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Effect of irrigation and nitrogen fertilization on the production of biogas from maize and sorghum in a water limited environment

The expansion of biogas feedstock cultivation may affect a number of ecosystem processes and ecosystem services, and temporal and spatial dimensions of its environmental impact are subject to a critical debate. However, there are hardly any comprehensive studies available on the impact of biogas feedstock production on the different components of nitrogen (N) balance. The objectives of the current study were (i) to investigate the short-term effects of crop substrate cultivation on the N flows in terms of a N balance and its components (N fertilization, N deposition, N leaching, NH₃ emission, N₂O emission, N recovery in harvested product) for different cropping systems, N fertilizer types and a wide range of N rate, and (ii) to quantify the N footprint of feedstock production in terms of potential N loss per unit of methane produced. In 2007/08 and 2008/09, two field experiments were conducted at two sites in Northern Germany differing in soil quality, where continuous maize (R1), maize–whole crop wheat followed by Italian ryegrass as a double crop (R2), and maize–grain wheat followed by mustard as a catch crop (R3) were grown on Site 1 (sandy loam), and R1 and a perennial ryegrass ley (R4) at Site 2 (sandy soil rich in organic matter). Crops were supplied with varying amounts of N (0–360 kg N ha⁻¹, ryegrass: 0–480 kg N ha⁻¹) supplied as biogas digestate, cattle slurry, pig slurry or calcium-ammonium nitrate (CAN).Mineral-N fertilization of maize-based rotations resulted in negative N balances at N input for maximum yield (Nopt), with R2 having slightly less negative balances than R1 and R3. In contrast, N balances were close to zero for cattle slurry or digestate treatments. Thus, trade-offs between substrate feedstock production and changes of soil organic matter stocks have to be taken into consideration when evaluating biogas production systems. Nitrogen losses were generally dominated by N leaching, whereas for the organically fertilized perennial ryegrass ley the ammonia emission accounted for the largest proportion. Nitrogen balance of the ryegrass ley at Nopt was close to zero (CAN) or highly positive (cattle slurry, digestate). Nitrogen footprint (NFP) was applied as an eco-efficiency measure of N-loss potential (difference of N input and N recovery) related to the unit methane produced. NFP ranged between −11 and +6 kg N per 1000 m³ methane at Nopt for maize-based rotations, without a significant impact of cropping system or N fertilizer type. However, for perennial ryegrass ley, NFP increased up to 65 kg N per 1000 m³. The loose relation between NFP and observed N losses suggests only limited suitability for NFP. 相似文献

Crop and cattle production responses to tillage and cover crop management in an integrated crop–livestock system in the southeastern USA

The expansion of biogas production from anaerobic digestion in the Po Valley (Northern Italy) has stimulated the cultivation of dedicated biomass crops, and maize in particular. A mid-term experiment was carried out from 2006 to 2010 on a silt loamy soil in Northern Italy to compare water use and energy efficiency of maize and sorghum cultivation under rain fed and well-watered treatments and at two rates of nitrogen fertilization. The present work hypothesis were: (i) biomass sorghum, for its efficient use of water and nitrogen, could be a valuable alternative to maize for biogas production; (ii) reduction of irrigation level and (iii) application of low nitrogen fertilizer rate increase the efficiency of bioenergy production. Water treatments, a rain fed control (I0) and two irrigation levels (I1 and I2; only one in 2006 and 2009), were compared in a split–split plot design with four replicates. Two fertilizer rates were also tested: low (N1, 60 kg ha⁻¹ of nitrogen; 0 kg ha⁻¹ of nitrogen in 2010) and high (N2, 120 kg ha⁻¹ of nitrogen; 100 kg ha⁻¹ of nitrogen in 2010). Across treatments, sorghum produced more aboveground biomass than maize, respectively 21.6 Mg ha⁻¹ and 16.8 Mg ha⁻¹ (p < 0.01). In both species, biomass yield was lower in I0 than in I1 and I2 (p < 0.01), while I1 and I2 did differ significantly. Nitrogen level never affected biomass yield. Water use efficiency was generally higher in sorghum (52 kg ha⁻¹ mm⁻¹) than in maize (38 kg ha⁻¹ mm⁻¹); the significant interaction between crop and irrigation revealed that water use efficiency did not differ across water levels in sorghum, whereas it significantly increased from I0 and I1 to I2 in maize (p < 0.01). The potential methane production was similar in maize and sorghum, while it was significantly lower in I0 (16505 MJ ha⁻¹) than in I1 and I2 (21700 MJ ha⁻¹). The only significant effect of nitrogen fertilization was found in the calculation of energy efficiency (ratio of energy output and input) that was higher in N1 than in N2 (p < 0.01). These results support the hypothesis that (i) sorghum should be cultivated rather than maize to increase energy efficiency, (ii) irrigation level should replace up to 36% of ETr and (iii) nitrogen fertilizer rate should be minimized to maximize the efficiency in biomass production for anaerobic digestion in the Po Valley. 相似文献

