首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 31 毫秒
1.
InfoCrop, a generic crop model, simulates the effects of weather, soils, agronomic management (planting, nitrogen, residues and irrigation) and major pests on crop growth, yield, soil carbon, nitrogen and water, and greenhouse gas emissions. This paper presents results of its evaluation in terms of its validation for rice and wheat crops in contrasting agro-environments of tropics, sensitivity to the key inputs, and also illustrates two typical applications of the model. Eleven diverse field experiments, having treatments of location, seasons, varieties, nitrogen management, organic matter, irrigation, and multiple pest incidences were used for validation. Grain yields in these experiments varied from 2.8 to 7.2 ton ha−1 in rice and from 3.6 to 5.5 ton ha−1 in wheat. The results indicated that the model was generally able to explain the differences in biomass, grain yield, emissions of carbon dioxide, methane and nitrous oxides, and long-term trends in soil organic carbon, in diverse agro-environments. The losses in dry matter and grain yield due to different pests and their populations were also explained satisfactorily. There were some discrepancies in the simulated emission of these gases during first few days after sowing/transplanting possibly because of the absence of tillage effects in the model. The sensitivity of the model to change in ambient temperature, crop duration and pest incidence was similar to the available field knowledge. The application of the model to quantify multiple pests damage through iso-loss curves is demonstrated. Another application illustrated is the use of InfoCrop for analyzing the trade-offs between increasing crop production, agronomic management strategies, and their global warming potential.  相似文献   

2.
灌溉作为调控土壤水分状况的重要措施,直接影响农田温室气体的排放过程。滴灌是一种高效节水灌溉技术,其对温室气体排放的影响受到广泛关注。通过查阅大量文献,综合分析了滴灌对农田土壤N2O排放影响的研究进展与发展趋势。文献资料显示,滴灌通过调控土壤湿度和温度环境,改变土壤微生物菌群和土壤中气体传输速度,进而影响土壤N2O的产生以及排放速率;与其他灌溉方式相比,滴灌不破坏土壤结构,土壤内部水、肥、气、热条件稳定,适宜于作物生长,有利于土壤有机氮的矿化。但目前滴灌条件下温室气体排放的空间异质性和多种温室气体的同步定量研究等方面仍存在一些不足(例如:滴灌条件下土壤干燥区和湿润区N2O排放通量间差异研究和不同种类温室气体的同期影响研究)。今后,要加强监测滴灌下多种温室气体同期排放和不同土壤区域N2O排放差异,加强从分子水平探究滴灌模式下土壤微生物对N2O气体产生过程的作用机理等方面的研究,为构建环境友好型农业模式提供科学依据。  相似文献   

3.
Cropping schemes have developed in east-central Argentina for rainfed soybean (Glycine max Merr.) production that invariably employ no-tillage management. Often these schemes include growing soybean in a sequence of crops including wheat (Triticum aestivum L.) and maize (Zea mays L.). The full impact of various rotation schemes on soil water balance through a sequence of seasons has not been explored, although the value of these rotations has been studied experimentally. The objective of this work was to investigate through simulations, potential differences in temporal soil water status among rotations over five years. In this study, mechanistic models of soybean (Soy), maize (Maz), and wheat (Wht) were linked over a five-years period at Marcos Juárez, Argentina to simulate soil water status, crop growth, and yield of four no-till rotations (Soy/Soy, Soy/Wht, Soy/Maz, and Soy/Maz/Wht). Published data on sowing dates and initial soil water contents in the first year from a no-till rotation experiment were used as inputs to the model. After the first year, soil water status output from the model was used to initiate the next crop simulation in the sequence. The results of these simulations indicated a positive impact on soil water balance resulting from crop residue on the soil surface under no-till management. Continuous soybean and the two-year soybean/maize rotation did not efficiently use the available water from rainfall. Residue from maize was simulated to be especially effective in suppressing soil evaporation. Thus, the Soy/Maz simulation results indicated that this rotation resulted in enhanced soil water retention, increased deep water percolation, and increased soybean yields compared with continuous soybean crops. The simulated results matched well with experimental observations. The three-crop rotation of Soy/Maz/Wht did not increase simulated soybean yields, but the additional water retained as a result of decreased soil evaporation resulting from the maize residue allowed the addition of a wheat crop in this two-year rotation. Simulated soybean yields were poorly correlated with both the amount of soil water at sowing and the rainfall during the cropping period. These results highlight the importance of temporal distribution of rainfall on final yield. These models proved a valuable tool for assessing the consequences of various rotation schemes now being employed in Argentina on temporal soil water status, and ultimately crop yield.  相似文献   

