca(OH) 2 and urea would be the alternative chemicals to NaOH or ammonia for improvement of the nutritive value of straw.

Effects of chemical treatments of barley straw on leaching, and digestibility by rumen fluid and cellulolytic bacteria

Effects of chemical treatments on in sacco and in vitro digestibility of barley straw by rumen fluid and pure cultures of celluloytic bacteria were studied to evaluate the pretreatment and to improve the poor quality feed. Chemicals were applied by dissolving them in water equivalent to 40% of the weight of the straw (dry matter basis). Pretreatment with 5% NaOH yielded the largest increase in sacco digestion followed by pretreatment with 2% (NH4)2SO3, 2.6% NH4OH, 1.6% NaHSO3 and untreated straw (control). In sacco dry matter digestibility of straw treated with NaOH and (NH4)2SO3 continued to increase as the concentration of chemical increased (1 to 7.5%), as it was the in vitro dry matter loss by leaching. Treatment of barley straw with 5% NaOH enhanced significantly (p<0.01) in vitro digestibility by rumen fluid, Fibrobacter succinogenes and Ruminococcus albus though the fermentation products by celluloytic bacteria were low, whereas the treatment with 5% (NH4)2SO3 inhibited in vitro digestibility by F. succinogenes and R. albus together with lower fermentation products. Dry matter loss by leaching and bacterial digestion from barley straw treated with NaOH and (NH4)2SO3 suggested the effect of pretreatment with these chemicals were based on leaching, and the celluloytic bacteria had little to do with digestion.

Treatment of barley straw with ammonia or urea solutions and digestibility of its structural carbohydrate fractions in sheep

Treatment of barley straw with ammonia or urea solutions and digestibility of its structural carbohydrate fractions in sheep

The calculations method used for optimising conditions of treatment of barley straw with calcium hydroxide: effects of level of calcium hydroxide and urea, moisture, treatment time and temperature on in vitro digestibility

This study was an attempt to investigate the treatment of barley straw to improve digestibility in vitro: factors considered were the amounts of calcium hydroxide (Ca(OH) 2) and urea used, together with other treatment conditions (moisture, treatment time and temperature). Chopped barley straw was treated with 25 treatment combinations: different levels of Ca(OH) 2 (20, 60, 100 and 120 g kg −1 straw) and urea (15, 45, 75 and 90 g kg −1 straw) using three moisture levels (300, 500 and 700 g H 2O kg −1 straw) in duplicate and ‘ensiled’ in a mini-silo for different periods (3, 4, 6, 8 and 9 weeks) at different temperatures (5, 10, 20, 30 and 35°C). Ensiled straw was examined for mould and in vitro organic matter digestibility (OMD) determined. The polynomial approximation was used to develop contour plots of the response surfaces in the regions of the maximum with an optimum level of Ca(OH) 2 and urea to obtain OMD. The results showed that the optimum moisture content of ensiled straw was 500 g kg −1 and that treatment for 3 weeks produced satisfactory results. Ensiling treated straw at different temperatures did not significantly affect digestibility in vitro, but mould incidence increased with temperature. Increasing the Ca(OH) 2 level to 60 g kg −1 straw dry matter (DM) gave linear improvement in digestibility in vitro. A level of 15 g urea kg −1 straw DM with Ca(OH) 2 could be used to prevent mould in ensiled straw.

Effect of ammonia treatment of barley straw on the dynamics of its degradation in the rumen

AbstractTwo experiments were designed to examine the effects of ammonia treatment of barley straw on rumen environmental conditions for fibre degradation, and to determine the effect of treatment on the soluble and insoluble fractions of straw. In experiment 1, rumen pH, and ammonia-nitrogen and volatile fatty acid concentrations in the rumen of sheep receiving untreated (US1) or ammonia-treated (TS1) straw were recorded. Also, both straws were incubated in the rumen of both groups of animals. There were no significant differences (P&amp;gt; 0·05) within rumen parameters, except for butyrate proportion, which was higher (P&amp;lt; 0·01) with TS1. Dry matter and neutraldetergent fibre disappearances of TS1 were higher (P&amp;lt; 0·001) than those of US1 at all the incubation times. Degradation of both straws in US1-fed sheep was not smaller, and in some periods of incubation was even greater, than in TS1-fed animals. In experiment 2, samples of untreated (US2) and treated (TS2) straw were incubated in wethers offered a mixture (50:50) of alfalfa hay and straw. Samples of US2 and TS2 were soaked in autoclaved rumen fluid to measure their solubility. It was clear that, although treatment increased the soluble fraction of US2 and TS2 by 52 and 65 g/kg respectively, from 0 to 72 h of incubation, increasing the differences between straws from 45 to 58 g/kg in that period, actual microbial action on the treated roughage was the more important factor, accounting for a difference between US2 and TS2 of 131 g/kg after 72 h incubation.

