731 resultados para cropping
Resumo:
The supply side of the food security engine is the way we farm. The current engine of conventional tillage farming is faltering and needs to be replaced. This presentation will address supply side issues of agriculture to meet future agricultural demands for food and industry using the alternate no-till Conservation Agriculture (CA) paradigm (involving no-till farming with mulch soil cover and diversified cropping) that is able to raise productivity sustainably and efficiently, reduce inputs, regenerate degraded land, minimise soil erosion, and harness the flow of ecosystem services. CA is an ecosystems approach to farming capable of enhancing not only the economic and environmental performance of crop production and land management, but also promotes a mindset change for producing ‘more from less’, the key attitude towards sustainable production intensification. CA is now spreading globally in all continents at an annual rate of 10 Mha and covers some 157 Mha of cropland. Today global agriculture produces enough food to feed three times the current population of 7.21 billion. In 1976, when the world population was 4.15 billion, world food production far exceeded the amount necessary to feed that population. However, our urban and industrialised lifestyle leads to wastage of food of some 30%-40%, as well as waste of enormous amount of energy and protein while transforming crop-based food into animal-derived food; we have a higher proportion of people than ever before who are obese; we continue to degrade our ecosystems including much of our agricultural land of which some 400 Mha is reported to be abandoned due to severe soil and land degradation; and yields of staple cereals appear to have stagnated. These are signs of unsustainability at the structural level in the society, and it is at the structural level, for both supply side and demand side, that we need transformed mind sets about production, consumption and distribution. CA not only provides the possibility of increased crop yields for the low input smallholder farmer, it also provides a pro-poor rural and agricultural development model to support agricultural intensification in an affordable manner. For the high output farmer, it offers greater efficiency (productivity) and profit, resilience and stewardship. For farming anywhere, it addresses the root causes of agricultural land degradation, sub-optimal ecological crop and land potentials or yield ceilings, and poor crop phenotypic expressions or yield gaps. As national economies expand and diversify, more people become integrated into the economy and are able to access food. However, for those whose livelihoods continue to depend on agriculture to feed themselves and the rest of the world population, the challenge is for agriculture to produce the needed food and raw material for industry with minimum harm to the environment and the society, and to produce it with maximum efficiency and resilience against abiotic and biotic stresses, including those arising from climate change. There is growing empirical and scientific evidence worldwide that the future global supplies of food and agricultural raw materials can be assured sustainably at much lower environmental and economic cost by shifting away from conventional tillage-based food and agriculture systems to no-till CA-based food and agriculture systems. To achieve this goal will require effective national and global policy and institutional support (including research and education).
Resumo:
Soil acidity and low natural fertility are the main limiting factors for grain production in tropical regionssuch as the Brazilian Cerrado. The application of lime to the surface of no-till soil can improve plant nutrition, dry matter production, crop yields and revenue. The present study, conducted at the Lageado Experimental Farm in Botucatu, State of São Paulo, Brazil, is part of an ongoing research project initi-ated in 2002 to evaluate the long-term effects of the surface application of lime on the soil?s chemical attributes, nutrition and kernel/grain yield of peanut (Arachis hypogaea), white oat (Avena sativa L.) and maize (Zea mays L.) inter cropped with palisade grass (Urochloa brizantha cv. Marandu), as well as the forage dry matter yield of palisade grass in winter/spring, its crude protein concentration, estimated meat production, and revenue in a tropical region with a dry winter during four growing seasons. The experiment was designed in randomized blocks with four replications. The treatments consisted of four rates of lime application (0, 1000, 2000 and 4000 kg ha−1), performed in November 2004. The surface application of limestone to the studied tropical no-till soil was efficient in reducing soil acidity from the surface down to a depth of 0.60 m and resulted in greater availability of P and K at the soil surface. Ca and Mg availability in the soil also increased with the lime application rate, up to a depth of 0.60 m. Nutrient absorption was enhanced with liming, especially regarding the nutrient uptake of K, Ca and Mg by plants.Significant increases in the yield components and kernel/grain yields of peanut, white oat and maize were obtained through the surface application of limestone. The lime rates estimated to achieve the maximum grain yield, especially in white oat and maize, were very close to the rates necessary to increase the base saturation of a soil sample collected at a depth of 0?0.20 m to 70%, indicating that the surface liming of 2000 kg ha−1is effective for the studied tropical no-till soil. This lime rate also increases the forage dry matter yield, crude protein concentration and estimated meat production during winter/spring in the maize-palisade grass inter cropping, provides the highest total and mean net profit during the four growing seasons, and can improve the long-term sustainability of tropical agriculture in the Brazilian Cerrado.
