ALBERT

Description: 1. Fifty-one experiments on the nitrogen, phosphate and potash requirements of maincrop potatoes were carried out in Great Britain in 1956–62. Each experiment tested four rates of each nutrient in all combinations and both total and riddled yields and quality data were obtained.2. Nitrogen requirement was influenced by previous cropping and the rainfall during the preceding winter. 50–80 lb/acre of N are recommended in mixed farming rotations depending on winter rainfall, and 120–150 lb/acre of N in arable rotations.3. Yield increases from phosphate were usually larger on soils with low citric-soluble phosphate. Nevertheless, irrespective of soil phosphate status, optimum rates of application were at least 120 lb/acre of P2O5 which was the highest rate tested in most of the experiments.

Description: SUMMARYSilage maize variety testing systems usually evaluate new varieties within properly defined maturity groups; within a maturity group, all varieties are harvested on a single harvest date. In a small country like Belgium where growing conditions are similar across the maize growing areas, all tested silage maize varieties, comprising different maturity groups, are harvested on a single date. Under this testing system, only few varieties are harvested at the physiological stage where they theoretically show their optimal performance. In the current research, eight silage maize varieties were monitored from 25 to 40% whole-crop dry matter (DM) content at three locations in Belgium during the period 2007–2009. The optimal harvest date was calculated as the date where whole-crop DM yield, ear DM yield and organic matter digestibility were maximal. The variety rank at the optimal harvest date was compared with the variety rank at any studied single harvest date. Harvest dates where the variety rank was not statistically different to the rank at the optimal harvest date were pooled in a ‘harvest window’. Based on the current data, the harvest window comprised a flexible harvest period of about 14 days. It was therefore concluded that applying a single harvest date is scientifically justified for the ranking of silage maize varieties in Belgium, when the whole-crop DM content is between 28·1 and 40·6% with a maximum difference of 7·2% between all compared varieties.

Description: SUMMARYThe objective of the present study was to calculate an optimal harvest period for both fresh and ensiled samples of forage maize and to calculate a set of harvest dates (called a harvest window), for which the variety ranking of the fresh forage corresponds with the variety ranking at the optimal harvest period calculated from the ensiled forage. Forage maize is fed almost exclusively as silage, but official variety trials with silage maize determine quality parameters in fresh (i.e. non-preserved) forage. Eight silage maize varieties were monitored at six harvest dates (from 25 to 40% dry matter content) in Merelbeke (Belgium) in 2013–15. At each harvest date, fresh samples were taken and half of the sampled material was ensiled in micro silos for 20 weeks. An optimal harvest period was calculated based on frequently measuring starch concentration and organic matter digestibility for both fresh and ensiled forage. Eventually, harvesting the silage maize at a dry matter content of 32–35% guaranteed an optimal harvest period. Based on the results of eight varieties, reporting variety ranks without going through the ensiling process continues to be a scientifically justified practice in Belgian official variety trials. Varieties with a superior fresh quality keep their leading position after ensiling, but variety differences become smaller after ensiling.

Description: Integrated crop-livestock systems (ICLS) are currently promoted agricultural production systems that aim to use better resources through production integration and intensification. While this system reduces some risks, it adds complexity and new risks to businesses due to interdependence between the agricultural modules. To deal with these issues, integrated risk management is required to reduce the effects of risks and to take advantage of the opportunities of an ICLS. Generically, enterprise risk management (ERM) meets this need by proposing comprehensive and coherent risk management, instead of managing agricultural module risks individually. However, there is a need to customize the ERM approach to ICLS. Therefore, the current study aims to develop a method to manage risks for ICLS based on ERM, integrating the management of risks and aligning risk management with the strategic objectives. A literature review, a pilot study, interviews with experts, four case studies and 20 practitioners supported the method development and evaluation through three versions. As a result, the method identifies and relates risks through process mapping with a qualitative and quantitative analysis of their impacts, determines risk responses based on willingness to take risks, and helps identify processes to control, communicate and monitor the risks. The method also stimulates the implementation of ICLS in market-oriented farms, providing an approach to increase the chances of ICLS success. The main difference from previous research lies in the integrative management of multiple risks, the alignment of risks with strategy and the consideration that a risk might be considered an opportunity.