4.
以土壤含水率下限作为灌水控制指标,即60%~70%占田持,灌水定额为15 mm,研究了小管出流、渗灌、滴灌与沟灌4种灌溉方式下温室内湿度的变化趋势以及对青椒生长情况的影响,并分析了不同灌溉方式下的作物病虫害发病率以及灌溉方式和温室内大气湿度的相关性。结果表明,灌溉方式和温室内大气湿度相关性显著,不同灌溉方式下的湿度差异明显,其中渗灌条件下温室的大气湿度最低。温室内温度和湿度呈异步变化,当温室温度控制在25~28℃范围内,可使温室内的湿度保持在低水平范围内,减少病虫害发生。渗灌条件下作物病虫害的发生率最小,与小管出流较接近,比沟灌降低约35%;而且渗灌条件下青椒的产量最高,为34650 kg/hm2。滴灌、渗灌和小管出流较沟灌增产分别为17%、39%、34%。  相似文献   

5.
设施农业具有可控的环境条件,可以通过工程技术手段实现作物的高效生产。大棚是设施农业的重要形式,能够显著提高作物的抗灾减灾和反季节生产能力。大棚作物的生长状况反映出大棚生产管理的效果,并作为农艺操作和产量预测的依据。为此,开发了通过计算机视觉分析大棚作物的植株颜色和发育阶段等生长信息的方法,利用专家系统挖掘视觉分析数据,评判作物的生长状况,预测后续生长趋势和最终产量。大棚黄瓜的试验结果表明:基于计算机视觉的数据挖掘可以准确评判黄瓜的生长状况,较为准确地预测成熟时期和最终产量,提高了大棚生产的智能化水平。  相似文献   

6.
水稻灌溉水量、氮肥和种植面积的高效管理有助于提升农业经济效益,提高资源利用效率和改善生态环境。以黑龙江省13个市(区)为研究区域,利用Meta分析量化不同灌溉方式和施氮量对水稻产量和温室气体(CO2、CH4、N2O)排放的影响,并建立水肥生产函数。在此基础上,以经济效益、温室气体排放量、水肥利用效率为目标函数构建多目标优化模型,以优化分配各地区的水肥资源,调整水稻种植面积。优化结果表明:控制灌溉和施加氮肥不同程度影响产量和温室气体排放,优化后水稻种植面积减少3.76%,水利用效率提高18.4%,灌溉水量均值为4513.54m3/hm2,氮肥施用量减少11%,氮肥利用效率提高32%,氮肥施用量均值为100kg/hm2;经济效益增加8.1%,温室气体排放降低10.6%。本模型可以量化表征区域尺度基于控制灌溉的水肥施用与产量及温室气体排放的响应关系,协同优化稻田水土肥资源最佳配比,平衡经济、温室气体排放和资源利用效率,有助于黑龙江省水稻不同目标间的水肥资源优化和种植面积调整,促进农业可持续发展,可为水稻水土肥资源优化与管理提供参考。  相似文献   

7.
温室黄瓜无土栽培营养液氮素管理模型的研究   总被引:1,自引:0,他引:1  
通过温室无土栽培黄瓜不同定植期不同施氮水平试验,分析了不同定植期黄瓜叶片含氮量随生育期的变化规律,以及叶片含氮量与叶片净光合作用速率和产量的定量关系,确定了不同光温条件下黄瓜叶片适宜含氮量的求算方法,以及盛果期黄瓜叶片含氮量与营养液氮素浓度的关系。在此基础上,建立了温室黄瓜无土栽培营养液氮素管理模型。结果表明,叶片适宜含氮量在开花前随生育期推进而增加,到开花期达到最大,开花后叶片适宜含氮量随生育期推进而逐渐降低,到盛果期达到较为稳定的状态。因此,盛果期的叶片含氮量可以作为温室黄瓜氮素管理指标。黄瓜叶片净光合作用速率和产量随盛果期叶片含氮量升高按负指数规律增加,在相同氮浓度的营养液灌溉条件下,春夏茬黄瓜盛果期的叶片适宜含氮量低于秋冬茬,春夏茬和秋冬茬黄瓜盛果期适宜的叶片含氮量分别为3.3%和3.6%,春夏茬和秋冬茬黄瓜无土栽培营养液适宜的氮素浓度分别为124 mg/L和96 mg/L。  相似文献   