Maize yield and water balance is affected by nitrogen application in a film-mulching ridge–furrow system in a semiarid region of China

Integrated crop–livestock systems can help achieve greater environmental quality from disparate crop and livestock systems by recycling nutrients and taking advantage of synergies between systems. We investigated crop and animal production responses in integrated crop–livestock systems with two types of winter cover cropping (legume-derived N and inorganic fertilizer N), two types of tillage [conventional disk (CT) and no tillage (NT)], and whether cover crops were grazed by cow/calf pairs or not. The 13-ha field study was a modification of a previous factorial experiment with four replications on Ultisols in Georgia, USA. Recurring summer drought severely limited corn and soybean production during all three years. Type of cover crop had little influence and grazing of cover crops had minor influence on crop production characteristics. Cattle gain from grazing of winter cover crops added a stable component to production. No-tillage management had large positive effects on corn grain (95 vs. 252 g m⁻² under CT and NT, respectively) and stover (305 vs. 385 g m⁻²) production, as well as on soybean grain (147 vs. 219 g m⁻²) and stover (253 vs. 375 g m⁻²) production, but little overall effect on winter wheat grain (292 g m⁻²) and stover (401 g m⁻²) production. Our results suggest that robust, diversified crop–livestock systems can be developed for impoverished soils of the southeastern USA, especially when managed under no tillage to control environmental quality and improve resistance of crops to drought. 相似文献

Quantifying production potentials of winter wheat in the North China Plain

《European Journal of Agronomy》2006,24(3):226-235

The North China Plain (NCP) is one of the major winter wheat (Triticum aestivum L.) producing areas in China. Current wheat yields in the NCP stabilize around 5 Mg ha⁻¹ while the demand for wheat in China is growing due to the increase in population and the change in diet. Since options for area expansion of winter wheat are limited, the production per unit of area need to be increased. The objective of this study is to quantify the production potential of winter wheat in the NCP taking into account the spatial and temporal variability caused by climate. We use a calibrated crop growth simulation model to quantify wheat yields for potential and water-limited production situations using 40 years of weather data from 32 meteorological stations in the NCP. Simulation results are linked to a Geographic Information System (GIS) facilitating their presentation and contributing to the identification of hotspots for interventions aimed at yield improvements. In the northern part of the NCP, average simulated potential yields of winter wheat go up to 9.7 Mg ha⁻¹, while average water-limited yields only reach 3 Mg ha⁻¹. In the southern part of the NCP, both average potential and water-limited yields are about 7.5 Mg ha⁻¹. Rainfall is the limiting factor to winter wheat yields in the northern part of the NCP, while in the southern part, the joint effect of low radiation and high temperature are major limiting factors. Temporal variation in potential yields throughout the NCP is low in contrast with the temporal variation in water-limited yields, which is especially great in the northern part. The study calls for the collection of location-specific and disaggregated irrigated and rainfed wheat yield statistics in the NCP facilitating the identification of hotspots for improvement of current wheat yields. 相似文献

Forage production,quality and water-use-efficiency of four warm-season annual crops at three sowing times in the Loess Plateau region of China

