作物花粉自动采集传感器的研制与定标

作物花粉自动采集传感器通过ARM（advanced RIS Cmachines）控制简易机械臂操作采样平台上的载玻片捕获空气中自由扩散的花粉粒子,并将载玻片置于生物显微镜下,通过CMOS（complementary metal-oxide-semiconductor）视频传感器将生物显微镜生成的光学图像转换成数字图像,经嵌入式ARM单片机计算处理并存储。利用外场实测资料和标准医用血球计数板,对仪器进行几何尺度标定及载玻片拍摄抽样定标。仪器光学放大倍数F定为328,视场真实面积S为1.516mm2,当拍摄抽样数N为50次时,花粉密度相关系数大于95%。当抽样精度一定,花粉浓度大时,可适当减少抽样数目。体积较小的水稻花粉需要拍摄抽样40次,而体积较大的玉米花粉则需要拍摄抽样80次。因系统几何失真引起的光学放大倍数F随显微视场半径变化,使得实测取样面积误差最大可达13.75%。     

湖北省主要作物生育期间热量资源变化的研究

气候变化会引起农业气候资源的变化，气候资源的变化又会导致作物生育期长短的变化。通过分析１９８０年以来湖北省几种主要农作物生育期间积温的变化，发现不同作物生育期间热量资源的变化在不同的地理位置存在明显差异，并因此引起作物生育期长短不均。山区热量资源以减少为主，作物生育期将延长；平原地区热量资源以增加为主，作物生育期将缩短。     

ENSO对全球及中国农业气象灾害和粮食产量影响研究进展

厄尔尼诺-南方涛动（ENSO）是全球性年际气候变率的主导模式,ENSO通过影响全球的大气环流,对全球许多地区的气温、降水和由气温、降水异常导致的农业气象灾害（如低温冷害、旱涝灾害等）及农作物生长发育、产量形成产生影响。综述前人对ENSO影响研究进展,所得主要结论如下：1）从全球范围来看,厄尔尼诺年,全球气温偏高,陆地平均年降水量减少;拉尼娜年,全球气温偏低,陆地平均年降水量增加;不同季节和不同类型EN-S0对全球气温和降水的影响有差异。在中国,厄尔尼诺年,大部分地区冬春季气温偏高,夏秋季气温偏低,拉尼娜年,大部分地区冬春季气温偏低,夏秋季气温偏高,不同年代下ENSO对我国气温的影响有所变化;厄尔尼诺年,全国降水以偏少为主,且ENSO对我国不同地区降水的影响与ENSO类型、发展阶段和发生年代有关。2）厄尔尼诺年,我国北方大部分地区初霜冻偏早,吉林延迟型冷害增加,黑龙江低温冷害多发,华北和西北地区易发生干旱;拉尼娜年,我国北方大部分地区初霜冻偏晚,西北地区易发生洪涝。气候变暖背景下,厄尔尼诺与东北低温的关系更为复杂。ENSO循环的不同阶段会影响我国旱涝的地区分布。3）厄尔尼诺年和拉尼娜年,全球水稻、小麦和玉米均以减产为主,不同国家和地区影响各异。其中,厄尔尼诺年,美国、巴西和阿根廷玉米产量增加,中国和津巴布韦玉米产量降低,印度小麦和水稻及菲律宾、印度尼西亚的雨季水稻均减产;拉尼娜年,美国、巴西和阿根廷玉米减产,印度小麦和水稻增产。在中国,厄尔尼诺对水稻和小麦产量的影响程度与当地灌溉条件有关。以上结论可为我国防御低温冷害、干旱等农业气象灾害,保障粮食安全,制定科学政策提供理论参考。     

基于作物模型灾损识别的黄淮区域冬小麦晚霜冻风险评估

利用近50年黄淮地区54个农业气象观测站的作物观测资料和气象资料,结合人工移动式霜箱试验结果,研究了WOFOST作物模型中增加晚霜冻影响的处理技术,揭示了晚霜冻对冬小麦各生长量的影响结果。利用修改后的作物模型提取晚霜冻灾损评估技术,建立以晚霜冻的危险性、暴露性和脆弱性为风险因子的风险评估模型,开展黄淮区域晚霜冻风险评估。结果表明,黄淮区域冬小麦晚霜冻风险分布呈西高东低分布,高风险地区主要分布在黄淮区域的河南西部、西南部、西北部及东部永城、沈丘一带。其中,黄淮西部的高风险主要是由晚霜冻高灾损引起的,河南西南部的高风险是由晚霜冻的高频率引起的,其西北部和东部的高风险则是由晚霜冻的高频率和高灾损共同引起的。     

Quantitative estimation of climate change effects on potential evapotranspiration in Beijing during 1951-2010

