The expansion of biogas production in Germany poses a challenge in terms of the production of substrates for co-fermentation and the efficient use of biogas residues as fertilizers. At present there is limited information on the fertilizer value of biogas residues from energy-cropping systems. A 2-year field experiment was conducted at two sites in northern Germany to quantify the yield, nitrogen (N) concentration and the N balance of maize (Zea mays L.) grown in different crop rotations: (i) maize monoculture (R1), (ii) maize – whole-crop wheat followed by Italian ryegrass as catch crop (R2) and (iii) maize – grain wheat followed by mustard as catch crop (R3). Crops were fertilized with different levels of biogas residues, cattle slurry, pig slurry, or mineral N fertilizer, which allowed quantification of the apparent N recovery (ANR) of the fertilizer types tested. The results revealed that crop rotation in interaction with N amount had a pronounced effect on the yield of maize. Maximum yield of 19·1 t dry matter (DM)/ha, corresponding to biogas production of 6685 m3N CH4/ha, was achieved in maize monoculture on a sandy loam site. Maize grown in R3 showed the lowest N response but had the highest yield under low N supply, whereas R2 generally had the lowest yield and N content. Differences in yield performance were reflected in the N balances, differing by 50 kg N/ha between R1 and R2, whereas R3 produced the lowest yield at low N supply. The carry-over effects from the preceding catch crops in R2 and R3, however, reduce the meaningfulness of the simple N balance. Nitrogen fertilizer type showed no interaction with crop rotation. Biogas residue application resulted in similar maize yielding performance to pig slurry and cattle slurry. However, relative N fertilizer value (RNFV) was 30% higher for biogas residue at optimal N supply, i.e. the minimum N input to achieve maximum DM yield.

The requirement for inorganic fertilizer nitrogen (N) by winter wheat crops in the United Kingdom is derived using the Department for Environment, Food and Rural Affairs (Defra) Fertilizer Manual. In the experimental programme described and discussed in the present paper, the appropriateness of these recommendations for winter wheat grown in Northern Ireland is examined.

Yield response to N varied in experiments conducted on two winter wheat cultivars (cvars) in Northern Ireland from 2007 to 2009. Consequently the optimum N rate (Nopt, defined as the rate of applied N where the value of the increase in yield equals the cost of the increment in fertilizer applied and beyond which additional N would not repay its cost) also varied from year to year. The band of fertilizer N rates over which margins were reduced by £20 (GBP) and £50 also varied from year to year. Changes in the N:grain price ratio affected Nopt to differing extents in the three experiments depending on the shape of the yield v. N response.

Nopt should therefore be considered as a range of N rates because (1) it varies from year to year and probably also field to field and (2) the margin of income from grain over cost of fertilizer varies little over a range of N rates because of the shape of the asymptotic response of yield to N. Alternatively, in high rainfall areas (annual rainfall >700 mm) of England, Wales and Northern Ireland, where Table C of the Fertilizer Manual (formerly RB 209) is used to determine soil nitrogen supply (SNS) index, a single N rate could be adopted at SNS indices of 2 or less (equating to soil N supplies of 100 kg/ha or less). A rate of 240 kg N/ha could be adopted based on the over-years function fitted to all results in the three experiments reported in the present paper and including treatments that vary in the splitting of N applied between the two applications and in their timing.

Grain N concentration rarely exceeded the guideline 19 mg/g for feed wheat crops identified in the Fertilizer Manual (Anon. 2010). Overall, N taken up by the crops was used efficiently, and particularly so at lower N rates. However, at low fertilizer N rates the contribution from ‘free’ soil N inflates the ‘apparent’ value of grain yield produced. The responses of yield and grain N concentration to N show that crop processes work to maximize yield at the expense of N concentration in the grain. Therefore there is less need to be concerned about identifying the optimum N rate and predicting fertilizer N requirement with a high degree of precision. Instead growers could assess and adjust the efficiency of their N use based on grain N concentration generally, rather than specifically assess whether their fertilizer N applications were close to Nopt. Essentially as grain N concentration increases, yield/kg of applied fertilizer N decreases. Thus at low grain N concentrations, yield could be increased by increasing N applications and at high grain N concentrations yield could be maintained and profitability increased by reducing N applications.

