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Agriculture, Volume 8, Issue 11 (November 2018)

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Cover Story (view full-size image) Biochar can significantly improve soil quality and crop growth. However not all biochars are [...] Read more.
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Open AccessArticle Increasing of Posture Changes as Indicator of Imminent Calving in Dairy Cows
Agriculture 2018, 8(11), 182; https://doi.org/10.3390/agriculture8110182
Received: 30 August 2018 / Revised: 7 November 2018 / Accepted: 16 November 2018 / Published: 20 November 2018
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Abstract
The careful monitoring of cows helps minimise pain and distress during calving; moreover, knowing the exact time of birth is important to ensure timely assistance and the adequate ingestion of colostrum by the calf. However, direct visual observation is time-consuming, and the continuous
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The careful monitoring of cows helps minimise pain and distress during calving; moreover, knowing the exact time of birth is important to ensure timely assistance and the adequate ingestion of colostrum by the calf. However, direct visual observation is time-consuming, and the continuous presence of an observer during stage two of calving can disturb cows. Video cameras or accelerometers recording the behaviour of cows can be integrated in systems using image analysis or locomotive activity to alert the farmer as to when calving is imminent. However, alerting systems require the input of benchmark information about behaviours and changes in behaviours that can be predictive of the time of calving. Eight cows in a calving barn were continuously video-monitored. The recordings of the 24 h before delivery were analysed by instantaneous time sampling to identify the behaviours associated with an imminent birth. The same were collected in an ethogram including lying, standing, walking, turning the head towards the abdomen, eating, ruminating, drinking, sniffing the ground, allogrooming, self-grooming, and posture-changing. In our conditions, the only behaviour that was significantly influenced by the distance to delivery was posture-changing (p < 0.0001). Two h before the delivery, the proportion of posture changes was different from all of the hourly proportions measured from −24 to −3 h relative to delivery (p < 0.005), resulting in 3.6 times the average of the previous 22 h relative to delivery. An increase of posture changes may be an indicator of calving approaching, but further studies are needed to input benchmark values in alerting systems. Full article
(This article belongs to the Special Issue Ethology and Animal Welfare)
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Open AccessReview Soil Organic Carbon Depletion from Forests to Grasslands Conversion in Mexico: A Review
Agriculture 2018, 8(11), 181; https://doi.org/10.3390/agriculture8110181
Received: 12 September 2018 / Revised: 7 November 2018 / Accepted: 10 November 2018 / Published: 18 November 2018
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Abstract
Land use change from forests to grazing lands is one of the important sources of greenhouse gas emissions in many parts of the tropics. The objective of this study was to analyze the extent of soil organic carbon (SOC) loss from the conversion
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Land use change from forests to grazing lands is one of the important sources of greenhouse gas emissions in many parts of the tropics. The objective of this study was to analyze the extent of soil organic carbon (SOC) loss from the conversion of native forests to pasturelands in Mexico. We analyzed 66 sets of published research data with simultaneous measurements of soil organic carbon stocks between native forests and pasturelands in Mexico. We used a generalized linear mixed effect model to evaluate the effect of land use change (forest versus pasture), soil depth, and original native forest types. The model showed that there was a significant reduction in SOC stocks due to the conversion of native forests to pasturelands. The median loss of SOC ranged from 31.6% to 52.0% depending upon the soil depth. The highest loss was observed in tropical mangrove forests followed by highland tropical forests and humid tropical forests. Higher loss was detected in upper soil horizon (0–30 cm) compared to deeper horizons. The emissions of CO2 from SOC loss ranged from 46.7 to 165.5 Mg CO2 eq. ha−1 depending upon the type of original native forests. In this paper, we also discuss the effect that agroforestry practices such as silvopastoral arrangements and other management practices like rotational grazing, soil erosion control, and soil nutrient management can have in enhancing SOC stocks in tropical grasslands. The results on the degree of carbon loss can have strong implications in adopting appropriate management decisions that recover or retain carbon stocks in biomass and soils of tropical livestock production systems. Full article
