Global climate change is predicted to shift seasonal temperature and precipitation patterns. An increasing frequency of extreme weather events such as heat waves and prolonged droughts is predicted, but there are high levels of uncertainty about the nature of local changes. Crop adaptation will be important in reducing potential damage to agriculture. Crop diversity may enhance resilience to climate variability and changes that are difficult to predict. Therefore, there has to be sufficient diversity within the set of available cultivars in response to weather parameters critical for yield formation. To determine the scale of such ‘weather response diversity’ within barley (Hordeum vulgare L.), an important crop in northern conditions, the yield responses of a wide range of modern and historical varieties were analysed according to a well-defined set of critical agro-meteorological variables. The Finnish long-term dataset of MTT Official Variety Trials was used together with historical weather records of the Finnish Meteorological Institute. The foci of the analysis were firstly to describe the general response of barley to different weather conditions and secondly to reveal the diversity among varieties in the sensitivity to each weather variable. It was established that barley yields were frequently reduced by drought or excessive rain early in the season, by high temperatures at around heading, and by accelerated temperature sum accumulation rates during periods 2 weeks before heading and between heading and yellow ripeness. Low temperatures early in the season increased yields, but frost during the first 4 weeks after sowing had no effect. After canopy establishment, higher precipitation on average resulted in higher yields. In a cultivar-specific analysis, it was found that there were differences in responses to all but three of the studied climatic variables: waterlogging and drought early in the season and temperature sum accumulation rate before heading. The results suggest that low temperatures early in the season, delayed sowing, rain 3–7 weeks after sowing, a temperature change 3–4 weeks after sowing, a high temperature sum accumulation rate from heading to yellow ripeness and high temperatures (⩾25°C) at around heading could mostly be addressed by exploiting the traits found in the range of varieties included in the present study. However, new technology and novel genetic material are needed to enable crops to withstand periods of excessive rain or drought early in the season and to enhance performance under increased temperature sum accumulation rates prior to heading.

The viability of commercial potato production is influenced by spatial and temporal variability in soils and agroclimate, and the availability of water resources where supplementary irrigation is required. Soil characteristics and agroclimatic conditions greatly influence the cultivar choice, agronomic husbandry practices and the economics of production. Using the latest (UKCP09) scenarios of climate change for the UK, the present paper describes a methodology using pedo-climatic functions and a geographical information system (GIS) to model and map current and future land suitability for potato production in England and Wales. The outputs identify regions where rainfed production is likely to become limiting and where future irrigated production would be constrained due to shortages in water availability. The results suggest that by the 2050s, the area of land that is currently well or moderately suited for rainfed production would decline by 88 and 74%, respectively, under the ‘most likely’ climate projections for the low emissions scenario and by 95 and 86%, respectively, for the high emissions scenario, owing to increased likelihood of dry conditions. In many areas, rainfed production would become increasingly risky. However, with supplementary irrigation, c. 0·85 of the total arable land in central and eastern England would remain suitable for production, although most of this is in catchments where water resources are already over-licensed and/or over-abstracted; the expansion of irrigated cropping is thus likely to be constrained by water availability. The increase in the volume of water required due to the switch from rainfed- to irrigated-potato cropping is likely to be much greater than the incremental increase in water demand solely on irrigated potatoes. The implications of climate change on the potato industry, the adaptation options and responses available, and the uncertainty associated with the land suitability projections, are discussed.