Poor soil and drought stress are common in semiarid areas of China, but maize has a high demand for nitrogen (N) and water. Maize production using the technique of double ridges and furrows mulched with plastic film are being rapidly adopted due to significant increases in yield and water use efficiency (WUE) in these areas. This paper studied N use and water balance of maize crops under double ridges and furrows mulched with plastic-film systems in a semiarid environment over four growing seasons from 2007 to 2010. To improve precipitation storage in the non-growing season, the whole-year plastic-film mulching technique was used. There were six treatments which had 0, 70, 140, 280, 420 or 560 kg N ha⁻¹ applied in every year for maize. In April 2011, spring wheat was planted in flat plots without fertilizer or mulch following four years of maize cultivation. After four years, all treatments not only maintained soil water balance in the 0–200 cm soil layer but soil water content also increased in the 0–160 cm soil layer compared to values before maize sowing in April 2007. However, under similar precipitation and only one season of spring wheat, soil water content in the 0–160 cm soil layer sharply decreased in all treatments compared to values before sowing in April 2011. Over the four years of maize cultivation, average yield in all treatments ranged from 4071 to 6676 kg ha⁻¹ and WUE ranged from 18.2 to 28.2 kg ha⁻¹ mm⁻¹. In 2011, the yield of spring wheat in all treatments ranged from 763 to 1260 kg ha⁻¹ and WUE from 3.5 to 6.5 kg ha⁻¹ mm⁻¹. The potential maximum grain yield for maize was 6784 kg ha⁻¹ with 360 kg N ha⁻¹ applied for four years, but considerable NO₃N accumulated in the soil profile. A lesser application (110 kg N ha⁻¹) to this tillage system yielded in 82% of the maximum, increased nitrogen use efficiency and mitigated the risk of nitrogen loss from the system. This study suggests that double ridge–furrow and whole-year plastic-film mulching could sustain high grain yields in maize with approximately 110 kg N ha⁻¹ and maintain soil water balance when annual precipitation is >273 mm in this semiarid environment. 相似文献

Increasing demand for livestock products is driving development of livestock systems worldwide. That requires improved and new forage production options. The Loess Plateau region in central-northern China is an important area for livestock production, as it supports11% and 19% of the country’s cattle and sheep, respectively (China statistical yearbook 2014). The rain-fed semi-arid environment of the Loess Plateau means that maximizing the water-use-efficiency (WUE) of forage production is vital to guarantee enough fodder supply the livestock demand. A three-year field experiment in north-west Loess Plateau compared forage production, water use and water-use-efficiency as well as crude protein (CP) content of forage maize, Sudan grass, foxtail millet and Japanese millet sown at three sowing dates according to the opening rain during 2011–2013. On average, forage maize produced the highest biomass (12.1 t ha⁻¹) and had the highest WUE (43.4 kg DM ha⁻¹ mm⁻¹). This was followed by Sudan grass (7.8 t ha⁻¹; 26.5 kg DM ha⁻¹ mm⁻¹), Japanese millet (6.7 t ha⁻¹; 26.2 kg DM ha⁻¹ mm⁻¹) and foxtail millet (6.7 t ha⁻¹; 24.6 kg DM ha⁻¹ mm⁻¹). Optimizing sowing date played an important role in maximizing forage production and WUE of all tested forages. Compared to the earliest sowing date, a delay of two weeks reduced forage production by 17% in maize, 35% in foxtail millet, and 16% in Japanese millet. A delay of four to six weeks reduced biomass yield by 58% in maize, 57% in foxtail millet, and 56% in Japanese millet. Late sowing also greatly reduced WUE of forage maize and foxtail millet by 33% and 42%, respectively, when compared to early sowing. The middle sowing date maximized forage production and WUE of Sudan grass in two of the three growing seasons, which was 20% and 38% higher than the early and late sowing, respectively. Late sowing in all forages reduced crop water use by 42–57 mm compared to the early sowing. Among four test crops, CP of Sudan grass (7.9%) and forage maize (7.7%) was higher than foxtail millet (6.8%) and Japanese millet (6.7%). Compared with early sowing, CP_f in late sowing significantly increased in Sudan grass and decreased in Japanese millet, in contrast, no evident sowing date effect was found in forage maize and foxtail millet. This study showed that all four warm-season annual grasses had high forage production potential, forage maize was the most reliable and efficient option. Forage maize and the millets could easily be integrated into existing cropping systems and provide opportunities as both grain and forage-producing crop to provide added flexibility for farmers. 相似文献

Energy of biomass sorghum irrigated with reclaimed wastewaters

Impact analysis of climate data aggregation at different spatial scales on simulated net primary productivity for croplands