(This article belongs to the Special Issue Soil Organic Carbon)
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Open AccessArticle How Does Water-Stressed Corn Respond to Potassium Nutrition? A Shoot-Root Scale Approach Study under Controlled Conditions
Agriculture 2018, 8(11), 180; https://doi.org/10.3390/agriculture8110180
Received: 22 October 2018 / Revised: 6 November 2018 / Accepted: 13 November 2018 / Published: 16 November 2018
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Abstract
Potassium (K) is generally considered as being closely linked to plant water dynamics. Consequently, reinforcing K nutrition, which theoretically favors root growth and specific surface, extends leaf lifespan, and regulates stomatal functioning, is often used to tackle water stress. We designed a greenhouse
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Potassium (K) is generally considered as being closely linked to plant water dynamics. Consequently, reinforcing K nutrition, which theoretically favors root growth and specific surface, extends leaf lifespan, and regulates stomatal functioning, is often used to tackle water stress. We designed a greenhouse pot-scale device to test these interactions on corn (Zea mays L.), and to analyze their links to plant transpiration. Three levels of K nutrition were combined with two water-supply treatments. Shoot and root development and growth were continuously measured during a 60-day-long experiment. Individual plant transpiration was measured by weighing pots and by calculating water mass balances. The results showed that, although K deficiency symptoms resembled those caused by water shortage, there was no advantage to over-fertilizing water-stressed plants. K failed to decrease either the transpiration per unit leaf surface or to improve water use efficiency. The link between K nutrition and plant transpiration appears solely attributable to the effect of K on leaf area. We conclude that K over-fertilization could ultimately jeopardize crops by enhancing early-stage water transpiration to the detriment of later developmental stages. Full article
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Open AccessReview Phylogeny and Expression of NADPH Oxidases during Symbiotic Nodule Formation
Agriculture 2018, 8(11), 179; https://doi.org/10.3390/agriculture8110179
Received: 30 October 2018 / Revised: 10 November 2018 / Accepted: 14 November 2018 / Published: 16 November 2018
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Abstract
The mutualistic interaction between gram-negative soil bacteria and the roots of legumes leads to the establishment of nodules, where atmospheric nitrogen is fixed. Nodulation is a multistep process with numerous essential players. Among these are reactive oxygen species (ROS), which are mainly generated
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The mutualistic interaction between gram-negative soil bacteria and the roots of legumes leads to the establishment of nodules, where atmospheric nitrogen is fixed. Nodulation is a multistep process with numerous essential players. Among these are reactive oxygen species (ROS), which are mainly generated by Nicotinamide Adenine Dinucleotide Phosphate (NADPH) oxidases. In plants, these enzymes are known as respiratory burst oxidase homologs (RBOHs). In legumes, these proteins are encoded by a multigene family with members that are differentially expressed in various tissues and organs at distinct developmental stages. RBOHs have critical roles at several stages of nodulation: in the early signaling pathway triggered by nodulation factors in the root hairs, during both the progression of infection threads and nodule ontogeny, and in nitrogen fixation and senescence. Data from the literature along with the analysis conducted here imply that legumes use different RBOHs for different stages of nodulation; these RBOHs belong to the same phylogenetic subgroup, even though they are not strictly orthologous. Accordingly, the regulation of activity of a given RBOH during the nodulation process probably varies among legumes. Full article
(This article belongs to the Special Issue Legume-rhizobia Symbiosis: Current Knowledge and Future Prospects)
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Open AccessArticle Biomass and Biogas Yield of Maize (Zea mays L.) Grown under Artificial Shading
Agriculture 2018, 8(11), 178; https://doi.org/10.3390/agriculture8110178
Received: 25 August 2018 / Revised: 5 November 2018 / Accepted: 9 November 2018 / Published: 12 November 2018
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Abstract
Agroforestry, as an improved cropping system, offers some advantages in terms of yield, biodiversity, erosion protection or habitats for beneficial insects. It can fulfill the actual sustainability requirements for bioenergy production like food supply, nature conservation, stop of deforestation. However, competition between intercropped
[...] Read more.
