A Study of the Effects of Silage Effluent on Concrete: Part 2, Significance of Environmental Factors

This paper outlines experiments studying the effects of environmental conditions on the deterioration of concrete by silage effluent. Effluent was allowed to flow at a controlled rate over concrete specimens for nine 28-d periods of flow, such that each period simulated 1 year's corrosion at the front of a 200 t horizontal silo. The effects of flow rate, heat, ultraviolet light, air and effluent type were studied. Ultrasonic pulse velocity readings were taken on a silo floor to investigate whether a weakened layer develops in a concrete silo floor prior to dissolution. Silage juice taken from silage in contact with the concrete floor and from silage 1 m above the floor of five farm silos was analysed and compared. The ultrasonic pulse velocity readings showed no evidence of a weakened layer beneath the corroded surface. The analysis of silage juice showed that the environment in the silage adjacent to the concrete floor becomes non-aggressive to concrete due to secondary clostridial fermentation. It was concluded that this was an important factor in silo durability which could explain the reduced corrosion occurring in concrete under silage, compared with concrete not covered by silage, in the same silo. The duration of effluent flow was considered to be very important in determining when secondary fermention could occur. It was also concluded that effluent type and flow rate could play a lesser role in determining the aggressiveness of the environment in different silos.     

Chemical Composition and Energy Value of Big Bale Silages made in England, 1984-1991

Averaged over 8 years, big bale silages made on farms in England had the following composition: dry matter (d.m.) 351 g/kg, pH 5·02, ammonia N 98 g/kg total N, crude protein 112 g/kg d.m., ash 91 g/kg d.m. and calculated metabolisable energy 10·1 MJ/kg toluene d.m.There was significant (p<0·001) year-to-year variation for each component measured. Silage ammonia N content decreased with d.m. content. The results indicated that a d.m. content of 300 g/kg was needed to produce reliably well preserved silage with less than 100 g ammonia N/kg total N. In addition, favourable weather conditions with little rain and high levels of sunshine were required to achieve this.     

Chemical Composition and Energy Value of Maize Silage Made on Farms in England and Wales 1984-92

The chemical composition of 960 samples of maize silage, made on commercial farms in England and Wales between 1984-1992, is described. The average composition was 302 g/kg dry matter (d.m.), pH 3·78, ammonia-N 60 g/kg N, 87 g/kg d.m. crude protein (CP), 292 g/kg d.m. modified acid detergent fibre (MADF), 678 g/kg d.m. neutral-detergent cellulase digestible organic matter (NCDG) and 301 g/kg d.m. starch. The predicted mean metabolizable energy content was 10·5 MJ/kg d.m. There was significant year-to-year variation for each variable. Ammonia-N and ash contents were negatively correlated and starch and metabolizable energy content were positively correlated with silage d.m. content.The results indicated that in recent years maize silage has consistently been made with d.m. contents above 300 g/kg, which should produce little or no effluent, and will lead to high silage intakes by animals.     

The Effect of Formic Acid with Formalin on Grass Silage Fermentation and the Performance of Dairy Cows

In the first experiment, perennial ryegrass with dry matter (DM) 260 g/kg and water-soluble carbohydrate (WSC) 140 g/kg DM was harvested as first-cut material on 25 May 1982. It was pre-wilted for 24 h prior to ensilage and treated with either a formic acid with formalin additive (WFF) at 4l/t or no additive (W) and ensiled in two adjoining covered 150 t bunker silos. Subsequently, both silages were satisfactorily fermented. Nevertheless, the pH, ammonia–N g/kg N and lactic-acid content were significantly lower and the residual WSC content significantly higher for WFF than W. Each silage was subsequently individually fed to ten Friesian and ten Holstein dairy cows, together with 10 kg/d of a compound feed containing 160 g/kg crude protein in a 70 d feeding trial. Additive treatment had no significant effect upon silage DM intake, milk output or composition. However, the daily liveweight losses of cows given WFF-treated silage were significantly higher than those given W.In the second experiment, perennial ryegrass (DM 180 g/kg and WSC 170–200 g/kg DM) harvested as first-cut material on 2 June 1983, was either cut and picked up within 20 min of cutting and treated with either the formic acid with formalin additive at 4l/t (NWFF) or no additive (NW); or wilted for a maximum of 24 h and treated with either the formic acid with formalin additive at 4l/t (WFF) or no additive (W). Wilting significantly increased subsequent silage DM. The pH of NW was significantly less than W, whilst the ammonia–N g/kg N of NWFF was significantly less than NW and W and that of W significantly higher than the other treatments. Additive treatment significantly increased the residual WSC content. Each silage was subsequently individually feed to 12 Friesian and 12 Holstein dairy cows together with 10 kg/d of a compound feed to 12 Friesian and 12 Holstein dairy cows together with 10 kg/d of a compound feed containing 160 g/kg protein in a 180 d feeding trial. The silage DM intake of WFF was significantly higher than NW. Silage treatment had no significant effect upon milk output or composition. The daily liveweight loss of cows given WFF-treated silage was significantly less than the other treatments, and the cows on NW had a significantly longer calving index than the other treatments.It is concluded that compared with non-additive-treated silage, formic acid with formalin applied at ensilage produced better fermented silage which, when subsequently given to lactating dairy cows, produced no significant increase in daily silage DM intake, milk output or composition, but had small significant effects upon liveweight change.     

