通辽地区玉米生产的热量条件分析

玉米是通辽市最主要的粮食作物,其丰歉决定农业年景的好坏。为了探讨在气候变暖的大背景下通辽市玉米生产的热量状况,为政府和生产部门的决策及气象业务、服务工作提供依据,笔者利用科尔沁、开鲁、鲁北、保康、甘旗卡、库伦、大沁他拉等7个国家基本气象站1959-2010年资料,对影响玉米生产的≥10.0℃积温和玉米生育期天数进行了分析研究,结果表明:(1)≥10.0℃积温、持续期和玉米生育期天数能满足玉米晚熟品种的生育需要,而且线性趋势递增明显,滑动t检验在80年代末或90年代初发生了突变,以上均在0.01或0.05的水平以上,存在一定的周期。(2)由于一些年份一些台站近几年出现初霜冻异常偏早,使生育期波动大,并有下降迹象,因此选择玉米品种不可盲目贪晚。     

京津冀地区夏玉米生产潜力时空变异及其与现实产量的对比分析(英文)

Crop potential productivity is a key index of scientifically appraising crop production and land population-supporting capacity. This study firstly simulated the potential and waterlimited yield of summer maize in the Beijing-Tianjin-Hebei (BTH) region using WOFOST model with meteorological data of 40 years, and then analyzed yield gaps between the actual and potential yield based on statistical data at county level. The potential and water-limited yield of summer maize in the BTH region is 6854–8789 kg/hm2 and 6434–8741 kg/hm2, and the weighted average for whole region is 7861 kg/hm2 and 7185 kg/hm2, respectively. The simulated yields gradually decrease from northeast to southwest with changes in climatic conditions particularly temperature and precipitation. Annual variation of potential yield is higher in the central and southern parts than the northeastern part. Compared to potential yield, the water-limited yield has higher coefficient of variation (CV), because of precipitation effects. The actual yield of summer maize was 2537–8730 kg/hm2, regionally averaged at 5582 kg/hm2, about 70% of the potential yield, implying that the region has room to increase the yield by improving crop management and irrigation systems.     

气候变化对石羊河、大凌河流域灌溉玉米生产的影响

全球气候变化及其影响越来越受到广泛关注,生态环境已相对恶化的地区未来将可能更加脆弱.选取生态环境已十分脆弱的石羊河和大凌河流域,采用区域气候模式与CERES-Maize模型相结合的方法,模拟分析了基准气候(BS,1961-1990年)和A2、B2两种气候变化情景下2011-2100年2个流域灌溉玉米生产的变化,以了解未...     

河南省夏玉米生长季水分供需时空变化特征

水分条件是制约河南夏玉米高产稳产的重要因素,本文利用河南省夏玉米生长季30个农业气象观测站1961～2011年逐日气象观测资料,计算不同生育阶段夏玉米需水量和水分亏缺量,分析其近50a的水分供需条件时空变化特征。结果表明：夏玉米各生育阶段需水量呈显著的下降趋势;各生育阶段之间水分亏缺量没有显著的年际变化。分析各生育阶段水分供需情况,水分亏缺量为正值表明水分供给不足,为负值表示水分有盈余,出苗一拔节期夏玉米水分亏缺量以负值为主,拔节一抽雄期正负交替各占一半,抽雄一乳熟期和乳熟-成熟期以正值为主。空间分布上,夏玉米各生育阶段需水量与各地海拔高度呈显著负相关,全生育期负相关系数为0．799;各阶段水分亏缺量也有一定的相似性,水分亏缺地区主要分布在豫西和豫西北大部,水分较充足的地区主要分布在漯河、南阳、驻马店等地。     

Superoxide Dismutase Plays an Important Role in Maize Resistance to Soil CO2 Stress

CO₂ capture and storage(CCS) has the risk of CO₂ leakage, and this leakage always increases soil CO₂ concentration, and the long-term CO₂ stress damages crop production in farmland. Using maize, the growth characteristics, such as plant height and yield, and physiological indexes(osmoregulation substances and antioxidant enzymes) were explored under different simulative CO₂ leakage conditions. Further, the relationship between maize physiolo...     

