Barley Fields Research Articles

Identification of predominant genes involved in regulation and execution of senescence-associated nitrogen remobilization in flag leaves of field grown barley

The transcriptomes of senescing flag leaves collected from barley field plots with standard or high nitrogen supply were compared to identify genes specifically associated with nitrogen remobilization during leaf senescence under agronomically relevant conditions. In flag leaves collected in field plots with high nitrogen supply, the decline in chlorophyll content was delayed. By comparing changes in gene expression for the two nitrogen levels, it was possible to discriminate genes related to nitrogen remobilization during senescence and genes involved in other processes associated with the late development of leaves under field conditions. Predominant genes that were more strongly upregulated during senescence of flag leaves from plants with standard nitrogen supply included genes encoding the transcription factor HvNAC026, serine type protease SCPL51, and the autophagy factors APG7 and ATG18F. Elevated expression of these genes in senescing leaves from plants with standard nitrogen supply indicates important roles of the corresponding proteins in nitrogen remobilization. In comparison, the genes upregulated in both flag leaf samples might have roles in general senescence processes associated with late leaf development. Among these genes were the transcription factor genes HvNAC001, HvNAC005, HvNAC013, HvWRKY12 and MYB, genes encoding the papain-like cysteine peptidases HvPAP14 and HvPAP20, as well as a subtilase gene.

Widespread Use and Frequent Detection of Neonicotinoid Insecticides in Wetlands of Canada's Prairie Pothole Region

Neonicotinoids currently dominate the insecticide market as seed treatments on Canada's major Prairie crops (e.g., canola). The potential impact to ecologically significant wetlands in this dominantly agro-environment has largely been overlooked while the distribution of use, incidence and level of contamination remains unreported. We modelled the spatial distribution of neonicotinoid use across the three Prairie Provinces in combination with temporal assessments of water and sediment concentrations in wetlands to measure four active ingredients (clothianidin, thiamethoxam, imidacloprid and acetamiprid). From 2009 to 2012, neonicotinoid use was increasing; by 2012, applications covered an estimated ∼11 million hectares (44% of Prairie cropland) with >216,000 kg of active ingredients. Thiamethoxam, followed by clothianidin, were the dominant seed treatments by mass and area. Areas of high neonicotinoid use were identified as high density canola or soybean production. Water sampled four times from 136 wetlands (spring, summer, fall 2012 and spring 2013) across four rural municipalities in Saskatchewan similarly revealed clothianidin and thiamethoxam in the majority of samples. In spring 2012 prior to seeding, 36% of wetlands contained at least one neonicotinoid. Detections increased to 62% in summer 2012, declined to 16% in fall, and increased to 91% the following spring 2013 after ice-off. Peak concentrations were recorded during summer 2012 for both thiamethoxam (range: <LOQ - 1490 ng/L, canola) and clothianidin (range: <LOQ – 3110 ng/L, canola). Sediment samples collected during the same period rarely (6%) contained neonicotinoid concentrations (which did not exceed 20 ng/L). Wetlands situated in barley, canola and oat fields consistently contained higher mean concentrations of neonicotinoids than in grasslands, but no individual crop singularly influenced overall detections or concentrations. Distribution maps indicate neonicotinoid use is increasing and becoming more widespread with concerns for environmental loading, while frequently detected neonicotinoid concentrations in Prairie wetlands suggest high persistence and transport into wetlands.

Assessing the combined use of reduced tillage and cover crops for mitigating greenhouse gas emissions from arable ecosystem