A cropping system is the consequence of environmental and socio-economic conditions that determine the intensity of agricultural land use. Accurate information on regional land use intensity and changes in land use intensity is important for food security and sustainable resource management in China. Therefore, a better understanding of the spatial and temporal changes in arable land use intensity (ALUI) based on the cropping system used is essential to comprehend the changes in land use and the sustainability of the food system. The purpose of the present study was to investigate the spatial difference in ALUI and how it has changed in China by comparing data on cropping systems from 1985 and 2005. The basic cropping system data were acquired from the 1985 reference book and the 2005 national land use investigation. The ALUI was defined by the application of inputs (irrigation water and fertilizer) to arable land and the duration of disturbances (the duration of cultivation and the frequency of cropping), and it was calculated using the information entropy approach at the cropping region scale (cropping region being defined by the geographical and climatic conditions at the beginning of the 1980s). Spatial and temporal changes in the ALUI in China over the past two decades were observed and analysed. The results indicated a clear pattern in ALUI, increasing from the north to the south in 2005. Furthermore, the ALUI significantly increased after the 1980s, but the rate of increase was lower in the south than in the north. The most intensive land use in 1985 was in the area of the lower reach of the Yangtze and Huai Rivers, and it expanded northwards towards the Huang-Huai-Hai plain in 2005. The large increase in intensity in the northern single-cropping regions was strongly associated with a rapid increase in inputs and longer duration of cultivation. Decreases in duration of cultivation and planting area helped slow the ALUI increase in multiple cropping regions, which were concentrated in coastal and economically developed regions where more fertile soil and suitable climates existed, allowing the growth of multiple crops. These results suggested that a decrease in the planting area and a slow increase in the ALUI in the lower reaches of the Yangtze River, South China, Southeast China and Northeast China should be of concern, but land use in some western regions should maintain the land production capacity to build sustainable cropping. In the future, it will be necessary to produce more food in a more sustainable way.

The impact of projected regional climate change on the migration of cabbage stem weevil (Ceutorhynchus pallidactylus) to oilseed rape crops in the Grand Duchy of Luxembourg is evaluated for past and future time spans. Several threshold-based statistical models for the emergence and the main migration of C. pallidactylus were chosen from the literature and combined with selected regional climate change projections of the EU ENSEMBLES project. Additionally, a simple degree-day based model was used to assess the plant development under expected climate change conditions. An earlier onset as well as a prolongation of the possible emergence times and the main migration periods was detected. The onset of stem elongation of oilseed rape was predicted to occur 3·0 days earlier per decade, while emergence of C. pallidactylus was expected to occur between 3·0 and 3·3 days earlier per decade. The main migration period of the weevil to the field may start 2·0 days earlier per decade under future climate conditions. Additionally, the time span of possible migration is prolonged for about 30 days under projected future climate conditions.

Knowledge of the spatio-temporal management of forage production and grazing in grass-based livestock systems is needed to simulate their functioning and then to propose new cutting and grazing practices that will achieve both environmental and economic benefits. The objectives of the present work were to characterize the types of grassland use in mountain bovine systems and relate them to field geographical characteristics to produce a conceptual model of grassland use. This model can be incorporated into a whole beef and/or dairy farm simulator of the impact of practice changes on environmental and productive performances. For this purpose, a survey of 72 farms was conducted in the traditional Salers system in the Massif Central (France). Information was gathered on geographical characteristics and cutting and/or grazing practices on three general groups of fields: cut only, cut and grazed, and grazed only fields. Principal component and hierarchical cluster analyses constructed 15 field use classes that account for the complexity of forage production and grazing management. Geographical determinants of grassland use follow a certain hierarchy: slope and carrying capacity influence the occurrence of cutting, and field area determines the possibility of allocating a cut field to grazing animals and of allocating a field to milked cows. The distance to the cowshed is involved in the allocation to milked or suckler cows and also influences the order of the cutting and grazing sequence. For the same combination of geographical characteristics, two types of grassland use may be observed, highlighting the flexibility of mountain systems. A conceptual model of grassland use is proposed as the basis for field use allocation in a whole farm model. Further investigation will consider the influence of field pattern characteristics on these relationships.