The sustainability of biomass sorghum (Sorghum bicolor L. Moench) in the Mediterranean environments is linked to the potential to increasing the crop productivity using irrigation water of different qualities: fresh and wastewater. An experiment was conducted in Southern Italy during 2012 and 2013 growing seasons to determine the biomass production and to estimate the yielded energy from sorghum irrigated with fresh water and municipal wastewaters. Two stages of wastewater reclamation process were compared: tertiary and secondary treatments.During the growing seasons, the crop growth (biomass and LAI) was surveyed on sorghum crops irrigated with three water qualities. In order to determine the effects of the irrigation water qualities on the final energy yielded, on the harvested biomass, structural components (cellulose, hemicellulose and lignin contents for deriving the ethanol production) and high heating value were analyzed. The data obtained during two crop seasons showed that, sorghum irrigated with municipal wastewater plant produced more dry biomass (23.3 vs 20.3 t ha⁻¹), energy yield (383 vs 335 GJ ha⁻¹), and ethanol (6824 vs 6092 L ha⁻¹) than sorghum biomass with fresh water. As a consequence, the water efficiency for producing bioenergy increased when the waste waters were supplied in substitution of fresh waters. Different indices were calculated for comparing the effect of the water quality on the water use efficiency (WUE) of biomass sorghum crops. 相似文献

Maize response to broadcast flaming at different growth stages: Effects on growth,yield and yield components

For spatial crop and agro-systems modelling, there is often a discrepancy between the scale of measured driving data and the target resolution. Spatial data aggregation is often necessary, which can introduce additional uncertainty into the simulation results. Previous studies have shown that climate data aggregation has little effect on simulation of phenological stages, but effects on net primary production (NPP) might still be expected through changing the length of the growing season and the period of grain filling. This study investigates the impact of spatial climate data aggregation on NPP simulation results, applying eleven different models for the same study region (∼34,000 km²), situated in Western Germany. To isolate effects of climate, soil data and management were assumed to be constant over the entire study area and over the entire study period of 29 years. Two crops, winter wheat and silage maize, were tested as monocultures. Compared to the impact of climate data aggregation on yield, the effect on NPP is in a similar range, but is slightly lower, with only small impacts on averages over the entire simulation period and study region. Maximum differences between the five scales in the range of 1–100 km grid cells show changes of 0.4–7.8% and 0.0–4.8% for wheat and maize, respectively, whereas the simulated potential NPP averages of the models show a wide range (1.9–4.2 g C m⁻² d⁻¹ and 2.7–6.1 g C m⁻² d⁻¹ for wheat and maize, respectively). The impact of the spatial aggregation was also tested for shorter time periods, to see if impacts over shorter periods attenuate over longer periods. The results show larger impacts for single years (up to 9.4% for wheat and up to 13.6% for maize). An analysis of extreme weather conditions shows an aggregation effect in vulnerability up to 12.8% and 15.5% between the different resolutions for wheat and maize, respectively. Simulations of NPP averages over larger areas (e.g. regional scale) and longer time periods (several years) are relatively insensitive to climate data aggregation. However, the scale of climate data is more relevant for impacts on annual averages of NPP or if the period is strongly affected or dominated by drought stress. There should be an awareness of the greater uncertainty for the NPP values in these situations if data are not available at high resolution. On the other hand, the results suggest that there is no need to simulate at high resolution for long term regional NPP averages based on the simplified assumptions (soil and management constant in time and space) used in this study. 相似文献

10.

Santiago M. Ulloa Avishek Datta Chris Bruening Brian Neilson Jared Miller George Gogos Stevan Z. Knezevic 《European Journal of Agronomy》2011,34(1):10-19