Field management activities have significant impacts on greenhouse gas (GHG) emissions from cropland soils. In this study, the effectiveness of combining reduced tillage with a mustard cover crop (RT–CC) to mitigate present and future GHG emissions from a fertilized spring barley field in the southeast of Ireland was assessed. The field site which had a free-draining sandy loam soil with low soil moisture holding capacity, had been managed for three years prior to measurements under two different tillage systems; conventional (CT) and RT–CC. Field measurements of soil CO2, N2O and CH4 emissions, crop biomass, water filled pore space (WFPS), soil temperature and soil nitrate were made to capture both steady state conditions as well as the management events. Field data were used to validate the DNDC (DeNitrification–DeComposition) model and future GHG emissions under two sets of climate projections were predicted. Although fertilizer use was the same for both treatments the RT–CC treatment had significantly (p<0.05) higher N2O emissions for both present and future climate. However, the inclusion of a cover crop with the RT treatment increased predicted soil organic carbon (SOC), which more than compensated for the higher N2O flux resulting in a lower total GHG balance (TGGB) compared with the CT treatment. Results show that the effectiveness of RT–CC in mitigating GHG emissions will depend crucially on the magnitude of compensatory increases in carbon dioxide uptake by the cover crop that will contribute to a reduction in the total GHG balance.

Indicators and trade-offs of ecosystem services in agricultural soils along a landscape heterogeneity gradient

Soil functions can be classified as supporting (nutrient cycling) and provisioning (crop production) ecosystem services (ES). These services consist of multiple and dynamic functions and are typically assessed using indicators, e.g. microbial biomass as an indicator of supporting services. Agricultural intensification negatively affects indicators of soil functions and is therefore considered to deplete soil ES. It has been suggested that incorporating leys into crop rotations can enhance soil ES. We examined this by comparing indicators of supporting soil services – organic carbon, nitrogen, water holding capacity and available phosphorous (carbon storage and nutrient retention); net nitrogen mineralisation rate and microbial biomass (nutrient cycling and retention) – in barley fields, leys and permanent pastures along a landscape heterogeneity gradient (100, 500 and 1000m radii). In addition, barley yields (provisioning service) were analysed against these indicators to identify trade-offs among soil services. Levels of most indicators did not differ between barley and ley fields and were consistently lower than in permanent pastures. Leys supported greater microbial biomass than barley fields. Landscape heterogeneity had no effect on the indicators or microbial community composition. However, landscape heterogeneity correlated negatively with yield and soil pH, suggesting that soils in heterogeneous landscapes are less fertile and therefore have lower yields. No trade-offs were found between increasing barley yield and the soil indicators. The results suggest that soil ES are determined at the field level, with little influence from the surrounding landscape, and that greater crop yields do not necessarily come at the expense of supporting soil services.

First Molecular Detection of Ramularia Leaf Spot (Ramularia collo-cygni) in Seeds and Leaves of Barley in Argentina.

The fungus Ramularia collo-cygni B. Sutton & J. M. Waller (Rcc) was identified as the causal agent of this emerging disease on barley (Hordeum vulgare L.) based on symptoms and signs on leaves and attributes of the fungus. The common name given to the disease was "necrotic sprinkling." This disease was found for the first time on barley in fields of Buenos Aires Province, Argentina, in 2001, with severities ranging from 60 to 100% (2). During the spring of 2012, the disease spread throughout most barley growing areas of the Pampean region, affecting almost all varieties of barley in the Buenos Aires, Entre Ríos, and Santa Fe provinces. The disease showed typical symptoms of small, brown spots on leaves, sheaths, and awns, and caused rapid loss of green leaf area and significant economic damage. The diagnosis of this disease is difficult by conventional techniques and has caused some confusion. In order to obtain appropriate information about the incidence of this pathogen in the most important barley growing region of Argentina, as well as to confirm its presence on seed, 39 seed samples containing 200 seeds each and eight leaf samples were analyzed using a real-time PCR diagnostic test (4). Thirty-five of the 37 seed samples had Rcc DNA levels above the minimum detection level (0.13 pg DNA). Ramularia has been described as a seedborne fungus previously (1) and seed infection could hasten the spread of the fungus to new geographically distinct areas. Moreover, leaf samples were microscopically assessed for conidophore presence and then ground for DNA extraction. Rcc DNA was detected by PCR in all eight leaf samples. To our knowledge, this is the first report about molecular detection of R. collo-cygni in barley seed of harvested samples from Argentina. Seeds infected/infested may also lead to new strains of the fungus arriving in barley fields and provide a source of inoculum for future epidemics (3).

