1971～2009年阜康绿洲气候变化规律分析

根据阜康市气象站1971～2009年平均气温、降水量资料,运用线性趋势估计、小波分析、距平与累积距平、滑动t检验等方法,对阜康绿洲年平均气温和降水量变化趋势、周期特征、突变特征进行分析.结果表明:(1)1971～2009年,阜康年平均气温和降水量均呈波动式上升;年平均气温以0.44℃/10a的线性倾向率上升,其相关系数...     

优化施肥对春小麦产量、氮素利用及氮平衡的影响

2009 ～ 2010年,在宁夏引黄灌区分别以宁春11号和宁春16号小麦为供试作物,利用田间试验研究了优化施肥(OPT)和习惯施肥(CON)对春小麦产量、氮素吸收利用和土壤硝态氮累积的影响,表观评估了土壤—小麦体系氮素平衡.结果表明,相对于CK处理,OPT和CON都显著提高春小麦籽粒产量地上部生物量,并促进籽粒N和地上...     

玉米淀粉生产中工艺水的综合利用

在介绍玉米淀粉生产工艺流程的基础上,进一步对工艺过程中的水资源利用问题进行探讨。在玉米淀粉的生产过程中,采用水环流工艺可以实现水资源的可持续利用,以提高玉米中淀粉的回收率和商品淀粉的质量。     

基于博弈论的农户土地利用行为研究——以陕西省米脂县孟岔村为例

以米脂县孟岔村为研究对象,通过设计农户问卷,将研究区农户划分为种粮农户、打工农户、种果农户、种粮兼顾打工农户等四大类,并利用GIS、GPS技术将土地利用的空间信息和农户微观主体的社会经济行为与特征联系起来.随后使用完全信息静态博弈,建立了不同类型农户的两两博弈关系模型,通过模型分析得出: (1) 农户以自身利益最大化为决策目标,并考虑了其他农户的决策行为对其产生的影响,孟岔村最终形成了"少数农户承包旱地经营果园,部分农户承包水浇地,部分农户完全脱离土地外出打工,大部分农户农忙时种粮和农闲时打工"的土地利用和家庭经营模式;(2) 上述土地利用模式使研究区域土壤侵蚀量有了明显的降低并有效地增加了农户的收入.     

贝加尔针茅＋线叶菊草地退化系列的定量划分和动态模型的建立

对贝加尔针茅(Stipa baicalensis) 线叶菊(Filifolium sibiricum)草地中贝加尔针茅、麻花头(Serratula centauroides)、日荫菅(Carex pediformis)和菊叶委陵菜(Potentilla tanacetifolia)4种主要植物的盖度、频度和植被指数进行了分析.结果表明: ①通过SPSS的聚类分析,实验区草地可以划分为3个草地退化系列,即轻度退化、中度退化、重度退化;②随草地退化程度的增强,贝加尔针茅的盖度、频度和指数表现出降低的趋势,麻花头与日荫菅的盖度、频度和植被指数表现出先增加后降低的趋势,而菊叶委陵菜盖度、频度和植被指数则表现出增加的趋势;③轻度退化、中度退化、重度退化3个不同退化系列的草地变化可通过 Y1=0.020 5X1 0.003 9X2 - 0.003 2X3 0.003 9X4 - 47.245 6;Y2=0.005 4X1 0.005 2X2-0.003 4X3 0.011 9X4-16.734 1;Y3=0.002 2X1 0.003 5X2-0.001 6X3 0.004 6X4-3.854 8(其中,Y表示最终的变化值,X1,X2,X3,X4分别表示草地最优状态时贝加尔针茅、麻花头、日荫菅和菊叶委陵菜4种植物的指数)来反映.     