The quality of seed is dependent on two very broad aspects: how healthy (disease-free) a seed is and its field performance (germination and vigour). The objective of the present study was to evaluate the effect of pesticidal seed treatments of maize (Zea mays L.) on seed germination and vigour, and on greenhouse emergence in the presence of Fusarium graminearum Schw. Maize seeds were treated with four pesticides: Apron® XL (metalaxyl), Thiram (thiram), Celest® XL (fludioxonil, metalaxyl) and Apron® Star 42 WS (thiamethoxam, metalaxyl, difenoconazole). Viability and vigour of the treated seeds were determined. Thereafter, seeds were planted under greenhouse conditions. The control consisted of water-treated seeds. None of the pesticides reduced the standard germination under laboratory conditions and none had any effect on the quantity of leachate (measured as conductivity) or moisture content of the seeds. The different treatments also had no effect on germination or on seedling weight increase among treatments after rapid imbibition and there was no difference in germination among treatments following the cold test. The proportion of diseased plants harvested from F. graminearum inoculated soil was significantly reduced by Apron® Star 42 WS and Celest® XL. The vigour tests indicated that none of the pesticides tested affected the seeds negatively and that plant biomass in the presence of the pathogen, F. graminearum, was increased after the application of the pesticides to the seeds, with the exception of seeds treated with Apron® XL.

The aim of the present investigation was to evaluate the antifungal activities of plant extracts which can be used to control bean and cowpea anthracnose. Acetone, ethyl acetate and water extracts of Ipomoea batatas, Carica papaya, Allium sativum, Syzygium cordatum, Chlorophytum comosum and Agapanthus caulescens were screened in vitro for their antifungal activities against Colletotrichum lindemuthianum and Colletotrichum dematium of common bean and cowpea using the agar disc infusion and microtitre double-dilution techniques. The same extracts were then tested for antifungal activity in vivo as seed treatments against anthracnose disease. The water extracts of Carica and Syzygium were active against C. lindemuthianum and had minimum inhibitory concentrations (MICs) of 1·56 mg/ml. Syzygium, Allium and Chlorophytum water extracts were active against C. dematium and MICs were 3·13, 6·25 and 12·5 mg/ml, respectively. The MICs of Allium, Syzygium and Agapanthus acetone extracts were 0·78, 3·13 and 6·25 mg/ml, respectively, against C. lindemuthianum and 0·78, 6·25 and 3·13 mg/ml against C. dematium. Agapanthus water extracts and all the acetone extracts tested in vivo effectively reduced the incidence and severity of bean anthracnose disease in the greenhouse. Agapanthus acetone, Allium water, and both acetone and water extracts of Carica and Syzygium performed well in vivo in reducing cowpea anthracnose disease and compared well with reductions due to the application of the synthetic fungicide fludioxonil+mefenoxam (the commercial product Celest® XL) applied at 25 gai/l and also with levels in the non-inoculated control. The Agapanthus, Carica, Syzygium and Allium extracts were active on both Colletotrichum spp. in vitro and also reduced anthracnose disease of bean and cowpea and are potential seed treatments in anthracnose disease control. The easy seed treatment process and the accessibility of plants used in the present study could lead to high adoption of the use of the plant extracts as seed treatments by resource-poor, smallholder farmers.

