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Food fraud surfaces regularly, anywhere in the world. Not only the companies involved in food fraud suffer from losses when food fraud occurs, other actors in the supply chain and branch of industry are often painted with the same brush. Milk has been a common fraud target in the past and, therefore, fraud is a concern for companies involved in milk production. In order to manage and prevent fraud in the milk supply chain, a good insight into the vulnerabilities of companies and their supply chain networks is pivotal. The aim of the current study is to understand (a) the fraud vulnerability of the general milk supply chain in the Netherlands and its tiers (farmers, processors, retailers) and (b) the differences in fraud vulnerability of farmers producing organic milk, green intermediate ‘pasture milk’ and conventional milk. The SSAFE food fraud assessment tool was slightly adapted to the milk supply chain and used to examine the fraud vulnerability of the 38 businesses of the three tiers in the study: 30 farmers, 4 milk processors and 4 retailers. Forty-eight fraud factors related to opportunities, motivations and control measures were examined. Subsequently, key fraud factors were identified. The three tier groups showed major similarities in motivation related fraud factors, and large differences in fraud opportunities and controls. There were also differences observed between the organic and non-organic farmers, with organic farmers being slightly more vulnerable than their non-organic counterparts. From this study it appears that the milk supply chain in the Netherlands is low to medium vulnerable to fraud but the key factors contributing to the vulnerability differ between the tiers (farmers, processors, retailers). Management of the fraud risks requires consideration of these differences.

A problem in loose housing systems for laying hens is the laying of eggs on the floor; these eggs need manual collection. This job is heavy and time-consuming and automated collection is desired. For collection using a robot, a collection path is required. A novel path planning algorithm is introduced for non-uniform repetitive area coverage (NURAC) paths and evaluated based on information about floor egg distribution probability. Firstly, a spatial map was developed that describes the potential for floor eggs at each location in a poultry house. Next, paths for floor egg collection are planned with a dynamic programming approach that covers the house floor area and frequently revisits locations with a high potential on floor eggs. These paths are compared with the paths used for floor egg collection by a farmer and evaluated with help of a simulated set of floor eggs. With respect to the average time eggs are present on the floor, paths planned for a robot are compared to two collection rounds of a farmer. With respect to the structure of the path and the number of visits to locations with a high potential, the robot paths outperform the farmer. Although optimality of the path is not guaranteed, the presented results are promising for the use of a robot to collect floor eggs, and will result in a reduction of the demand for manual labour. Extending the floor egg model with feedback information could further improve the results.

Food fraud is as old as mankind but has advanced in the last decades. Fraud regarding the gross composition of food has progressed in the direction of the addition of unconventional adulterants. Furthermore, consumers are more and more interested in how and where their foods are produced and pay price premiums for organic foods, fair trade, animal welfare considering, and sustainable food products. Since these products are very similar to their conventional counterparts in terms of composition, they provide an additional challenge. The knowledge regarding occurrence, type of meat fraud, causes and damage caused to the sector is limited. There is a need for extensive identification of the vulnerabilities and criminogenic factors. These insights offer leads for detection and prevention. The article deals with a first step into the inventory of these vulnerabilities and factors affecting meat fraud, by assessing fraud risks related to products, companies and the meat supply chain.

Efforts to define and quantify soil quality are not new, but establishing consensus about a set of standardized indicators remains difficult. Also, the view of land managers is usually not taken into account when evaluating various sets of indicators. Our objective was to compare, in functional terms, soil quality assessments based on 29 indicators, a subset with 8 of those indicators, and 4 indicators selected independently by farmers, based on their perceptions of soil quality. The assessments were made for three different rice management systems in Camaqua, Rio Grande do Sul state, Brazil, on soils of four soil textural classes based on clay content ( 600 g kg−1). The effects of land management practices on soil functions (water infiltration, storage and supply; nutrient storage, supply and cycling; and sustained biological activity) were evaluated. Soil quality was best assessed using the entire set of 29 indicators, but use of smaller indicator sets showed the same trends among management systems, textural classes, and soil functions, thus providing meaningful information on soil quality for land managers.

In Chile, cow carcasses present the highest bruise prevalence compared with other cattle categories; however, the causes of the bruises are frequently unknown. In this study, 52 cull cows were transported to the slaughterhouse in three batches under identical transport conditions. A combination of direct observation and video analyses was used to determine moment, pre-slaughter stage and cause of potential bruising events during the period from loading on the farm until stunning at the slaughterhouse. After slaughter, number of bruises, location on the carcass and characteristics of the bruises were assessed. Seventy-eight bruises were observed on 37 carcasses. Fifty-two bruises were linked back to their causal event. Results showed that 46% of these bruises were a result of interactions between animal and facility, and most of them were inflicted in the stunning box, 27% of the bruises originated from animal–animal interactions and were mostly inflicted during lairage, another 27% was a result of human–animal interactions and were mostly inflicted during loading and unloading of animals. The percentages of potential bruising events resulting in a bruise were 43%, 9% and less than 1% for animal–facility, human–animal and animal–animal interactions, respectively. Most bruises on the back site were inflicted when the animal was in the stunning box (91.2%), whereas bruises on the pin site were mostly (75%) inflicted during loading at the farm. One may conclude that in relative short journeys (=4 h) directly from farm to the slaughterhouse and long lairage times (>12 h), most bruises are the result of circumstances at the slaughterhouse. A substantial amount of these bruises could be avoided by proper animal handling and adequate stunning facilities.

Automatic feeding systems (AFSs) enable more frequent delivery of feedstuffs compared to conventional feeding systems (CFSs). The objective was to estimate the effect of the feeding system (CFS versus AFS) and of the associated feeding and milking related actions on the visiting patterns to automatic milking systems (AMSs). The AMS log files of 20 Dutch dairy farms that fed total mixed rations (TMR) and milked automatically for the year 2009 were analysed: 9 farms used a CFS, 11 farms fed with an AFS. The effects of the feeding system on the mean daily AMS visits were determined using an F-test and on the hourly AMS visits using a restricted maximum likelihood (REML) analysis. To assess the effect of feeding and milking related actions on the AMS visiting patterns the patterns were decomposed into Fourier harmonics, the effects of the actions were analysed with transfer functions and lagged variables and parameters were estimated with REML. No statistical differences were found for the mean daily AMS visits between the CFS (2.567 milkings day-1, 2.056 refusals day-1 and 0.105 failures day-1) and AFS farms (2.614 milkings day-1, 2.483 refusals day-1 and 0.118 failures day-1). The cows at the AFS farms were milked significantly earlier (at 7:00 and 8:00 AM) than at the CFS farms. Feed delivery reduced the milkings cow-1 h-1 slightly and almost significantly in the hour of feed delivery, while AMS cleanings and fetching of cows had a more significant effect on the hourly cow visits to the AMS.