Agroforestry, as an improved cropping system, offers some advantages in terms of yield, biodiversity, erosion protection or habitats for beneficial insects. It can fulfill the actual sustainability requirements for bioenergy production like food supply, nature conservation, stop of deforestation. However, competition between intercropped species for water, nutrients and light availability has to be carefully considered. A field trial with shading nets was conducted in Southwest Germany to evaluate the influence of different shading levels (−12, −26, and −50% of full sunlight) on biomass growth, dry matter yield and biogas quality parameters of maize (Zea mays L., cv. ‘Corioli CS’). Shading the plants causes a delayed development, a reduction in height and leaf area index and a slower senescence. Dry matter yields were reduced about 18%, 19%, and 44% compared to 21.05 Mg ha−1 year−1 at full sunlight. Biogas and methane yields were also significantly reduced, the 50% shading treatment showed a reduction of 45% for both parameters. Further, shading led to higher crude protein and crude ash contents. If silage maize is grown under shade, the yields of dry matter, biogas, and methane are nearly halved under 50% shade. Cultivation up to 26% shading could be possible. Full article
(This article belongs to the Special Issue Energy and Agriculture)
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Open AccessArticle Sustainability of Improved Crop Varieties and Agricultural Practices: A Case Study in the Central Rift Valley of Ethiopia
Agriculture 2018, 8(11), 177; https://doi.org/10.3390/agriculture8110177
Received: 9 September 2018 / Revised: 1 November 2018 / Accepted: 5 November 2018 / Published: 9 November 2018
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Abstract
Technological change has been the major driving force for increasing agricultural productivity and promoting agriculture development in developing countries. To improve the agricultural productivity and farmers’ livelihoods, several agricultural technologies (improved crop varieties and related agricultural practices) were introduced by various agencies to
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Technological change has been the major driving force for increasing agricultural productivity and promoting agriculture development in developing countries. To improve the agricultural productivity and farmers’ livelihoods, several agricultural technologies (improved crop varieties and related agricultural practices) were introduced by various agencies to the farmers in the Rift Valley of Ethiopia. Thus, the objective of this study is to identify these technologies, and evaluate their characteristics and sustainability. The data were collected from farmers, agricultural extension workers, and agricultural experts, through a series of focus group discussions, key informant interviews, and farm observations, selected through purposive and random sampling techniques. Results showed that extension systems, social networks, or research projects were the agencies that introduced the technologies to the farmers. Haricot beans (Phaseolus vulgaris L.) and early and mid-maturing maize (Zea mays L.), as well as agricultural practices like row-sowing, banding fertilizer application, intercropping, and traditional rainwater-harvesting, were found to be in continuous use by the farmers. In contrast, the use of extra-early-maturing maize, sorghum (Sorghum bicolor L.) and finger millet (Eleusine coracana L.), as well as the use of related practices, including harvesting maize at physiological maturity, seed priming and fertilizer microdosing, were the technologies that were discontinued at the time of pursuing this study. Most of the continuing technologies had a high potential for reducing the vulnerability of the rain-fed agriculture to rainfall variability. Regardless of sources, the national extension system supported technologies that were integrated into the system only. Most of the discontinued technologies were found to be introduced by the research projects. These technologies were not brought into the attention of policy-makers for their integration into the extension system. The farmers also disliked a few of them for unfitting the existing socioeconomic setting. Whereas, the technologies that were introduced by the social networks were found to be widely used by the farmers, though they were not supported by the extension system. This is because most such technologies offer better yield and income. For instance, social networks have popularized haricot beans and hybrid maize because of their higher benefits to farmers. Farmers consider both socioeconomic and agroecological conditions for selecting and using technologies, whereas the extension system centers on existing agroecological conditions for recommending and supporting agricultural technologies. Consideration of both socioeconomic and agroecological settings would increase the prospect of a technology for sustainable adoption. Overall, rainfall variability, high price and poor access to improved seeds, farmers’ poor economic conditions, and the inadequate linkage between extension systems, social networks and research projects, remain critical factors influencing the sustainable use of agricultural technologies. It is, thus, commendable that policymakers should consider local socioeconomic and agroecological settings in recommending and supporting agricultural technologies besides instituting a strong consortium of extension systems, research institutes, research projects, social networks and farmers for improved agricultural technology development, extension system and sustainable adoption. Full article
