Estimates on soil organic carbon (SOC) and nitrogen (N) stocks in soils cannot be directly calculated from routine soil analyses, since these often lack measurements on soil bulk density (Bd). Hence, flexible pedotransfer functions are required that allow the calculation of SOC stocks from gravimetrically determined SOC contents. The present paper aimed to: (1) quantify SOC and N stocks in grassland topsoils for a Northern Dutch region dominated by dairy farming and (2) analyse the relationships between SOC and bulk density at the field level. As estimates of SOC and N stocks are potentially affected by soil compaction, the combined measurements on soil bulk density and soil organic matter (SOM) were also evaluated with respect to critical limits for soil compaction using soil density (Sd) for sandy soils and packing density (Pd) for clay soils. The SOC and Bd measurements were done in the upper 0·1–0·2 m of grasslands at 18 dairy farms, distributed across sandy, clay and peat soils. Both farm data and grassland management data were collected. Non-linear regressions were used to analyse relationships between Bd and SOM. Significant non-linear relationships were found between gravimetric SOC contents and bulk density for the 0–0·1 m layer (R2=0·80) and the 0·1–0·2 m layer (R2=0·86). None of the fields on sandy soils or clay soils indicated signs for limited rooting in the topsoil although some fields appear to approach the critical limit for compaction for the 0·1–0·2 m layer. Stocks of SOC in the top 0·2 m at farm level were highest in the peat soils (21·7 kg/m2) and lowest in the sandy soils (9·0 kg/m2). Similarly, N stocks were highest for farms on peat soil (1·30 kg/m2) and lowest for farms on sandy soil (0·60 kg/m2). For the sandy soils, the mean SOC stock was significantly higher in fields with shallow groundwater tables.

Characterization of plant varieties is traditionally based on phenotypic observation. However, some varieties have very similar morphological characteristics, which make it difficult to distinguish between them. The present study employed 15 microsatellite markers distributed across all linkage groups (LG) of the chickpea genetic map to characterize 32 commercial chickpea cultivars and determine the usefulness of these markers for cultivar identification. These markers showed a high level of polymorphism; a total of 154 different alleles were detected, with a mean of 10·3 alleles per locus. The polymorphic information content (PIC) value ranged from 0·455 to 0·897. All the markers, with the exception of TA130, TA135 and TA144, were considered to be informative (PIC>0·7), indicating their potential usefulness for cultivar identification. A subset of markers (TA186, TA200, TA106, TA113, TA117 and TA30) was sufficient to identify all the cultivars studied. In order to confirm their discriminatory power, 16 unreleased chickpea cultivars (V1–V16) were screened and all of them presented different patterns. Therefore, these microsatellites can be regarded as a reference set for chickpea cultivar identification and their profiles can be used as a DNA fingerprint for each registered cultivar, avoiding redundancy of identical cultivars as well as to protect breeders' rights.

Brassica rapa subsp. rapa L. includes three different crops: turnips (roots), turnip greens (leaves) and turnip tops (inflorescences). A collection of B. rapa subsp. rapa from north-western Spain is currently kept at ‘Misión Biológica de Galicia’ (a research centre of the Consejo Superior de Investigaciones Científicas (CSIC), Spain). This collection has been characterized based on morphological and agronomical traits. A better understanding of the genetic diversity present in the collection is necessary in order to optimize its use and maintenance. The objectives of the present work were to assess the genetic diversity present in the B. rapa subsp. rapa collection, to establish genetic relationships among populations and to study the genetic structure of the collection. Eighty populations were analysed based on 18 simple sequence repeats (SSRs). Populations showed a broad range of genetic diversity, thus offering good potential for further genetic improvement. Most of the variability was found within the population level, probably due to high rates of allogamy, to migration and/or interchange of seed among local growers. Populations showed a low level of differentiation, grouping in just one cluster, and therefore they can be considered as samples of a highly variable metapopulation that can be used for B. rapa breeding programmes.