Effect of Additives on Grass Silage Fermentation and Effluent Production,and on Intake and Liveweight Change of Young Cattle

Data from 11 experiments, conducted mainly at ADAS Liscombe Research Centre during 1989–1992, were used to compare silages made with additives which included formic acid, an acid–salt-type additive, sulphuric acid, liquid inoculant and a cultured inoculant with a non-additive-treated control. The silages were made from herbage with dry matter (DM) 170 g/kg and water-soluble carbohydrate (WSC) 21 g/kg.Compared with the non-additive-treated silage, formic-acid treatment significantly reduced silage pH, ammonia–N, acetic acid, butyric acid, total short-chain fatty acid and total acid content and significantly increased the proportion of lactic acid expressed as a proportion of the total acids. The acid–salt-type additive significantly decreased pH, lactic acid, acetic acid, total short-chain fatty acids and total acid content and significantly increased WSC. Sulphuric acid significantly reduced pH and ammonia-N. The liquid inoculant had no significant effect upon any silage fermentation parameters, and the cultured inoculant significantly reduced pH and acetic acid and significantly increased the proportion of lactic acid expressed as a proportion of total acids.Effluent production was higher with acid treament, but the effect was not significant. The effluent from the acid–salt-type additive-treated silage had a significantly higher DM and WSC than the other treatments.The silage DM intakes of the formic acid (5·36 kg/d), sulphuric acid (5·29 kg/d) and the acid–salt-type additive (5·20 kg/d) were significantly higher than those of the untreated silage (4·76 kg/d), and the daily live-weight gains given by the acid–salt-type additive (0·71 kg/d) and formic acid (0·68 kg/d) treated silages were significantly higher than those of the untreated silage (0·58 kg/d).It is suggested that the improvements in silage preservation obtained from additive use at ensilage were closely reflected in terms of animal performance. The acid– salt-type additive and formic-acid treatments were most effective, the liquid inoculant and sulphuric acid inter mediate between the acid–salt-type additive or formic acid and untreated silage, whilst the cultured inoculant was similar to untreated silage.     

A Study of the Effects of Silage Effluent on Concrete: Part 1, Significance of Concrete Characteristics

This paper outlines an experimental facility that was used to study the effects of silage effluent on concrete by simulating the front of a 200 t horizontal silo. An effluent flow rate of 1431 of effluent per m² concrete per d and a flow period of 28 d were used to cause the corrosion associated with each year of service. Nine simulated years were studied and the effects on some durability related properties of concrete were assessed. The concrete mix variables studied were the effects of water and cement contents, water-reducing admixtures, pozzolanic admixtures, and the type of coarse aggregate. Only the surface of the concrete was affected by the effluent and it corroded at a rate of about 1 mm per simulated year. The importance of a low water/cement ratio in producing durable concrete was shown. Water-reducing admixtures and pozzolanas showed potential for reducing the deterioration of farm silos. The type of coarse aggregate was important in controlling the surface roughness.     

2ZLF-500型轮刀式青贮饲料切碎机的设计

针对青贮饲料的特点和畜牧业养殖户的要求,创新设计了2ZLF-500型轮刀式青贮饲料切碎机,阐述了该机的结构组成和工作过程,并对主要工作部件结构和参数进行了设计,确定了其主要技术参数。该机的设计提高了饲草的青贮质量、饲草使用的可靠性和利用率,对饲草青贮技术的推广应用、促进畜牧业的持续稳定发展和形成节粮型的畜牧业结构都具有十分重要的意义。     

黑龙江省青贮玉米收获机械现状及发展趋势

青贮玉米收获机是青贮玉米饲料机械化生产中重要的农业装备之一。为此,分析了黑龙江省青贮玉米收获机械的现状和发展趋势;指出了青贮玉米收获机械发展中存在的问题;提出了相应的解决对策。其目的是为进一步加快黑龙江省青贮玉米收获机械的发展献计献策。     

