太行山前平原高产农区土壤水分特征及农田节水潜力

根据连续4年对非耕地和田间土壤水分的测定，分析了太行山前平原高产农区土壤水分的变化规律，并根据该区主要作物冬小麦和夏玉米的需水规律，提出了农田节水潜力的两个方面。     

中国首都圈土地沙化过程及防治对策——以河北省丰宁县小坝子乡为例

以河北省丰宁县小坝子乡的土地沙化为例，从地质过程、生物过程、人文过程探讨和研究了沙化演变与治理对策，指出了治穷和治沙的关系，绿化与水平衡的因果关系，提出绿色、人文、科技结合，林草兼顾、经济发展与环境建设是步，是为北京堵沙源、保水源的有效措施。     

不同供水条件对冬小麦根系分布、产量及水分利用效率的影响

通过中科院栾城农业生态试验站3种不同降水年型的田间灌水试验，研究了不同供水条件对冬小麦根系分布、产量及水分利用效率的影响，旨在为华北地区冬小麦建立优化灌溉制度，提高水分利用效率，达到节水增产目的提供理论依据。试验结果表明，冬小麦根系主要集中分布在80 cm以上土层，随土层深度的增加，根长密度呈指数下降；综合分析根系对不同土层的水分吸收、作物耗水组成及产量、水分利用效率与总耗水的关系，提出华北地区冬小麦最佳灌水方式是：丰水年灌0水、平水年灌1水(拔节水)、枯水年灌2水(拔节水和抽穗水)，次灌水量60～75 mm，具有明显的节水增产效益。     

喷灌条件下土壤NO3--N含量的空间变异性研究

作物生长所需的养分主要来源于土壤 ,因而土壤作为作物生长的营养库 ,其养分的变异必然会引起作物生长的变异。北方旱地土壤氮素形态一般以硝态氮为主 ,所以开展土壤NO- 3 N含量空间变异性研究对于科学合理地制定农田施肥方案 ,提高氮肥利用率 ,促进变量施肥技术的发展 ,实现精     

Long-term consequences of tillage,residue management,and crop rotation on maize/wheat root rot and nematode populations in subtropical highlands

Densely populated and intensively cropped, the subtropical highlands of the world have severe agricultural sustainability problems resulting from soil erosion and fertility decline. In 1991, the International Maize and Wheat Improvement Center (CIMMYT) initiated a long-term field experiment with zero tillage under rainfed conditions at its semi-arid highland experiment station in Mexico (2240 m asl; 19.31°N, 98.50°W; Cumulic Phaeozem) to evaluate the effects of tillage, residue management, and rotation on maize and wheat production. Long-term effects on root rot and nematode populations – and their possible detrimental effects on yield – were monitored from 1998 to 2003 to evaluate the sustainability of the cropping system. In general, wheat showed less root rot incidence than maize. Crop residue retention reduced the numbers of the nematode Pratylenchus thornei in both crops, as did zero tillage compared with conventional tillage. Conventional tillage with continuous maize and residue removal, the common farmer practice in this region, reduced yield and dramatically increased P. thornei. Zero tillage with residue removal resulted in low values for yield, root rot, and nematode populations, especially under maize monoculture. Under zero tillage and residue retention, root rot incidence in maize was moderate, parasitic nematode numbers were low, and yield was highest compared to alternative practices. In wheat, the highest yields were observed under zero tillage and residue retention, with intermediate root rot incidence. Zero tillage with rotation and residue retention enhanced water availability, soil structure, and nutrient availability more than conventional tillage. Microbial life diversity increased under zero tillage and residue retention, which may useful for biological control and integrated pest management.     

河北日光温室气象灾害影响和气象服务评估

通过问卷形式,对河北省日光温室蔬菜生产经销者和技术人员对气象服务的满意度,低温冻害、寡照、大风、雪灾4种主要气象灾害对日光温室蔬菜产量、品质、贮藏、运输、销售的影响率,用于日光温室气象灾害防御及补救的费用占所有气象灾害防御和补救费用百分率,以及菜农接受气象服务的投入占收成的百分率等进行调查,并利用德尔菲法对气象灾害防御和补救费用及气象服务的效益进行定量化评估.结果表明,多数被调查者认为低温冻害和寡照对日光温室蔬菜产量和品质有较大影响,其中认为低温冻害影响率大于15％的人数分别占45.6％、53.7％,认为寡照灾害影响率大于15％的人数分别占37.8％、35.4％,认为大风和雪灾的影响相对较小;70％以上的人认为大风和寡照对日光温室蔬菜贮藏、运输和销售的影响率在20％以下,超过50％的人认为低温冻害对蔬菜贮藏影响率大于30％,认为雪灾对蔬菜贮藏、运输和销售的影响率大于30％的人数分别占31.0％、63.9％和53.0％.被调查者对日光温室4种主要气象灾害的气象服务满意度均达96％以上.对大风、低温冻害、寡照和雪灾的防御和补救的费用占所有气象灾害防御及补救费用的平均百分率分别为20.3％、15.8％、13.0％和19.4％,4种灾害的气象服务平均贡献率分别为3.08％、2.25％、1.90％和2.55％.按近l0a（2004-2013）河北省日光温室蔬菜产业年平均生产总值计算,大风灾害气象服务效益最高,平均每年达2.941亿元,其它依次为雪灾、低温冻害和寡照,总效益平均每年达9.340亿元.     