Weed management is a major constraint in organic crop production. Propane flaming could be an additional tool for weed control in organic maize (Zea mays L.) production. However, tolerance of maize to broadcast flaming must be determined first to optimize the use of propane. Field experiments were conducted at the Haskell Agricultural Laboratory of the University of Nebraska, Concord, NE in 2008 and 2009 to determine maize response to five propane doses applied at three growth stages of V2 (2-leaf), V5 (5-leaf) and V7 (7-leaf). The propane doses tested were 0, 13, 24, 44 and 85 kg ha^?1. Flaming treatments were applied utilizing a custom built research flamer mounted on the back of a four-wheeler moving at a constant speed of 6.4 km h^?1. The response of maize to propane flaming was evaluated in terms of visual crop injury (1, 7, 14 and 28 days after treatment—DAT), effects on dry matter (14 DAT), yield components (plants m^?2, ears plant^?1, kernels cob^?1 and 1000-kernel weight) and grain yield. The response of different growth stages of maize to propane doses was described by log–logistic models. Overall, maize response to broadcast flaming varied among growth stages and propane doses. In general, maize at V5 was the most tolerant stage for broadcast flaming, whereas V2 stage was the most susceptible to flaming resulting in the highest visual crop injury ratings, dry matter reductions and the largest loss of yield and its components. At 28 DAT, the maximum visual crop injury rating of 7% was estimated for flaming done at V5 stage compared to significantly higher injuries of 43% and 12% for V2 and V7 growth stages, respectively. An arbitrarily assigned 2.5% yield reduction was evident with 33, 16 and 11 kg ha^?1 of propane for V5, V2 and V7 growth stages, respectively, suggesting that maize flamed at V5 stage can tolerate higher dose of propane for the same yield reduction compared to other growth stages. Moreover, the maximum yield reductions with the highest propane dose of 85 kg ha^?1 were 3% for V5, 11% for V7 and 17% for V2 stage. Based on these results, flaming has a potential to be used effectively in organic maize production when conducted properly at V5 stage. However, there are both benefits and concerns associated with the use of flame weeding. The preservation of the soil from erosion and the protection of the surface and underground water from chemical pollution can be seen as benefits, while the concerns include higher energy use, and the release of greenhouse gasses. 相似文献

11.

An analysis of agricultural sustainability of cropping systems in arable and dairy farms in an intensively cultivated plain

Mattia Fumagalli Marco Acutis Fabrizio Mazzetto Francesco Vidotto Guido Sali Luca Bechini 《European Journal of Agronomy》2011,34(2):71-82

In Lombardy region (northern Italy) agricultural systems are mostly based on cereals and forage crops, and are normally intensively cultivated. To monitor and analyse the most important agri-environmental issue of this area (water pollution by nitrates and plant protection products, non-renewable fossil energy exploitation, weed dynamics), we conducted an integrated agronomic, environmental and economic assessment of arable and dairy farming using indicators.The structural and management data about farming and cropping systems were collected by periodic interviews over a 3-year period in seven (three arable and four dairy) representative farms.The nitrogen surplus calculated at field scale ranged from low (27 kg N ha^?1) to high (339 kg N ha^?1) values, depending by the amount of chemical and organic fertilisers applied. Fossil inputs ranged from 11.2 to 46.0 GJ ha^?1; the highest values were due to the high use of machinery and chemical inputs. The efficiency factor in energy transformation (an indicator of the dependence of food and feed production on non-renewable energy) ranged from 5.0 to 12.2. Large variability was also observed for economic performance (gross margin; from -364 to 1078 € ha^?1). The lowest values were observed where the total costs of production (fixed and variable) were elevated. The simplification of cropping systems was responsible for a high probability of weed populations development. The values of Load Index, an indicator describing the potential toxicity of plant protection products on non-target organisms, showed an elevated use of active substances due to the dominance of maize.The indicator-based assessment, founded on a relatively simple data collection procedure, described crop management by combining different aspects into few quantities and highlighted its critical environmental issues. The work represents a starting point for improving cropping system management in the study area; the same procedure could be re-applied if data about improved management scenarios were available. 相似文献

12.

Attainable yield achieved for plastic film-mulched maize in response to nitrogen deficit

Impact of tillage and mulch management on economics,energy requirement and crop performance in maize–wheat rotation in rainfed subhumid inceptisols,India

Nitrogen (N) stress limits the yields of maize (Zea mays L.) that have been plastic film-mulched in northwest China. Using the tested Hybrid-Maize simulation model, which was combined with field experiments using four levels of N fertilisers (0, 100, 250 and 400 kg N ha⁻¹), we aimed to understand the variability of the attainable yield in response to N stress under plastic film mulching. We show that the application of N250 or N400 results in 100% simulated potential LAI, which is, thus, close to 100% of the simulated potential of both biomass and grain yield. However, N stress treatments significantly decreased the biomass and grain yields, achieving only 40–50% of the simulated potential (N0 treatment) and 70–80% of the simulated potential (N100 treatment). Growth dynamic measurements showed that N stress significantly decreased the LAI, delaying the source capacity growth (canopies) around the silking stage and resulting in lower final kernel numbers. The lower LAI resulted in decreased dry matter accumulation and allocation during the reproductive stage; this decrease led to a decrease in the kernel growth rate and in the grain filling duration, which resulted in a significantly lower kernel weight. This knowledge could be helpful for the optimisation of N management to close the yield gaps of dryland maize in semi-arid monsoon climate regions. 相似文献

13.