Resumo:
Landfill leachates carry nutrients, especially N and K, which can be recycled in cropping systems. We applied doses of landfill leachate (0 [Control], 32.7, 65.4, 98.1, and 130.8 m3 ha-1 ) three times in 2008 and three times in 2009 on a clay Rhodic Kandiudult soil. In 2009, black oat (Avena strigosa L.) and corn (Zea mays L.) were cropped in succession and assessed for concentration of nutrients in leaves and for shoot biomass and grain yield, respectively. As a positive control, an additional treatment with urea (120 kg ha-1 of N) was studied in corn. Soil was sampled at four depths (down to 60 cm) in three sampling dates to assess chemical and biochemical properties. Concentration of nutrients in leaves, oat biomass (8530?23,240 kg ha-1), and corn grain yield (4703-8807 kg ha-1 ) increased with increasing doses of leachate. There was a transient increase in the concentration of nitrate in soil (3-30 mg kg-1), increasing the risk of N losses by leaching at doses above 120 kg ha-1 N, as revealed by an estimated N balance in the cropping system. Sodium and K in soil also increased with increasing doses of leachate but decreased as rainfall occurred. The activity of dehydrogenase decreased about 30% from the control to the highest dose of leachate and urea, suggesting an inhibitory effect of mineral N on microbial metabolism. Landfill leachate was promising as a source of N and K for crop productivity and caused minor or transient effects on soil properties.
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O objetivo deste trabalho foi avaliar a produtividade de grãos de milho cultivado na 2ª safra em função da consorciação com espécies de Brachiaria e aplicação de N em cobertura.
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Water is one of the most important factors influencing crop production in rainfed cropping systems. In tropical regions, supplemental irrigation reduces the risk of yield losses associated to water deficit due to insufficient rainfall. Water deficit in regions with irregularities in rainfall may be overcome with the use of supplemental irrigation, a technique based on the application of water at amounts below the crop?s evapotranspiration (ETc). We investigated the potential of supplemental irrigation as a strategy to increase yield of maize grown under tropical conditions. We used the CSM-CERES-Maize model of the Decision Support System for Agrotechnology Transfer (DSSAT) to simulate irrigation strategies of maize in six counties in the state of Minas Gerais, Brazil. Our results indicate significant differences on simulated crop yield in response to supplemental irrigation. As a consequence, water productivity was improved with reductions of 10% and 15% of full irrigation depths in one of the six counties while in two the water productivity was higher when full irrigation was applied.
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The continuous soybean-maize crop succession in the tropical region of Brazil has led to significant increases in the population size of root-knot (Meloidogyne incognita and M. javanica ) and root-lesion nematodes (Pratylenchus brachyurus), which make soils unsuitable for soybean cropping. A greenhouse study was conducted to identify sunflower genotypes adapted to the tropical region of Brazil and that are resistant to M. incognita, M. javanica and/or P. brachyurus . Two experiments for each nematode were conducted in a completely randomized design with six replicates. Gall index was calculated from visual scores (0?5) of gall intensity on roots for the root-knot nematode. Initial and final population density and reproduction factor were also measured for each nematode. Sunflower genotypes varied in resistance to the nematodes. Sunflower hybrids BRS 321 and BRS 323 were resistant to M. javanica and P. brachyurus and exhibited low gall index for M. incognita . The cultivars are good alternatives to using in the succession of soybean in nematode-infested areas of the tropical regions of Brazil. No sunflower genotype was identified as resistant to M. incognita and thus sunflower cropping is not indicated in areas infested with this nematode.
Resumo:
Research networks provide a framework for review, synthesis and systematic testing of theories by multiple scientists across international borders critical for addressing global-scale issues. In 2012, a GHG research network referred to as MAGGnet (Managing Agricultural Greenhouse Gases Network) was established within the Croplands Research Group of the Global Research Alliance on Agricultural Greenhouse Gases (GRA). With involvement from 46 alliance member countries, MAGGnet seeks to provide a platform for the inventory and analysis of agricultural GHG mitigation research throughout the world. To date, metadata from 315 experimental studies in 20 countries have been compiled using a standardized spreadsheet. Most studies were completed (74%) and conducted within a 1-3-year duration (68%). Soil carbon and nitrous oxide emissions were measured in over 80% of the studies. Among plant variables, grain yield was assessed across studies most frequently (56%), followed by stover (35%) and root (9%) biomass. MAGGnet has contributed to modeling efforts and has spurred other research groups in the GRA to collect experimental site metadata using an adapted spreadsheet. With continued growth and investment, MAGGnet will leverage limited-resource investments by any one country to produce an inclusive, globally shared meta-database focused on the science of GHG mitigation.