Since both the spatial and vertical heterogeneities in soil properties have an impact on crop growth and yield, accurate characterization of soil properties at high sampling resolution is a preliminary step in successful management of soil-water-plant system. Conventional soil sampling and analyses have shown mixed economical returns due to the high costs associated with labor-intensive sampling and analysis procedures, which might be accompanied with map uncertainties. Therefore, the conventional laboratory methods are being replaced or complemented with the analytical soil sensing techniques. The objective of this chapter is to review different soil sensing methods used to characterize key soil properties for management of soil-water-plant system. This will cover laboratory, in situ in the field, and on-line measurement methods. This review chapter is furnished with an overview of background information about a sensing concept, basic principle and brief theory, various factors affecting the output of the sensor, and justification of why specific soil properties can be related with its output. The literature review is succeeded with an integration and analysis of findings in view of application in the precision agriculture domain. Potentials and limitations of current sensor technology are discussed and compared with commonly used state-of-the-art laboratory techniques. As sensing is commonly addressed as a very technical discipline, the match between the information currently collected with sensors and those required for site-specific application of different inputs, and crop growth and development is discussed, highlighting the most accurate method to measure a soil property for a given application.

The objective of this study was to test the reliability of the post-mortem evaluation of bruise characteristics using a newly extended protocol. Intra-observer reliability of the observations was assessed with three meat graders, each of whom blindly examined 50 photos of bovine carcasses in two sessions, with 1 week in between. The agreement was “substantial” for number of bruises per carcass, and size and shape of the bruises; whereas it was “moderate” for colour and severity grade. Inter-observer reliability of the observations was assessed with four meat graders who each examined the same 46 carcasses at the slaughter-line. Inter-observer agreement for number of bruises per carcass ranged between observer pairs from “fair” to “moderate.” The agreement for number of bruises scored per anatomical site was “very low” for all observers. The most concordant bruise feature was size, followed by colour and shape. The bruise scoring protocol was associated with high level of intra-observer reliability and low inter-observer reliability. A further calibration of the observer judgments is needed to reach a more uniform scoring of the observers.

By sampling aerosolized microorganisms, the efficiency of a bioaerosol sampler can be calculated depending on its ability both to collect microorganisms and to preserve their culturability during a sampling process. However, those culturability losses in the non-sampling processes should not be counted toward the sampling efficiency. Prior to the efficiency assessment, this study was designed to investigate the culturability losses in three non-sampling processes: (1) the tracer uranine induced loss; (2) the loss during aerosolization (pre-sampling process); and (3) the bacteria and uranine recovery in air sample handling procedures for the samples of the Andersen 6-stage impactor and the Airport MD8 (post-sampling process). The results indicated that uranine had no significant effect on the culturability of Enterococcus faecalis, Escherichia coli, and Mycoplasma synoviae in suspensions (P > 0.05), but negatively affected the culturability of Campylobacter jejuni (P = 0.01). The culturability of E. faecalis, E. coli, and M. synoviae was not affected by stresses caused by aerosolization (P > 0.05). Only 29% of C. jejuni were still culturable during aerosolization (P = 0.02). In the air sample handling procedures, the four species of bacteria were recovered without significant losses from the samples of the Andersen impactor, but only 33-60% uranine was recovered. E. faecalis, E. coli, and M. synoviae were recovered without significant losses from the samples of the Airport MD8. More C. jejuni was recovered (172%), probably due to multiplication or counting variation. It is suggested that tracer and bacteria should be aerosolized separately when the tracer negatively affects the bacterial culturability. In both pre- and post-sampling processes, losses of bacterial culturability (or multiplication) may occur, which should be taken into account when assessing the efficiencies of bioaerosol samplers.

Emissions of air pollutants from livestock houses may raise environmental problems and pose hazards to public health. They can be reduced by scrubbers installed at the air outlets of livestock houses. In this study, three multi-stage scrubbers were evaluated in terms of their effectiveness in reducing emissions of airborne dust, total bacteria, ammonia, and CO2 from pig houses in winter. The three multi-stage scrubbers were one double-stage scrubber (acid stage+ bio-filter), one double-stage scrubber (acid stage + bio-scrubber), and one triple-stage scrubber (water stage + acid stage + bio-filter). Results showed that these scrubbers reduced concentrations of PM10 by 61% to 93%, concentrations of PM2.5 by 47% to 90%, concentrations of airborne total bacteria by 46% to 85%, and concentrations of ammonia by 70% to 100%. Concentrations of CO2 were not affected. Most of the airborne bacteria emitted from the pig houses were larger than 3.3 µm (73% to 95%). The multi-stage scrubbers removed 53% to 92% of them, compared with -42% to 20% removal effectiveness of the bacteria in the size range of 0.65 to 3.3 µm. The triple-stage scrubber was the most efficient in removing dust and ammonia. Compared to single-stage scrubbers, all three multi-stage scrubbers performed more consistently in reduction of PM10, PM2.5, total bacteria, and ammonia emissions from livestock houses and removed these pollutants more efficiently. It should be noted that all measurements were performed in winter at low ventilation rates, thus at low loadings of the multi-stage scrubbers

In an airborne transmission experiment, Campylobacter in the air was sampled by three types of bioaerosol samplers (all-glass impinger AGI-30, Andersen six-stage impactor, and OMNI-3000) in four broiler rooms. In each room, five 14-day- old broilers inoculated with Campylobacter jejuni were kept in a central cage located in the middle of the room. Another ten broilers, as susceptible animals, were kept individually in ten cages surrounding the central cage at a distance of approximately 75 cm. Air samples were taken on eight days: the day before inoculation (BI) as a negative control, and 1, 3, 6, 9, 14, 21, and 29 days post-inoculation (PI). Presence of C. jejuni was investigated with the culture method for culturable bacteria and with the PCR test for bacterial DNA. Results showed that Campylobacter infection of susceptible broilers occurred in all four rooms; however, no culturable C. jejuni could be detected in any of the air samples. This might have been the result of the low number of broilers in the room and the unfavorable conditions for Campylobacter survival, leading to Campylobacter concentrations below the detection limits of the bioaerosol samplers. The PCR test showed that DNA of C. jejuni was detected in the air samples on the first day PI, but no bacterial DNA was detected on the following days. It is concluded that the three samplers used in this study are not able to alarm Campylobacter outbreaks through an airborne route when low bacterial concentrations are present. Developments of new sampling techniques with low detection limits are required for biosecurity assessment.