In order to study pollen-mediated gene flow in transgenic maize (Zea mays L.) in the Huang-huai-hai region of China, field trials were conducted in Jinan, Shandong Province in 2006 and 2007. The frequencies of gene flow from the donor plots, planted with transgenic maize as a pollen source, to the receptor plots, planted with non-transgenic maize, under different temporal or spatial separations were evaluated. The results showed that the frequency of pollen-mediated gene flow of the als gene from transgenic maize to non-transgenic maize decreased significantly with increasing distance. No gene flow was detected at 300 m. At a distance of 30 m, delaying the planting date of the transgenic maize by 1 week decreased the frequency of gene flow by 70%. A delay of 2 weeks decreased the gene flow frequency by more than 90%, while no gene flow was seen when the sowing date was delayed by 3 weeks. The results suggest that an appropriate isolation distance of 300 m or a temporal separation of 3 weeks could prevent gene flow from transgenic maize to non-transgenic maize in the Huang-huai-hai region.

Protein in forage legumes is often poorly utilized by ruminants and high nitrogen (N) losses are expected. The objective of the present study was to investigate the effects of forage legumes (white clover, WC; red clover, RC; lucerne, LG; and birdsfoot trefoil, BT) in binary mixtures with perennial ryegrass (G) under different defoliation systems (silage, simulated grazing and grazing) on agronomic performance and forage quality. A high proportion of legumes may favour dry matter (DM) yield and the defoliation system may reduce the persistence of certain forage legumes, with a negative influence on the energy and N yield. Annual DM yield under grazing was highest for WC mixtures (WC+G, 1059·2 g DM/m²) compared to all other mixtures, confirming its adaptation to grazing. Mixtures with RC (RC+G) and LG (LG+G) performed similarly to WC+G, whereas BT mixtures (BT+G) were less competitive under more intensively used systems. Analyses of crude protein, cell wall characterization and protein fractionation showed a three-way interaction between year, mixture and defoliation system. RC and BT resulted in a positive protein quality of the mixtures, probably due to their content of secondary plant compounds. In conclusion, different forage legumes did not perform equally in the cutting and grazing systems, and both legume species and defoliation systems interacted in the production of forage of high protein quality for ruminant nutrition.

The application of organic composts to soil may affect the availability of micronutrients and their concentration in plants. The present field research study compared soil micronutrient extractability after 5 years of organic fertilization v. conventional inorganic fertilization. Iron (Fe), copper (Cu), manganese (Mn) and zinc (Zn) were extracted from soil using diethylene triamine pentaacetic acid (DTPA) and the data obtained were compared with the concentration of these micronutrients in the edible portion of the crop. The study was carried out on a loam soil classified as a Xerofluvent. The soil was fertilized with composted plant residues or with conventional inorganic fertilizer and all treatments were replicated four times in a randomized complete block design. In all cases a crop rotational system was applied. The use of organic fertilization resulted in a higher extractability for all the elements studied; however, the micronutrient content in the edible part of the crops was variable depending on the plant species and element. Crop yields depended on the type of crop rather than the type of soil fertilization. The present study showed that the use of plant compost and the elimination of synthetic fertilizers result in an increase of Fe, Cu, Mn and Zn extractability compared to soil treated with inorganic fertilization, which should provide long-term fertility benefits.

Genes for adaptation to climatic conditions can have an impact on the expression of genes for agricultural productivity. This study tested the hypothesis that winter wheat cultivars registered in middle Europe (especially the Czech and Slovak Republics) during the period 1976–2009 were differentially adapted to different regions, reflecting selection for different allelic combinations. This was tested by analysing for the presence of alleles at the Rht and Ppd loci using molecular markers and gibberellic acids (GA) response tests. Four allelic variants (174, 192, 165 and 198-bp) were detected at the Xgwm261 locus linked to Rht8 on chromosome 2D. The 198-bp allele was rare, but present in some of the most widely grown cultivars. Of 85 cultivars grown in the area of Czech Republic, the 174-bp allele predominated in frequency and area (39 cultivars), often in combination with Ppd-D1b (30 out of 39 cultivars) and Rht-D1b (15 out of 30 cultivars). In neighbouring Slovakia, the 192-bp allele, generally associated with Ppd-D1a, was detected in 30 out of 40 cultivars; in 12 cultivars accompanied by a GA-insensitive allele on 4B chromosome (pedigree analyses indicated a high prevalence of the Rht-B1d allele). The 192-bp (Rht8)/Ppd-D1a linkage block was broken up in 7 out of 22 cultivars that carried the 192-bp allele in the ‘Czech collection’. Analysis of the effects of year of registration on allele frequency showed a decline in GA-insensitive cultivars released recently in both countries, and great changes in the frequency of the 2D alleles during the period 1981–2009 in the Czech Republic. The pedigrees of successful cultivars were examined to find probable sources of Xgwm261 192-bp, 174-bp and 165-bp alleles on 2D and Rht genes located on chromosomes 4B and 4D. These results will impact on breeding strategies and the exploitation of existing registered wheat cultivars in different regions and growing systems.

