PM—Power and Machinery: Development of a Slow Active Suspension for Stabilizing the Roll of Spray Booms,Part 1: Hybrid Modelling

In this paper, a hybrid model of a spray boom with cable suspension is developed. It combines an analytical modelling procedure with identification techniques to cope with the limited power in the excitation actuator. The analytical model was used to optimize the passive boom suspension, while the identification part is the first step in the design of a slow active suspension.     

PM—Power and Machinery: Development and Evaluation of Kenaf Harvesting Technology

Laboratory and field tests have demonstrated that a component approach to harvesting kenaf and separating the fibre and core has a lot of potential. Machines used for harvesting kenaf required only minor, if any, modification. The straw-walker from a combine harvester proved to work very well to separate the kenaf fibre and core. More work needs to be performed to expand the prototype separator into a production unit. Transportation of the whole stalk material from field sites to the processing facility proved to be expensive due to the low density of the material. In-field separation could reduce this cost by 50 per cent.     

PM—Power and Machinery: Seed Loss when Cutting a Standing Crop of Oilseed Rape with Two Types of Combine Harvester Header

Oilseed rape has the potential to expand as an industrial crop. However, as oilseed rape matures, seed loss occurs by dehiscence of the seed from the pods prior to harvest and also as a result of crop disturbance by machinery during harvest. Seed loss of 600 kg ha⁻¹, 25% of the recorded yield, is not uncommon. This directly increases the price for industrial users and can also reduce oil purity because volunteer plants in subsequent oilseed rape crops may have a different oil fatty acid profile. Oilseed rape plants also persist as weeds in subsequent crops. An experiment was carried out to identify the cause of, and quantify contributions to, seed loss from two different designs of header fitted to the combine harvester; a standard header and a header with a conveyor fitted behind the cutterbar, claimed to assist crop flow into the auger. Seed loss was measured using trays placed in the ripening crop prior to harvest. Seed shed before harvest, 11 kg ha⁻¹, was low as a result of the relatively settled weather conditions. There was a significant difference between losses from the two types of header. The loss from each side knife was the same, but because of the differing header widths, translated into losses of 18·4 and 34·6 kg ha⁻¹ for the conveyor-assisted and standard headers, respectively, showing the advantage of using a wider header in reducing this loss. Excluding shedding loss and side knife losses, seed loss from the conveyor-assisted header was 59 kg h⁻¹ against 104 kg h⁻¹ with the standard header. Loss caused only by the cutterbar of the conveyor-assisted header, 27 kg ha⁻¹, was less than half that of the standard header cutterbar, showing the effectiveness of the combination of forward positioning of the cutterbar and conveyor-assistance. At 2001 costs, the conveyor-assisted header would recover its additional purchase price in five years if used to harvest 171 ha of oilseed rape per year.     

PM—Power and Machinery: Innovative Systems to reduce Vibrations on Agricultural Tractors: Comparative Analysis of Acceleration transmitted through the Driving Seat

The vibration transmitted through the seat of a four-wheel drive tractor, developing 92 kW at the p.t.o., and equipped with front suspension axle and shock absorber for the implement, were measured and analysed according to the ISO standard. Several tests were carried out in different conditions considering: type of operation (transfer with and without mounted implement, ploughing, harrowing); type of track (conglomerate bituminous track, macadam dirt track, country lane); connected and disconnected suspension and/or shock absorber and a range of forward speeds. In the transfer test on track, the vehicle suspension caused an average acceleration reduction of about 15%, and it could reach 30%. The shock absorber displayed a variable behaviour depending on the test condition; it could cause both attenuation and amplification, although the combination with the suspension often involves a high average reduction in acceleration (24%). In the soil tillage tests, the suspension could cause a substantial reduction in acceleration (up to 36%), but only in some conditions. With reference to the benefit for the driver due to the acceleration attenuation involved by the systems, it is important to note that, during soil tillage, the vehicle suspension could compromise the driver's health through an increase in daily exposure time of about 50% during ploughing and of more than 100% during harrowing.     

Examining the Effects of the Destroying Ammunition,Mines, and Explosive Devices on the Presence of Heavy Metals in Soil of Open Detonation Pit: Part 1—Pseudo-total Concentration

This paper presents the results of determining the pseudo-total concentration of five heavy metals in the soil on which the destruction of ammunition, mines, and explosive devices is carried out by the method of open detonation. In the analyzed area, the concentrations of cadmium, lead, nickel, copper, and zinc were determined, while from the physical properties of the soil were determined the granulometric composition and the pH. The aim of the study is to determine the origin and total load on heavy metals and, based on that, to assess the dangers and impact of the site in terms of the soil pollution by heavy metals. In accordance with the regulations of Bosnia and Herzegovina, the results of the soil testing showed a significant load of copper (up to seven times) and cadmium (up to six times), and exceeding the allowed values for nickel and zinc in some places. Lead was the only metal whose concentration was within the maximum allowed and according to that the soil was classified as unpolluted. A sample of soil from the edge of the pit is the only sample in which all heavy metals, except Ni, were within the maximum allowable concentration. In regard to the concentration of the examined metals, the soil of the pit is classified as medium polluted from the aspect of copper, cadmium, and nickel and highly contaminated with zinc. The concentrations of copper and zinc in the examination area correspond to contaminated soil that represents ecological risk, which requires soil remediation.     