Managed grasslands provide environmental and agronomic services that can be predicted from the botanical and functional composition of the vegetation. These are influenced by management, edaphic and climatic factors. The present report set out to estimate and analyse the relative importance of management, soil and climate factors on botanical and functional characteristics of grassland vegetation. A set of 178 French grasslands having a large pedoclimatic and management gradient was selected, and information collected on botanical composition, pedoclimatic factors and management. Six vegetation characteristics were considered: two botanical (floristic composition and species dominance) and four functional (proportion of entomophilous species, number of oligotrophic species, leaf dry matter content and date of flowering). First, the links between the characteristics of the vegetation were analysed to check for any redundancy among them; all were kept. Second, it was demonstrated that botanical and functional characteristics were not driven by the same factors: functional composition was characterized by management, edaphic and climatic factors, whereas botanical composition was influenced mainly by climatic and edaphic factors plus other factors. Interactions between factors also have to be taken into consideration to predict botanical and functional composition of grasslands. Functional and botanical characteristics of vegetation help to predict ecosystem services delivered by grasslands and may be used in combination.

Sugarcane (Saccharum spp.) ratoon crops comprise more than 0·50 of India's sugarcane acreage and reduce the cost of cultivation by 25–30%. However, ratooning is seldom practised beyond 1–2 ratoons because the yield declines in successive ratoons due to compacted soils with decreased fertility restricting root development and plant growth. Therefore, a field experiment on sugarcane was conducted from 1998 to 2003 at the Sugarcane Research Institute, Muzzaffarnagar (Uttar Pradesh), India to evaluate the effects of combinations of trash management with key cultural practices (stubble shaving, ridge dismantling, sub-soiling along stubble rows, trash mulching and earthing-up) on growth and yield of sugarcane up to the third ratoon. Two treatment combinations (ridge dismantling+stubble shaving+sub-soiling along stubble rows+trash mulching at 8 t/ha (T5) and all these plus earthing-up in June (T6)) showed similar growth, yield and economics of ratoon crops. Both these treatments produced significantly higher shoot populations, leaf area index (LAI), dry matter (DM) accumulation, net assimilation rate (NAR), number of millable canes, ratoon cane yield and sugar, soil organic carbon (SOC) content at harvest and higher net returns besides lowering weed density, weed dry weight and bulk density of soil compared with other treatments. T6 produced the highest cane yield of 77, 72 and 65 tonnes (t)/ha, which was 23, 27 and 29% more than trash burning alone (T1) in first, second and third ratoon crops, respectively. Although T6 had the same yield as T5, it led to significantly lower soil bulk density at 0–150 mm depth, higher SOC contents and greater benefit: cost ratios in the first, second and third ratoon crops, respectively compared with trash burning only. Adoption of the crop management components, separately or in combination, improved on trash burning only (the control treatment). Trash mulching sustained the improved yield and economic returns of sugarcane ratoon crops.

The control of barley yellow dwarf virus (BYDV) and its aphid vectors in minimum tillage (MT) and conventionally tilled (CT) winter barley by insecticide seed and foliar spray treatments was investigated in 2001, 2002 and 2003. Similar investigations were undertaken on winter wheat in 2004, 2005 and 2006. Aphids numbers in autumn and BYDV in spring on barley and wheat were significantly lower on MT relative to CT crops, in two of the six seasons. An insecticide spray at Zadoks growth stage (GS) 25 significantly reduced aphids and virus in both MT and CT crops in three of the six seasons of the study. An additional spray at GS 22 provided no benefit. Aphids were significantly fewer in three of the six seasons on crops grown from insecticide treated seeds, relative to untreated seeds. Both MT and CT barley sprayed at GS 25 had significantly fewer aphids than the seed treatment in one of the three seasons. Seed-treated MT and CT barley had significantly less BYDV than controls but significantly more than crops sprayed at GS 25. CT wheat grown from insecticide-treated seed had significantly less BYDV than controls. Overall, CT barley grown from insecticide-treated seed had 6-fold more BYDV than the sprayed crop, while untreated barley had 22-fold more than the spray treatment. In MT barley, the comparable values were 3- and 10-fold respectively. BYDV was almost exclusively the MAV strain. The grain yield for insecticide-sprayed CT barley was significantly greater in two of three seasons than that for untreated plots. In general, MT and CT barley receiving an insecticide spray had greater grain yield than barley grown from insecticide-treated seed, with differences being significant in one of three seasons. It is concluded that BYDV in MT and CT cereals is better controlled by applying a pyrethroid insecticide spray between GS 23 and 25, in autumn, than by treating the seed with a nitroguanidine-type insecticide. In MT crops, a single spray between GS 23 and 25 will give effective control of MAV-type BYDV.