The guidance of a vehicle in an outdoor setting is typically implemented using a Real Time Kinematic Global Positioning System (RTK-GPS) potentially enhanced by auxiliary sensors such as electronic compasses, rotation encoders, gyroscopes, and vision systems. Since GPS does not function in an indoor setting where educational competitions are often held, an alternative guidance system was developed. This article describes a guidance method that contains a laser-based localization system, which uses a robot-borne single laser transmitter spinning in a horizontal plane at an angular velocity up to 81 radians per second. Sensor arrays positioned in the corners of a flat rectangular table with dimensions of 1.22 m × 1.83 m detected the laser beam passages. The relative time differences among the detections of the laser passages gave an indication of the angles of the sensors with respect to the laser beam transmitter on the robot. These angles were translated into Cartesian coordinates. The guidance of the robot was implemented using a uni-directional wireless serial connection and position feedback from the localization system. Three experiments were conducted to test the system: 1) the accuracy of the static localization system was determined while the robot stood still. In this test the average error among valid measurements was smaller than 0.3 %. However, a maximum of 3.7 % of the measurements were invalid due to several causes. 2) The accuracy of the guidance system was assessed while the robot followed a straight line. The average deviation from this straight line was 3.6 mm while the robot followed a path with a length of approximately 0.9 m. 3) The overall performance of the guidance system was studied while the robot followed a complex path consisting of 33 sub-paths. The conclusion was that the system worked reasonably accurate, unless the robot came in close proximity (

BACKGROUND: An apparently large disparity still exists between developed and developing countries in historical trends of the amounts of nitrogen (N) fertilizers consumed, and the same situation holds true in China. The situation of either N overuse or underuse has become one of the major limiting factors in agricultural production and economic development in China. The issue of food security in N-poor regions has been given the greatest attention internationally. Balanced and appropriate use of N fertilizer for enriching soil fertility is an effective step in preventing soil degradation, ensuring food security, and further contributing to poverty alleviation and rural economic development in the N-poor regions. RESULTS: Based on the China Statistical Yearbook (2007), there could be scope for improvement of N use efficiency (NUE) in N-rich regions by reducing N fertilizer input to an optimal level (=180 kg N ha-1), and also potential for increasing yield in the N-poor regions by further increasing N fertilizer supply (up to 116 kg N ha-1). For the N-rich regions, the average estimated potential of N saving and NUE increase could be about 15% and 23%, respectively, while for the N-poor regions the average estimated potential for yield increase could be 21% on a regional scale, when N input is increased by 13%. CONCLUSION: The study suggests that to achieve the goals of regional yield improvement, it is necessary to readjust and optimize regional distribution of N fertilizer use between the N-poor and N-rich regions in China, in combination with other nutrient management practices.

A novel centre of gravity measurement system for small tractors with the principle of the three-point reaction is presented. According to the prototype of a small tractor gravity centre test platform, a mathematic multi-body dynamics prototype was built to analyze the measurement error in the centre of gravity measurement system. For the precision evaluation, interrelationships among the factors were studied which included the test platform structural parameters, the error of measurement sensors and the displacement of drive-pillar and the mass of measurement object. In succession, a virtual collaborative model of the centre of gravity measurement system was built and verified by a real prototype-based measurement platform. A modified gray model GM(1,1), which was used for forecasting the gravity height of small tractors, was proposed to avoid deviation of test data and so improved the measurement accuracy. A series of standard test object experiments were carried out, and the results showed that the relative error of the gravity height was up to 0.93%

The guidance of a vehicle in an outdoor setting is typically implemented using a Real Time Kinematic Global Positioning System (RTK-GPS) potentially enhanced by auxiliary sensors such as electronic compasses, rotation encoders, gyroscopes, and vision systems. Since GPS does not function in an indoor setting where educational competitions are often held, an alternative guidance system was developed. This article describes a guidance method that contains a laser-based localization system, which uses a robot-borne single laser transmitter spinning in a horizontal plane at an angular velocity up to 81 radians per second. Sensor arrays positioned in the corners of a flat rectangular table with dimensions of 1.22 m × 1.83 m detected the laser beam passages. The relative time differences among the detections of the laser passages gave an indication of the angles of the sensors with respect to the laser beam transmitter on the robot. These angles were translated into Cartesian coordinates. The guidance of the robot was implemented using a uni-directional wireless serial connection and position feedback from the localization system. Three experiments were conducted to test the system: 1) the accuracy of the static localization system was determined while the robot stood still. In this test the average error among valid measurements was smaller than 0.3 %. However, a maximum of 3.7 % of the measurements were invalid due to several causes. 2) The accuracy of the guidance system was assessed while the robot followed a straight line. The average deviation from this straight line was 3.6 mm while the robot followed a path with a length of approximately 0.9 m. 3) The overall performance of the guidance system was studied while the robot followed a complex path consisting of 33 sub-paths. The conclusion was that the system worked reasonably accurate, unless the robot came in close proximity (

Records of cattle slaughtered at two Chilean slaughterhouses (SLH1 and SLH2) were used to determine prevalence and risk factors for carcasses with bruises. Bruise prevalence amounted to 12.3% but differed between slaughterhouses (20.8% for SLH1 and 8.6% for SLH2 respectively). Bruise severity grade 1 (mild) was most frequently recorded. The type of the animal, source of animal, the level of fat cover and lairage time were associated with the presence of bruises. Older categories of animals and animals that pass through a market before being moved to the slaughterhouse are more prone to show bruises. The results also indicate that under the reported Chilean circumstances animals that have longer lairage times (over 12 h) have a significantly reduced risk for bruises, except for oxen. Presence of bruises is also significantly associated with increased carcass pH values.

Rainfed crop production in northern China is constrained by low and variable rainfall, and by improper management practices. This study explored both the impact of long-term rainfall variability and the long-term effects of various combinations of maize stover, cattle manure and mineral fertiliser (NP) applications on maize (Zea mays L.) yields and water use efficiency (WUE) under reduced tillage practices, at Shouyang Dryland Farming Experimental Station in northern China from 1993 onwards. The experiment was set up according to an incomplete, optimal design, with 3 factors at five levels and 12 treatments including a control with two replications. Grain yields were greatly influenced by the amount of rain during the growing season, and by soil water at sowing. Annual mean grain yields ranged from 3 to 10 t ha-1 and treatment mean yields from 4.2 to 7.2 t ha-1. The WUE ranged from 40 in treatments with balanced nutrient inputs in dry (weather/or soil) years to 6.5 kg ha-1 mm-1 for the control treatments in wet years. The WUE averaged over the 15-year period ranged from 11 to 19 kg ha-1 mm-1. Balanced combination of stover (3000–6000 kg), manure (1500–6000 kg) and N fertiliser (105 kg) gave the highest yield and hence WUE. It is suggested that 100 kg N per ha should be a best choice, to be adapted according to availability of stover and manure. Possible management options under variable rainfall conditions to alleviate occurring moisture stress for crops must be tailored to the rainfall pattern. The potentials of split applications, targeted to the need of the growing crop (response nutrient management), should be explored to further improve grain yield and WUE.

