旱地果园穴贮肥水地膜覆盖试验研究

<正> 山丘地区,山岭薄地多,地力差、水源奇缺,沟谷洼地多种植农作物。在保证粮食生产的前提下,为了增加经济收入,搞好立体种植,果树只好上岭、进山,发展旱地果园。为了使有限的水肥发挥最大的经济效能,解决旱地果园的缺水、少肥,提高地力,增加产量,自1989～1991年,我们对山楂、桃等果树进行了穴贮肥水地膜覆盖试验。     

渭北地区旱地果园渗池节水灌溉技术研究

采用黏土护底的渗池补水方式,于１９９７年渭北旱塬旱地果园果树不同生育阶段,进行了部分根系灌水试验,在对土壤含水量,果树生长发育情况和产量测定的基础上,提出了特定年份渭北地区旱地果园适宜灌水方式及有限灌溉制度,灌水定额１０５ｍ＾３／ｈｍ＾２,灌水次数视不同频率年１￣４次。     

山丘区果园地下陶管渗灌技术的应用研究

１９８６～１９９３年，在山东省临沭县山丘区旱地果园，进行了地下陶管渗灌技术的应用研究，结果表明，每次灌水可在３０～３５ｄ使果树根际土壤的相对湿度保持田间持水量的６０％～８０％，为果树提供了良好的土壤水、肥、气、热条件，从而促进了果树根系及地上部分的生长发育。每年增产苹果７２０４．５０ｋｇ／ｈｍ２，节水２５１４．３０ｍ３／ｈｍ２，增值１０４６４．４５元／ｈｍ２。这一渗灌技术可作为我国北方旱地果园一种新的有效的节水灌溉技术推广应用。     

陕西岐山:新潮果农用“枪”施肥

<正>今年6—7月的持续干旱,导致陕西省岐山县大部分果园生长不良,果树叶片偏小,果实膨大受阻,特别是位于台塬坡地的董家台村果园,自麦收后叶片几乎停滞未长,小而干涩,缺乏生机,但是,却独有一家果园,肥厚深绿的叶片和累累硕果如鹤立鸡群般昭示着主人管理上的独到之处,园主赵万军逢人便夸水肥一体化技术给他带来的惊喜。水肥一体化技术是国家苹果产业技术体系西安综合试验站岗位专家通过两年多的试验示范,提出     

坡地果树保水丰产栽培技术研究

坡地果树保水丰产栽培技术研究课题利用微机动态模拟果树年生长过程和果园水环境变化，对果树年生长周期需水规律进行定量研究，对20多项果树生长特征值进行量化，根据气象学、土壤学、生态学、果树栽培学等多学科专业知识开发了果树诊断及咨询系统，可根据果园的立地条件、果树品种和经营管理水平等估测其果园的年产量和生产潜力，找出影响产量的限制因子，提出保水丰产栽培及病虫害防治方案，帮助果农应用现代化科技手段，科学地规划、管理果园，以达到优质、高产的目的。     

穴贮肥水覆膜配套旱井技术在山地果园中的应用

山地丘陵地带,气候温和,适宜多种北方果树生长。山地丘陵果树,虽有丰富的光热资源,但干旱、土壤瘠薄,仍是生产优质果品的主要限制因子。近几年,生物覆膜、滴灌渗灌、穴贮肥水、地膜覆盖、旱井等果树旱作节水技术,在山地果园中得到了广泛应用,并取得了明显成效。在一系列旱地节水技术的推广中,我们发现穴贮肥水地膜覆盖与旱井技术有机结合更适合山地果园应用。1穴贮肥水覆膜与旱井结合的原理(1)穴贮肥水地膜覆盖技术是把果树的浇水、施肥、保墒结合在一起,在局部范围内为根系生长发育创造良好环境,从而保证果树正常生长结果。从节水栽培的角…     

旱地作物生育对土壤水肥耦联的响应研究进展

水肥是作物生长发育的基本物质基础,也是制约农业的主要因素。90年代以来我国在水肥对旱作 农业生产的协同效应方面做了大量的定性或定量研究工作,较为系统、深入地分析了旱地作物生长发育及产量对农田土壤水肥的响应。在总结分析的基础上指出水肥对旱地作物作用大小是随水肥相对平衡而变化。     