Herbage allowance (HA) impacts performance of grazing cattle as well as sward structure and herbage yield. The objective of the current study was to compare average daily gain (ADG) of Nellore steers on Marandu palisadegrass (Brachiaria brizantha (Hochst ex A. Rich.) Stapf. cv. Marandu) pastures in response to HA. Treatments were applied as 5, 10, 15 and 20 kg dry matter (DM) per 100 kg live weight (LW) per day HA5, HA10, HA15 and HA20), in rotationally stocked pastures under a 35-day grazing cycle (28 days of rest and 7 days of grazing). The trial was carried out in Pirassununga, Brazil, during two summer seasons in 2003 and 2004, each divided into four grazing cycles. Individual animal (250 kg yearling steers) gain increased with HA up to HA15 (mean=0·69 kg/head per day) during each of four grazing cycles per year. The 2-year gain per area was greater for HA5 and HA10 than for HA15 and HA20 and average stocking rate was 9·6, 6·7, 5·4 and 4·6 head/ha for HA5 to HA20, respectively. In addition to the effects of HA on ADG, changes in sward structure, especially sward height, help to explain variation in daily gain in both years. The HA10 treatment provides higher gain per area without excessively reducing individual animal performance, and thus may be the level of choice for optimizing animal output in pasture-only systems.

Improvements in farming systems and food supply will come from: increased production efficiencies per unit land area or per unit input of key components such as water or fertilizer; from less negative impact on local and global environments, allowing sustainable biodiversity goals to be integrated with production performance; and from enhanced approaches to bringing global supply and demand in balance, allowing internationally agreed goals for biosphere stability to be shaped, managed and delivered. Each stage will deliver significant improvements to current farming approaches. Modern engineering methods and technology advances have enhanced productivity in all major industries, and farming is yet to make much progress by developing and adopting these technologies. Sensors, control and integrated management systems will be major features, delivering enhanced farming productivity per unit input and per person employed, complemented by decreased environmental impacts and lower losses in the food chain. New insights into modelling and interpreting systems' performance will provide key contributions to optimization and control under complex challenges.

This paper provides a brief update on the potential impacts of climate change on marine ecosystems and marine wild capture fisheries based on the scientific literature published since 2007. Current models predict shifts in fish distributions of 45–60 km per decade, with 0·80 of species moving poleward. With a high CO2 emissions scenario, little overall change in the global maximum potential fisheries catch is projected (±1%), although with high spatial variability: decreases of 40% are projected for the tropics, with increases of 30–70% for higher latitudes. Tropical nations appear to be most vulnerable to the impacts of climate change on fisheries production. Coupled atmosphere–ocean–fish production–human society models are beginning to be developed for specific market systems. Results suggest that how society responds can have as large or larger an effect as the strength of the climate impact. Good observations of the impacts of climate change exist for high latitude, coral reef and North Atlantic systems. Management strategies are being developed to address climate change and fisheries, including risk and vulnerability assessment frameworks, pro-active planning with stakeholders regarding potential impacts and responses and examining existing regulations to identify gaps created by altered species distributions (e.g. unregulated fishing in newly ice-free areas). Overall, fisheries governance systems are needed which are flexible and can quickly adapt to changing ecological and human societal conditions. Significant knowledge gaps include a comprehensive and co-ordinated global network of observations to help distinguish climate change from variability, and increased detail in the structure and processes of models. Necessary next steps include reducing the uncertainties of climate impacts models at present, understanding the synergistic effects of multiple stressors and the inclusion of humans into coupled models and socio-economic analyses, in particular at regional and local scales. In the intermediate term, developing nations in tropical regions are likely to be most negatively impacted, whereas developed nations at higher latitudes are most likely to benefit. In the longer term, overall marine food security will depend on the impacts of climate change on marine primary production, for which the present projections are highly uncertain. Adoption of an integrated social–ecological approach that improves the adaptive capacities of ecological and human social systems will help to sustain food security from marine wild capture fisheries.