The desorption isotherms of miscanthus, Miscanthus × giganteus (stems and leaves) were determined separately by using the saturated salt solutions method at three temperatures (25, 50 and 70 °C) within a range from 5 to 90% relative humidity. Experimental curves of desorption isotherms were fitted to Modified Henderson, Modified Halsey, Modified Oswin and Modified Chung-Pfost models and evaluated by Residual Sum of Squares (RSS), Standard Error Estimation (SEE) and Mean Relative Deviation (MRD) methods. The Modified Oswin model was found to be the most suitable for describing the correlation between equilibrium moisture content, relative humidity and temperature.

This paper describes a model to calculate the concentrations of (Z)-3-hexenol, a-pinene, a-terpinene, ß-caryophyllene, and methyl salicylate in a greenhouse on the basis of their source and sink behaviour. The model was used to determine whether these volatile organic compounds (VOCs) can be used to indicate Botrytis cinerea infection in a large-scale tomato production greenhouse with a volume of 5 × 104 m3 containing 2.2 × 104 plants. Seven experiments were done to parameterise the model for these VOCs. Based on model predictions, the B. cinerea-induced increase in concentration of methyl salicylate is detectable in a large-scale tomato production greenhouse when: (a) windows are fully opened, and (b) the increase continues for at least 1 h, and (c) 5% of the plants are infected. The B. cinerea-induced increase in concentration of methyl salicylate is also detectable when: (a) windows are closed, and (b) the increase continues for at least 6 h, and (c) 5% of the plants are infected. The B. cinerea-induced increase in concentration of (Z)-3-hexenol is detectable under all conditions studied. However, it is expected that besides infected plants, many additional sources of (Z)-3-hexenol exist including plant debris and nearby field crops especially upon harvest or stress. The B. cinerea-induced increases in concentration of a-pinene, a-terpinene and ß-caryophyllene are probably undetectable in a large-scale tomato production greenhouse. Therefore, it is recommended to focus on the detection of methyl salicylate to indicate B. cinerea infections in large-scale tomato production greenhouses.

The objectives of this study were to determine the reflectance properties of volunteer potato and sugar beet and to assess the potential of separating sugar beet and volunteer potato at different fields and in different years, using spectral reflectance characteristics. With the ImspectorMobile, vegetation reflection spectra were successfully repeatedly gathered in two fields, on seven days in 2 years that resulted in 11 datasets. Both in the visible and in the near-infrared reflection region, combinations of wavelengths were responsible for discrimination between sugar beet and volunteer potato plants. Two feature selection methods, discriminant analysis (DA) and neural network (NN), succeeded in selecting sets of discriminative wavebands, both for the range of 450–900 and 900–1650 nm. First, 10 optimal wavebands were selected for each of the 11 available datasets individually. Second, by calculating the discriminative power of each selected waveband, 10 fixed wavebands were selected for all 11 datasets analyses. Third, 3 fixed wavebands were determined for all 11 datasets. These three wavebands were chosen because these had been selected by both DA and NN and were for sensor 1: 450, 765, and 855 nm and for sensor 2: 900, 1440, and 1530 nm. With the resulting three sets of wavebands, classifications were performed with a DA, a neural network with 1 hidden neuron (NN1) and a neural network with two hidden neurons (NN2). The maximum classification performance was obtained with the near-infrared sensor coupled to the NN2 method with an optimal adapted set of 10 wavebands, where the percentages were 100 ± 0.1 and 1 ± 1.3% for true negative (TN) classified volunteer potato plants and false negative (FN) classified sugar beet plants respectively. In general the NN2 method gave the best classification results, followed by DA and finally the NN1 method. When the optimal adapted waveband sets were generalized to a set of 10 fixed wavebands, the classification results were still at a reasonable level of a performance at 87% TN and 1% FN for the NN2 classification method. However, when a further reduction and generalization was made to 3 fixed wavebands, the classification results were poor with a minimum performance of 69% TN and 3% FN for the NN2 classification method. So, these results indicate that for the best classification results it is required that the sensor and classification system adapt to the specific field situation, to optimally discriminate between volunteer potato and sugar beet pixel spectra

Smallholder farmers in Ethiopia practice traditional tillage systems using an ard plow called Maresha. Traditional tillage systems that involve repeated cultivations with the Maresha plow have caused land degradation (a.o. formation of a plow pan) and poor utilization of rainwater that led to low crop productivity. Experience in other countries has shown that conservation tillage systems could improve utilization of rain water through increased infiltration. However, the implements used for conservation tillage in other countries were found to be too heavy and too expensive for smallholder farmers in Ethiopia. On the other hand, lighter and low cost implements have been developed in Ethiopia as modifications to the Maresha plow. These implements are the Subsoiler, the Tie-ridger, and the Sweep. Field tests were carried out to evaluate the modified implements and a rip plant type of conservation tillage systems using the modified implements. The results showed that the Subsoiler reached a depth of approx. 24 and 27 cm after 1 resp. 2 passes through the furrow made by the Maresha, and thus was capable of disrupting the plow pan. Compared to the Maresha plow and the inverted broad bed maker (BBM), the Tie-ridger required less draft power (79 kg vs. 96 for the Maresha and 103 for the BBM) and lower lifting force (−43%) while forming furrows with larger (+36 resp. +15%) cross-sectional areas. The Sweep enabled deeper root growth of tef ( Eragrostis tef (Zucc.) ) apart from accomplishing sowing operations faster (+50%). It is concluded that the newly developed implements are suitable to undertake conservation tillage under smallholder farming systems in the semi-arid regions of Ethiopia. The rip-plant type of conservation tillage systems, however, was not found to be viable for maize ( Zea mays ) production under the study conditions in which loss of soil moisture through evaporation is high. Both grain and biomass yields were highest in the conventional systems, although differences were statistically not significant. On the other hand, a reduced tillage system tested on tef resulted in higher grain yields as compared to conventional tillage.

Lowland soils are commonly found in the state of Rio Grande do Sul, Southern of Brazil, where they represent around 20% of the total area. Deficient drainage is the most important natural characteristic of these soils which therefore are mainly in use for irrigated rice (Oriza sativa). Degradation in these soils is progressively getting stronger since the intensity of agricultural activities leads to a higher soil density, and a lower water infiltration rate. There is a growing interest by farmers to grow other crops such as soybean in rotation with (flood) irrigated rice but this degradation has become an obstacle to do so. This study was done with the objective to assess the soil physical and chemical quality of the three rice management systems (conventional, semi-direct and pre-germinated) most used in the region of Camaqua municipality, Rio Grande do Sul state, Brazil. Samples were collected from 21 rice farms with 2 different types of lowland soil (Albaqualf and Humaquepts). The soil samples were analysed for physical and chemical properties. Using multivariate analysis of covariance (Mancova), the effects of the natural variability in terms of soil clay content were separated from the management effects. The analysis revealed that soil physical and chemical properties were affected by the management practices adopted by farmers. The results showed that the major effect of the management systems was on a physical property: bulk density. An increase in soil density in the pre-germinated and conventional systems was found to be caused by a significant reduction in the volume occupied by micropores, an indication of structural degradation. The semi-direct management system, associated with less intensive tillage operations retained better soil conditions and a better organic matter status. The chemical properties significantly affected by management (total N, Ca, Mg, Fe, cation exchange capacity (CEC), and potential acidity [PA]) all had their highest values in the semi-direct management system. This study confirmed that the physical soil degradation forms the main obstacle for growing other crops in a rotation with rice.