(This article belongs to the Special Issue Agriculture Policies: Experiences and Challenges)
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Open AccessBrief Report Rearing Male Layer Chickens: A German Perspective
Agriculture 2018, 8(11), 176; https://doi.org/10.3390/agriculture8110176
Received: 19 October 2018 / Revised: 1 November 2018 / Accepted: 6 November 2018 / Published: 9 November 2018
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Abstract
The killing of male layer hybrids in the hatcheries, at a day-old, is common practice but it also raises strong socio-ethical concerns. In recent years, three different approaches to avoid this killing have been developed—the in ovo sex determination, the rearing of male
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The killing of male layer hybrids in the hatcheries, at a day-old, is common practice but it also raises strong socio-ethical concerns. In recent years, three different approaches to avoid this killing have been developed—the in ovo sex determination, the rearing of male layers for meat, and the use of dual-purpose breeds. In Germany, about one million male layers are raised each year in the organic and conventional sector. Regarding animal health and welfare, this concept seems favourable. However, the main challenge, that is, to what extent these animals can be kept in a resource-friendly and ecologically sustainable way, remains yet to be solved. Currently, for a niche, this approach contributes to the diversification of the German market. It serves as an example for reacting to societal concerns immediately, before feasible solutions are available for the entire system of modern poultry production. Full article
(This article belongs to the Special Issue Farm Animal Welfare)
Open AccessArticle Investigating the Influence of Biochar Particle Size and Depth of Placement on Nitrous Oxide (N2O) Emissions from Simulated Urine Patches
Agriculture 2018, 8(11), 175; https://doi.org/10.3390/agriculture8110175
Received: 30 September 2018 / Revised: 22 October 2018 / Accepted: 1 November 2018 / Published: 7 November 2018
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Abstract
The use of biochar reduces nitrous oxide (N2O) emissions from soils under specific conditions yet the mechanisms through which interactions occur are not fully understood. The objectives of this glasshouse study were to investigate the effect of (i) biochar particle size,
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The use of biochar reduces nitrous oxide (N2O) emissions from soils under specific conditions yet the mechanisms through which interactions occur are not fully understood. The objectives of this glasshouse study were to investigate the effect of (i) biochar particle size, and (ii) the impact of soil inversion—through simulated mouldboard ploughing—on N2O emissions from soils to which cattle urine was applied. Pine biochar (550 °C) with two different particle sizes (<2 mm and >4 mm) was mixed either into the top soil layer at the original 0–10 cm depth in the soil column or at 10–20 cm depth by inverting the top soil to simulate ploughing. Nitrous oxide emissions were monitored for every two to three days, up to seven weeks during the summer trial and measurements were repeated during the autumn trial. We found that the use of large particle size biochar in the inverted soil had significant impact on increasing the cumulative N2O emissions in autumn trial, possibly through changes in the water hydraulic conductivity of the soil column and increased water retention at the boundary between soil layers. This study thus highlights the importance of the role of biochar particle size and the method of biochar placement on soil physical properties and the implications of these on N2O emissions. Full article
(This article belongs to the Special Issue Biochar and Soil: What Is behind Its Impacts?)
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Open AccessArticle Monitoring of Pesticides in the Cultivation of Nopal Vegetable (Opuntia ficus-indica (L.)) Mill, Morelos, México
Agriculture 2018, 8(11), 174; https://doi.org/10.3390/agriculture8110174
Received: 3 September 2018 / Revised: 17 October 2018 / Accepted: 27 October 2018 / Published: 6 November 2018
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Abstract
The presence of pesticide residues in vegetable and fruit products, as a consequence of inappropriate application in some cases, constitutes a risk to the health of the exposed population. In Mexico, the official norm, NOM-003-STPS-1999, only allows the use of pesticides with the