Integrated management of herbicide resistant Alopecurus aequalis in wheat and barley fields

Integrated management of herbicide resistant Alopecurus aequalis in wheat and barley fields

Mustard catch crop enhances denitrification in shallow groundwater beneath a spring barley field

Over-winter green cover crops have been reported to increase dissolved organic carbon (DOC) concentrations in groundwater, which can be used as an energy source for denitrifiers. This study investigates the impact of a mustard catch crop on in situ denitrification and nitrous oxide (N2O) emissions from an aquifer overlain by arable land. Denitrification rates and N2O-N/(N2O-N+N2-N) mole fractions were measured in situ with a push–pull method in shallow groundwater under a spring barley system in experimental plots with and without a mustard cover crop. The results suggest that a mustard cover crop could substantially enhance reduction of groundwater nitrate NO3--N via denitrification without significantly increasing N2O emissions. Mean total denitrification (TDN) rates below mustard cover crop and no cover crop were 7.61 and 0.002μgkg−1d−1, respectively. Estimated N2O-N/(N2O-N+N2-N) ratios, being 0.001 and 1.0 below mustard cover crop and no cover crop respectively, indicate that denitrification below mustard cover crop reduces N2O to N2, unlike the plot with no cover crop. The observed enhanced denitrification under the mustard cover crop may result from the higher groundwater DOC under mustard cover crop (1.53mgL−1) than no cover crop (0.90mgL−1) being added by the root exudates and root masses of mustard. This study gives insights into the missing piece in agricultural nitrogen (N) balance and groundwater derived N2O emissions under arable land and thus helps minimise the uncertainty in agricultural N and N2O-N balances.

Using optimal combination method and in situ hyperspectral measurements to estimate leaf nitrogen concentration in barley

Leaf nitrogen concentration (LNC), a good indicator of nitrogen (N) status in crops, is of special significance to diagnose nutrient stress and guide N fertilization in fields. Due to non-destructive and quick detectability, hyperspectral remote sensing plays a unique role in detecting LNC in crops. Barley, especially malting barley, is very demanding for N nutrition and requires timely monitoring and accurate estimation of N concentration in barley leaves. Hyperspectral techniques can help make effective diagnosis and facilitate dynamic regulation of plant N status. In this study, canopy reflectance spectra (between 350 and 1 050 nm) from 38 typical barley fields were measured as well as the corresponding LNC in Hailar Nongken, China’s Inner Mongolia Autonomous Region in July, 2010. Existing spectral indices that are considered to be good indicators for assessing N status in crops were selected to estimate LNC in barley. In addition, the optimal combination (OC) method was tested to extract the sensitive indices and first-order spectral derivative wavebands that are responsible for variation of leaf N in barley, and expected to develop some combination models for improving the accuracy of LNC estimates. The results showed that most of the selected indices (such as NPCI, PRI and DCNI) could adequately describe the dynamic changes of LNC in barley. The combined models based on OC performed better in comparison with the individual models using either spectral indices or first-order derivatives and the other methods (such as PCA). A combined model that integrated the first-order derivatives from five wavebands with OC performed well with R 2 of 0.82 and RMSE of 0.50 for LNC in barley. This good correlation with ground measurements indicates that hyperspectral reflectance and the OC method have good potential for assessing N status in barley.

Prevalence and diversity of Escherichia coli isolated from a barley trial supplemented with bulky organic soil amendments: green compost and bovine slurry

A barley field trial supplemented with bulky organic soil amendments, municipal compost or bovine slurry was sampled for Escherichia coli to test the hypothesis that E.coli isolated from the soil or from barley plants were derived from bovine slurry. A qualitative analysis showed that a total of 12% of the bulk soil cores and 16% of harvested grain samples yielded E.coli. The strongest association for positive detection of E.coli from soil was with time of year and for slurry-treated plots, with irrigation. However, E.coli were detected in plots from all treatment types and not exclusively associated with bovine slurry. Phylogroup, plasmid profiling and population genetics analysis (multilocus sequence typing) revealed extensive genetic diversity. Identical sequence types for slurry and soil isolates were detected, indicative of direct transfer into the soil, although not frequently. Host interaction assays with selected isolates showed a variation in the ability to colonize barley roots, but not in interactions with bovine cells. The work has implications in appropriate use of E.coli as a faecal indicator as isolates were widespread and diverse, reinforcing the view that some are a natural part of the microflora in agricultural systems. Faecal deposition is considered to be the main process that introduces Escherichia coli into soil, giving rise to their use as a faecal indication species and the potential for cycling pathogens in agricultural systems. We found that bovine slurry was not the main source of E.coli in a barley trial and a high degree of diversity was present in the collection. The findings support the hypothesis that the population structure of E.coli in secondary habitats is shaped by the environment and highlight the drawbacks of its use as a faecal indicator species.

