论雨水利用及其农业供水的意义

从我国农业供水角度讨论了我国水资源评价与利用的若干理论问题,结合农业与农村供水探讨了雨水利用,提出了 全面开展雨水利用的若干建议。     

Spatio-temporal variability of precipitation, temperature and agricultural drought indices in Central Italy

The agricultural sector is probably the one that will suffer most directly from the climatic variations expected at the global level. In particular, the analysis of the changes expected in water availability and demand is fundamental in order to correctly establish both the present water resource management and the definition of new strategies. In this paper the time series of some climatic and agro-climatic indices in the Region of Umbria (Central Italy) have been analyzed with the aim of finding signs of climate changes and identifying the potential impacts on the agricultural water balance. The aforesaid indices include the precipitation, the mean maximum and minimum temperatures (Tmin, Tmax), the mean temperature range (ΔT), the reference evapotranspiration (ET0) and two drought indices, Standardized Precipitation Index (SPI) and Standardized Deficit Index (SDI, based on the difference between ET0 and precipitation). These indices were analyzed with reference to different periods (in particular the average growing and irrigation seasons). Furthermore, more specific information was obtained by analyzing the simulated water requirement (CWR) and evapotranspiration deficit (ED) of two typical annual crops (corn and sunflower). The time series of the indices were quantified for 38 stations in the region and they were then analyzed with non-parametric tests both at single sites and at the regional level. The tendencies in cumulated precipitation are generally decreasing (particularly during the wet period) and they are also characterized by a defined spatial pattern. The rainfall reduction during the irrigation season, although less widespread, could have the most important practical consequences. The significant trends detected for both the Tmax and Tmin are mainly positive, and they are more evident for Tmin, often resulting in a reduction of ΔT. ET0 shows a prevailing stationary condition due to the counteracting effects of the prevalent reduction observed for the ΔT and the increment of the mean temperature. At any rate, with reference to the irrigation season, ET0 trends are mainly positive. The results obtained for SPI and SDI are in accordance with the tendencies of non-standardized indices with an expectation of extreme drought event occurrence doubled or even tripled over a 30-year time span. Finally, the analysis of the CWR for corn and the ED for sunflower shows a relevant presence of significant positive trends whose impacts can be estimated in respective mean increments of about 23% and 44% over a 50-year time span.     

Modeling long-term soil carbon dynamics and sequestration potential in semi-arid agro-ecosystems

Long-term soil carbon (C) dynamics in agro-ecosystems is controlled by interactions of climate, soil and agronomic management. A modeling approach is a useful tool to understand the interactions, especially over long climatic sequences. In this paper, we examine the performance of the Agricultural Production Systems sIMulator (APSIM) to predict the long-term soil C dynamics under various agricultural practices at four semi-arid sites across the wheat-belt of eastern Australia. We further assessed the underlying factors that regulate soil C dynamics in the top 30 cm of soil through scenario analysis using the validated model. The results show that APSIM is able to predict aboveground biomass production and soil C dynamics at the study sites. Scenario analyses indicate that nitrogen (N) fertilization combined with residue retention (SR) has the potential to significantly slow or reverse the loss of C from agricultural soils. Optimal N fertilization (N_opt) and 100% SR, increased soil C by 13%, 46% and 45% at Warra, Wagga Wagga and Tarelee, respectively. Continuous lucerne pasture was the most efficient strategy to accumulate soil C, resulting in increases of 49%, 57% and 50% at Warra, Wagga Wagga and Tarlee, respectively. In contrast, soil C decreases regardless of agricultural practices as a result of cultivation of natural soils at the Brigalow site. Soil C input, proportional to the amount of retained residue, is a significant predictor of soil C change. At each site, water and nitrogen availability and their interaction, explain more than 59% of the variation in soil C. Across the four sites, mean air temperature has significant (P < 0.05) effects on soil C change. There was greater soil C loss at sites with higher temperature. Our simulations suggest that detailed information on agricultural practices, land use history and local environmental conditions must be explicitly specified to be able to make plausible predictions of the soil C balance in agro-ecosystems at different agro-ecological scales.     