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The presence of pesticide residues in vegetable and fruit products, as a consequence of inappropriate application in some cases, constitutes a risk to the health of the exposed population. In Mexico, the official norm, NOM-003-STPS-1999, only allows the use of pesticides with the phytosanitary registry, the responsible state commission for the control of the process and use of pesticides and toxic substances, which recommends doses and permitted crops. Despite the above, it is still common to find pesticide residues in some vegetable products. In this study, the following were detected: Chlorpyriphos, Dimetomorph I, Malathion, Omethoate, Carbendazim, and Imidacloprid in Nopal. The study was carried out in two collection centers located in the state of Morelos. In total, sixty samples were taken, thirty for each collection center, for a period of 10 months. To determine the pesticide residues, the analytical methodology was used, according to the guide, SANTE/11945/2015; in a laboratory accredited by the Mexican Accreditation Entity A. C. in the norm, NMX-EC-17025-IMNC-2006. The procedure for extracting analytes was carried out using the method, QuEChERS. The highest concentration of the pesticides detected in the samples obtained from the non-Certified Supply Center were Chlorpyrifos 0.309 mg/kg (MRL 0.01), Dimetomorf I 0.029 mg/kg (MRL 0.01), Malathion 0.155 mg/kg (MRL 0.01), Omethoate 0.032 (MRL 0.01), Carbendazim 0.090 mg/kg (MRL 0.01), and Imidacloprid 0.058 mg/kg (MRL 0.01). Thirty percent of the samples analyzed showed pesticide residues; the most frequent were Carbendazim. The results for the estimated daily intake (EDI) oscillated between 6.5 × 10−5 and 1.3 × 10−4 mg/kg body weight for the vegetable, Nopal. In principle, it could be concluded that the consumption of Nopal with pesticide residues does not represent any toxicological risk for human health, however, the risk cannot be ruled out due to the intake of other vegetables and fruits that are cultivated in the Mexican Republic, which probably present pesticide residues, which together would raise potential risks to human health. Full article
(This article belongs to the Special Issue Pesticides in Agriculture System)
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Open AccessReview A Multi-Actor Literature Review on Alternative and Sustainable Food Systems for the Promotion of Cereal Biodiversity
Agriculture 2018, 8(11), 173; https://doi.org/10.3390/agriculture8110173
Received: 28 September 2018 / Revised: 30 October 2018 / Accepted: 31 October 2018 / Published: 2 November 2018
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Abstract
Organic and low-input food systems are emerging worldwide in answer to the sustainability crisis of the conventional agri-food sector. “Alternative” systems are based on local, decentralized approaches to production and processing, regarding quality and health, and short supply-chains for products with strong local
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Organic and low-input food systems are emerging worldwide in answer to the sustainability crisis of the conventional agri-food sector. “Alternative” systems are based on local, decentralized approaches to production and processing, regarding quality and health, and short supply-chains for products with strong local identities. Diversity is deeply embedded in these food systems, from the agrobiodiversity grown in farmers’ fields, which improves resilience and adaptation, to diverse approaches, contexts and actors in food manufacturing and marketing. Diversity thus becomes a cross-sectoral issue which acknowledges consumers’ demand for healthy products. In the framework of the European project “CERERE, CEreal REnaissance in Rural Europe: embedding diversity in organic and low-input food systems”, the paper aims at reviewing recent research on alternative and sustainable food systems by adopting an innovative and participatory multi-actor approach; this has involved ten practitioners and twenty-two researchers from across Europe and a variety of technical backgrounds in the paper and analysis stages. The participatory approach is the main innovation and distinctive feature of this literature review. Partners selected indeed what they perceived as most relevant in order to facilitate a transition towards more sustainable and diversity based cereal systems and food chains. This includes issues related to alternative food networks, formal and informal institutional settings, grass root initiatives, consumer involvement and, finally, knowledge exchange and sustainability. The review provides an overview of recent research that is relevant to CERERE partners as well as to anyone interested in alternative and sustainable food systems. The main objective of this paper was indeed to present a narrative of studies, which can form the foundation for future applied research to promote alternative methods of cereal production in Europe. Full article
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Open AccessArticle How Management Factors Influence Weed Communities of Cereals, Their Diversity and Endangered Weed Species in Central Europe
Agriculture 2018, 8(11), 172; https://doi.org/10.3390/agriculture8110172
Received: 20 October 2018 / Revised: 30 October 2018 / Accepted: 31 October 2018 / Published: 2 November 2018
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Abstract
The loss of weed biodiversity in agricultural fields is a global issue that needs to be counteracted to preserve their supported ecosystem services and food webs. Many short-term efforts are undertaken to conserve weed species, especially already endangered ones, but several years after