Very high resolution crop surface models (CSMs) from UAV-based stereo images for rice growth monitoring In Northeast China

Abstract. Unmanned aerial vehicles (UAVs) became popular platforms for the collection of remotely sensed geodata in the last years (Hardin &amp;amp; Jensen 2011). Various applications in numerous fields of research like archaeology (Hendrickx et al., 2011), forestry or geomorphology evolved (Martinsanz, 2012). This contribution deals with the generation of multi-temporal crop surface models (CSMs) with very high resolution by means of low-cost equipment. The concept of the generation of multi-temporal CSMs using Terrestrial Laserscanning (TLS) has already been introduced by Hoffmeister et al. (2010). For this study, data acquisition was performed with a low-cost and low-weight Mini-UAV (&lt; 5 kg). UAVs in general and especially smaller ones, like the system presented here, close a gap in small scale remote sensing (Berni et al., 2009; Watts et al., 2012). In precision agriculture frequent remote sensing on such scales during the vegetation period provides important spatial information on the crop status. Crop growth variability can be detected by comparison of the CSMs in different phenological stages. Here, the focus is on the detection of this variability and its dependency on cultivar and plant treatment. The method has been tested for data acquired on a barley experiment field in Germany. In this contribution, it is applied to a different crop in a different environment. The study area is an experiment field for rice in Northeast China (Sanjiang Plain). Three replications of the cultivars Kongyu131 and Longjing21 were planted in plots that were treated with different amounts of N-fertilizer. In July 2012 three UAV-campaigns were carried out. Establishment of ground control points (GCPs) allowed for ground truth. Additionally, further destructive and non-destructive field data were collected. The UAV-system is an MK-Okto by Hisystems (http://www.mikrokopter.de) which was equipped with the high resolution Panasonic Lumix GF3 12 megapixel consumer camera. The self-built and self-maintained system has a payload of up to 1 kg and an average flight time of 15 minutes. The maximum speed is around 30 km/h and the system can be operated up to a wind speed of less than 19 km/h (Beaufort scale number 3 for wind speed). Using a suitable flight plan stereo images can be captured. For this study, a flying height of 50 m and a 44% side and 90% forward overlap was chosen. The images are processed into CSMs under the use of the Structure from Motion (SfM)-based software Agisoft Photoscan 0.9.0. The resulting models have a resolution of 0.02 m and an average number of about 12 million points. Further data processing in Esri ArcGIS allows for quantitative comparison of the plant heights. The multi-temporal datasets are analysed on a plot size basis. The results can be compared to and combined with the additional field data. Detecting plant height with non-invasive measurement techniques enables analysis of its correlation to biomass and other crop parameters (Hansen &amp;amp; Schjoerring, 2003; Thenkabail et al., 2000) measured in the field. The method presented here can therefore be a valuable addition for the recognition of such correlations.

Evaluation of Fusarium head blight in barley infected by Fusarium graminearum

Fusarium head blight, which is primarily caused by Fusarium graminearum, is a devastating disease in the barley field. A real-time PCR protocol was developed to evaluate the growth of this pathogen in the host plant tissues. All four strains harbored the gene encoding ATP-BINDING CASSETTE TRANSPORTER (FgABC; FGSG_00541) as a single copy within their genomes. Our Southern blot result was identical with the genomic data for F. graminearum strain PH-1. Based on the crossing point (CP) values obtained in our TaqMan real-time PCR analysis, two standard curves describing the relationship among the CP value, FgABC copy number, and amount of fungal DNA were constructed. Chronological enumeration of fungal growth was coincided with the symptom development.