Effect of Formic Acid with Formalin or Barley Incorporation into Grass Silage on Silage Fermentation and the Performance of Dairy Cows

Perennial ryegrass was ensiled in three different ways: (1) with a formic acid with formalin silage additive at 4·0 l/t; (2) with an addition of 50 kg/t ground barley; and (3) no-additive. Formic acid with formalin produced well-fermented silage, which, when subsequently given to lactating dairy cows significantly enhanced daily dry matter (DM) intake and butterfat, protein and butterfat plus protein output and reduced the liveweight decrease experienced with the other treatments. The addition of ground barley at ensilage provided less benefit in terms of fermentation, but had a more pronounced effect upon daily silage DM intake and milk yield than formic acid with formalin treatment. The daily liveweight losses of cows given the non-additive-treated and ground-barley-treated silages were significantly higher than those given formic acid with formalin treated silage. Silage treatment had no significant effect upon cow fertility.     

覆盖作物对土壤物理特性及旋耕作业的影响分析

覆盖作物可改善土壤持水能力,但是对土壤硬度的影响与土壤含水率有关。对覆盖作物进行耕前割倒作业可解决旋耕作业时在旋耕刀辊上产生的缠绕问题。大量作物残茬置于土壤表层会影响后续作物的播种质量和出芽率,所以对于干物质量大的覆盖作物不宜直接采用旋耕作业。     

The Influence of Cement Content and Water/Cement Ratio on the Durability of Portland Cement Concretes exposed to Silage Effluent

This paper outlines the findings of a study on the influence of cement content (275–425 kg/m³) and water/cement ratio (0·45 to 0·75) on the durability of concrete exposed to silage effluent. The test facility exposed concrete specimens to a controlled flow of effluent such that the volume of effluent in each 28 day cycle of exposure simulated one year's volume and expected period of effluent flow at the front of a well-drained 200 t horizontal silo. The relative performance of the concrete mixes was assessed over 10 cycles through measurement of saturated mass loss and surface depth change. The saturated mass loss measurement gave more consistent results. Optimum performance was recorded in concretes of cement content 325 and 375 kg/m³with water/cement ratios of 0·55 and 0·50, respectively. The studies indicate that water/cement ratio is a more critical variable than cement content. Deterioration increased significantly when the water/cement ratio exceeded 0·5. Increasing the cement content beyond the minimum recommended value in current national specifications (350 kg/m³) did not lead to a reduction in mass loss rate. The benefits of high cement content concretes is questioned, therefore, not least because of the increased risk of early-thermal cracking. It is postulated that specifications should limit the maximum water/cement ratio and both maximum and minimum cement content.     

不同灌水方式和施肥量对青贮玉米生长和产量的影响

青贮玉米是河北省粮改饲的主要目标作物。为制定合理的水肥管理措施,提高青贮玉米的产量,选取灌水方式和施肥量作为因子进行青贮玉米试验。灌水方式设置畦灌和沟灌两个水平,施肥量设置4个水平,肥料用量在300~750 kg/hm^+2之间。研究结果表明,沟灌与畦灌相比,株高和鲜重分别增加2.2%和3.6%,沟灌有利于青储玉米的生长和产量的提高。施肥量对青储玉米的生长和产量影响显著,施肥量600 kg/hm^+2时青储玉米生长状况和产量最好,与750、450和300 kg/hm^+2施肥量水平相比,株高、叶面积指数、叶绿素和鲜重分别增加0.11%~27.8%、4.01%~10.55%、1.1%~1.8%和3.6%~15.6%。青储玉米鲜重产量介于69.09至81.4 t/hm^+2之间。相关性和回归分析结果表明青储玉米鲜重与株高和叶面积指数之间呈极显著正相关,沟灌、施肥量600 kg/hm^+2的处理组合有助于株高和叶面积生长,因此也有助于获得较高的青储玉米产量。     

宁夏黄土高原区滴灌青贮玉米灌溉参数试验研究

针对宁夏黄土高原区青贮玉米灌溉土地生产效率低、灌溉方式粗放、对产量影响不明确等技术问题,通过田间试验,分析不同土壤水分下限对滴灌青贮玉米株高、净光合速率、蒸腾速率、水分生产效率及产量的影响。结果表明:1青贮玉米株高增加量,处理F7最大,F8次之,F4最低;2日平均净光合速率,处理F7最高,为20.08μmol/(m~2·s),处理F1最低,为8.01μmol/(m~2·s);日平均蒸腾速率,处理F8最高,为3.57 mmol/(m\+2·s),处理F1最小,为1.71 mmol/(m~2·s);3处理F7产量最高,为89 724 kg/hm~2,处理F1最低,为57 136.5 kg/hm~2,同时,处理F7水分生产效率也达到最大值,为20.67 kg/m3;综合考虑作物产量和水分生产效率,滴灌青贮玉米土壤水分下限以处理F7为宜。     