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The loss of weed biodiversity in agricultural fields is a global issue that needs to be counteracted to preserve their supported ecosystem services and food webs. Many short-term efforts are undertaken to conserve weed species, especially already endangered ones, but several years after expiration, eventually result in species-poor communities. Understanding drivers of community composition is key to prevent biodiversity loss. To understand the factors that shape weed communities and influence weed diversity and endangered weed species, we monitored conventional and organic cereal fields in two regions of southwestern Germany. A redundancy analysis was performed on vegetation recordings and data from a farmer survey. Crop species, herbicide use, farming system, nitrogen, and light availability had the strongest impact on weed diversity. The weed communities were dominated by Alopecurus myosuroides, Galium aparine, Viola arvensis, Polygonum convolvulus, and Veronica persica, and were mainly shaped by crop species, tillage, location in the field, and timing of herbicide application. Bromus grossus and Bromus secalinus, two endangered weed species, survived in conventional field margins as a result of the use of herbicides with gaps for Bromus species. Conservation efforts are not restricted to organic farming and should consider the major drivers of weed communities. Precision farming techniques are available to create networks of habitats for endangered and common weed species and subsequently increase agro-biodiversity per se. Full article
(This article belongs to the Special Issue Weed Management)
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Open AccessArticle Miscanthus Biochar had Limited Effects on Soil Physical Properties, Microbial Biomass, and Grain Yield in a Four-Year Field Experiment in Norway
Agriculture 2018, 8(11), 171; https://doi.org/10.3390/agriculture8110171
Received: 13 August 2018 / Revised: 8 October 2018 / Accepted: 18 October 2018 / Published: 27 October 2018
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Abstract
The application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its utility to improve plant growth and soil quality. In this context, we
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The application of biochar to soils is a promising technique for increasing soil organic C and offsetting GHG emissions. However, large-scale adoption by farmers will likely require the proof of its utility to improve plant growth and soil quality. In this context, we conducted a four-year field experiment between October 2010 to October 2014 on a fertile silty clay loam Albeluvisol in Norway to assess the impact of biochar on soil physical properties, soil microbial biomass, and oat and barley yield. The following treatments were included: Control (soil), miscanthus biochar 8 t C ha−1 (BC8), miscanthus straw feedstock 8 t C ha−1 (MC8), and miscanthus biochar 25 t C ha−1 (BC25). Average volumetric water content at field capacity was significantly higher in BC25 when compared to the control due to changes in BD and total porosity. The biochar amendment had no effect on soil aggregate (2–6 mm) stability, pore size distribution, penetration resistance, soil microbial biomass C and N, and basal respiration. Biochar did not alter crop yields of oat and barley during the four growing seasons. In order to realize biochar’s climate mitigation potential, we suggest future research and development efforts should focus on improving the agronomic utility of biochar in engineered fertilizer and soil amendment products. Full article
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Open AccessArticle Turnover of Minerals and Organics in the Postharvest Herbage of Annuals and Perennials: Winter Wheat and Goldenrod
Agriculture 2018, 8(11), 170; https://doi.org/10.3390/agriculture8110170
Received: 26 September 2018 / Revised: 22 October 2018 / Accepted: 23 October 2018 / Published: 25 October 2018
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Abstract
Crossing annual cereals, legumes, and oilseeds with wild rhizomatous relatives is used to create perennial lines that fruit over 2–3 seasons. Contrary to annual crops, the year-round vegetation cover should contribute to carbon sequestration, soil formation, and root mineral preservation. Soil erosion, nutrient
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Crossing annual cereals, legumes, and oilseeds with wild rhizomatous relatives is used to create perennial lines that fruit over 2–3 seasons. Contrary to annual crops, the year-round vegetation cover should contribute to carbon sequestration, soil formation, and root mineral preservation. Soil erosion, nutrient leaching, and labor expenses may be reduced. While deep-rooted grasses actually inhibit nitrate leaching, advantages in nutrient storage and soil formation are not yet shown. Therefore, the turnover of organics and minerals in the perennial goldenrod was compared with that of winter wheat between blooming and resprouting (28 February) by gravimetry and ICP-MS. From blooming (23 August) to harvest (13 November), goldenrod stalks of 10,070 (given in kg ha−1) lost 23% by dry weight (DW) and released 14.9/9.6/65.7 in NPK and 2193 in water-soluble organics via leaching and root exudation. Apart from a transient rise of 28.8 in N around 13 November, the stubble/rhizome system held CaKMg(N)P stable at a level avoiding metal stress from 23 August to 28 February. Filling seeds in wheat excluded net losses of minerals and organics from anthesis to harvest (23 July). Stubbles (16 cm) and spilt grains of 2890 represented 41.8/2.91/62.5 in NPK and lost 905 in biomass with 25.4/1.8/59.8 in NPK to the soil by 28 February. In wheat-maize rotations, ploughing was avoided until early March. Weeds and seedlings emerged from spilt grains replaced losses in stubble biomass, N, and P but left 40.5 in K unused to the soil. In wheat-wheat rotations, organics and minerals lost by the down-ploughed biomass were replenished by the next-rotation seedlings that left only 18.3 in K to the soil. In summary, off-season goldenrod rhizomes did not store excess minerals. The rate of mineral preservation corresponded with the quantity of the biomass irrespective of its perennial habit. Released water-soluble organics should foster microbial carbon formation and CO2 efflux while soil improving gains in humate C should depend on the lignin content of the decaying annual or perennial biomass. Clues for NPK savings by perennials were not found. Full article