Peeyush Sharma Vikas Abrol R.K. Sharma 《European Journal of Agronomy》2011,34(1):46-51

Different tillage systems (conventional, minimum, raised bed and no tillage) and four mulch levels (control, polythene, straw and soil) were compared in maize (Zea mays) and wheat (Triticum aestivum) production for three years on an experimental field (sandy loam) located at Dry Land Research Sub Station, Dhiansar, Jammu. Each treatment was replicated four times in split plot design. The aim of the research was to determine the influence of tillage and mulch practices on economics, energy requirement, soil physical properties and performance of maize and wheat. Tillage methods significantly affected the soil physical properties as change in soil moisture contents and infiltration rate of soil was recorded. The soil moisture contents in minimum tillage (MT) were maximum (12.4%, 16.6%) in surface soil as compared to conventional tillage (CT) in maize and wheat crops, respectively. Comparing to the CT infiltration rate was (1.16times, 1.21times and 1.11times) higher in minimum tillage (MT), no tillage (NT) and raised bed (RB), respectively in kharif season. Similar results were also found in rabi season. The greatest maize yield of 1865 kg ha^?1 was achieved with CT system while not significantly lower yield was achieved with MT system (1837 kg ha^?1). However, wheat yield was recorded higher in MT as compare to the CT system. Comparing to the energy requirement of different operations, MT required 34.3% less, NT 31.1% less and RB 46.0% less than the CT system. MT system saved 2.5 times energy in tillage operation compared to the CT system. The economic analysis also revealed that the maximum benefits could be obtained from MT (EUR 202.4 ha^?1) followed by RB (EUR 164.2 ha^?1) and NT (EUR 158.3 ha^?1) and lowest in CT (EUR 149.5 ha^?1). Benefit-cost ratio was highest in MT (0.71) and lowest in CT (0.44). Results revealed that mulch significantly affected the soil physical properties and growth of maize. The maximum soil moisture content, infiltration rate and grain yield of maize and wheat recorded higher in mulching practices over no mulch treatment. Polythene mulch and straw mulch were almost equally valuable in maize and wheat sequence. Tillage (minimum) and mulch (polythene and straw) have pronounced effect on soil physical properties (improved infiltration rate and conserve soil water), energy requirement, economics and growth of maize and wheat. 相似文献

14.

Mechanisation of organic fertiliser spreading,choice of fertiliser and crop residue management as solutions for maize environmental impact mitigation

The environmental impact of crop production is mainly related to fossil fuels consumption and to fertilisers application. Emissions arising from the spreading of organic and mineral fertilisers are important contributors for impact categories such as eutrophication and acidification. The choice of the fertilisers and of the spreading techniques as well as the crop residues management can deeply affect the environmental impact related to crop cultivation.In this study, seven scenarios describing fertilising schemes characterised by different organic and mineral fertilisers and by different mechanisation were compared. The aim is to evaluate, using the Life Cycle Assessment (LCA) method, how the environmental performances of grain maize production were affected by these different fertilisers schemes. The study was carried out considering a cradle to farm gate perspective and 1 t grain maize was selected as functional unit. Inventory data were collected on a farm located in Po Valley (Northern Italy) during year 2013 and were processed using the composite method recommended by the International Reference Life Cycle Data System (ILCD). The compared scenarios involved organic and mineral fertiliser distribution and were: pig slurry incorporation after >3 days after spreading (BS), fast pig slurry incorporation within 2 h from spreading (AS1), direct soil injection of pig slurry (AS2), pig slurry incorporation (after >3 days) with straw collection (AS3), digestate spreading instead of pig slurry (after >3 days) (AS4), only mineral fertilisers (i.e. urea and superphosphate) distribution (AS5) and only mineral fertilisers (i.e. calcium ammonium nitrate and superphosphate) distribution (AS6).The results were not univocal, since climate and soil conditions as well as physical and chemical fertiliser characteristics differently affected the environmental load, especially for particulate matter formation, terrestrial acidification and terrestrial eutrophication impact categories. AS1 and AS2 showed the most beneficial results for these impact categories (between ↙67% and ↙73% respect to worst scenario). AS6, on the opposite, showed the highest environmental impact for those impact categories mainly affected by energy and fossil fuel consumption (climate change, ozone depletion, human toxicity with carcinogenic effect, particulate matter, freshwater eutrophication, freshwater ecotoxicity and mineral, fossil and renewable resources depletion), categories on which AS3 and AS4 were the best solutions. AS3 was the most impacting for terrestrial acidification and eutrophicationA sensitivity analysis was carried out varying grain maize yield (mostly affected: marine eutrophication) and ammonia volatilisation losses due to organic fertilisers (mainly affected: terrestrial acidification and eutrophication).The achieved results can be useful for the development of ⬓spreading rules⬽ that drive the application of organic fertilisers in agricultural areas where there is an intense livestock activity. 相似文献