高原环境对拖拉机、农用运输车安全性能的影响及对策

着重从青藏高原的地理、气候、道路等环境特点,分析高原环境对拖拉机、农用运输车安全生产影响的因素,提出预防措施,以确保安全生产。     

廊坊市农业产业化发展策略分析

通过对廊坊市农业产业化发展现状的深度调查和研究,指出廊坊市在农业产业化发展中存在的若干问题,并提出进一步推进廊坊市农业产业化发展所需要采取的措施和策略。      

基于BP_Adaboost的农机行驶轨迹状态识别

农业机械运动轨迹不仅包括田间作业轨迹,还包括道路行驶轨迹。有效区分农机行驶过程中田间作业和道路行驶等作业轨迹,可精确划分有效作业地块和精准评估农机作业效率,从而实现农机的远程智能管理。通过对农机轨迹点属性的分析,提取典型特征数据,利用BP_Adaboost方法建立的训练模型对农机轨迹点进行识别,将道路与田间交界处易错轨迹点重新标记后再次训练,轨迹识别正确率达96.89%。该方法既避免了传统聚类算法对阈值和参数依赖的问题,也有效解决了将道路行驶轨迹误识别为田间作业轨迹的难题。      

Yield and Quality of Mixed Seed Crops of Timothy ( Phleum pratense ) and Clovers ( Trifolium spp.) in an Organic Cropping System

Seed production of timothy ( Phleum pratense L.) in mixed crops with alsike ( Trifolium hybridum L.), white ( T. repens L.) or red ( T. pratense L.) clover was evaluated in an organic cash crop system. No fertilizer was applied except for household compost in the sowing year. While the first year crops of the alsike clover/timothy and red clover/timothy leys were harvested for clover seed, the first year crop of the white clover/timothy ley and all second year crops were harvested for timothy seed. The botanical composition of the alsike clover/timothy crop averaged 89/11 in the first ley year, and 8/92 in the second year. The corresponding yields averaged 443 kg ha -1 clover seed and 849 kg ha -1 timothy seed, respectively. Second year seed yields of timothy from mixtures with red and white clover were, in turn, 7% higher and 44% lower than from the corresponding mixture with alsike clover. First year seed yields of alsike clover from the alsike clover/timothy combination, and first year yields of timothy from the timothy/white clover combination were mostly rejected because of insufficient purity. In contrast, first year seed yields of red clover from the red clover/ timothy combination, and second year yields of timothy from all combinations, never failed to met the international requirement of maximum 1% contamination of one particular species in certified seed.     

Simulating the effects of tax exemptions on fertiliser use in Benin by linking biophysical and economic models

The sluggish increase in the area productivity of staple crops is a major factor causing increased dependence of African countries on food imports. The increased use of mineral fertiliser may dramatically improve the food balance of many countries and result in lower food prices, higher food supply and consumption, and improved food security and nutritional status. In Benin, West Africa, political measures to improve farmers’ access to fertiliser are biased in favour of cotton production. This article simulates the impact of universal tax exemptions for fertiliser use on crop yields, food balances, and the use of land resources for the most important staple crops in Benin using a crop growth model and an agricultural sector model. The simulation results indicate that tax exemptions on fertiliser use could have positive effects on physical productivity and would increase food security until 2025 as compared to a baseline scenario. At the same time, the pressure on land resources would not be aggravated, so that better access to fertiliser may help to curb excessive cropland expansion in Benin.     

产学研一体化培养高素质应用型人才的实践探索

产学研一体化有效推动高素质应用型人才培养计划改革与完善,培养学生综合实践能力和创新精神,提高人才培养质量;锻造一支科研能力强的教师队伍,促进学科建设的发展,促进学术团队的建设,极大提升科研成果的转化能力;增强企业自主创新能力,推进社会长足发展。     

“气候好”农产品贵德软梨评价指标研究

为了提高贵德梨果的栽培经济效益,本研究选取贵德名优农产品中取得地理标志的产品贵德软梨,开展了“气候好”农产品气候品质认定,确定了评价指标。采取综合认证方法,考虑影响农产品生长的生态适应性、当年的气候条件、管理水平和当年水果品质情况所占的比重,赋予不同的权重。并对各项分析打分,得到综合分数来确定。选取2020年贵德县园艺场的软梨进行了认定指标评价,结果表明2020年贵德县园艺场光热资源丰富、水分条件适宜、光热水匹配良好、气候优势明显,有利于优质软梨生产,2020年出产的贵德软梨气候品质等级为“特优”。