旱地作物生育对土壤水肥耦联的响应研究进展

水肥是作物生长发育的基本物质基础,也是制约农业的主要因素。９０年代以来我国在水肥对旱作农业生产的协同效应方面做了大量的定性或定量研究工作,较为系统、深入地分析了旱地作物生长发育及产量对农田土壤水肥的响应。在总结分析的基础上指出水肥对旱地作物作用大小是随水肥相对平衡而变化。     

LabVIEW软件平台在果园生态环境远程监测系统中的应用

在果园的生产管理中，环境对果树的生长发育、栽培技术的实施、病虫害的预防等产生极其重要的影响。应用LabVIEW虚拟仪器开发平台，结合数据采集模块和各种传感器，实现了果园生态环境数据的实时采集，并利用LabVIEW自带的远程面板技术让客户远程监控服务器端。试验结果表明：系统能较好地实现果园生态环境远程实时监测，为果树生产管理提供决策依据。     

果树水肥一体化技术浅析

水肥一体化是现代农业技术中具有高效、节水、节肥等优点的一种技术方法,结合了灌溉和施肥两大环节,省去了烦琐的栽培种植步骤,提高了水肥资源的利用效率和果实的产量。在果树种植中应用水肥一体化技术能够进一步提升经济效益。基于此,以广西南宁市武鸣区果树种植为例,探究果树水肥一体化技术。     

Role of selenium in mitigation of cadmium toxicity in pepper grown in hydroponic condition

Selenium (Se) is an essential element for humans but is not considered as essential for plants. However, its beneficial role in improving plant growth and stress tolerances is well established. In order to study the role of Se in cadmium (Cd) toxicity in pepper (Capsicum frutescens cv. Suryankhi Cluster), this experiment was carried out in greenhouse conditions. Treatments comprised Cd [0, 0.25, and 0.5 mM cadmium chloride (CdCl₂)] and Se [0, 3, and 7 µM sodium selenite (Na₂SeO₃)] with three replications. The result showed that Cd decreased chlorophyll a, chlorophyll b, and carotenoids, whereas Se supplementation diminished Cd toxicity on photosynthetic pigment. Selenium at 7 µM significantly increased the leaf area in the plants grown at 0.25 mM Cd. The application of Se at 3 µM with 0.25 mM Cd and Se at 3 µM and Se at 7 µM with 0.5 mM Cd increased the activity of catalase (CAT). Selenium at 7 µM decreased the proline content of pepper leaves exposed to Cd at 0.5 mM (30%). Selenium significantly enhanced the antioxidant activity of leaves, which was diminished by Cd toxicity. In general, Se has a beneficial effect on plant growth and is an antioxidant enzyme of pepper cv. Suryankhi Cluster under Cd stress and non-stress conditions.     

Accumulation of copper in soils and leaves of tomato plants in greenhouses in Turkey

Copper (Cu)‐containing fertilizers, fungicides, and bactericides has been used extensively in the greenhouses in the Antalya province in recent decades with the use of such materials tending to increase year by year. The level of DTPA‐extractable Cu was determined in 210 soils (0–20 and 20–40 cm depth) and 105 leaf samples obtained from 105 tomato greenhouses. The DTPA‐extractable Cu contents of the soils taken from the 0–20 depth ranged between 0.76 and 88.03 mg kg^‐1 (mean 7.79 mg kg^‐1). The percentage of soils containing DTPA‐extractable Cu greater than the critical toxicity level (20 mg kg^‐1) was 8.1. The Cu content of tomato leaf samples ranged between 2.4 and 1,490 mg kg^‐1 (mean 166.5 mg kg^‐1). The Cu concentration in leaf samples was very high due to the intensive use of foliar applied Cu‐containing chemicals. As a consequence, 24.8% of the leaf tomato samples analyzed contained over 200 mg Cu kg^‐1, the maximum accepted tolerance level. Therefore, it may be necessary to reduce the use of Cu‐containing pesticides and fertilizers, or at least reduce the amount of Cu‐containing fertilizers being used in those greenhouses where Cu‐containing pesticides have been or are being used.     