15.

Spatial and temporal uncertainty of crop yield aggregations

Comparative assessment of maize,finger millet and sorghum for household food security in the face of increasing climatic risk

The aggregation of simulated gridded crop yields to national or regional scale requires information on temporal and spatial patterns of crop-specific harvested areas. This analysis estimates the uncertainty of simulated gridded yield time series related to the aggregation with four different harvested area data sets. We compare aggregated yield time series from the Global Gridded Crop Model Intercomparison project for four crop types from 14 models at global, national, and regional scale to determine aggregation-driven differences in mean yields and temporal patterns as measures of uncertainty.The quantity and spatial patterns of harvested areas differ for individual crops among the four data sets applied for the aggregation. Also simulated spatial yield patterns differ among the 14 models. These differences in harvested areas and simulated yield patterns lead to differences in aggregated productivity estimates, both in mean yield and in the temporal dynamics.Among the four investigated crops, wheat yield (17% relative difference) is most affected by the uncertainty introduced by the aggregation at the global scale. The correlation of temporal patterns of global aggregated yield time series can be as low as for soybean (r = 0.28).For the majority of countries, mean relative differences of nationally aggregated yields account for 10% or less. The spatial and temporal difference can be substantial higher for individual countries. Of the top-10 crop producers, aggregated national multi-annual mean relative difference of yields can be up to 67% (maize, South Africa), 43% (wheat, Pakistan), 51% (rice, Japan), and 427% (soybean, Bolivia). Correlations of differently aggregated yield time series can be as low as r = 0.56 (maize, India), r = 0.05 (wheat, Russia), r = 0.13 (rice, Vietnam), and r = −0.01 (soybean, Uruguay). The aggregation to sub-national scale in comparison to country scale shows that spatial uncertainties can cancel out in countries with large harvested areas per crop type. We conclude that the aggregation uncertainty can be substantial for crop productivity and production estimations in the context of food security, impact assessment, and model evaluation exercises. 相似文献

16.

Ultraviolet-B radiation and nitrogen effects on growth and yield of maize under Mediterranean field conditions