Sugar-beet crops, Beta vulgaris spp. vulgaris (L), suffer from premature bolting and flowering as a consequence of prolonged exposure to cold conditions (vernalization). This reduces crop yield and quality and could be avoided if bolting-resistant varieties were available. Traditionally, development of bolting-resistant varieties has relied on selection against the annual growth habit associated with the bolting gene B. However, this has failed to deliver crops that can be reliably sown in early spring or grown over winter without the risk of bolting. New breeding targets and selection strategies are required and have become tractable with the recent development of the vernalization-intensity model. This model uses parameters for the intensity and duration of vernalization (vernalization hours) to predict bolting responses and discriminates between varieties by the minimum number of vernalization hours needed to induce bolting (vernalization requirement (VR)) and by the increase in bolting incidence for each extra vernalizing hour once the VR has been satisfied (bolting sensitivity (BS)). Since the vernalization-intensity model was developed from variety-assessment trials data, the present work sought to refine and test it through controlled environment (CE) experiments in which seven sugar-beet varieties were exposed to differing levels of accurately defined vernalization treatments and scored for bolting rates to determine their VR and BS values. The results confirmed and improved the model and showed that VR, not BS, has more potential for developing bolting resistant varieties. It was also observed that there exist in current varieties, the genetic potential to breed for higher VR. Further experiments assessed the correlation of attainment of VR with changes in gene expression and shoot apical meristem (SAM) morphology to identify potential markers for this trait. It was found that the time when VR is attained correlates with up-regulation of gibberellin biosynthetic genes and floral transcription factors in leaf and shoot apices; most prominently, GIBBERELLIN 20-OXIDASE 2 (BvGA20ox2) and FLOWERING LOCUS T 2 (BvFT2). To integrate the results with weather data, temperature records for the past 47 years from the Broom's Barn weather station were used to develop a tool for predicting accumulated vernalization hours based on sowing date. The results, together with data from the CE experiments, were used to establish VR-breeding targets for bolting-resistant varieties for spring- and autumn-sown sugar-beet crops. The present paper shows that integration of weather, VR and genetic data provide useful tools to aid both cultivation and breeding selection. For growers, it provides a weather data tool to assist with the selection of suitable sowing dates. For breeders, it provides the first identification of molecular genetic factors that correlate with VR and the physiological changes associated with vernalization responses in sugar beet. The results suggest that gene-expression profiles can be developed into tools for quantifying bolting resistance in beet, thereby providing a cost-effective, high-throughput and simple method for breeders to apply the vernalization-intensity model.

Red clover (Trifolium pratense L.) silage usually contains lower contents of non-protein nitrogen (NPN) compared with other forage legumes. This is often attributed to the polyphenol oxidase (PPO) activity in red clover, although in most field studies the PPO activity was not measured. Therefore, a laboratory ensiling experiment with three red clover cultivars and one white clover cultivar as control grown in two management systems (with and without mechanical stress) over 2 consecutive years was conducted. Fresh, wilted and ensiled clover herbage was sampled at four cutting dates per year to determine the crude protein (CP) fractions according to the Cornell Net Carbohydrate and Protein System. The specific PPO activity was measured photometrically in fresh clover leaves. The content of CP fraction A (NPN) increased from fresh over wilted to ensiled clover herbage at the expense of the content of CP fraction B (true protein), irrespective of species, cultivar and year. The most important source of variation for all CP fractions and the calculated rumen-undegradable protein contents was generally the herbage condition, except for CP fraction C (unavailable protein). White clover silage consisted of higher contents of CP fraction A and lower contents of CP fraction B3 in CP compared with red clover silage. As a result, the calculated rumen-undegradable protein content of white clover silage was lower than that of all red clover cultivars. In conclusion, the extent of proteolysis during ensiling among the silages made from the herbage of different red clover cultivars was primarily influenced by the stage of maturity at harvesting and the degree of wilting at ensiling. The variation in specific PPO activity could not be related to the extent of proteolysis.

Maize (Zea mays L.), a major staple food crop in West and Central Africa (WCA), is adapted to all agro-ecologies in the sub-region. Its production in the sub-region is greatly constrained by infestation of Striga hermonthica (Del.) Benth. The performance and stability of the extra-early maturing hybrids, which are particularly adapted to areas with short growing seasons, were assessed under Striga-infested and Striga-free conditions. A total of 120 extra-early hybrids and an open-pollinated variety (OPV) 2008 Syn EE-Y DT STR used as a control were evaluated at two locations each under Striga-infested (Mokwa and Abuja) and Striga-free (Ikenne and Mokwa) conditions in 2010/11. The Striga-resistant hybrids were characterized by higher grain yield, shorter anthesis–silking interval (ASI), better ear aspect, higher numbers of ears per plant (EPP), lower Striga damage rating, and lower number of emerged Striga plants at 8 and 10 weeks after planting (WAP) compared with the susceptible inbreds. Under Striga infestation, mean grain yield ranged from 0·71 to 3·18 t/ha and 1·19 to 3·94 t/ha under Striga-free conditions. The highest yielding hybrid, TZEEI 83×TZEEI 79, out-yielded the OPV control by 157% under Striga infestation. The hybrids TZEEI 83×TZEEI 79 and TZEEI 67×TZEEI 63 were the highest yielding under both Striga-infested and Striga-free conditions. The genotype main effect plus genotype×environment interaction (GGE) biplot analysis identified TZEEI 88×TZEEI 79 and TZEEI 81×TZEEI 95 as the ideal hybrids across research environments. Twenty-three pairs of simple sequence repeat (SSR) markers were used to assess the genetic diversity among the inbred lines. The correlations between the SSR-based genetic distance (GD) estimates of parental lines and the means observed in F1 hybrid under Striga infestation and optimum growing conditions were not significant for grain yield and other traits except ASI under optimum conditions. Grain yield of inbreds was not significantly correlated with that of F1 hybrids. However, a significant correlation existed between F1 hybrid grain yield and heterosis under Striga infestation (r=0·72, P<0·01). These hybrids have the potential for increasing maize production in Striga endemic areas in WCA.