This study describes the effects of floor system, digital dermatitis (DD) and interdigital dermatitis and heel-horn erosion (IDHE) on locomotion performance in 225 dairy cows of 12 commercial dairy herds. Nine herds were kept in cubicle houses with concrete passageways (either solid, slatted, or grooved concrete) and three herds were kept in straw yards. Animals were at most five times examined at monthly intervals for lesion severity of DD and IDHE and for locomotion score. Locomotion score was rated on a scale ranging from 1 to 5 (from normal to severe) and disturbed locomotion (lameness) was defined as a scoreor =3. A logistic regression model was used to analyze the 943 observations using lameness (yes/no) as outcome variable. The proportion of observations scored as lame (locomotion scoreor =3) increased from 18% 1 month after trimming to 29% at 4 months after trimming. Severe lesions of DD and IDHE were associated with a significantly higher proportion of lame cows. The proportion of animals with disturbed locomotion increased from 16% to 40% as the severity of DD increased and from 17% to 30% with increasing severity of IDHE lesions. Locomotion performance highly differed between the cubicle house and straw yard group. Only 1% of all gaits in straw yard cows were scored as lame, while in cubicle housed cows these percentages varied from 24% to 46% with grooved floors showing the highest average locomotion score. Due to the extreme low incidence of lameness in straw yards, the statistical analysis had to be restricted to observations on concrete floors (n=744). The logistic regression model with lameness (yes/no) as dependent variable and random effects of cow and herd resulted in Odds Ratios for severe DD and IDHE of, respectively, 3.2 and 3.2, both significantly larger than unity. Cows housed at grooved concrete floors showed the highest OR of 6.5 compared to solid concrete floors. Recovery of lameness was poor as disturbance in gait lasted several months.

Based on differences in dynamic response times in the crop production process, a hierarchical decomposition of greenhouse climate management is proposed. To a large extent the proposed decomposition builds on the time-scale decomposition of singularly perturbed systems commonly found in the literature. Main difference with these existing theoretical concepts is that the proposed decomposition is able to deal with rapidly fluctuating deterministic external inputs or disturbances acting on the fast sub-processes. For an example of economic optimal greenhouse climate management during one lettuce production cycle, the decomposition was successfully evaluated in simulations. Using these favourable results, a hierarchical concept for economic optimal greenhouse climate management is derived and discussed in view of application in horticultural practice.

Pathogen attack and herbivore infestation have a major impact on plant health. In a model study, these two plant health issues were simulated to study whether plant health can be monitored at greenhouse scale through the analysis of volatile organic compounds (VOCs) in greenhouse atmosphere. To simulate pathogen attack and herbivore infestation, we repeatedly stroked the stems of tomato plants (Lycopersicon esculentum) and repeatedly removed their side shoots. In addition, we studied the effect of fruit picking on the concentration of plant-emitted VOCs in greenhouse atmosphere. Analysis of air samples obtained before these treatments revealed up to 17 VOCs that are known to be released from tomato plants, of which the most dominant one was the monoterpene ß-phellandrene. When plants were 7 weeks old, the concentration of this VOC was approximately 0.06 ppbv before treatment. When plants were 12 weeks old, this concentration was raised to approximately 0.14 ppbv. Stroking of the stems, removing the side shoots and fruit picking resulted in an increase in the concentrations of all mono- and most sesquiterpenes up to 60-fold, which was expected because these VOCs are well-known constituents of trichomes. The treatments did not result in substantially increased concentrations of the stress-related compounds ¿-copaene, methyl salicylate and (E,E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene. In contrast to stroking and fruit picking, shoot removal resulted in the emission of the lipoxygenase-derived product (Z)-3-hexenol in greenhouse atmosphere expressing cell membrane degradation. The findings presented in this paper focus on the feasibility of monitoring plant health through the analysis of VOCs in greenhouse air, but findings might also be relevant for atmospheric chemistry.

Melkvee kan op een veel duurzamere manier worden gehouden dan wij nu doen. Het lijkt lastig, maar het is wel mogelijk: een melkveehouderij, waarin de koe het goed heeft, de ondernemer een goede boterham verdient, die het milieu ontziet en ook nog eens tegemoet komt aan de wensen van de burger. De ontwerpen, die het project Kracht van Koeien heeft opgeleverd, laten zien dat dit op termijn mogelijk is. En ook hoe we daar morgen al aan kunnen werken

Studies of bruises, as detected on carcasses at the slaughterhouse, may provide useful information about the traumatic situations the animals endure during the pre-slaughter period. In this paper, we review scientific data on the prevalence, risk factors and estimation of the age of bruises in beef cattle. Risk factors such as animal characteristics, transport conditions, stocking density, livestock auction and handling of the animals are discussed. Investigation of the age of bruises could provide information on when in the meat chain bruises occur and, could help to pinpoint where preventive measures should be taken, from the stage of collecting the animals on the farm until slaughter. We review the methods available to assess the age of the bruises; data on human forensic research are also included. The feasibility to identify traumatic episodes during the pre-slaughter period, in order to improve animal welfare is discussed.

Aims of this study are to analyze growth pattern and development Of Cut chrysanthemum and test simple regression models in relation to light level and plant density. Cut chrysanthemum (Chrysanthemum morifolium), cv. Reagan Improved, was grown at four different plant densities of 16, 32, 64 or 80 plants m(-2) combined with three different light levels of 100%, 66% or 43% of light in three greenhouse compartments in summer at Wageningen University in the Netherlands. Plant fresh and dry mass, stem strength, number of flowers and stem length had shown interactive effects between light level and plant density. All these parameters increased with increased light level and with increased plant density; however, the decrease as a result of light reduction was much larger at low plant densities except for stem length. Stem length increased with increased plant density, following a saturation-type of response, except for the lowest light level, where an optimum-response was observed, resulting in a reduced stem length at the highest density. Dry mass production per m(2) greenhouse area and final leaf area index increased with increased light level and with increased plant density. Light use efficiency (LUE, unit dry mass per unit of cumulative intercepted PAR) was 48% higher at lower light levels than 100%. LUE also showed a quadratic response to plant density in range of 16 and 80 plant m(-2). Using an existing empirical linear model for plant, fresh mass and number of flowers for cut chrysanthemum showed overestimation in plant fresh mass and under estimation for number of flowers at the lowest plant density in all light level in this study. Plant shape, calculated as a ratio between stern length and a length between a node with first lateral stem to top point of plant, linearly decreased with increased LAI. Plant qualities hence strongly varied depending on crop canopy like leaf area index. Although the simple regression models are good tools for summary of experiment, it does not fit at lower plant density. To produce a constant product quality throughout the year, optimal number of plant m(-2) with amount of available light should be considered through the growing period.