SW—Soil and Water: Construction of an Artificial Perched Watertable,Part 1: Air Permeability of Soils and Aspects of Soil Failure

The annual precipitation in the Three-river Plain of the People's Republic of China is only 500–600 mm and, besides, the rainfall is uneven; 60–70% of the annual precipitation occurs in July and August and there is almost no rainfall in the winter and spring seasons. Experiments were conducted to form the artificial perched watertable where the runoff caused in summer could preferably be held, by injecting high-pressure air into the soil. A horizontal soil cavity is required, so this paper deals with the determination of the air permeability of soils and the difference in the soil failure mechanisms due to the different air permeabilities.The results show that the air permeability k of 10 m² s⁻¹ MPa⁻¹ defined the situation between the fluidization and the V-shaped soil failure. When the value of k was from 10 to 0·1 m² s⁻¹ MPa⁻¹, the V-shaped soil failure took place and when it was less than 0·1 m² s⁻¹ MPa⁻¹, the soil cavity production took place. In order to produce the soil cavity in the B horizon of the planosol or Cg1 horizon of the meadow soil by air injection, the value of k for these soils should be less than 0·1 m² s⁻¹ MPa⁻¹ and the soil water content of these soils should be more than 30% d.b.     

SE—Structures and Environment: Optimal Control Strategies for Carbon Dioxide Enrichment in Greenhouse Tomato Crops,Part II: Using the Exhaust Gases of Natural Gas Fired Boilers

Optimized control strategies for carbon dioxide (CO₂) enrichment of greenhouse tomato crops using CO₂ from the exhaust gases of boilers burning natural gas are presented. In one group of strategies, the heat produced during CO₂ generation which exceeds the immediate heat requirement of the greenhouse is stored as hot water and used subsequently for heating. The simulations show that, use of optimal control can increase the financial margin of crop value over the combined expenditure on gas used for CO₂ and heating by £2·3 m⁻² (11%) when heat is not stored and by £4·9 m⁻² (24%) when heat is stored, compared with enriching with CO₂ only when heating is required. A 30% increase in gas price reduced the financial margin by 11%, whereas a 30% increase in tomato price increased the margin by 40%. The capacity of the heat store places a limit on the amount of heat that can be stored and consequently on the amount of natural gas that can be burnt and the associated amount of CO₂ produced during the day. The optimum size of heat store is 20×10⁻³ m³ per unit greenhouse area.     

Facing the peat CO2 threat: digital mapping of Indonesian peatlands—a proposed methodology and its application

Journal of Soils and Sediments - We conducted this project to develop a feasible method for mapping tropical peat lands of Bengkalis Island—as a test site—in Indonesia. The method based...     

Reviewing SEBAL input parameters for assessing evapotranspiration and water productivity for the Low-Middle São Francisco River basin,Brazil: Part A: Calibration and validation

There is a growing interest in quantifying regional scale actual evapotranspiration (ET) for water accounting and for water productivity assessments at river basin scale. Methods that provide point values fail to describe the situations at larger scales. Remote sensing measurements can be used at different spatial scales. This paper applies the theory of the Surface Energy Balance Algorithm for Land (SEBAL). SEBAL was originally derived for Egypt, Spain and Niger [Bastiaanssen, W.G.M., 1995. Regionalization of surface flux densities and moisture indicators in composite terrain: a remote sensing approach under clear skies in Mediterranean climates. Ph.D. dissertation, CIP Data Koninklijke Bibliotheek, Den Haag, The Netherlands. 273 pp.] and was calibrated and validated using ground measurements from four flux sites and from seven agro-meteorological stations in the semi-arid region of the Low-Middle São Francisco River basin, Brazil. Measured parameters included surface albedo, surface temperature, atmospheric and surface emissivity, soil heat flux, surface roughness, net radiation, air temperature gradients, sensible heat flux, latent heat flux, evaporative fraction, and photosynthetically active radiation. The daily ET was estimated (RMSE of 0.38 mm d^?1) for mixed agricultural and natural ecosystems. The improved coefficients for the local conditions can now be used to study the impact of expanding irrigated agriculture on the regional water balance and to quantify the water productivity of irrigated horticulture that is the largest water consumer in the Brazilian semi-arid region. Both applications are described in an accompanying paper (Part B).     

Sustainable management of tropical small island ecosystems for the optimization of soil natural capital and ecosystem services: a case of a Caribbean soil ecosystem—Aripo savannas Trinidad

Journal of Soils and Sediments - The unsustainable use of soil natural capital and ecosystem services is of global concern due to damage and losses on a worldwide scale. This situation is further...     