Water balance of Swamp Mahogany and Rhodes grass irrigated with treated sewage effluent

Water balance of Swamp Mahogany (Eucalyptus robusta Sm.) and Rhodes grass (Chloris gayana Kunth var. Callide) plantations was studied in large experimental plots, which were irrigated with secondary treated sewage effluent. The tree plots designated as T10, T20, T30 and T40 received four different nitrogen (N) concentrations of 10, 20, 30 and 40 mg/l, respectively. The grass plot designated as G30 received one N level (30 mg/l). The objective of the study was to compare growth and water use of these plantations and the possible effluent losses to the environment.There was little response to N treatment in the first year of tree growth. A significant response to high N concentration was observed in tree treatment plots in the second year of the growth. Thus, at 20 month stage, the T40 trees reached a height of 4.1 m and had a leaf area index (LAI) of 2.5 compared with 2.2 m and 1.6, respectively in T10 trees. As expected, the T40 treatment had the largest interception losses (10%) and the least runoff and interflow. There was a progressive decrease in runoff and interflow with reductions in the level of nitrogen applied.Annual evapotranspiration was calculated to be 982 and 1191 mm, in the first and second year for grass compared with 1126 and 1269 mm, respectively for the T30 treatment. Grass and trees receiving the same concentration of N in effluent (30 mg/l) were transpiring at similar monthly rates, with crop factors of 0.79 for the grass and 0.85 for the trees, which were not statistically different. These results in plots subject to regular effluent irrigation are markedly different from findings of previous studies, which indicated a very large increase in water use of trees compared to grass vegetation under dryland conditions. Although evapotranspiration utilised the largest portion of the incoming water to the plots, the need for irrigation was reduced by the occurrence of frequent rainfall at the site. Runoff comprised the largest off site loss mechanism, especially during high rainfall periods indicating that coastal areas with low irrigation demand provide a limited opportunity for land disposal of effluent. Other site characteristics such as shallow soils increase the risks of environmental pollution through runoff from application site. Increase in area of application and adoption of a filtering technique will reduce risks to the soil and the environment.     

青贮秸秆铡揉机的设计与试验

鉴于铡揉的青(干)玉米秸秆、麦秸等农作物秸秆及牧草物料适用于养殖牛羊牲畜及生物质能发电等领域,可有效推动粮改饲政策进一步实施,设计了一种青贮秸秆铡揉机。为此,提出了青贮秸秆铡揉机的设计方案,并对青贮秸秆铡揉机的输送喂入装置、铡揉装置及抛料装置进行优化设计,并通过试验数据计算得到青玉米秸秆的物料相对含水率平均值为55%,秸秆铡揉长度为1 060mm,秸秆破节率的平均值达91%,标准草长率为8 9%。设计的青贮秸秆铡揉机对于助推畜牧养殖业的产业化发展,提高畜牧养殖产品肉奶品质、避免秸秆资源浪费及减少环境污染具有重要的现实意义。     

Water balance and water use efficiency of different land uses in western Himalayan valley region

Various land uses, including sole plantations of leucaena and eucalyptus, maize–wheat, chrysopogon grass or turmeric and their tree crop mixtures were compared for period of nine years in two sequences for runoff, water use and water use efficiency on nine large erosion plots on 4% slope. Availability of water during summers and climatic evaporative (EP) demand during winters appear to be the governing factors for seasonal water use. About 70% of annual water consumption occurs during the four months (July to October) of rainy season. During this season water use was about 3–4 times to EP for trees and grass and 2.5 times for maize. The water use equals EP regardless the land use during winter season, while it reduced to about one-third to half of EP in the summer season. Annual water use is found to be closely linked with runoff reduction efficiency of the land use. Sole plantations of leucaena and eucalyptus showed negligible runoff losses and their water use approximated annual rainfall. Agroforestry land uses also reduced runoff and increased water use and water use efficiency. Seasonal crops exploited 1.5 m depth of profile more exhaustively than trees, whereas trees used soil water down to 3.0 m depth. Therefore, in tree crop mixtures more efficient soil water use was observed as compared to monocropping systems. Results of this study indicate that water conserved under sole tree plantations and due to tree intervention in agroforestry land uses through runoff reduction, is utilised to meet increased evapotranspiration demand, and hence ground water recharge in appreciable quantities is unlikely.     