Animals have various behavioural and physiological needs that are important for welfare. Fulfilment of these needs depends on the quality of housing, management and animal characteristics. The objective of this study was to develop a model to assign welfare scores to husbandry systems for dairy cattle, based on scientific results, and thereby supporting the design of new, welfare-friendly systems. COWEL is a computer-based decision support system that contains attributes regarding housing and management conditions. These attributes are technical specifications that contain various technical units called levels. These levels are ranked from best-to-worst regarding welfare, based on scientific information about animal-based parameters. This information, inserted in the model as statements, was weighted depending on the impact it has on welfare by using weighting categories. Thereafter, a weighting factor was calculated for each attribute which determines how important an attribute is for welfare. The COWEL model contains 2,343 statements on dairy cattle welfare from 476 sources found during a literature survey. The model was applied to four husbandry systems, namely a tie-stall, cubicle housing, a straw yard and a pasture-based system. The welfare scores, calculated by COWEL for these husbandry systems, correspond with the general opinion about these systems. A tie-stall receives a low and a pasture-based system a high welfare score: 211 and 271, respectively. A husbandry system can receive a maximum of 313 on the welfare scale of COWEL. We conclude that COWEL can be used to rank husbandry systems on a welfare scale, and may be a useful tool to develop new, sustainable and welfare-friendly systems for dairy cattle

In 2003 beleefde het Field Robot Event (FRE) in Wageningen zijn primeur. De FRE is een internationale wedstrijd, waarin field robots met elkaar de competitie aangaan om zo goed mogelijk autonoom door een perceel te navigeren en een landbouwkundige taak uit te voeren. Dit jaar wordt het Field Robot Event voor de 7e keer gehouden in een bijzondere editie: de samenwerkende Europese onderzoeksgroepen binnen het EU FutureFarm project demonstreren hun ‘prototype robotic systems’ en parallel aan het FRE wordt de Joint International Agricultural Congress gehouden. Nu de 7e editie in aantocht is, stellen we ons in dit artikel de vraag in hoeverre de afgelopen 6 edities hebben bijgedragen aan het realiseren van deze doelstellingen

In the last 15 years a significant increase in greenhouse area has occurred in Mexico, from a modest 50 hectares in 1990 to over 2,000 hectares in 2004. The rapid increase in greenhouse area is a result of an attractive export market, USA. Mexican summer midday temperatures are well above crop optimum and cooling is needed if heat stress induced crop growth reduction is to be prevented. The objective of this study was to determine the effectiveness and feasibility of greenhouse cooling systems for tomato culture under desert, humid tropic and temperate Mexican weather conditions. These climate regions are represented by Mexicali, Merida and Huejutla respectively. The cooling systems included a variety of passive and active systems, which through an engineering design methodology were combined to suit the climate conditions of the 3 regions. The evaluation was conducted via simulation, taking into account the most important temperature effects on crop growth and yield. The results showed that the cooling systems were effective in decreasing heat stress to plants. Investment costs of greenhouse with cooling equipment were under USD 50 m-2 and operational costs were under USD 10 m-2 for all equipment combinations and treatments except for the humid tropic climate of Merida. Solutions for Merida were both economically and physically not feasible due to too high humidity levels. This model study clearly indicates that cooling is feasible in desert and moderate climate regions of Mexico but in humid tropic climate regions feasibility is a problem. Application of design methodology and design evaluation with help of simulation greatly contributed to pointing out effective and non-effective solutions to reduce heat stress in hot climates.

A hermetically sealed ferrocement bin was conceived by application of a systematic design process. It consisted of a frustum of a cone with a conical bottom supported by three vertical columns with V-shaped cross-section. A labour and material saving model was developed to contain 2.5 tons of paddy. After detailed designing of the bin, it was constructed and the actual cost incurred was investigated before introducing to the farmer who requires this type o fbin for on-farm storage of paddy.

The objective of this paper is to demonstrate the need of a multiple design parameter approach to greenhouse design. To illustrate this need, we determined the combined effects of cover design parameters on tomato production of a passive greenhouse, that is a greenhouse with only natural ventilation and seasonal whitewash for climate management. The design parameters investigated in this research were the transmission of the cover for photosynthetically active radiation (PAR) and near infrared (NIR) radiation, the emission coefficient for long wave radiation of the cover and the ventilation area. First, we developed a model to link the tomato yield to the cover design parameters, through their effects on greenhouse climate. The model was validated by comparing the simulated greenhouse climate and yield with data obtained from field studies conducted in Almería, Spain. Thereafter, the sensitivity of the yield to the cover design parameters was analysed for three greenhouse configurations. This analysis gave insight into the effects of the cover design parameters on crop yield. Results showed that the sensitivity of the yield to a single design parameter depended on the absolute values of the other ones. For example, the yield in a greenhouse with a high ventilation capacity was the most sensitive to PAR transmission (0.45 % more yield for each 1% increase of PAR transmission) while in a greenhouse with a low ventilation capacity the crop yield is most sensitive to the ventilation area (0.63 %) and NIR transmission (-0.56 %). In addition, the yield sensitivity to the design parameters also varied over time because of changing outdoor climate conditions. In conclusion, a significant improvement of greenhouse design can be attained only through a multifactorial approach that accounts for the joint effect of design parameters, local climate and desired production period upon crop yield.

Earlier research has revealed that considerable energy savings can be achieved by maintaining an average temperature in the greenhouse in stead of maintaining rigid pre-defined temperature `blue-prints¿. A model based optimal control approach has proven to be a suitable framework to tackle these kind of control problems and it has been shown that these algorithms can be implemented on-line. But, when on-line optimal temperature control is considered, interesting questions arise, some of which are still unresolved. The issue tackled in this paper concerns the relation between the resolution of the control strategy (sample time) and energy savings of the control strategy. One would expect that an accurate and frequent anticipation to changing outdoor climate conditions might result in reduced energy consumption. It was indicated in the literature that a sample-time of 0.25 h or 1 hour should be sufficient, but these choices were hardly motivated. In this research, the relation between the control resolution and energy savings was quantitatively investigated using a dynamic greenhouse climate model and measurements of Dutch outdoor climate conditions containing high-frequency components. The results indicate that for an open-loop optimal control problem concerning the realization of an average temperature during a fixed period of one day using a minimum amount of energy with full a-priori knowledge of the outdoor weather, a resolution of the heating profile between half an hour and a hour suffices to produce accurate results in terms of energy conservation. These results were not much affected by parameter variations (heat capacity of the air, the solar heating efficiency) or opening and closing of thermal screens.