Treatment of barley straw with ligninase: effect on activity and fate of the enzyme shortly after being added to straw

Two experiments investigated the potential of Phanerochaete chrysosporium ligninase to delignify straw and thereby improve its digestibility for ruminants. In Experiment 1, milled straw was added to media containing the fungus P. chrysosporium, with or without addition of extra ligninase, and the effects of treatments on chemical composition and digestibility in vitro were measured after 5 days. There was no effect ( P > 0.05) of ligninase on either digestibility or chemical composition as measured by Van Soest methods. Ligninase activity was assessed at days 3, 4 and 5; no activity could be detected. Experiment 2 showed that water-soluble component(s) from barley straw inhibited ligninase activity; 10 μl of water extract completely inactivated 5.0 units of ligninase in 1.0 ml of solution. However, sodium dodecyl sulphate (SDS)-gel electrophoresis in Experiment 2 showed that the enzyme as a protein had not been degraded.

Digestibility and energy value of combinations of forage mixtures

The metabolisable energy (ME) system currently used in the UK assumes the digestibility and energy values of individual forages to be additive. Production experiments have cast doubt as to whether this is consistently the case. Accordingly an experiment was devised to test the effect of mixing forages in different proportions on the digestibility and energy value of the resulting combinations. Forage mixtures were based on grass silage A (GSA) with either untreated (UTS) or sodium hydroxide treated barley straw (TS) which was included at 0, 150, 250 and 400 g kg −1 dry matter (DM); maize silage (MS) with lucerne silage (LS) and maize silage with grass silage B (GSB) were included in the forage mixtures at 0, 250, 500 and 750 g kg −1 DM. Digestibility, digestible energy and ME contents for all 18 forage mixtures were measured in vivo using mature wether sheep. When compared with grass silage only, the inclusion of UTS or TS decreased digestibility coefficients and ME contents. Additions of small amounts of either GSB or LS (250 g kg −1 DM) to MS dramatically reduced the digestible organic matter in the dry matter (714 to 625 g kg −1 and 714 to 651 g kg −1 respectively) compared with MS fed on its own. Cell wall digestibility was also reduced below that calculated from the proportions and the measurements of the forages fed alone. This work has shown that one forage can influence the value of another in terms of digestion and nitrogen utilisation.

Chemical treatment of lignocellulosic residues with urea

A series of comparative studies were undertaken to determine the effects of treatment with anhydrous ammonia and urea mode under different conditions on digestibility and/or voluntary intake of barley straw, wheat straw and maize stover. The following experiments were carried out: Experiment 1: methods of ammoniation of barley straw — in which the treatment of barley straw with anhydrous ammonia (3.56% dry matter (DM) basis and 22.4% moisture content), and with urea applied in solution during baling (6.2% DM basis and 30.5% moisture) or in stack (5.5% DM basis and 35.5% moisture) were studied. Experiment 2: urea levels — wheat straw was treated with urea in increasing dosages (3, 4, 5 and 6% DM basis and 30% moisture). Experiments: modifications in form of application — a comparative study was undertaken of treatments of barley straw with urea in solution with and without plastic cover, together with treatment with urea in solid form (4% DM basis and 25% moisture). Experiment 4: voluntary intake by sheep of wheat straw treated with urea — the influence of moisture content (20, 30 and 40%), the form of urea application (solid or solution) and the addition of crude soya bean (3% DM basis), as a source of external ureases, were studied. The treatments were carried out on 300 kg DM stacks of wheat straw; urea was applied at 3% DM basis. Experiment 5: urea treatment of maize stover — maize stover was treated with urea in solution (4% DM basis and 30% moisture), with urea in solid form (4.3% DM basis and 23.3% moisture), and with urea in solid form (4.3% DM basis and 23.3% moisture) and addition of crude soya bean (4.2% DM basis). All the treatments caused an increase in total nitrogen content and a decrease in neutral detergent fibre content as well as a significant effect ( P < 0.01) on the digestibility of the organic matter (DOM) in the straw. In Experiment 1 the digestibility increased 14.8, 12.8 and 11.7 percentual points in treatments with anhydrous ammonia, urea at baling and urea in stack, respectively. In Experiment 2 the four dosages of urea used were effective, and caused increases in DOM of 7.3, 5.3, 7.4 and 9.0 percentual points for dosages of 3%, 4%, 5% and 6%, respectively. Experiment 3 showed that modifications in the technique were possible, but that the highest digestibility was for plastic-covered urea. Experiment 4 showed that the addition of crude soya bean only had an influence when the treatment was applied at a low moisture level (20%) and that the application of urea in solid form gave an intake of DM lower than that observed for urea in solution. Finally, in Experiment 5 the application of crude soya bean on maize stover was particularly effective both on DOM and on voluntary intake.

Ft‐ir spectroscopy as a tool for the study of biological and chemical treatments of barley straw

AbstractDiffuse reflectance Fourier transform infrared (FT‐IR) spectroscopy has been used to characterise the changes in barley straw when subjected to biological and chemical treatments. The untreated and treated straws were also analysed by traditional analytical techniques for neutral sugar residues and lignin. A comparison between the spectroscopic data and the chemical analyses showed that FT‐IR spectroscopy was a quick and non‐destructive analytical technique which could be used to assess the efficacy of treatments applied to annual plants.