Jojoba [Simmondsia chinensis (Link) Schneider] is a dioecious plant grown for its seeds, which are the source of liquid wax or jojoba oil. The sex of jojoba plants cannot be determined with morphological characters until the plants reach reproductive maturity at 3 or more years old. This difficulty of early sex determination imposes severe constraints in breeding studies and in the sex allocation of seedlings in seed orchard establishment, and importantly in a priori mating designs to produce superior jojoba individuals. This study reports three new cleavage-amplified polymorphic sequence (CAPS) assays, which identify male and female individuals distinctly. One of the assays could also identify hermaphrodite jojoba plants existing in nature or obtained using mutagenesis studies.

Pedigree analysis was used to study the genetic background of 66 Indian early maturing potato selections, the pedigree of which was traced back to 35 ancestors. Six of the 35 contributed 0·42 of the genetic base, which shows the narrow genetic base of Indian early maturing genotypes. Genotypes 2814 (a)1 (f=0·145) and 3069 (d)4 (f=0·145) were the ancestors which appeared most frequently. Based on the coefficient of relationship, the 66 selections were grouped into seven groups with one common ancestor in almost all the selections within a group. The genotypes Kufri Ashoka, Kufri Pukhraj, AGB-69-1, Kufri Jyoti, Kufri Alankar, Kufri Lauvkar and Kufri Kuber were identified as very important parents/ancestors, carrying specific gene complexes valuable in new selections. Crosses between selections from different diversity groups can result in the selection of useful clones while increasing or maintaining genetic diversity, which is desirable to ensure sustainable breeding progress in the future.

The development of organic agriculture has raised the demand for crop varieties well-adapted to organic farming systems. Most of the varieties presently cultivated in organic agriculture were developed from conventional breeding programmes. The objective of the present work was to study the adaptability to organic farming systems of lentil (Lens culinaris Medik.) varieties developed from conventional breeding programmes. Twenty varieties were evaluated over five environments under organic and conventional farming systems from 2005 to 2007. Genotype×system interactions (GSI) for grain yield were significantly different in four out of the five environments and GSI explained 0·03–0·17 of the variance. Spearman's rank correlation index of the 20 varieties between the conventional and organic system ranged from 0·27 to 0·93 in the five environments. Direct selection of the top five varieties in organic systems resulted in significantly higher grain yields than indirect selection in one out of the five environments. However, among the top five varieties, the highest yielding varieties under conventional farming systems were not always the highest yielding varieties under organic farming systems. These results indicate that the demands of organic agriculture for yield performance could be only partially satisfied by varieties developed under conventional breeding programmes.

NASPOT 11 is a recently released sweet potato cultivar, bred by participatory plant breeding (PPB) in Uganda. It is already grown extensively by farmers who call it Tomulabula. In on-farm and on-station yield trials, Tomulabula yielded as well as the researcher-bred variety NASPOT 1 and sometimes more than the local landraces Dimbuka and New Kawogo, which have also been released. Farmers were asked to what extent Tomulabula, NASPOT 1 (the most popular station-bred cultivar in Uganda) and the local indigenously bred cultivar they were currently growing satisfied 52 attributes previously identified by farmers as beneficial in sweet potato. Those cultivars whose breeding involved farmers (Tomulabula and the local cultivar) were perceived mostly to satisfy a broad range of attributes (i.e. had few ‘Very Bad’ scores) while those which involved researchers (Tomulabula and NASPOT 1) were the most frequently rated as ‘Very Good’ for specific attributes. Instances were observed and accounts given of how Tomulabula is sold at a premium and how it had improved farmers’ lives. These outcomes are attributed to PPB combining the strengths of farmers and researchers. The involvement of the Ugandan National Sweetpotato Program (UNSP) ensures that planting material will be conserved and also available in adequate amounts for official distribution.