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Open AccessArticle Micronutrient Availability in Alternative Foods During Agricultural Catastrophes
Agriculture 2018, 8(11), 169; https://doi.org/10.3390/agriculture8110169
Received: 22 August 2018 / Revised: 9 October 2018 / Accepted: 23 October 2018 / Published: 25 October 2018
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Abstract
Several catastrophes could block the sun, including asteroid/comet impact, super volcanic eruption, and nuclear war with the burning of cities (nuclear winter). Previous work has analyzed alternate food supplies (e.g., mushrooms growing on dead trees, bacteria growing on natural gas). This was shown
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Several catastrophes could block the sun, including asteroid/comet impact, super volcanic eruption, and nuclear war with the burning of cities (nuclear winter). Previous work has analyzed alternate food supplies (e.g., mushrooms growing on dead trees, bacteria growing on natural gas). This was shown to be technically capable of feeding everyone with macronutrients (protein, carbohydrates, and lipids) and minerals, although economics and politics remain uncertain. The present work analyzes vitamin availability in such alternative food scenarios. The vitamin content of various alternate foods is compared to the US recommended daily allowance (RDA) as well as the average requirement defined by the European Food Safety Authority (EFSA) and insufficiencies of single food sources are discussed. Single alternate food sources are always deficient in some vitamins, and the problems associated with this are discussed. To prevent disease in an alternative food scenario a wide range of foods must be consumed, or the diet must be supplemented. Backup plans discussed include chemical synthesis of vitamins, plants grown with artificial light and growing bacteria rich in certain vitamins. Finally, insights from this analysis are provided for combating existing micronutritional deficiencies using alternative foods today. Full article
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Open AccessReview Sustainability of Urban Agriculture: Vegetable Production on Green Roofs
Agriculture 2018, 8(11), 168; https://doi.org/10.3390/agriculture8110168
Received: 21 September 2018 / Revised: 15 October 2018 / Accepted: 23 October 2018 / Published: 25 October 2018
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Abstract
The practice of producing vegetables on green roofs has been gaining momentum in recent years as a method to facilitate agricultural sustainability in urban areas. Rooftop gardens are becoming an important part of the recent rejuvenation of urban agriculture, and offers alternative spaces
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The practice of producing vegetables on green roofs has been gaining momentum in recent years as a method to facilitate agricultural sustainability in urban areas. Rooftop gardens are becoming an important part of the recent rejuvenation of urban agriculture, and offers alternative spaces to grow vegetable products for urban markets. Green roofs create spaces for the production of vegetable crops, which then generate opportunities for integrating agriculture into urban communities. However, vegetable production activities on rooftops are currently minimal due to multiple challenges that must be overcome before widespread implementation will occur, and these are presented and discussed herein in great detail. Although intensive green roof systems (>15 cm medium depths) are thought to be most suited for vegetable production, the greatest potential for sustained productivity is probably through extensive systems (<15 cm depths) due to weight load restrictions for most buildings. Thus, shallow-rooted vegetables that include important salad greens crops are thought to be the most suited for extensive systems as they can have high productivity with minimal inputs. Research presented herein agree that crops such as lettuce, kale and radish can be produced effectively in an extensive green roof medium with sufficient nutrient and moisture inputs. Other research has indicated that deeper-root crops like tomato can be produced but they will require constant monitoring of fertility and moisture levels. Vegetable production is a definite possibility in urban areas on retrofitted green roofs using minimal growing substrate depths with intensive seasonal maintenance. Rooftop agriculture can improve various ecosystem services, enrich urban biodiversity and reduce food insecurity. Food production provided by green roofs can help support and sustain food for urban communities, as well as provide a unique opportunity to effectively grow food in spaces that are typically unused. The utilization of alternative agricultural production systems, such as green roof technologies, will increase in importance as human populations become more urbanized and urban consumers become more interested in local foods for their families. Although cultivation of food on buildings is a key component to making cities more sustainable and habitable, green roofs are not the total solution to provide food security to cities. They should be viewed more as a supplement to other sources of food production in urban areas. Full article