The conservation of arable weeds at crop edges of barley fields in northeast Spain

AbstractThe effects of weed control practices and fertilisation on weed flora and crop yield were evaluated in crop edges of barley fields in northeastern Spain. The study was carried out in four organic and four conventional barley fields. In each field, four permanent plots were delimited at the crop edge, and fertilisation and weed control treatments in a factorial design were applied over 3 years. Weed composition and the aboveground biomass of weeds and barley were recorded before the crop harvest in the first and the third year. We found relatively low values of species richness per field, as well as low values of weed biomass, especially in the organic crop edges (3.9% of total biomass). Weeds were significantly reduced by herbicide applications on conventional fields and were not affected by weed harrowing on organic fields or fertilisation. These results demonstrate that specific measures are needed to enhance biodiversity at crop edges both in organic and conventional fields. Our results also suggest that under Mediterranean conditions and among impoverished weed communities, limiting the use of herbicides is crucial to enhancing arable diversity and that, contrary to findings found in previous studies in temperate climates, fertilisation and weed harrowing have little effect on weeds.

Combining Cultural Practices with Herbicides Reduces Wild Oat (Avena fatua) Seed in the Soil Seed Bank and Improves Barley Yield

A study was initiated in 2001at four locations in western Canada to investigate an integrated approach to managing wild oat, the region's worst weed. The study examined the effects of combining semidwarf or tall barley cultivars with normal or twice-normal barley seeding rates in either continuous barley or a barley–canola–barley–field pea–barley rotation. Herbicides were applied at 25, 50, and 100% of recommended rates. The first phase of the study was completed in 2005. This paper reports on the second phase, which was continued for four more years at two of the locations, Beaverlodge and Fort Vermilion, AB, Canada. The objective was to determine the long-term impact of the treatments on wild oat seed in the soil seed bank. In 2009 (final year), the diverse rotation combined with the higher barley seeding rate (optimal cultural practice) resulted in higher barley yields and reduced wild oat biomass compared to continuous barley and lower barley seeding rate (suboptimal cultural practice). In contrast to the first phase, barley yield was higher with the semidwarf cultivar, and cultivar had no effect on wild oat management. Wild oat seed in the soil seed bank decreased with increasing herbicide rate, but amounts were often lower with the optimal cultural practice. For example, at the recommended herbicide rate at Beaverlodge, an approximate 40-fold reduction in wild oat seed occurred with the optimal compared to the suboptimal cultural practice. The results indicate that combining optimal cultural practices with herbicides will reduce the amount of wild oat seed in the soil seed bank, and result in higher barley yields. Optimal cultural practices may also compensate for reduced herbicidal effects in terms of reducing wild oat seed accumulation in the soil seed bank and increasing barley yield. The results have implications for mitigating the evolution of herbicide resistance in wild oat.

A comparison of energy use and productivity of wheat and barley (case study)

Comparison of energy productivity of different crops can be used as an effective tool to prioritize crops planting in each area. This study was conducted in order to compare wheat and barley farms of Sistan and Baluchestan province in Iran in relation to various aspects of energy consumption at 2009. 100 wheat and 100 barley fields were selected randomly from main 11 cities in the studied region. Input data and yield of wheat and barley fields were collected in the form of questionnaires in a face-to-face interview. Results showed that total energy inputs of wheat and barley fields were 32492.97 and 25655.81MJha−1, respectively. Total energy outputs for wheat and barley fields were 48517.24 and 49800.87MJha−1, respectively. Based on these results the amount of energy use efficiency for wheat and barley fields were 1.49 and 1.94, respectively, and the amount of energy productivity for mentioned fields were 0.056 and 0.066. The share of renewable energy as one of the sustainability indexes of agricultural systems was 19.60 for wheat and 14.60 for barley fields. Therefore, it seems that barley production is more efficient from various aspects of energy consumption rather than wheat in the studied region.