Description: SUMMARYPhenological models are considered key tools for the short-term planning of viticultural activities and long-term impact assessment of climate change. In the present study, statistical phenological models were developed for budburst (BUD), flowering (FLO) and veraison (VER) of 16 grapevine varieties (autochthonous and international) from the Portuguese wine-making regions of Douro, Lisbon and Vinhos Verdes. For model calibration, monthly averages of daily minimum (Tmin), maximum (Tmax) and mean (Tmean) temperatures were selected as potential regressors by a stepwise methodology. Significant predictors included Tmin in January–February–March for BUD, Tmax in March–April for FLO, and Tmin, Tmax and Tmean in March–July for VER. Developed models showed a high degree of accuracy after validation, representing 0·71 of total variance for BUD, 0·83 for FLO and 0·78 for VER. Model errors were in most cases 〈 5 days, outperforming classic growing degree-day models, including models based on optimized temperature thresholds for each variety. Applied to the future scenarios RCP4·5/8·5, projections indicate earlier phenophase onset and shorter interphases for all varieties. These changes may bring significant challenges to the Portuguese wine-making sector, highlighting the need for suitable adaptation/mitigation strategies, to ensure its future sustainability.

Description: SUMMARYThe herbicide chlorsulfuron is commonly applied to cereals and may persist in alkaline soil long enough to damage subsequent sensitive crops. Sewage water, a potential source of the heavy metal cadmium (Cd), is used to irrigate agricultural soils in many developing countries. The current work evaluated the effects of the residual herbicide chlorsulfuron and Cd on maize seedlings, with particular attention to the mechanism of their action on plant growth. Maize seeds were planted in soil that had been sprayed with chlorsulfuron and Cd, after which residues in both seedlings and the soil were measured. The chlorsulfuron dose was correlated with the amount of residue found in seedlings but not in the soil. In all, 39 metabolites were identified in seedlings using the Automated Mass spectral Deconvolution and Identification System software program and the retention index method. The combination of chlorsulfuron and Cd significantly reduced multiple metabolites in the shikimate pathway, malic acid and citric acid production in the tricarboxylic acid cycle, and lactic acid, glucose, aspartic acid, asparagine and 3-glycerophosphoric acid production. In addition, chlorsulfuron caused an increase in multiple amino acids, including tyrosine, methionine and asparagine, and a marked decrease in caffeic and cinnamic acids (the secondary metabolites derived from the shikimate pathway and galactose). Finally, chlorsulfuron and Cd stress markedly increased shikimate acid, decreased 3-glycerophosphoric acid and caused negative correlations between the amounts of phenylalanine and tyrosine and those of quinic- and cinnamic-acid. In conclusion, chlorsulfuron and Cd did not have a synergistic effect on maize seedlings; rather, the combination of these pollutants had an antagonistic effect on some amino acids.

Description: Bacterial inoculation of soybean seeds to improve biological nitrogen fixation is a well-known practice to achieve higher seed and protein yield with reduced fertilization. The optimal inoculation strategy in temperate regions is unknown because soybeans are rarely cultivated under colder growing conditions. The aim of the present work was to determine the most suitable inoculation strategy for soybean cultivation in Belgium. Field trials were set up with four Bradyrhizobium inoculants (HiStick, Force 48, Biodoz and Optimize) at two locations over 2 years (2014–2015) and compared with a non-inoculated control treatment. In addition, HiStick was tested at three doses and Optimize at two time periods prior to sowing. Under Belgian conditions, all inoculants were effective in establishing rhizobial symbiosis, resulting in increased yield, protein content, protein yield and thousand-grain weight compared with the non-inoculated control. A single dose of HiStick was sufficient to establish symbiosis. Pre-inoculation with Optimize 2 weeks before sowing gave an intermediate performance for most parameters between the non-inoculated control treatment and inoculation with Optimize 24 h prior to sowing. Among the four products tested, Biodoz seemed the best product for inoculation under cool growing conditions. Based on the atpD gene, the bacterial strain of Biodoz showed complete similarity with Bradyrhizobium diazoefficiens, while strains of other products were identified as Bradyrhizobium japonicum. In vitro growing capacity of the Biodoz strain at 8 °C was higher compared with the other strains. Better cold adaptation of the Biodoz strain might be a possible explanation for the better performance of Biodoz in Belgium.