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Wheat amylase-trypsin inhibitors (ATIs) are a family of wheat proteins, which play an important role in plant defence against pest attacks. ATIs are also of great interest for their impact on human health and recently ATIs have been identified as major stimulators of innate immune cells. In this study, ten selected wheat samples with different ploidy level and year of release were used for the agronomic trial, for in vitro enzymatic assays and for ATIs gene sequencing. Wheat samples were grown under organic farming management during three consecutive cropping years at two growing areas (Italy and USA). The PCA analysis performed on the deduced amino acid sequences of four representative ATIs genes (WMAI, WDAI, WTAI-CM3, CMx) evidenced that the ten wheat varieties can be differentiated on the basis of their ploidy level, but not with respect to ancient or recently developed wheat genotypes. The results from in vitro alpha-amylase and trypsin inhibitory activities showed high variability among the ten wheat genotypes and the contribution of the genotype and the cropping year was significant for both inhibitory activities. The hexaploid wheat genotypes showed the highest inhibitory activities. Einkorn showed a very low or even absent alpha-amylase inhibitory activity and the highest trypsin inhibitory activity. It was not possible to differentiate ancient and recently developed wheat genotypes on the basis of their ATIs activity. The weather conditions differently affected the two inhibitory activities. In both cultivation areas, higher precipitation and lower high mean temperatures correlated with lower alpha-amylase inhibitory activities, while there were different correlations considering trypsin inhibitory activity for the two growing areas. The protein content negatively correlated with both inhibitory activities in USA and Italy. This information can be important in the understanding of plant defence mechanisms in relation to the effect of both genotype and abiotic and biotic stress.
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Two-year field trials were conducted in northern Italy with the aim of developing a trapcrop-based agroecological approach for the control of flea beetles (Chaetocnema tibialis (Illiger), Phyllotreta spp. (Chevrolat) (Coleoptera: Chrysomelidae)) and Lygus rugulipennis Poppius (Hemiptera: Miridae), key pests of sugar beet and lettuce, respectively. Flea beetle damage trials compared a trap cropping treatment, i.e., a sugar beet plot with a border of Sinapis alba (L.) and Brassica juncea (L.) with a control treatment, i.e., a sugar beet plot with bare soil as field border. Sugar beets grown near trap crops showed a significant decrease (≈40%) in flea beetle damage compared to control. Moreover, flea beetle damage varied with distance from the edge of the trap plants, being highest at 2 m from the edge, then decreasing at higher distances. Regarding L. rugulipennis on lettuce two experiments were conducted. A semiochemical-assisted trap cropping trial was supported by another test evaluating the efficacy of pheromones and trap placement. In this trial, it was found that pheromone baited traps caught significantly more specimens of L. rugulipennis than unbaited traps. It was also found that traps placed at ground level produced larger catches than traps placed at the height of 70 cm. In the semiochemical-assisted trap cropping experiment, a treatment where lettuce was grown next to two Alfa-Alfa borders containing pheromone baited traps was compared with a control treatment, where lettuce was grown near bare soil. This experiment showed that the above-mentioned strategy managed to reduce L. rugulipennis damage to lettuce by ≈30%. From these studies, it appears that trap crop-based strategy, alone or with baited traps, made it possible to reduce crop damage to economically acceptable levels and to minimize the need for insecticide treatments, showing that those strategy could be implemented in organic farming as a means of controlling insect pests.
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In Europe, the current demand for vegetable oils and the need to find alternative crops for the regions most affected by climate change (i.e., Mediterranean basin) may be a launchpad for camelina [Camelina sativa (L.) Crantz] to be steadily introduced in European cropping systems. Camelina is mainly known for the unique composition of its oil, with a fatty acids profile including more than 50% content of essential linoleic and linolenic fatty acids, and a high tocopherol content. Being tocopherols part of the vitamin E family of antioxidants, the added value of growing camelina in harsh environments could be the enhancement of tocopherol content in camelina oil, thus having a more stable and nutritionally valuable product. With the final purpose of fully valorize camelina as a tolerant, valuable-oil producing crop for the Mediterranean basin, the main aim of this study was to investigate whether and how sowing date, cultivar choice, and abiotic stresses can affect tocopherol content and composition in camelina oil. The results showed that cultivar choice and growing conditions influenced total tocopherol, γ-tocopherol, and α-tocopherol contents. Moreover, heat stress trial revealed that high temperature increased α-tocopherol content, while no effect was observed in total tocopherols and in γ-tocopherol content. Finally, drought increased total tocopherols in camelina, and in drought-sensitive lines an increase in α-tocopherol was observed. This study allowed to acquire awareness on camelina resistance to abiotic stresses, coupled with a better knowledge on tocopherol content and composition in relation to cultivar, sowing date, and abiotic stresses. This will have an impact for the introduction of camelina as an alternative crop in harsher environments, such as the Mediterranean basin, to produce an oil suitable for food, feed, and industrial applications.
Resumo:
Description of the development of a product able to deliver an autonomous page construction from a predefined plan. The processes involve Machine Learning techniques for text fitting on shapes, Beam Search for associations and Deep Learning for autonomous cropping of images.