Automated feeding and milking of dairy cows enables the application of individual cow settings for concentrate supply and milking frequency. Currently, general settings are used, based on knowledge about energy and nutrient requirements in relation to milk production at the group level. Individual settings, based on the actual individual response in milk yield, have the potential for a marked increase in economic profits. In the present study, adaptive dynamic models for online estimation of milk yield response to concentrate intake and length of milking interval are evaluated. The parameters in these models may change over time and are updated through a Bayesian approach for online analysis of time series. The main use of dynamic models lies in their ability to determine economically optimal settings for concentrate intake and milking interval length for individual cows at any day in lactation. Three adaptive dynamic models are evaluated, a model with linear terms for concentrate intake and length of milking interval, a model that also comprises quadratic terms, and an enhanced model (EM) in order to obtain more stable parameter estimates. The linear model is useful only for forecasting milk production and the estimated parameters of the quadratic model were found to be unstable. The parsimony of the EM leads to far more stable parameter estimates. It is shown that the EM is suitable for control and monitoring, and therefore promises to be a valuable tool for application within precision livestock farming.

Accurate field data on the paddock area affected by cow urine depositions are critical to the estimation and modelling of nitrogen (N) losses and N management in grazed pasture systems. A new technique using survey-grade global positioning system (GPS) technology was developed to precisely measure the paddock spatial area coverage, diversity and distribution of dairy cattle urine patches in grazed paddocks over time. A 4-year study was conducted on the Lincoln University Dairy Farm (LUDF), Canterbury, New Zealand, from 2003 to 2007. Twelve field plots, each 100 m2 in area, were established on typical grazing areas of the farm. All urine and dung deposits within the plots were visually identified, the pasture response area (radius) measured and position marked with survey-grade GPS. The plots were grazed as part of the normal grazing rotation of the farm and urine and dung deposits measured at 12-week intervals. The data were collated using spatial (GIS) software and an assessment of annual urine patch coverage and spatial distribution was made. Grazing intensities ranged from 17 645 to 30 295 cow grazing h/ha/yr. Mean annual areas of urine patches ranged from 0·34 to 0·40 m2 (4-year mean 0·37±0·009 m2), with small but significant variation between years and seasons. Mean annual urine patch numbers were 6240±124 patches/ha/yr. The mean proportional area coverage for a single sampling event or season was 0·058 and the mean proportional annual urine patch coverage was 0·232±0·0071. There was a strong linear relationship between annual cow grazing h/ha and urine patch numbers/ha (R2=0·69) and also annual urine patch area coverage (R2=0·77). Within the stocking densities observed in this study, an annual increase of 10 000 cow grazing h/ha increased urine patch numbers by 1800 urine patches/ha/yr and annual urine patch area coverage by 0·07. This study presents new quantitative data on urine patch size, numbers and the spatial coverage of patches on a temporal basis.

The objective of the present study was to determine the optimal culling strategy in relation to biological and economic efficiency (BE and EE, respectively) and annualized net revenue (AN) in the Japanese Black cow–calf production system with special reference to the beef quality of culled cows. The herd model focused on two ways of mating: one-mating trial system (ONE) and continuous-mating trial system (CON). ONE assumed that heifers that fail to conceive are culled and cows that fail to conceive are culled at weaning of their calves, while CON assumed that mating continues until all females theoretically conceive. Least square means of carcass data of Japanese Black cows collected from a cooperative farm in Japan were used to estimate the carcass price of a cow by parity and Beef Marbling Standard (BMS) number. The simulation, assuming the current production situation in Japan, indicated that sales of culled cows accounted for 0·10–0·20 of total sales and was an important element in total production. Comparisons between ONE and CON showed that production efficiency in the current situation is higher in CON. The BE, EE and AN were higher in CON than in ONE. The two economic indicators were less sensitive to changes in annual discount rate but highly sensitive to changes in female calf price and BMS number of cows, indicating the importance of considering fluctuations in calf price and potential quality of culled cows’ carcasses when estimating the economically optimal parity of culling. The three indicators derived different optimal solutions even in the same mating trial systems, stressing the importance of choice of production indicators when determining the culling strategy and evaluating animal production.