Agrichemical use on wheat and barley crops in New Zealand in 2008–09

Agrichemical usage on cereal crops grown in New Zealand was assessed from spray diaries for 45 barley fields and 81 wheat fields. From the 2008–09 growing season, 2.13 kg ai/ha (0.35 kg ai/t grain) and 2.93 kg ai/ha (0.31 kg ai/t grain) of agrichemicals of low-moderate human toxicity were applied to barley and wheat fields, respectively. For each crop, 0.31 and 0.33 kg ai/ha of fungicides, 0.14 and 0.28 kg ai/ha of insecticides, 1.46 and 1.47 kg ai/ha of herbicides and 0.22 and 0.85 kg ai/ha of plant growth regulators were applied. The data were reviewed with respect to pesticide resistance management guidelines. Although more than half of the agrichemical active ingredients (ai) applied, mostly herbicides, were classified by the Hazardous Substances and New Organisms (HSNO) Act 1996 as having high water or soil eco-toxicity, the amounts applied to the cereals on a per hectare basis were small (1.14 and 0.84 kg ai/ha, respectively) compared with that applied to comparable horticultural crops. Agrichemical use in cereal crops in New Zealand has remained generally static since 1998 despite incremental increases in yield, reflecting the arable sector's focus on protecting and building farm biodiversity, integrated pest management and agrichemical management.

Flow and stability of natural pest control services depend on complexity and crop rotation at the landscape scale

Summary Increasing landscape complexity can enhance biodiversity and ecosystem services in agroecosystems. However, policies based on conversion of arable land into semi‐natural habitats to increase landscape complexity and ecosystem services can be difficult to implement. Although it appears to be a promising management option, nothing is known about the effect of increasing landscape diversity through crop rotations on the delivery of ecosystem services. In this study, we examined how landscape complexity and crop rotation intensity in the landscape at different spatial scales affect the flow and the stability of natural pest control services in barley fields using manipulative cage experiments. Exclusion experiments revealed that natural enemies can have a strong impact on aphid population growth and that the delivery of pest control services is strongly dependent on the landscape context. We found that the overall level of pest control increased with landscape complexity and that this effect was independent of crop rotation intensity. In addition, the within‐field stability in pest control services increased with crop rotation intensity in the landscape, although stability in parasitism rates decreased. Multiple spatial scales analyses showed that the mean level of natural pest control was best predicted by landscape complexity at the 0·5‐km and the 1‐km spatial scales. The stability in overall pest control decreased with proportion of ley at the 2·5‐km and the 3‐km spatial scales. Synthesis and applications. Our study disentangled, for the first time, the relative effects of landscape complexity and crop rotation intensity on the delivery of an ecosystem service. We show that combined management of semi‐natural habitat and crop rotation can stabilize and enhance natural pest control in agricultural landscapes. Our findings have important implications in terms of management options to maintain and enhance ecosystem services in agroecosystems. They suggest that conservation of heterogeneous landscapes, characterized by a higher proportion of semi‐natural habitats such as pastures and relatively small fields, is essential for maintaining and enhancing effective biological control in agroecosystems.

Soil phosphorus–crop response calibration relationships and criteria for winter cereal crops grown in Australia

Soil testing is the most widely used tool to predict the need for fertiliser phosphorus (P) application to crops. This study examined factors affecting critical soil P concentrations and confidence intervals for wheat and barley grown in Australian soils by interrogating validated data from 1777 wheat and 150 barley field treatment series now held in the BFDC National Database. To narrow confidence intervals associated with estimated critical P concentrations, filters for yield, crop stress, or low pH were applied. Once treatment series with low yield (&lt;1 t/ha), severe crop stress, or pHCaCl2 &lt;4.3 were screened out, critical concentrations were relatively insensitive to wheat yield (&gt;1 t/ha). There was a clear increase in critical P concentration from early trials when full tillage was common compared with those conducted in 1995–2011, which corresponds to a period of rapid shift towards adoption of minimum tillage. For wheat, critical Colwell-P concentrations associated with 90 or 95% of maximum yield varied among Australian Soil Classification (ASC) Orders and Sub-orders: Calcarosol, Chromosol, Kandosol, Sodosol, Tenosol and Vertosol. Soil type, based on ASC Orders and Sub-orders, produced critical Colwell-P concentrations at 90% of maximum relative yield from 15 mg/kg (Grey Vertosol) to 47 mg/kg (Supracalcic Calcarosols), with other soils having values in the range 19–27 mg/kg. Distinctive differences in critical P concentrations were evident among Sub-orders of Calcarosols, Chromosols, Sodosols, Tenosols, and Vertosols, possibly due to differences in soil properties related to P sorption. However, insufficient data were available to develop a relationship between P buffering index (PBI) and critical P concentration. In general, there was no evidence that critical concentrations for barley would be different from those for wheat on the same soils. Significant knowledge gaps to fill to improve the relevance and reliability of soil P testing for winter cereals were: lack of data for oats; the paucity of treatment series reflecting current cropping practices, especially minimum tillage; and inadequate metadata on soil texture, pH, growing season rainfall, gravel content, and PBI. The critical concentrations determined illustrate the importance of recent experimental data and of soil type, but also provide examples of interrogation pathways into the BFDC National Database to extract locally relevant critical P concentrations for guiding P fertiliser decision-making in wheat and barley.