Reviewing SEBAL input parameters for assessing evapotranspiration and water productivity for the Low-Middle São Francisco River basin,Brazil: Part B: Application to the regional scale

The intensification of irrigated agriculture in the semi-arid region of Brazilian North-east results in a change of natural vegetation by irrigated fruit crops. New applications of remote sensing technologies are presented in this paper to estimate the impact of this land use change on regional water consumption – and ultimately the water balance – in Low-Middle São Francisco River basin. Ten Landsat images for a period from 2001 to 2007 were used, together with the locally calibrated Surface Energy Balance Algorithm for Land (SEBAL) and agro-meteorological data to derive information on regional actual evapotranspiration (ET), biomass production (BIO), and crop water productivity (CWP). The Landsat-based results revealed that regional mean ET for irrigated crops was 3.6 mm d^?1 being higher than for natural vegetation (1.4 mm d^?1). Similar incremental ET values between natural and irrigated ecosystems were found from micro-meteorological field experiments. The consequence of this land use change on São Francisco River's downstream stream flow was assessed by estimating volumetric incremental evapotranspiration at the regional scale. The bio-physical crop water productivity per unit of actual evapotranspiration (CWP_ET) varied between 0.4 and 1.7 l of wine per m³ of water for wine grapes; 1.7 and 4.0 kg of fruits per m³ of water for table grapes; and 2.2 and 5.0 kg of fruits per m³ of water for mangos. The accompanying paper (Part A) describes the calibration and validation of SEBAL steps witnessed under the actual field conditions in this study area.     

Biodegradation of litter in Eucalyptus pauciflora communities—I: Techniques for comparing the effects of fungi and insects

Intact leaves of E. pauciflora were confined either in litter bags of three mesh sizes (5, 1 and 0.5 mm) or 5 mm mesh size bags after treatment with benomyl, zineb, DDT or dieldrin to assess the effects of insects and fungi on decomposition. In the untreated material, there was a loss in dry weight and total phosphorus of about 45 and 60% respectively and an initial gain in total nitrogen of up to 10% followed by a loss of between 70 and 86% of the original amount. There was no significant difference between the effects of the mesh sizes. A different pattern was observed for the insecticide and fungicide treated leaves which suggested that the fungi tended to mineralize phosphorus but immobilize nitrogen while the insects tended to mineralize or remove by migration both phosphorus and nitrogen.     

PH—Postharvest Technology: Diffusive Drying Kinetics in Wheat,Part 2: applying the Simplified Analytical Solution to Experimental Data

Reanalysis of the drying background in wheat showed that analytical solutions may be employed in this grain to estimate diffusion coefficients by using the simplified equation for short times instead of the time-consuming series. Sixteen thin-layer drying curves of hard wheat were measured (airflow ≈ 0·3 kg m⁻²s⁻¹) covering four air temperatures (35–70°C) at each of four initial moisture content levels (0·189–0·269 decimal, d.b.). Experimental curves of the moisture ratio versus time grouped by initial moisture content showed the expected strong accelerating effect of temperature on drying rate. Besides, when the same curves were grouped by temperature, the moisture ratios corresponding to higher initial moisture contents fell, after some time, consistently faster, showing that the diffusion coefficient should increase somehow with water concentration. The short time simplified diffusive equation fitted each curve very well, with values of the coefficient of determination above 0·99. Values of the diffusion coefficient for the whole kernel ranged from 1·4×10⁻¹¹to 7·1×10⁻¹¹m⁻²s⁻¹, presenting the classical Arrhenius temperature dependency (activation energy ≈ 27·0 kJ mol⁻¹), but with a pre-exponential factor that depends linearly on initial moisture content. This diffusive kinetics is expected to be useful for fast and accurate dryer simulation.     

Razorbacks: Feral Pigs as Agricultural Pests,Disruptors of Ecosystems,Reservoirs of Contagion,and Favored Game for Sport and Subsistence Hunters: A Review of the Literature, 2005–2011

Whether they are called “razorbacks,” as is common in the southern United States (and where they are notably the official sports mascots of the University of Arkansas), or “wild boar,” in much of the rest of the world, feral pigs are interbreeding subtypes of Sus scrofa, the same pig domesticated over 5,000 years ago. Once they have become established in the wild, these formerly manageable animals rapidly undergo a dramatic reversion to a wild appearance, may display aggression toward humans, engage in agriculturally and ecologically damaging behaviors, and spread diseases to both livestock and humans. They are the targets of many ongoing, increasingly sophisticated, science-based, eradication efforts.     

Investigations on the radioactive contamination of crop plants as a result of H-bomb detonation (Part 2) Root and foliage uptake of “Bikini ash”

The Foliar Uptake by Squash Plant

The radioactive ash for experimental use, hereafter referred to as “Bikini ash”, was prepared by igniting the heavily contaminated substances on board No. 5 Fukuryu Maru at about 650°C, followed by sifting through a 100 mesh sieve. On ignition some parts of the fission products, particularly iodine, ruthenium and tellurium would have possibly been lost to the air.     

River and harbor remediation: “polluter pays,” alternative finance,and the promise of a “circular economy”

Journal of Soils and Sediments - Contaminated sediments in rivers, lakes, and harbors around the world result in diminished ecological health, degradation of environmental resources, economic...