The objective of this paper is to demonstrate that optimal greenhouse design must account for (and be combined to) optimal climate management. We prove this by showing that different strategies and set-points to control the greenhouse ventilators result in different ¿optimal sets¿ of design parameters. We determined these optimal sets for a passive greenhouse in Almería, Spain where tomatoes were grown. The greenhouse design parameters investigated in this research were: 1) the transmission of the cover for photosynthetically active radiation (PAR), 2) the transmission of near infrared (NIR) radiation and 3) the emission coefficient for longwave radiation of the cover. Six optimal sets of design parameters were determined by maximising the marginal revenues (crop yield minus costs of design parameters), under given climate conditions, and for different ventilation control strategies. Each ventilation control strategy had different set-points for the air temperature and carbon dioxide concen¬tration to control the greenhouse ventilators. To solve this optimization problem we used a dynamic crop-greenhouse model and an optimization algorithm. The model described the combined influence of the relevant design parameters, outdoor climate and ventilation control upon economic crop yield, through their effect on indoor climate. The yearly costs of the design parameters were empirically derived from prices, physical properties and lifespan of a number of greenhouse cover materials. Results showed that indeed for different strategies and set-points to control the green¬house ventilators different ¿optimal sets¿ of design parameters and marginal revenues were obtained. For example, the difference between the highest optimal NIR trans¬mission 1.00 and the lowest optimal NIR transmission 0.40 was 60%, while the highest marginal revenues 16.94 ¿m-2 differed 18,7% with the lowest marginal revenues of 13.77 ¿ m-2. Additionally, it was found that the cover design parameters were time dependent. In conclusion, only a combined optimal control and design approach that takes into account the best climate control strategy and the time dependency of the design parameters will ensure optimal design parameters and maximum marginal revenues.

The poultry sector in the Netherlands is confronted with the EU ban on conventional cages, the public debate on the welfare of hens in furnished cages, the limited perspectives of currently used more welfare-friendly single- or multi-tiered systems (either indoor or outdoor), and with questions about the natural behaviour of animals and the robustness of current production systems. To arrive at new and sustainable husbandry systems for laying hens a new design approach was developed and applied. The work-scheme of the approach consisted of four phases: (1) collecting information and network building, (2) a thorough analysis of problems followed by making strategic choices, (3) developing a structured design, and (4) reporting and communication. The approach incorporated interdisciplinary and multi-stakeholder interactive methods, integrating scientific and tacit knowledge. The main results of the study were (1) a Brief of Requirements for the laying hen, the farmer and the citizen/consumer as key players in a sustainable development, and (2) two new attractive and feasible husbandry concepts for future egg production. The approach succeeded in identifying the underlying needs and requirements of actors, bridging the gap between seemingly conflicting requirements and stimulating new initiatives towards sustainable development.

The paper presents results of research on inverse kinematics algorithms to be used in a functional model of a cucumber harvesting robot consisting of a redundant manipulator with one prismatic and six rotational joints (P6R). Within a first generic approach, the inverse kinematics problem was reformulated as a non-linear programming problem and solved with a generic algorithm. Solutions were easily obtained, but the considerable calculation time needed to solve the problem prevented on line implementation. To circumvent this problem, a second, less generic approach was developed consisting of a mixed numerical-analytic solution of the inverse kinematics problem exploiting the particular structure of the P6R manipulator. This approach facilitated rapid and robust calculation of the inverse kinematics of the cucumber harvester. During the early stages of the cucumber harvesting project, this inverse kinematics algorithm was used to off-line evaluate the ability of the robot to harvest cucumbers using 3D-information of a cucumber crop obtained in a real greenhouse. Thereafter, the algorithm was employed successfully in a functional model of the cucumber harvester to determine if cucumbers were hanging within the reachable workspace of the robot and to determine a collision-free harvest posture to be used for motion control of the manipulator during harvesting.

Informatie over omvang en grootte van kippenhouderijen in Nederland en de verdeling per bedrijfssysteem.

Traditional tillage systems practiced by farmers in semi-arid regions of Ethiopia are characterized by repeated and cross plowing with an indigenous plow called Maresha . Repeated and cross plowing have led to land degradation. Conservation tillage systems that advocate minimum soil disturbance can alleviate land degradation problems. However, before introducing reduced tillage systems, it was found necessary to study why farmers undertake repeated plowing. The study was undertaken in two semi-arid areas called Melkawoba and Wulinchity located in the central rift valley of Ethiopia and on two major crops; Tef ( Eragrostis Tef (Zucc.)) and maize ( Zea mays XX ). Fifty farmers from each area were randomly selected and interviewed using a structured questionnaire. The results showed that farmers in the study area plow repeatedly in order to completely disturb unplowed strips of land left between adjacent furrows. Unplowed strips are the results of the V-shaped furrows created by the Maresha plow. Farmers generally do not plow before the soil is wetted by rainfall. Wetting and drying cycles due to dry spells occurring between rainfall events force farmers to plow frequently to avoid moisture losses through surface runoff, evaporation and weed transpiration. Tef fields are plowed 4–5 times while maize fields are plowed 3–4 times. Tillage frequency increased with the education level and experience of farmers; with their perception about the purpose of tillage such as moisture conservation, weed control and soil warming; and with resource availability such as area of land and family labor. Tillage frequency was higher for Tef than for maize and in heavy soils than in light soils.

Crop production in the dryland farming areas of northern China is constrained by low and variable rainfall. This article presents the analysis of the relationships between variations in rainfall and yields of winter wheat and spring maize. The analysis is based on data from both several short-term and our ongoing long-term field experiments in dryland farming research projects in Tunliu, Linfen, Shouyang, and Luoyang. Grain yields of wheat and maize ranged from 1,548 to 5,169 and from 2,612 to 8,789 kg ha-1 respectively, with differences up to above 200% (between dry and wet years). Wheat yields are sensitive to growing season rainfall but also correlated to water use (ET), whereas maize yields are sensitive to the critical time of water supply (especially June rainfall) but not correlated to ET. The ratio of grain yields to soil water at sowing is an important indicator, showing close relationships between yields and soil water-related ratio within the rainfed crops site. Comparison between the indices of water use efficiency (WUE) and precipitation use efficiency (PUE) suggests that the index WUE is more grain-related indicator than the PUE used for assessing rainfed crop water use by both maize and wheat. The index PUE should be used in caution, especially for wheat crops in dry years. Our results indicate that options to alleviate crop moisture stress must be tailored to the rainfall pattern. This holds especially for conservation tillage with response nutrient management practices that aim at enhancing water use efficiency.