Description: Cucumber powdery mildew is a destructive foliar disease caused by Podosphaera xanthii (formerly known as Sphaerotheca fuliginea) that substantially damages the yield and quality of crops. The control of this disease primarily involves the use of chemical pesticides that cause serious environmental problems. Currently, numerous studies have indicated that some plant extracts or products potentially have the ability to act as natural pesticides to control plant diseases. It has been reported that turmeric (Curcuma longa L.) and its extract can be used in agriculture due to their insecticidal and fungicidal properties. However, the most effective fungicidal component of this plant is still unknown. In the current study, the crude extract of C. longa L. was found to have a fungicidal effect against P. xanthii. Afterwards, eight fractions (Fr.1–Fr.8) were gradually separated from the crude extract by column chromatography. Fraction 1 had the highest fungicidal effect against this pathogen among the eight fractions. The active compound, (+)-(S)-ar-turmerone, was separated from Fr 1 by semi-preparative high-performance liquid chromatography and identified based on its 1H nuclear magnetic resonance (NMR) and 13C NMR spectrum data. The EC50 value of (+)-(S)-ar-turmerone was found to be 28.7 µg/ml. The compound also proved to have a curative effect. This is the first study to report that the compound (+)-(S)-ar-turmerone has an effect on controlling this disease. These results provide a basis for developing a new phytochemical fungicide from C. longa L. extract.

Description: 〈div data-abstract-type="normal"〉〈p〉A completely randomized experiment was designed to evaluate the effects of 〈span〉α〈/span〉-amylase (AMY) and glucoamylase (GLU) on total losses, fermentative profile, chemical composition and amylolytic activity of rehydrated maize. Eighty-four experimental silos of rehydrated maize [0.33 litres/kg ground maize, 4-mm theoretical particle size, and 625 g/kg dry matter (DM)] were assigned to the following treatments: (1) control (CON), no enzyme addition; (2) GLU added at 300 µl/kg of ground maize (as-fed); and (3) AMY added at 300 µl/kg of ground maize. Seven silos from each treatment were opened after 7, 14, 21 and 28 days. Differences among treatments were evaluated through orthogonal contrasts (CON 〈span〉v.〈/span〉 enzymes, and AMY 〈span〉v.〈/span〉 GLU). Time effects were decomposed using polynomial regression. Glucoamylase silage exhibited greater total losses than AMY. Enzymes increased acetate and lactic acid concentrations and decreased ethanol concentration. Regardless of treatment, gas, effluent and total fermentative losses linearly increased, whereas DM recovery linearly decreased with higher storage length. Glucoamylase silage had lower ammonia nitrogen and higher lactic acid concentrations than AMY. Enzyme treatments decreased silage neutral detergent fibre content and increased 〈span〉in vitro〈/span〉 DM degradation. Glucoamylase silage exhibited a more moderate starch content and greater 〈span〉in vitro〈/span〉 DM degradation than AMY. Storage time linearly decreased DM, starch and fibre content of rehydrated maize. 〈span〉In vitro〈/span〉 degradation of DM linearly increased as the storage length increased. This study showed evidence that enzymes with amylolytic activity, particularly GLU, improve the fermentative profile and DM degradation of rehydrated maize silage.〈/p〉〈/div〉

Description: 〈div data-abstract-type="normal"〉〈p〉Detailed representation of ingesta inflow to and digesta outflow from the rumen is critical for improving the modelling of rumen function and herbage intake of grazing ruminants. The objective of the current work was to extend a mechanistic model of a grazing ruminant, MINDY, to simulate the dynamic links between ingestive and digestive processes as affected by forage and sward features (e.g. sward structure, herbage chemical composition) as well as the internal state of the animal. The work integrates existing aspects of forage ingestion, oral physiology and rumen digestion that influence ingesta characteristics and digesta outflows from the rumen, respectively. The paper describes the structure and function of the new development, assessing the new model in terms of dynamic changes of oral processing of ingesta and rumen dilution rate under different grazing contexts. MINDY reproduces characteristics of ingesta inflow to and digesta outflow from the rumen of grazing ruminants, achieving temporal patterns of occurrence within and between meals, similar to those for grazing animals reported in the literature. The model realistically simulates changes in particle size distribution of the ingestive bolus, bolus weight and rumen dilution rate in response to contrasting grazing management regimes. The new concepts encoded in MINDY capture the underlying biological mechanisms that drive the dynamic link between ingestion and digestion patterns. This development advances in the understanding and modelling of grazing and digestive behaviour patterns of free-ranging ruminants.〈/p〉〈/div〉