A new Expert System for greenness identification in agricultural images

It is well-known that one important issue emerging strongly in agriculture is related with the automation of tasks, where camera-based sensors play an important role. They provide images that must be conveniently processed. The most relevant image processing procedures require the identification of green plants, in our experiments they comes from barley and maize fields including weeds, so that some type of action can be carried out, including site-specific treatments with chemical products or mechanical manipulations.The images come from outdoor environments, which are affected for a high variability of illumination conditions because of sunny or cloudy days or both with high rate of changes.Several indices have been proposed in the literature for greenness identification, but under adverse environmental conditions most of them fail or do not work properly. This is true even for camera devices with auto-image white balance.This paper proposes a new automatic and robust Expert System for greenness identification. It consists of two main modules: (1) decision making, based on image histogram analysis and (2) greenness identification, where two different strategies are proposed, the first based on classical greenness identification methods and the second inspired on the Fuzzy Clustering approach. The Expert System design as a whole makes a contribution, but the Fuzzy Clustering strategy makes the main finding of this paper. The system is tested for different images captured with several camera devices.

Which crop production system is more efficient in energy use: wheat or barley?

Efficient use of energy helps to achieve increased production and productivity and contributes to the economy, profitability, and competitiveness of agricultural sustainability of rural communities. Evaluation of wheat and barley production systems in view of energy balance was conducted in Khorasan Razavi Province, Iran. Data were collected by using a face-to-face questionnaire from wheat and barley fields in 2011. Results revealed that total energy input for wheat was 51,040 MJ ha−1 and for barley 44,866; in wheat and barley systems, renewable energy was consumed by 25.43 and 23.53 %, while non-renewable energy was consumed by 74.57 and 76.47 %, respectively. Energy use efficiency, energy productivity, and net energy were 1.7 kg MJ−1, 0.088 kg MJ−1, and 35,987 MJ ha−1 in wheat system and 1.83 kg MJ−1, 0.092 kg MJ−1, and 33,833 MJ ha−1 in barley system, respectively. Energy intensiveness in wheat fields (61.84 MJ $−1) was higher than in barley fields (58.71 MJ $−1). Also, benefit-to-cost ratio in wheat system (1.59) was higher than in barley system (1.35). In general, production in barley fields was more sustainable than wheat production because, in view of ecological indices such as amount of energy use and renewable energy consumption, it was more environment-friendly production.

Role of maize stover incorporation on nitrogen oxide emissions in a non-irrigated Mediterranean barley field

Aims Agricultural soils in semiarid Mediterranean areas are characterized by low organic matter contents and low fertility levels. Application of crop residues and/or manures as amendments is a cost-effective and sustainable alternative to overcome this problem. However, these management practices may induce important changes in the nitrogen oxide emissions from these agroecosystems, with additional impacts on carbon dioxide emissions. In this context, a field experiment was carried out with a barley (Hordeum vulgare L.) crop under Mediterranean conditions to evaluate the effect of combining maize (Zea mays L.) residues and N fertilizer inputs (organic and/or mineral) on these emissions.