The EU-Rotate_N model was developed as a tool to estimate the growth and nitrogen (N) uptake of vegetable crop rotations across a wide range of European climatic conditions and to assess the economic and environmental consequences of alternative management strategies. The model has been evaluated under field conditions in Germany and Norway and under greenhouse conditions in China. The present work evaluated the model using Italian data to evaluate its performance in a warm and dry environment. Data were collected from four 2-year field rotations, which included lettuce (Lactuca sativa L.), fennel (Foeniculum vulgare Mill.), spinach (Spinacia oleracea L.), broccoli (Brassica oleracea L. var. italica Plenck) and white cabbage (B. oleracea convar. capitata var. alba L.); each rotation used three different rates of N fertilizer (average recommended N1, assumed farmer's practice N2=N1+0·3×N1 and a zero control N0). Although the model was not calibrated prior to running the simulations, results for above-ground dry matter biomass, crop residue biomass, crop N concentration and crop N uptake were promising. However, soil mineral N predictions to 0·6 m depth were poor. The main problem with the prediction of the test variables was the poor ability to capture N mineralization in some autumn periods and an inappropriate parameterization of fennel. In conclusion, the model performed well, giving results comparable with other bio-physical process simulation models, but for more complex crop rotations. The model has the potential for application in Mediterranean environments for field vegetable production.

Increasing irrigation efficiency is a major goal for fruit production in dry Mediterranean environments. The present study was conducted in three consecutive years (2007–09) under typical Mediterranean conditions and tested the effect of partial rootzone drying (PRD) on yield and fruit quality of two apple cultivars: Gala, with fruit maturing in summer and Fuji, with fruit maturing in autumn. Three irrigation treatments were imposed: conventional irrigation (CI), PRD (0·50 of CI water on one side of the rootzone, which was alternated periodically) and continuous deficit irrigation (DI, 0·50 of CI water on both sides of the rootzone). During the 2008 and 2009 irrigation seasons, DI reduced tree water status, and to some extent soil moisture, compared with CI and PRD. In all the years and both cultivars, DI reduced crop load by 11 and 5% over CI and PRD, respectively. In cvar Fuji, DI reduced production per tree by 9% and yield efficiency by 16% compared with CI. In all years for cvar Gala and in 2 of the 3 years for cvar Fuji, PRD and DI increased fruit soluble solid content by 5–6%, whereas PRD improved peel colour only in cvar Fuji and in 2 of the 3 years. In cvar Gala, DI fruit showed 27% more sorbitol and 55% more sucrose than PRD fruit. In both cultivars, PRD determined greater marketable yield and profit than DI. Irrigation water productivity (IWP) was increased by both PRD and DI, and in Fuji, PRD induced 18% greater IWP than DI. The different responses of the two cultivars to irrigation treatments can be attributed to differences in canopy size, crop load and mostly to the different timing of fruit growth. In particular, undergoing fast fruit growth during the irrigation period seems to induce permanent yield reductions in DI (but not PRD) trees of cvar Fuji, whereas water deficit during late fruit growth and lower crop load may have cancelled the negative effect of DI in the smaller trees of cvar Gala.