Climate change is likely to affect hydrological cycle through precipitation, evapotranspiration, soil moisture etc. In the present study, an attempt has been made to study the climate change and the sensitivity of estimated evapotranspiration to each climatic variable for a semi-arid region of Beijing in North China using data set from 1951 to 2010. Penman-Monteith method was used to calculate reference crop evapotranspiration (ETo). Changes of ETo to each climatic variable was estimated using a sensitivity analysis method proposed in this study. Results show that in the past 60 years, mean temperature and vapor pressure deficit (VPD) were significantly increasing, relative humidity and sunshine hours were significantly decreasing, and wind speed greatly oscillated without a significant trend. Total precipitation was significantly decreasing in corn season (from June to September), but it was increasing in wheat season (from October to next May). The change rates of temperature, relative humidity, VPD, wind speed, annual total precipitation, sunshine hours and solar radiation were 0.42℃, 1.47%, 0.04 kPa, 0.05 m·s-1, 25.0 mm, 74.0 hours and 90.7 MJ·m-2 per decade, respectively. In the past 60 years, yearly ETo was increasing with a rate of 19.5 mm per decade, and total ETos in wheat and corn seasons were increasing with rates of 13.1 and 5.3 mm per decade, respectively. Sensitivity analysis showed that mean air temperature was the first key factor for ETo change in the past 60 years, causing an annual total ETo increase of 7.4%, followed by relative humidity (5.5%) and sunshine hours (-3.1%); the less sensitivity factors were wind speed (0.7%), minimum temperature (-0.3%) and maximum temperature (-0.2%). A greater reduction of total ETo (12.3%) in the past 60 years was found in wheat season, mainly because of mean temperature (8.6%) and relative humidity (5.4%), as compared to a reduction of 6.0% in ETo during corn season due to sunshine hours (-6.9%), relative humidity (4.7%) and temperature (4.5%). Increasing precipitation in the wheat season will improve crop growth, while decreasing precipitation and increasing ETo in the corn season induces a great pressure for local government and farmers to use water more efficiently by widely adopting water-saving technologies in the future.     

旱作水稻稻茬小麦增产栽培技术研究

水稻稻茬小麦因水稻收获晚、适耕期短、整地困难、播种质量差等因素的影响,很难适期播种,加之水稻稻茬土壤板化,理化性状差,导致稻茬小麦的单产长期低而不稳,在200kg上下徘徊。为改变这一现状,我们提出了以旱作水稻替代水稻,并进行试验研究。结果表明,旱作水稻比水稻早熟10天,并能调整土壤理化性状,旱作水稻稻茬小麦比水稻稻茬小麦增产100kg。     

陕西关中富硒土壤研究及开发利用——以三原—阎良地区为例

通过对三原—阎良地区土壤与农作物采样分析研究,发现该地区土壤环境总体清洁,足硒—富硒土壤占调查区总面积的94.62%,富硒土壤分布广,具备了开发富硒农产品的基本土壤条件;大宗粮食作物均达富硒水平,其中油菜富硒率100%,小麦富硒率99.4%,玉米富硒率88.1%,大部分蔬菜也都达到了富硒蔬菜的标准,适合种植富硒大宗粮食作物和蔬菜;农作物硒与土壤硒整体相关性较好,玉米硒含量与根系土硒含量相关系数为0.788,小麦硒含量与根系土硒含量相关系数为0.612,富硒产业发展前景好。三原—阎良地区是陕西省关中地区重要的粮食、蔬菜产地,建议选择示范点开展富硒农产品种植试点,为关中地区富硒资源开发利用提供科学依据,在此基础上打造建设一批富硒粮食、蔬菜产业基地,更好地支撑服务乡村振兴战略和精准脱贫攻坚战。     

土壤—作物系统中重金属元素的地球化学行为

对我国部分土壤和作物中重金属元素的分布特征作了概括性的论述，指出重金属元素的富集或贫化与成土母质、土壤环境等因素密切相关。母质母岩中元素含量高则相应土壤中该元素富集；土壤偏碱性或氧化条件下，重金属元素的有效性低；重金属元素通常富集于土壤表层0-20cm层位。不同种类的粮食、蔬菜对土壤中重金属元素具有不同程度的吸收和富集能力，叶类菜比茎类菜对重金属具有更强的吸收和富集能力，粮食作物的根比籽粒含重金属更多。对已污染的土壤大多采用生物修复和生态修复方法。     

农作物成熟、收获动态预报和农产品交售、收购资金计划调度初探

在具体分析农作物成熟，收获和农产品交售，收购过程的基础上，根据历年农产品收购进度资料，初步探讨了农作物成熟，收获动态预报和农产品交售，收购之间的动态变化关系，建立了农作物成熟，收获动态预报模型，为农产品交售，收购资金合理计划，调度提供了科学依据。     

Dependence of wheat and rice respiration on tissue nitrogen and the corresponding net carbon fixation efficiency under different rates of nitrogen application

To quantitatively address the role of tissue N in crop respiration under various agricultural practices, and to consequently evaluate the impact of synthetic fertilizer N application on biomass production and respiration, and hence net carbon fixation efficiency （Encf）, pot and field experiments were carried out for an annual rotation of a rice-wheat cropping system from 2001 to 2003. The treatments of the pot experiments included fertilizer N application, sowing date and planting density. Different rates of N application were tested in the field experiments. Static opaque chambers were used for sampling the gas. The respiration as CO2 emission was detected by a gas chromatograph. A successive biomass clipping method was employed to determine the crop autotrophic respiration coefficient （Ra）. Results from the pot experiments revealed a linear relationship between Ra and tissue N content as Ra = 4.74N-1.45 （R^2= 0.85, P 〈 0.001）. Measurements and calculations from the field experiments indicated that fertilizer N application promoted not only biomass production but also increased the respiration of crops. A further investigation showed that the increase of carbon loss in terms of respiration owing to fertilizer N application exceeded that of net carbon gain in terms of aboveground biomass when fertilizer N was applied over a certain rate. Consequently, the Encf declined as the N application rate increased.