Effects of ammonium and inorganic carbon enrichment on growth and yield of a hydroponic tomato crop

Effects of varying the proportions of NO₃^— and NH₄⁺ in the growth medium on seedling growth and tomato fruit yield (Lycopersicon esculentum L. cv. Trust F1) were investigated in greenhouse hydroponic experiments. The presence of NH₄⁺ as the sole N source (11 mM) was toxic: it curtailed growth and decreased chlorophyll content of the leaves. However, at low concentration (10 % of total N), the presence of NH₄⁺, with or without added dissolved inorganic carbon (DIC), increased vegetative growth and fruit yield by ˜ 15 %, and enhanced taste/flavor of the fruits. In DIC‐enriched treatment, pH was maintained at 5.8 by addition of KHCO₃ or as CaCO₃. The presence of NH₄⁺, at 10 % of total N, inhibited NO₃^— uptake rates by ˜ 27 %. The rates of uptake of NO₃^— and NH₄⁺ were comparable (13.3 and 14.2 mmol plant^—1 d^—1, respectively, in the presence of DIC, and 14.7 and 14.0 mmol plant^—1 d^—1, respectively, in the absence of DIC), despite such a large difference in their concentrations in the nutrient feed solution. A higher proportion of NH₄⁺ (up to 50 % of total N) had no further significant effect upon early vegetative growth, but in a long‐term experiment resulted in a high incidence of blossom end‐rot (BER) disease, thereby severely curtailing fruit yield. The presence of even 1.1 mM NH₄⁺ reduced Ca²⁺ and Mg²⁺ accumulation in the leaves as well as in fruits.     

2013年沈阳地区汛期水情趋势分析

针对沈阳地区旱涝发生的基本规律,根据多年来开展水文中长期预报所应用的理论和方法,总结水情趋势预测工作的经验,对2013年水情趋势进行分析预测。     

天山北坡平原区水面蒸发的实验研究

本文以新疆地勘局昌吉地下水均衡试验场２０ｍ６３水面蒸发池水面蒸发量及常规气象观测资料为基础,应用灰色关联分析方法分析了各气象要素对水面蒸发量的影响程度,给出了Ｅ６０１蒸发四和Φ２０蒸发器水面蒸发折算系数,建立了计算水面蒸发量的经验公式。     

Integrating multiple electromagnetic data to map spatiotemporal variability of soil salinity in Kairouan region,Central Tunisia

Soil salinization is a major problem affecting soils and threatening agricultural sustainability in arid and semi-arid regions,which makes it necessary to establish an efficient strategy to manage soil salinity and confront economic challenges that arise from it.Saline soil recovery involving drainage of shallow saline groundwater and the removal of soil salts by natural rainfall or by irrigation are good strategies for the reclamation of salty soil.To develop suitable management strategies for salty soil reclamation,it is essential to improve soil salinity assessment pro cess/mechanism and to adopt new approaches and techniques.T his study mapped a recovered area of 7200 m2 to assess and verify variations in soil salinity in space and time in K airouan region in Central Tunisia,taking into account the thickness of soil materials.Two electromagnetic conductivity meters(EM38 and EM31)were used to measure the electrical conductivity of saturated soil-paste extract(ECe)and apparent electrical conductivity(E Ca).Multiple linear regression was established between ECe and ECa,and it was revealed that ECa-EM38 is optimal for E Ce prediction in the surface soils.Salinity maps demonstrated that the spatial structure of soil salinity in the region of interest was relatively unchanged but varied temporally.Variation in salinity at the soil surface was greater than that at a depth.These findings can not only be used to track soil salinity variations and their significance in the field but also help to identify the spatial and temporal features of soil salinity,thus improving the efficiency of soil management.     

干旱区农田土壤水分地温变化规律及其相互关系

以干旱区农田灌溉后土壤水分、地温实测数据为基础,研究了其土壤水分、地温各自的变化规律及两者的相互关系.结果表明,各层含水量之间具有高相关性,基本达到了极显著的水平.这与土壤水分灌溉时由上而下的逐渐下渗,以及蒸发时由下而上的逐层上升有密切的关系.各层地温间的相关性大,除地面温度外,其余各层地温间的相关水平为显著或极显著水平,且相邻土层地温间均呈极显著相关.土壤水分及地温剖面垂直变化特征明显,并具有动态性.土壤水分含量大时,两者的垂直变异系数小,反之变异系数大.0～20 cm、地面(0 cm)分别为剖面含水量及地温变异强度的最大层,属中等变异强度.土壤水分及温度之间的负相关性明显.地面温度是预测表层、底层土壤水分的良好指标,利用回归分析法建立的土壤水分与地温间的函数关系可为推测土壤水分提供依据.