Open AccessArticle Delineation of Agricultural Drainage Pipe Patterns Using Ground Penetrating Radar Integrated with a Real-Time Kinematic Global Navigation Satellite System
Agriculture 2018, 8(11), 167; https://doi.org/10.3390/agriculture8110167
Received: 18 September 2018 / Revised: 18 October 2018 / Accepted: 19 October 2018 / Published: 24 October 2018
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Abstract
Better methods are needed for mapping agricultural drainage pipe systems. Prior research on small test plots indicates that ground penetrating radar (GPR) is oftentimes capable of detecting buried drainage pipes; however, the feasibility of employing this geophysical technique in larger field areas has
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Better methods are needed for mapping agricultural drainage pipe systems. Prior research on small test plots indicates that ground penetrating radar (GPR) is oftentimes capable of detecting buried drainage pipes; however, the feasibility of employing this geophysical technique in larger field areas has not been adequately evaluated. Ground penetrating radar integrated with a Real-Time Kinematic (RTK) Global Navigation Satellite System (GNSS) may be an effective and efficient means of mapping drain lines within agricultural fields. Therefore, GPR-RTK/GNSS was tested in three agricultural settings; with Site 1 and Site 2 located in Beltsville, MD, USA and Site 3 near Columbus, OH, USA. Soils at the three sites ranged from silty clay loam to loamy sand. A GPR unit with 250 MHz antennas was used to detect drainage pipes, and at Sites 1 and 2, a physical GNSS base station was utilized, while a virtual base station was employed at Site 3. The GPR-RTK/GNSS configurations used in this study delineated a complex rectangular drainage pipe system at Site 1, with one set of drainage pipes oriented southwest-northeast and a second oriented southeast-northwest. At Site 2, a herringbone drain line pattern was outlined, and at Site 3, random drain lines were found. When integrated with RTK/GNSS, spiral or serpentine GPR transects (or spiral/serpentine segments of a GPR transects) were utilized to provide insight on drain line directional trends. Consequently, given suitable field conditions, GPR integrated with RTK/GNSS can be a valuable tool for farmers and drainage contractors needing to map subsurface drainage systems. Full article
(This article belongs to the Special Issue Sensors Application in Agriculture)
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Open AccessArticle Relationship of Salinity Tolerance to Na+ Exclusion, Proline Accumulation, and Antioxidant Enzyme Activity in Rice Seedlings
Agriculture 2018, 8(11), 166; https://doi.org/10.3390/agriculture8110166
Received: 31 August 2018 / Revised: 17 October 2018 / Accepted: 18 October 2018 / Published: 23 October 2018
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Abstract
Rice is a staple crop for over 50% of the world’s population, but its sensitivity to salinity poses a threat to meeting the worldwide demand. This study investigated the correlation of salinity tolerance to Na+ exclusion, proline accumulation, and the activity of
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Rice is a staple crop for over 50% of the world’s population, but its sensitivity to salinity poses a threat to meeting the worldwide demand. This study investigated the correlation of salinity tolerance to Na+ exclusion, proline accumulation, and the activity of antioxidant enzymes in some rice cultivars originating from Egypt. Giza 182 was shown to be the most tolerant of the five cultivars, as judged by visual symptoms of salt injury, growth parameters, and patterns of Na+ accumulation, while Sakha 105 appeared to be highly susceptible. In detail, Giza 182 accumulated the lowest Na+ concentration and maintained a much lower Na+/K+ ratio in all plant organs in comparison to Sakha 105. The salinity-tolerant varieties had higher accumulation of proline than the salinity-susceptible cultivars. The salinity-tolerant Giza 182 accumulated a higher concentration of proline, but the lipid peroxidation (MDA) level was significantly reduced compared to in the salinity-susceptible Sakha 105. In addition, Giza 182 had stronger activity of both catalase (CAT) and ascorbate peroxidase (APX) compared to Sakha 105. The findings of this study reveal that the salinity tolerance in rice is primarily attributable to Na+ exclusion, the accumulation of proline in rice organs, a low Na+/K+ ratio, and a low level of lipid peroxidation. The levels of the antioxidant enzymes CAT and APX and the accumulation of proline may play important roles in salinity tolerance in rice. However, the comparative involvement of individual antioxidant enzymes in salinity stress in rice should be further investigated. Giza 182 has the potential to be cultivated in salinity-affected areas, although the effects of salinity stress on its grain yield and quality should be evaluated during the full crop cycle. Full article
(This article belongs to the Special Issue Response and Tolerance of Agricultural Crops to Salinity Stress)
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