8.
Agro-hydrological models have widely been used for optimizing resources use and minimizing environmental consequences in agriculture. SMCR_N is a recently developed sophisticated model which simulates crop response to nitrogen fertilizer for a wide range of crops, and the associated leaching of nitrate from arable soils. In this paper, we describe the improvements of this model by replacing the existing approximate hydrological cascade algorithm with a new simple and explicit algorithm for the basic soil water flow equation, which not only enhanced the model performance in hydrological simulation, but also was essential to extend the model application to the situations where the capillary flow is important. As a result, the updated SMCR_N model could be used for more accurate study of water dynamics in the soil-crop system. The success of the model update was demonstrated by the simulated results that the updated model consistently out-performed the original model in drainage simulations and in predicting time course soil water content in different layers in the soil-wheat system. Tests of the updated SMCR_N model against data from 4 field crop experiments showed that crop nitrogen offtakes and soil mineral nitrogen in the top 90 cm were in a good agreement with the measured values, indicating that the model could make more reliable predictions of nitrogen fate in the crop-soil system, and thus provides a useful platform to assess the impacts of nitrogen fertilizer on crop yield and nitrogen leaching from different production systems.  相似文献   

9.
刘林桃  张恒嘉 《农业工程》2022,12(12):78-83
作物所处的土壤环境对提高作物产量和品质至关重要。为深入研究土壤生产力可持续发展提供理论依据,迫切需要了解现阶段作物水氮耦合效应对土壤环境的影响,重点总结了作物水氮耦合效应对土壤容重、孔隙度、含水量、温度、养分、有机质、酶活性、微生物和气体排放等土壤环境的影响,并提出未来水氮耦合的重点研究方向,以期为土壤的高效生产和可持续利用提供理论依据。   相似文献   

10.
人工智能(Artificial Intelligence,AI)辅助种植有助于提高设施园艺作物精准化管理水平、缓解日益凸显的劳动力紧缺问题。草莓是典型的劳动密集型园艺作物,研究对比采用不同AI种植策略和关键技术对草莓温室生产的调控效果,可对园艺作物种植的AI技术改进和产业化应用提供参考。本研究对比分析了4个不同AI种植策略对草莓生长发育和产量及品质的调控效果,并以人工种植管理为参照,对AI种植的技术特点和存在问题进行了分析。结果表明,知识图谱、深度学习、视觉识别、作物模型和作物生长仿真器等技术在草莓AI种植中各有优势。其中,AI-1组采用知识图谱技术将专家经验、作物数据和环境数据进行融合,建立了标准化草莓种植知识结构和智慧种植决策方法,对作物生产发育的调控较为稳健,以较低的投入获得了最高产值。与人工种植管理相比,AI种植策略组的平均产量提高了1.66倍,平均产值提高了1.82倍,最高投入产投比提高了1.27倍。针对高产优质的目标,在配备较完善的智能化设备和控制组件的温室生产条件下,AI辅助种植能有效提高草莓种植管控的精准度,减少水肥和劳动力的投入,获得较高的收益,但也存在对人工管理扰动的模拟难、作物本体信息采集难等问题。  相似文献   