The Effect of Formic Acid with Formalin Addition and Wilting on Silage Fermentation and Intake,and on Liveweight Change of Young Cattle

Data from seven experiments conducted at ADAS Liscombe Centre during 1980–1983 were used to compare formic acid with formalin-treated unwilted (FF) and wilted silage (WFF) with wilted non-additive-treated (W) silage made from herbage [dry matter (DM) of 172 g/kg and water-soluble carbohydrate (WSC) 114 g/kg DM]. Following ensilage, the DM content of FF was significantly less than W and WFF. Compared with W, WFF treatment significantly decreased silage pH, ammonia–N and butyric-acid content and significantly increased the residual WSC, whereas FF significantly reduced pH, ammonia–N, butyric acid, protein and ash content and significantly increased lactic acid, acetic acid and lactic acid expressed as a proportion of total acid content. DM losses were significantly higher for FF than from W or WFF treatments. W and WFF significantly increased subsequent silage DM intake compared to FF. Daily liveweight gains were, however, significantly higher on FF compared with W but not WFF treatment. It is suggested that FF treatment of unwilted silage produced well-fermented silage, which when fed to growing cattle had a lower DM intake, but higher liveweight gain than wilted silage, and that when compared with wilted silage (W) formic acid with formalin treatment (WFF) improved fermentation, but provided no significant benefit in terms of either silage DM intake or liveweight gain.     

Some Physical Properties of Lentil Seeds

Several physical properties of lentil seed were evaluated as a function of moisture content. The average diameter, thickness, unit mass and volume of seed were 6·64 mm, 2·65 mm, 0·070 g and 49·08 mm³respectively at 6·5% m.c.d.b. Studies on rewetted seed showed that as moisture content increased from 6·5 to 32·6% d.b., bulk density decreased from 1190 to 935 kg/m³, porosity increased from 27·4 to 32·0%, projected area increased from 56 to 82 mm²and terminal velocity increased from 10·95 to 12·06 m/s. The static and dynamic coefficients of friction of lentil seed against galvanized sheet metal, plywood and rubber surfaces increased with moisture content in the range from 6·5 to 32·6% d.b. The largest coefficient of friction was against a rubber surface, ranging from 0·374 to 0·532. The effect of moisture content was as great as or greater than the difference between the surfaces.     

Prospects of micro-irrigation in India

The demand for land and water in India is continuously escalating due to increased population. The land can be used intensively on even up to 3 crops in a year for which water is needed. Therefore water management and increased production are very essential and crucial for the development.Research studies conducted in India by various institutions have indicated that water saving is about 40–80% and the yield increase is up to 100% for different crops by using micro-irrigation. The incremental benefit-drip cost ratio (B_I/C_D) worked out for various crops ranges from 1.35 to 13.35 excluding water saving and 2.78 to 32.32 including water saving. It has also been proved that drip irrigation, which is a type of micro-irrigation, is technically feasible and socially acceptable not only for large farms but also in small and marginal farms.Drip irrigation can be adopted to large areas irrigated from wells especially for wide spaced high value crops. This method is also suitable for hilly and undulated tracts, coastal sand terrains, and to a great extent in the water scarce areas of South and Western India. About 18 million ha are under fruit, vegetables and plantation crops and the present area under drip is only about 55,000 ha. Therefore the potential and prospects of drip irrigation is very high in the coming years.     

Response of silage yield to land application of out-wintering pad effluent in Ireland

Out-wintering pads (OWPs) are a low capital-cost cattle housing system gaining popularity in Ireland and other countries. OWPs consist of a layer of timber residue over an artificially drained surface that separates solid and liquid excreta created during animal confinement. Residues from OWPs that require management include liquid effluent (urine and water) and spent timber residue (timber soiled with manure). The current strategy for on-farm management of effluent and spent timber residue is to apply them to grassland used for the production of silage. The objective of this study was to determine the dry matter (DM) yield response of first and residual cut silage to three rates of OWP effluent applied to grassland. These results were compared to silage crop response to inorganic N fertilizer and to cattle slurry (manure and urine) from a conventional livestock housing system. In four out of five trials, application of OWP effluent of up to 29 kg ha⁻¹ of total N input resulted in a significant DM yield response compared to control treatments for first cut silage. The efficiency of OWP effluent ranged from 74 to 90% at the highest application rate (29 kg N ha⁻¹) compared to inorganic fertilizer for first cut silage DM yield. Cattle slurry N efficiency was 16-50% at a similar N application rate (27.9 kg N ha⁻¹) for first cut silage DM yield.