结合高光谱像素级信息和CNN的玉米种子品种识别模型

玉米作为中国重要粮食作物,品种众多,易出现错分现象,影响农业安全和粮食生产。针对传统基于卷积神经网络CNN（Convolutional Neural Network）的高光谱图像作物品种识别模型所需建模样本数量巨大的问题,提出基于高光谱像素级信息和CNN的玉米种子品种识别模型。首先,获取不同品种玉米种子在400—1000 nm范围内的高光谱图像,提取样本全部像素的203维光谱信息,利用主成分分析PCA（Principal Component Analysis）算法将光谱维度降至8维。在实验中,样本的像素级光谱信息（即：样本的全部像素的光谱信息）除应用于CNN模型外,也应用于支持向量机（SVM）和K近邻分类（KNN）模型中,结果表明：在相同模型中,基于像素级光谱信息比基于米粒级光谱信息（即：每粒样本所有像素光谱信息的平均值）识别效果好;在相同情况下,CNN模型比SVM和KNN模型的识别效果好;基于像素级光谱信息和CNN的品种识别模型识别效果最稳定,依据像素级分类结果采用多数投票策略对玉米种子样本进行识别,样本识别精度高达100%（注：100%为建模集样本与测试集样本数量为0.27和0.32时的识别精度,随着测试集样本数量的增加,该识别精度将有所降低）。最后,使用t分布随机邻域嵌入（t-SNE）算法实现CNN输出特征值的可视化,验证了基于高光谱像素级信息和CNN的品种识别模型的有效性。在建模样本极少的情况下,实现了玉米种子品种的无损、高效识别,为精准农业提供了理论基础。     

陕西夏玉米产量与气象条件的关系

采用相关分析、正交多项式及积分回归等方法,对陕西1971～2003年夏玉米的单产与气象因子的关系进行了分析.得出：陕西夏玉米的气象波动指数为0.1672,占夏玉米产量波动的73.1%;气象产量存在着约5年的周期性波动;6月中、下旬降水量、7月下旬气温、8月中旬降水量和9月日照时数是影响陕西夏玉米产量的关键气象因子.     

Ecotoxicity of Cadmium to Maize and Soybean Seedling in Black Soil

Ecotoxicity and bioavailability of cadmium(Cd)to the maize(Zea mays L.)and the soybean(Glycine max(L.)Merr.)were investigated by acute toxicity experiment in the laboratory with black soil.Ecotoxicity and bioavailability of Cd were quantified by calculating the median effective concentration(EC50)and bioaccumulation factor(BAF).The measurement endpoints used were seed germination and seedling growth(shoot and root).The results showed that concentrations of Cd in the soil had adverse effect on the growth of roots and shoots.Seed germination was not the sensitive indicator for the ecotoxicity of Cd in the soil,while the growth of roots was the most sensitive measurement endpoint.Absorbability and transport of Cd in plants depended on the test crop species and Cd concentrations in the soil.The maize retains more Cd in its roots,while the soybean transports more Cd to the shoots from roots.     

Greater effect of canopy conductance in regulating the energy partition above the maize field in arid northwest China

The partition of available energy into evapotranspiration affected by environmental and physiological factors is critical in understanding the water cycle and optimizing the water management in the field. Our study attempted to accurately quantify the environmental and physiological control on variability in evaporative fraction (EF) based on the Penman–Monteith model. The eddy covariance method was used to measure water flux over a canopy and then calculate the EF above a maize field in northwest China in 2007. Results indicate that the EF was lower in other growth stages than in the heading stage, so the EF value in the heading stage was taken as the standard value. The decreases in EF caused by canopy conductance and environmental factors were 0.176 and ?0.026, accounting for 117% and ?17% of the total difference in EF, respectively. Such results were mainly due to the following: (1) the variation of maize canopy conductance was greater than that of the environmental factors, such as air temperature, air humidity, wind speed and radiation; (2) the EF of the maize was more sensitive to variation in canopy conductance than the environmental factor. Our study revealed that crop physiological factor played an important role in determining the energy partition processes and reducing the sensible heat flux in the maize field. Copyright © 2012 John Wiley & Sons, Ltd.     

玉米生育模拟模式区域应用研究之水分利用子模式

应用ＳＰＡＣ系统水分循环原理,建立了适合玉米生育的水分利用子模式;利用该模式模拟分析了辽宁省海城市、昌图县、阜新蒙古族自治县３ 地区的土壤水分动态变化过程、农田蒸发和蒸腾过程,并结合作物生物学特性建立了水分胁迫对作物生理过程的影响函数。经计算,该模式模拟结果（ 除个别期次外） 的相对误差范围海城为０．１３％ ～３４．９％ ,昌图为０ ．４４％ ～３２ ．５ ％ ,阜新为２．６％ ～２６．１％ 。