Despite a highly variable climate and fragile soils, dryland farming systems in Australia continue to be productive and viable. This review nominates the farming practices, and their development through investment in science and technology, that have helped sustain dryland farming systems in Australia. It sets the context for dryland agriculture in Australia and specifically examines the risks and returns from technological innovations over the past 30 years. It then examines possible sources of productivity gains in the next 20 years.

Australian dryland farming systems have performed favourably compared to the agricultural sectors in most other countries over the past 30 years. Australian Research, Development and Extension (RD&E) has been a significant contributor to the realized agricultural productivity growth over this period. However, growth in the productivity of agriculture appears to have slowed down in the last 10 years: this is partly a result of extended dry conditions and declining growth in public investment in RD&E. It is reflected in slowing rates of technology adoption on broadacre farms and changes in investment confidence of farm owners.

Future productivity gains will require continued strong investment in RD&E to meet current and emerging challenges. Future technologies and policies will help improve productivity by removing inefficiencies, increasing the efficiency of resource use and developing breakthrough innovations.

As evidenced by Australia's success in productivity growth, meeting the global challenge to produce more food in the future will depend partly on investments in RD&E, risk management systems, farmer skill and human capital and policies that encourage efficiency gains.

A reliable evaluation of crop nutritional status is crucial for supporting fertilization aiming at maximizing qualitative and quantitative aspects of production and reducing the environmental impact of cropping systems. Most of the available simulation models evaluate crop nutritional status according to the nitrogen (N) dilution law, which derives critical N concentration as a function of above-ground biomass. An alternative approach, developed during a project carried out with students of the Cropping Systems Masters course at the University of Milan, was tested and compared with existing models (N dilution law and approaches implemented in EPIC and DAISY models). The new model (MAZINGA) reproduces the effect of leaf self-shading in lowering plant N concentration (PNC) through an inverse of the fraction of radiation intercepted by the canopy. The models were tested using data collected in four rice (Oryza sativa L.) experiments carried out in Northern Italy under potential and N-limited conditions. MAZINGA was the most accurate in identifying the critical N concentration, and therefore in discriminating PNC of plants growing under N-limited and non-limited conditions, respectively. In addition, the present work proved the effectiveness of crop models when used as tools for supporting education.

Land-use intensification requires more farm inputs to sustain or increase farm product outputs. However, a common concern for land-use intensification is the potential deterioration of soil. The North Otago Rolling Downlands (NORD) region of New Zealand is drought prone, and although traditionally limited to extensive sheep farming, there are large-scale conversions to intensive cattle grazing operations such as dairy farming resulting from an irrigation scheme commissioned in 2006. Pallic soils (Aeric Fragiaqualf in US Soil Taxonomy) such as those in the NORD region are prone to soil compaction because of their ‘high’ structural vulnerability under intensive management. To address these concerns, a field trial was established on a common NORD Pallic soil (Timaru silt loam) to determine how land-use intensification affects indicators of soil quality (macroporosity, bulk density, structural condition score, total and mineralizable carbon and nitrogen and earthworms) and pasture production. The treatments compare irrigated v. dryland pasture and sheep v. cattle grazing on 16 plots. The findings show that soil physical quality responds more quickly to changes in land-use pressure than do biochemical and organic indicators. Both irrigation and cattle grazing, particularly in combination, increased soil compaction; macroporosity on irrigated plots grazed by cattle ranged from 9·1 to 13·3% v/v at a depth of 0–50 mm, compared to dryland plots with sheep grazing (18·9–23·0% v/v). Soil compaction/damage has implications for pasture production, soil hydrology and nutrient movement. Land management practices for intensive cattle grazing of irrigated soil prone to treading damage therefore need to implement high compaction risk strategies to avoid or ameliorate potential changes to soil quality.