11.
The practice of long fallowing, by omitting a year of cropping, is gaining renewed focus in the low rainfall zone of the northern agriculture region of Western Australia. The impetus behind this practice change has been a reduced use of pasture breaks in cereal crop rotations, and the belief that a fallow can improve soil water accumulation and thus buffer the negative effects of dry seasons on crop yields. We evaluated the benefits of long fallowing (full stubble retention, no weed growth allowed) in a continuous wheat sequence via simulation modelling with APSIM at two rainfall locations and five soil types. The simulated benefits to long fallowing were attributable to soil water accumulation only, as the effects on soil nitrogen, diseases or weeds were not evaluated.The long-term (100 years) mean wheat yield benefit to fallowing was 0.36-0.43 t/ha in clay, 0.20-0.23 t/ha in sand and loam, and 0-0.03 t/ha in shallow sand and shallow loams. Over the range of seasons simulated the response varied from −0.20 to 3.87 t/ha in the clay and −0.48 to 2.0 t/ha for the other soils. The accumulation of soil water and associated yield benefits occurred in 30-40% of years on better soils and only 10-20% on poorer soils. For the loam soil, the majority of the yield increases occurred when the growing-season (May-September) rainfall following the fallow was low (<210 mm) and the difference in plant available soil water at sowing between fallowed and continuously cropped soil was high (>30 mm), although yield increase did occur with other combinations of growing-season rainfall and soil water. Over several years of a crop sequence involving fallow and wheat, the benefits from long fallowing due to greater soil water accumulation did not offset yield lost from omitting years from crop production, although the coefficient of variation for inter-annual farm grain production was reduced, particularly on clay soils during the 1998-2007 decade of below-average rainfall. We conclude that under future drying climates in Western Australia, fallowing may have a role to play in buffering the effects of enhanced inter-annual variability in rainfall. Investigations are required on the management of fallows, and management of subsequent crops (i.e. sowing earlier and crop density) so as to maximise yield benefits to subsequent crops while maintaining groundcover to prevent soil erosion.  相似文献   

12.
《Agricultural Systems》2005,85(2):101-119
Reducing the energy derived from fossil fuels within agricultural systems has important implications for decreasing atmospheric emissions of greenhouse gases, thus assisting the arrest of global warming. The identification of crop production methods that maximise energy efficiency and minimise greenhouse gas emissions is vital. Sugar beet is grown in a variety of locations and under a variety of agronomic conditions within the UK. This study identified thirteen production scenarios, representative of over 90% of the UK beet crop, which included five soil types, nine fertiliser regimes and nine crop protection strategies. The fossil energy input, the overall energy efficiency and the global warming potential (GWP) of each production scenario was assessed. This study did not consider the processing of the beet to extract sugar.The overall energy input of the UK beet crop ranges between 15.72 and 25.94 GJ/ha. It produces between 7.3 and 15.0 times as much energy in dry matter at the sugar factory gate as consumed in its production, with an average ratio of 9.7. It has an average GWP of 0.024 eq. t CO2 per tonne of clean beet harvested, equivalent to 0.0062 eq. t CO2 per GJ output. The energy input into each scenario was dictated largely by the energy associated with crop nutrition. The smallest energy inputs per hectare were to crops grown under organic conditions or conventional crops grown on fertile soils (clay loam, silt or peat) or sand soil with broiler manure applied. Those crops with the greatest energy input were grown on sand soil that was irrigated and had mineral fertiliser applied. Although the organic scenario grown on sandy loam soil had one of the smallest energy inputs per hectare, the low yield meant that the energy input was similar per tonne of beet harvested to the conventional crops grown on sandy loam soil. The extra distance travelled by organic beet from the farm to the factory increased the energy input per tonne above that of the conventional scenarios. The GWP was smallest for the conventional crops on the fertile peat and silt soils and greatest on the irrigated sand soils and the sandy loam soils. The organic scenario had a similar GWP to the conventional scenarios on sandy loam to the farm gate, although the greater diesel requirement for transport increased the GWP overall. The GWP per GJ of output for sugar beet in England is similar to published values for wheat.  相似文献   

13.
温室是实现作物优质高效生产的重要设施,可以在一定程度上克服传统农业难以解决的限制因素,消除对作物生长不利的环境条件,使其部分或者全部脱离外界气候条件及土壤因素的制约,达到作物高产出、高质量、高效益和工厂化生产的目标。先进温室生产系统的标志之一是可基于温室环境控制系统进行温室生产过程调控,为作物构造合适的生长环境,以提高产量,改善质量。温室生产过程性能的好与坏取决于控制算法。在检索中外文献基础上,介绍了目前控制算法的类型、存在的问题、改进措施和未来发展趋向。   相似文献   