The objective of the current study was to determine the accuracy of the prediction of live weight (LW) from body measurements (BMs) by using digital image analysis on female Holstein calves. The calves were measured with a measurement stick and digital image analysis. The following linear parameters were taken: body length (BL), wither height (WH), chest depth (CD), hip height (HH) and hip width (HW). LW and BMs were recorded at birth, at weaning and at 24 weeks of age. Regression coefficients, which included all BMs at birth, gave a low R2 value (66·7%), but the R2 value was found to be 87·6 and 86·0% at weaning and 24 weeks of age, respectively. A high correlation coefficient was found among LW and CD, HH and HW at weaning (0·90, 0·91 and 090, respectively) and at 24 weeks of age (0·89, 0·90 and 0·91, respectively). The results confirm that for female Holstein calves, digital image analysis is an effective measuring system for the prediction of LW from BMs.

Parametric approaches have been used widely to model animal growth and study the impact of growth profile on performance. Individual variation is often not considered in such approaches. However, non-parametric modelling allows this. Such an approach, based on spline functions, was used to study the importance of growth profiles from age 0 to 15 months (i.e. insemination) on milk yield and composition in primiparous cows. A dataset of 447 heifers was used for analysis of growth performance; 296 of them were also used to study impact on lactation. All of them originated from a French experimental herd and were born between 1986 and 2006. Clustering methods were also tested. Comparison of spline methods showed that a cubic spline interpolation method, with no smoothing parameter, was best suited to studying heifer growth. Similarly, partitioning around medoids proved the most accurate clustering method for classifying heifer growth into groups. The results of these analyses agreed with those previously published, supporting the utility of these methods. A final study on the impact of breakdowns in the growth curves was performed. A breakdown was considered only when the derivative of the interpolation function was negative or zero. Of the 447 heifers initially used, 125 (Gr0), 175 (Gr1) and 147 (Gr2) had no, one, or two or more breakpoints during the 0–15 months of age period. Milk yield on a 305 d basis was significantly reduced with an increased number of breakpoints (6548 v. 6828 and 6905 kg for Gr2, Gr1 and Gr0 animals, respectively). Fat content was also higher in Gr2 than in Gr0 groups, but overall, no difference in total fat or protein-corrected milk production was noted. The intersection between groups for growth and groups for breakdowns confirmed that animals with two or more breakdowns belonged more frequently to the group with the lowest growth performance. These results offer the possibility of analysing large databases, originating from an automatic collecting system (e.g. milking robots) or from different herds, breeds, genetics, etc. These approaches could also be used for studies on body score index, girth development, lactation profiles, etc. and in other species, such as dairy goats or beef cattle. They could find use in the development of new models of prediction, e.g. the probability of heat appearance on an animal basis, which could be included among useful management tools.

The aim of the current work was to investigate the possibility of modifying the existing mean stage by weight (MSW) system for evaluating the average development stage in alfalfa. The modification was performed with the aim of providing a simplified system that may be used to evaluate the alfalfa development stage and to predict its nutritive value for ruminants. The suggested modification consists of designating an MSW value on the basis of the fresh weight of all morphological stages in a fresh green plant, as opposed to the original method which is based on weighing all morphological stages dried at 65 °C. The investigation was done on 141 samples of one alfalfa cultivar, collected from the same location during the first three growth cycles: spring growth, the first and the second regrowth. On all collected samples the following characteristics were determined: MSW, modified MSW (mean stage by fresh weight (MSFW)), crude protein (CP), neutral detergent fibre (NDF), acid detergent fibre (ADF), acid detergent lignin (ADL), crude ash (CA) and in vitro organic matter digestibility (IVOMD). For these characteristics of chemical composition (apart from CA) and nutritive value the regressions were calculated for their prediction based on MSW and MSFW. The regressions were derived for individual growth cycles and all cycles combined. A trend for an increase in the coefficient of determination (R2) was identified as well as a decrease in root-mean-square error (RMSE) for all equations derived for all investigated characteristics from the spring growth to the second regrowth. A deviation from this trend was observed only in equations derived for IVOMD. A very high correlation was observed between MSW and MSFW (r=0·999). The determined R2 and RMSE were very similar within the same growth cycle in all regressions for prediction of chemical composition and nutritive value derived for MSW and MSFW. Based on the results of this investigation the MSFW appears to be a quick and accurate method for determining the average development stage in alfalfa which can therefore be recommended for both scientific research and practical field use, as well as for prediction of its chemical composition and nutritive value.