玉米生长后期的根系分布研究

为了研究玉米生长后期根系的生长发育规律,利用中国气象局固城农业气象试验站大型根剖面系统,采用微根管观测系统及方形整段标本法和地下根系室玻璃窗,对‘屯玉46号’玉米根系的生长状况进行了试验研究。结果表明:垂直方向上,方形整段标本法和微根管法测得的根长密度占整层总根长密度比例的变化趋势一致,相关系数分别为0.987和0.717,且两种方法在0~20 cm土层的根长密度比例均为最大。0~60 cm土层为玉米根系生长活跃区,方形整段标本法测得根长密度生长量为其余层的4倍。两种方法测得的根长密度无显著差异,相关系数为0.830,均匀性水平较好。玉米成熟期根系的水平幅度较乳熟期窄,下层根系仍处于生长中,垂直深度增加。玻璃窗与方形整段标本法观测的根深测定结果存在差异,这可能与观测环境条件不一致有关。     

Phenotypic variations of wheat cultivars from the North China Plain in response to cadmium stress and associated single nucleotide polymorphisms identified by a genome-wide association study

Understanding the genetic mechanisms for cadmium (Cd) uptake and translocation in common wheat (Triticum aestivum) is of significance in food Cd contamination control. In this study, a diverse panel of 132 wheat cultivars was collected from the North China Plain. The cultivars were evaluated in terms of their phenotypic variations in response to Cd stress and subjected to a genome-wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with the phenotypic variations at the seedling stage. Significant phenotypic variations with high heritability were observed among the wheat cultivars exposed to 40 μmol L^-1 Cd for the studied traits, including root length (RL), shoot length (SL), root and shoot dry biomasses (RDW and SDW, respectively), root and shoot Cd concentrations (RCD and SCD, respectively), and Cd translocation factor (TF). Mean RCD, SCD, and TF ranged from 1.0 to 33.8, 0.125 to 2.022, and 0.009 to 0.321 mg g^-1, respectively. Cluster analysis showed that wheat cultivars with higher RL, SL, RDW, and SDW under Cd stress were able to accumulate more Cd in root, leading to a lower Cd TF. Mixed linear model-based association analysis detected 17 novel significant marker-trait associations (MTAs), four of which were significant at a genome-wide scale. Most of the significant MTAs controlled Cd TF and explained 17.17%-26.47% of the phenotypic variations. Some of the SNP loci were physically close to a reported Cd-related quantitative trait locus or gene on wheat chromosomes. Results of this study provided a list of wheat cultivars with the potential of low Cd accumulation and enriched our knowledge on the genetic basis of Cd uptake and translocation in wheat. Pyramiding breeding of superior alleles detected in this study may additionally reduce Cd accumulation of improved wheat cultivars with excellent agronomic traits.     

浸提法测定玉米叶绿素含量的改进

以玉米叶片为试材,研究了8种不同有机溶剂浸提液提取叶绿素的效率及低温冷冻对叶绿素提取的影响。试验中采用叶绿素仪先预叶片;冷冻—高温快速浸提试验,采用先称取样品,后冷冻方式。结果表明:室温(25℃)下,浸提法要优于研磨法,混合液浸提叶绿素比单独用丙酮或乙醇浸提快,其中丙酮∶乙醇=2∶1的浸提液浸提速度快而稳,是试验中最佳的叶绿素提取方法。最佳浸提时间在浸提16h时。叶片冷冻处理后,快速浸提能够缩短叶绿素浸提时间。由于受光照、高温的影响,测定值普遍较低。     

高产抗病夏大豆新品种化诱446的选育

化诱446大豆是应用化学诱变剂DES及PYM复合处理冀豆4号湿种子经累代选择鉴定育成的新品种。该品种具有产量高、品质优、抗病、抗倒性强等优点。经3年品比试验,2年的区域试验,1年的生产试验均比对照品种冀豆7号增产显著,居参试品种首位。适宜在河北省中南部及同类气候区夏播推广应用。