14.
Water distribution can be nonuniform along the furrow length under surface irrigation. This “down field” nonuniformity is combined with “inter-row” non-uniformity which is a consequence of differences in infiltration characteristics across the plot. Global nonuniformity of application depth causes variation of yield, drainage and nitrogen leaching. In addition to that, due to year-to-year variability of climate, irrigation depths range significantly (from 0 to 360 mm/season). The objective of this paper is to study the impact of the nonuniformity of irrigation-water distribution within a furrow plot on yield, water and nitrogen losses when climate variation is taken into account. Six maize vegetation seasons on a Chromic Luvisol soil in the Sofia region with varying irrigation requirements are considered. Irrigation water is distributed in relative terms over the plot at different levels of nonuniformity (coefficient of variation Cv ranging from 13 to 66%) by the FURMOD model. Water and nitrogen cycle and crop growth are simulated then compared at 30 representative points in the set with various “climate-irrigation nonuniformity” combinations by the CERES-maize model. It was established that non-uniformity of irrigation is not important in wet vegetation periods. The drier the irrigation season, the higher the yield loss and risk to environment due to nonuniformity of irrigation water distribution. In moderate and dry irrigation seasons it causes yield losses of 2–14%, significant variation (30% < Cv < 200%) of drainage, nitrogen leaching and residual soil nitrate over the furrow set. Surface irrigation performances can be improved by reducing lateral nonuniformity of stream advance.  相似文献   

15.
Crop growth models have been used in simulating the soil water balance for purposes of irrigation management and yield predictions. The application of CropSyst, a cropping systems simulation model, was evaluated for Cedara, South Africa. Simulations included soil water balance of fallow land and rainfed and irrigated winter crops [oats (Avena sativa), Italian ryegrass (Lolium multiflorum) and rye (Secale cereale)]; and irrigation scheduling of the winter crops. Soil, plant, weather and management inputs were used for the soil water balance simulations. Model crop parameters were used from past experiments or obtained from model documentation, with a slight modification to account for varietal differences. The fallow land soil water simulations were more accurate for dry than for wet soil. For all three winter crops, the model consistently over-estimated the soil water content in the upper layers, with a good agreement for the deeper layers until a large precipitation event occurred to which the model responded more slowly than that observed. Simulations using model-scheduled irrigation based on 0.4 and 0.6 maximum allowable depletion criteria indicated that the observed applied irrigation in the field was more than that required. Soil water depletion and accumulated transpiration simulations were similar in both the observed and model-scheduled irrigations, but total soil evaporation and percolation were greater in the case of the observed than the model-scheduled irrigations. Irrigation scheduling using crop growth models may assist in avoiding over- or under-application of irrigation applications by ensuring efficient utilization of rain and irrigation.  相似文献   

16.
隋俊杰 《农业工程》2012,(Z1):35-38
随着我国蔬菜生产的发展,设施蔬菜栽培面积不断扩大。但目前设施种植的蔬菜作物种类有限,超量施用和单一施用化学肥料,致使出现土壤结构破坏、肥力衰退和病虫危害加重等现象。因此,设施蔬菜的连作障碍比露地栽培更为突出。该文介绍了土壤电消毒灭虫机原理、组成和性能指标、作业程序及应用效果。旨在为推广土壤电消毒灭虫机的应用,解决土壤连作障碍提供有益探索。  相似文献   

17.
Application of water saving irrigation strategies in agriculture has become increasingly important. Both modelling and experimental work are needed to gain more insights into the biological and physical mechanisms in the soil-plant system, which regulates water flow in the system and plays a central role in reducing crop transpiration. This paper presented a mechanistic model (Daisy) developed based on data obtained in the SAFIR project on measured leaf gas exchange and soil water dynamics in irrigated potato crops grown in a semi-field environment subjected to different irrigation regimes. Experimental data was compared to simulated results from the new enhanced Daisy model which include modelling 2D soil water flow, abscisic acid (ABA) signalling and its effect on stomatal conductance and hence on transpiration and assimilation, and finally crop yield. The results demonstrated that the enhanced Daisy model is capable of simulating the mechanisms underlying the water saving effects of the partial root-zone drying (PRD) irrigation as compared with the conventional full irrigation (FI). However the simulated effect on both crop yield and water use in this particular experiment was negligible indicating more experimental studies are necessary in order to improve on the model.  相似文献   