An experiment was carried out in 2006 in the Ebro Valley of Spain to test the differences in chemical composition, ruminal degradation, in vivo digestibility and intake between lucerne hays cut at sunrise (AM) or at sunset (PM). Measurements were carried out at 0·50 flowering during spring, summer and autumn growth cycles. PM hays showed higher contents of soluble carbohydrates, starch and total non-structural carbohydrates than AM hays. No significant differences between times of cutting were found for crude protein, neutral detergent fibre, acid detergent fibre or acid detergent lignin. Effective degradability of dry matter (DM) was higher in autumn PM hay (0·57±0·008) than AM hay (0·47±0·008). No differences between times of cutting were found for hays cut in spring or summer. Effective degradability of nitrogen was significantly higher in summer and autumn PM hays than in AM hays. However, degradability did not differ significantly between times of cutting for the hays cut in spring. Differences in organic matter digestibility averaged 0·02±0·008 in spring and 0·05±0·008 in autumn, but no differences were found between cutting times for lucerne hays in summer. For DM intake, differences between PM and AM hays were significant in spring (57±2·0 v. 46±2·0 g/kg BW0·75, respectively) and summer (60±2·0 v. 52±2·0 g/kg BW0·75, respectively), but not significant in autumn (55±2·0 v. 51±2·0 g/kg BW0·75, respectively). Finally, digestible organic matter intake in sheep was higher for PM (34±1·3, 36±1·3 and 32±1·3 g/kg BW0·75) than for AM hays (27±1·3, 30±1·3 and 27±1·3 g/kg BW0·75) in spring, summer and autumn, respectively. In conclusion, cutting lucerne at sunset could be a simple management strategy for improving the feed value of hays.

The effects of yeast Saccharomyces cerevisiae, either inactivated (by osmotic pressure, designated IY) or provided as a culture containing live yeast cells (YC), on ruminal fermentation of two different diets were investigated in vitro. Total mixed rations (TMR) having forage:concentrate ratios of 0·6:0·4 (medium–high forage diet) and 0·2:0·8 (low-forage diet) were incubated in batch cultures of mixed ruminal micro-organisms to which either IY (to reach concentrations of 500 and 250 mg product/l incubation medium) or YC (at a concentration of 150 mg product/l) were added directly as powder. To evaluate the effects of the additive on ruminal microbial population, sheep used as donors of rumen fluid were allocated to three experimental groups: Control (no additive), IY and YC, that received a diet with the corresponding additive for 10 days. With both diets, YC decreased ruminal pH compared to control, whereas IY had no effect. Adding yeast products to the high-fibre diet affected total volatile fatty acid (VFA) production and VFA composition, in general with a slight increase in IY and a significantly greater increase in response to the addition of YC. Ammonia nitrogen (P=0·006), total gas production (P<0·001) and in vitro dry matter disappearance (IVD) (P<0·001) showed the highest values with YC. Methane production was higher than the control when the IY inoculum was used, and increased even more with the YC inoculum (P<0·001). With the high-concentrate TMR, no effects on total VFA concentration were observed when yeast additives were used. Similar trends were shown for lactate and methane production and total gas production, where values tended to be higher when using the YC inoculum (P values of 0·055, <0·001, 0·006 and <0·001, respectively). After 144 h of incubation, differences were observed only with the high-fibre diet in the cumulative gas production at 24 h of incubation and in the average fermentation rate, which was greater with YC, although the asymptotic gas production was not affected. These results indicate that live yeasts affect ruminal fermentation slightly more than inactivated yeasts, although both products require a regular administration and some adaptation of the ruminal microbial population for the stimulatory effects to become apparent. The effects of yeasts on ruminal fermentation are diet-dependent, being more noticeable with a high-fibre substrate, and subtle with a high-concentrate diet.