This study was conducted to examine if the pre-compression stress sigma(pc) is the major critical stress influencing soil physical quality indices, i.e. air permeability K-g and air-filled porosity (AFP). Topoils of five soil series were collected from the Isfahan Province in central Iran. Treatments consisted of: five soil types (sandy loam to clay), four matric suctions (10, 20, 50 and 80 kPa), three values for the maximum axial stress sigma(pc) (200, 400 and 600 kPa), and three loading types with 10 loading cycles. The loading types were a confined compression test (CCT), a semi-confined compression test (SCCT) and a kneading compression test (KCT). Soil type and matric suction, loading type, maximum applied stress and number of loading cycles significantly affected log [K-g], void ratio e, and AFP. The Significance of the loading cycle's number implies that though the up, of the soil was not exceeded, the soil physical properties were considerably changed. A gradual transition from elastic-to-plastic deformation was observed on the stress-strain curves obtained from CCT. The stress-strain curves of the SCCT were sharp at sigma(pc) due to the semi-confined condition, which allows lateral deformation during loading. Cyclic loading was not always accompanied by significant irreversible strain but this could result in up to 10 times the decrease in K-g. For the fine-textured soils, CCT resulted in a significantly greater reduction in K-g, a and AFP when compared with KCT. The opposite trend was observed for the coarse-textured soils. The KCT homogenised the pore system and resulted in more decrease of K-g when compared with CCT at matric suctions of 10 and 20 kPa. However, at the matric suctions of 50 and 80 kPa, KCT created an open microstructure, which led to relatively higher values of K-g. The results show that the sigma(pc) might not be a real critical stress from a view of soil physical quality indices (i.e. K-g and AFP), especially at low matric suctions. Thus, the characterisation of soil compaction may not be completely accounted by a bulk property such as void ratio, but additional information about pore characteristics are needed to describe the effect of compaction on soil physical quality. (c) 2007 IAgrE. Published by Elsevier Ltd. All rights reserved.

A model was developed as a tool for designing straw-bedded sow group-housing systems with low ammonia emission. Using mechanistic and empirical relationships it calculates the total ammonia emission by integrating ammonia volatilisations from all the urine pools in the house. The reference data were from a house with a floor comprising 60% straw bedding, 14% drinking area (slatted floor with pit), 3% waiting area (slatted floor with pit) and 23% alley (solid floor). Simulations were performed to elucidate the effect of the distribution of the urinations over the different surfaces, relating this to the size and distribution of the urine pools, and the area of the surfaces urinated upon. The results were compared with emission data from an entire sow house. When the default settings were a urine production of 7 l/d per sow, a urination frequency of 5 times a day per sow, and urinations distributed evenly over the four emitting surfaces the model estimated the ammonia emission from the entire house as 11.7 g/d per sow, and the relative contributions of the straw bed, the drinking area, the waiting area and the alley as, respectively, 27%, 22%, 9% and 42%. By comparison, the actual emission from the house was 8.7 g/d per sow. The 90% confidence interval was 6.5¿10.9 g/d per sow. Increasing the size of the urine pool from 0.14 m2 to 1.40 m2 in the model simulations caused ammonia emission initially to increase from 9.7 to 12.1 g/d per sow when the pool volume was 0.47 m2. If the pool was bigger, emission fell to 10.6 g/d per sow because, though the larger emitting area increases ammonia emission, the increase is outweighed by the reduction in emission caused by successive, superseding urinations on the same spot. If the entire emitting area was assumed to be straw bedding, the calculated emission from the house was 5.8 g/d per sow. Assuming slatted and concrete floors without straw bedding increased the emission to 16.5 g/d per sow. It is concluded that measures to reduce the ammonia emission from the bedded sow house should be aimed at decreasing the emission from the solid floor and/or allowing more urinations on the straw bed. The model is a useful design tool for achieving emission reduction from group-housing systems for sows with straw bedding. Its predictive power would be improved by inputting data on the actual size of the urine pool and urinating behaviour of sows.

A long-term experiment was carried out in the dryland of northern China to assess the effects of applications of maize stover, cattle manure and NP (1:0.44) fertilizer on partial nitrogen (N), phosphorus (P) and potassium (K) balances, extractable soil N (SEN), P and K, and soil organic matter (SOM) in a spring maize cropping system, under reduced tillage conditions. The experiment was set-up according to an incomplete, optimal design, with three factors at five levels and 12 treatments, including a control with two replications. Statistical analyses using multiple regression models showed that the partial N, P and K balances were strongly influenced by annual variations in the amounts of soil water at seeding (SWS) and growing season rainfall (GSR). Most treatments had positive P but negative N and K balances. Cumulative P and K balances were reflected in extractable soil P (P-Olsen) and K (exchangeable K), but the weak relationships indicated that the sorption of P and buffering of K were strong. Cumulative balances of effective organic carbon (C) were weakly related to soil organic C (SOC) content after 12 years. Negative C balances were related to decreases in SOC, but positive C balances were not translated into increases in SOC. The analysis of nutrient balances and soil fertility indices revealed that nutrient inputs in most treatments were far from balanced. It is concluded that the concepts of `ideal soil fertility level¿ and `response nutrient management¿ provide practical guidelines for improving nutrient management under the variable rainfall conditions of dry land areas in northern China.

Soil and residue manipulation can assist weed management by killing weeds mechanically, interfering in weed lifecycles, facilitating operations and enhancing crop establishment and growth. Current tillage systems often compromise these functions, resulting in heavy reliance on herbicides, particularly in no-till systems. Herbicides are an exhaustible resource, so new approaches to merge soil conservation and non-chemical weed management are needed. This paper broadly reviews various preventive and curative non-chemical weed management tactics. It also demonstrates how innovations can be derived from functional requirements of weed management operations, and from biological processes and weaknesses in weed's lifecycles. Mechanical weeding and enhancement of weed seed mortality are highlighted as examples. Major limitations with mechanical weeding include limited weed control in crop rows at early vulnerable crop stages, weather-dependent effectiveness, and difficulties in handling crop residues. Precise steering and depth control, improved seedbed friability and lighter tractors or controlled traffic could bring considerable improvements. To expose weed seeds to predators, position them for fatal germination, viability loss or low emergence may require completely different soil displacement patterns than those of current implements and systems. Controlled traffic and precise strip tillage offer good opportunities for implementing these weed management strategies in minimum-tillage systems.

Voor de implementatie van een geïntegreerde geoptimaliseerde jaarrond beheersingsstrategie is nog veel operationele kennis over de aardappelziekte nodig.Duurzame beheersing van Phytophthora infestans is pas mogelijk als de complexe onderdelen voldoende op elkaar zijn afgestemd en worden vertaald naar geïntegreerde praktische oplossingen. Binnen dit thema van het Parapluplan Phytophthora worden de resultaten uit de andere thema's vertaald naar praktische oplossingen. In dit artikel wordt een aantal van de projecten uit de Toolbox toegelicht