18.
The root zone water quality model (RZWQM) was developed primarily for water quality research with a generic plant growth module primarily serving as a sink for plant nitrogen and water uptake. In this study, we coupled the CERES-Maize Version 3.5 crop growth model with RZWQM to provide RZWQM users with the option for selecting a more comprehensive plant growth model. In the hybrid model, RZWQM supplied CERES with daily soil water and nitrogen contents, soil temperature, and potential evapotranspiration, in addition to daily weather data. CERES-Maize supplied RZWQM with daily water and nitrogen uptake, and other plant growth variables (e.g., root distribution and leaf area index). The RZWQM-CERES hybrid model was evaluated with two well-documented experimental datasets distributed with DSSAT (Decision Support System for Agrotechnology Transfer) Version 3.5, which had various nitrogen and irrigation treatments. Simulation results were compared to the original DSSAT-CERES-Maize model. Both models used the same plant cultivar coefficients and the same soil parameters as distributed with DSSAT Version 3.5. The hybrid model provided similar maize prediction in terms of yield, biomass and leaf area index, as the DSSAT-CERES model when the same soil and crop parameters were used. No overall differences were found between the two models based on the paired t test, suggesting successful coupling of the two models. The hybrid model offers RZWQM users access to a rigorous new plant growth model and provides CERES-Maize users with a tool to address soil and water quality issues under different cropping systems.  相似文献   

19.
Bio-economic models can be used to assess the impact of policy and environmental measures through economic and environmental indicators. Focusing on agricultural systems, farmers’ decisions in terms of cropping systems and the associated crop management at field scale are essential in such studies. The objective of this paper is to present a study using a bio-economic model to assess the impact of the Nitrate Directive in the Midi-Pyrenees region (France) by analyzing, at the farm scale, farm income and three environmental indicators: nitrate leaching, erosion and water consumption. Two scenarios, the 2003 CAP reform (baseline scenario) and the Nitrate Directive (policy scenario), with a 2013 time horizon, were developed and compared for three representative arable farm types in the Midi-Pyrenees region. Different types of data characterizing the biophysical context in the region (soil, climate), the current cropping systems (rotation, crop management) and farm resources (irrigated land, labor) were collected to calibrate and run the models. Results showed that the implementation of the Nitrate Directive may not affect farm income. However, significant modifications to cropping systems and crop allocation to soil types were simulated. Contrary to expectations, nitrogen leaching at the farm scale did not change. Overall water consumption increased and soil erosion decreased due mainly to a modification in cropping patterns and management by soil type. This study provides an example of unanticipated effects of policy and trade-offs between environmental issues.  相似文献   

20.
Irrigation scheduling based on the daily historical crop evapotranspiration (ETh) data was theoretically and experimentally assessed for the major soil-grown greenhouse horticultural crops on the Almería coast in order to improve irrigation efficiency. Overall, the simulated seasonal ETh values for different crop cycles from 41 greenhouses were not significantly different from the corresponding values of real-time crop evapotranspiration (ETc). Additionally, for the main greenhouse crops on the Almería coast, the simulated values of the maximum cumulative soil water deficit in each of the 15 consecutive growth cycles (1988–2002) were determined using simple soil-water balances comparing daily ETh and ETc values to schedule irrigation. In most cases, no soil-water deficits affecting greenhouse crop productivity were detected, but the few cases found led us to also assess experimentally the use of ETh for irrigation scheduling of greenhouse horticultural crops. The response of five greenhouse crops to water applications scheduled with daily estimates of ETh and ETc was evaluated in a typical enarenado soil. In tomato, fruit yield did not differ statistically between irrigation treatments, but the spring green bean irrigated using the ETh data presented lower yield than that irrigated using the ETc data. In the remaining experiments, the irrigation-management method based on ETh data was modified to consider the standard deviation of the inter-annual greenhouse reference ET. No differences between irrigation treatments were found for productivity of pepper, zucchini and melon crops.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号