Questions as to which crop to grow, where, when and with what management, will be increasingly challenging for farmers in the face of a changing climate. The objective of this study was to evaluate emergence, yield and financial benefits of maize, finger millet and sorghum, planted at different dates and managed with variable soil nutrient inputs in order to develop adaptation options for stabilizing food production and income for smallholder households in the face of climate change and variability. Field experiments with maize, finger millet and sorghum were conducted in farmers’ fields in Makoni and Hwedza districts in eastern Zimbabwe for three seasons: 2009/10, 2010/11 and 2011/12. Three fertilization rates: high (90 kg N ha⁻¹, 26 kg P ha⁻¹, 7 t ha⁻¹ manure), low (35 kg N ha⁻¹, 14 kg P ha⁻¹, 3 t ha⁻¹ manure) and a control (zero fertilization); and three planting dates: early, normal and late, were compared. Crop emergence for the unfertilized finger millet and sorghum was <15% compared with >70% for the fertilized treatments. In contrast, the emergence for maize (a medium-maturity hybrid cultivar, SC635), was >80% regardless of the amount of fertilizer applied. Maize yield was greater than that of finger millet and sorghum, also in the season (2010/11) which had poor rainfall distribution. Maize yielded 5.4 t ha⁻¹ compared with 3.1 t ha⁻¹ for finger millet and 3.3 t ha⁻¹ for sorghum for the early plantings in the 2009/10 rainfall season in Makoni, a site with relatively fertile soils. In the poorer 2010/11 season, early planted maize yielded 2.4 t ha⁻¹, against 1.6 t ha⁻¹ for finger millet and 0.4 t ha⁻¹ for sorghum in Makoni. Similar yield trends were observed on the nutrient-depleted soils in Hwedza, although yields were less than those observed in Makoni. All crops yielded significantly more with increasing rates of fertilization when planting was done early or in what farmers considered the ‘normal window’. Crops planted early or during the normal planting window gave comparable yields that were greater than yields of late-planted crops. Water productivity for each crop planted early or during the normal window increased with increase in the amount of fertilizer applied, but differed between crop type. Maize had the highest water productivity (8.0 kg dry matter mm⁻¹ ha⁻¹) followed by sorghum (4.9 kg mm⁻¹ ha⁻¹) and then finger millet (4.6 kg mm⁻¹ ha⁻¹) when a high fertilizer rate was applied to the early-planted crop. Marginal rates of return for maize production were greater for the high fertilization rate (>50%) than for the low rate (<50%). However, the financial returns for finger millet were more attractive for the low fertilization rate (>100%) than for the high rate (<100%). Although maize yield was greater compared with finger millet, the latter had a higher content of calcium and can be stored for up to five years. The superiority of maize, in terms of yields, over finger millet and sorghum, suggests that the recommendation to substitute maize with small grains may not be a robust option for adaptation to increased temperatures and more frequent droughts likely to be experienced in Zimbabwe and other parts of southern Africa. 相似文献

17.

《European Journal of Agronomy》2000,12(2):117-125

The effects of an increase in UV-B radiation on growth and yield of maize (Zea mays L.) were investigated at four levels of applied nitrogen (0, 100, 200 and 300 kg ha⁻¹ of N) under Mediterranean field conditions. The experiment simulated a 20% stratospheric ozone depletion over Portugal. Enhanced UV-B and N deficiency decreased yield and total biomass production by 22–49%. High UV-B dose reduced yield, total biomass and growth of N-fertilized maize plants but did not affect N-stressed plants to the same extent. The response of grain yield to N was smaller with enhanced UV-B radiation. The underlying mechanisms for these results are discussed. 相似文献

18.

Natural 13C abundance and carbon storage in Danish soils under continuous silage maize

《European Journal of Agronomy》2005,22(2):107-117

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19.

The effect of succeeding crop and level of N fertilization on N leaching after break-up of grassland

《European Journal of Agronomy》2009,30(4):200-207

Depending on soil and management, ploughing up grassland for use as arable land can lead to an increase in the release of mineralized nitrogen and a high risk of nitrogen leaching during winter. The amount of N leaching is also dependent on the N efficiency of following crops and the level of N fertilization.In a field experiment in northwest Germany permanent grassland was ploughed and used as arable land. The experiment was conducted over 2 years at three sites and investigated two main factors: (i) succeeding crops, either spring barley (and catch crop)–maize or silage maize–maize; and (ii) N-fertilization either nil or moderate (120 kg N ha⁻¹ for barley or 160 kg for maize). Plant yields, the soil mineral nitrogen (SMN) content and the nitrate leaching losses over winter were determined. On average for the 2-year period, the SMN in autumn and the nitrate leaching losses during winter for the rotation barley–maize were 76 kg ha⁻¹ SMN and 81 kg N ha⁻¹ N leaching losses, and for maize–maize they amounted to 108 and 113 kg ha⁻¹, respectively. The SMN and N leaching losses for the plots with no N fertilizer were 49 and 52 kg N ha⁻¹ and for the plots fertilized at a moderate N level they were 135 and 142 kg N ha⁻¹, respectively.We conclude that although the extent of nitrate leaching is influenced by the site conditions and management of the grassland prior to ploughing, the management after ploughing is the decisive factor. The farmer can significantly reduce nitrate leaching with his choice of succeeding crop and the amount of N fertilization. 相似文献

20.

Optimising crop production and nitrate leaching in China: Measured and simulated effects of straw incorporation and nitrogen fertilisation