红壤区不同肥力水稻土根际硝化作用特征

通过根际培养箱(三室)——速冻切片技术研究了红壤地区高、低两种肥力下水稻苗期根表、根际和土体土壤矿质态氮含量和硝化强度,以及水稻生长、氮素积累的差异。结果表明,肥力水平对水稻根表和根际土壤铵态氮(NH4+-N)含量无显著影响,但高肥力显著提高土体土壤NH4+-N含量,以及根表、根际和土体土壤硝态氮(NO3--N)含量及硝化强度。两种肥力水稻土硝化强度最大值均出现在距根表2 mm处,分别为0.20和0.31μmol kg-1 h-1。土体土壤硝化强度随距根表距离增加而降低,低肥力土壤在距根表10～40mm处时硝化强度接近本底值,而高肥力土壤在距根表20～40 mm处时接近本底值。与不种水稻的CK相比,种植水稻显著提高根际土壤硝化强度。高肥力能显著改善水稻生长,增加植株氮素积累量,尤其显著促进根系生长及通气组织发育。由于红壤稻田肥力水平的差异造成水稻根际硝化强度以及水稻吸收NO3-的差异,导致高肥条件下水稻显示出更强的生长势和氮素吸收利用能力。因此,合理提高红壤稻田肥力水平对改善红壤区水稻根际土壤硝化作用及水稻氮素营养具有重要意义。     

Occurrence of Sexual Hormones in Sediments of Mangrove in Brazil

The presence of sexual hormones (female estrogens) was assessed in sediments of a mangrove located in the urban region of southern Brazil. The estrogens are involved in human sexual reproduction. They act as the chemical messengers, and they are classified as natural and synthetic. The estrogens inputs in the environment are from treated and untreated sewage. The presence of estrogens in sewage is excretion from the female due to natural production and use of contraceptives (synthetic estrogens). With the indiscriminate release of sewage into the environment, estrogens can be found in rivers, lakes, and even in oceans. In this work, the presence of estrone (E1), 17-??-estradiol (E2), and 17-??-ethynilestradiol (EE2) in eight sedimentary stations in Itacorubi mangrove located on Santa Catarina Island, south Brazil, was investigated. Historically, the Itacorubi mangrove has been impacted by anthropogenic activities because the mangrove is inserted in the urban area of the Florianopolis. The estrogen EE2, used as contraceptive, had the highest concentration in mangrove sediment, 129.75?±?3.89 ng/g. E2 was also found, with its concentration ranging from 0.90?±?0.03 to 39.77?±?1.19 ng/g. Following the mechanism, under aerobic or anaerobic conditions, E2 will first be oxidized to E1, which is further oxidized to unknown metabolites and finally to CO₂ and water (mineralized). EE2 is oxidized to unknown metabolites and also finally mineralized. Theoretically, under anaerobic conditions, EE2 can be reduced to E1 even in environments such as mangrove which is essentially anaerobic.     

自由基在鸡肾病发生中的作用研究

肾病即急性肾小管坏死.鸡肾病在养鸡生产中极为常见,尤其近年来,鸡肾病的发生日益增多,由于其发生机制不清楚,临床治疗鸡肾病的依据不足,致使治疗效果不佳,为此,提出本研究以探讨鸡肾病的发生机制,为本病防治提供理论依据.     

Meta-analysis in the Selection of Groups in Varieties of Citrus

Brazil is the largest producer of oranges (Citrus sinensis) in the world. The nutrient management of tree orchards is designed from experiments with a limited number of varieties. This knowledge is transferred to other varieties by diagnosing tissue nutrient composition and tree demand. Compositional data analysis has been first applied to tissue analysis of agricultural crops using centered log ratios with compositional nutrient diagnosis (CND-clr). The isometric log ratio (ilr) transformation is a new approach based on binary nutrient ratios and the principle of orthogonality (CND-ilr). We analyzed eleven nutrients: nitrogen (N), sulfur (S), phosphorus (P), potassium (K), calcium (Ca), magnesium (Mg), boron (B), copper (Cu), zinc (Zn), manganese (Mn), and iron (Fe) in leaf tissue samples across 108 commercial plots (thirty-one grow Valencia, twenty-two Hamlim, twenty Pera, and thirty-five Natal). Nutrients were partitioned between macro- and micronutrients as well as anionic and cationic species. The effect size of varieties over Valencia was quantified by the mean and standard deviation of ilr values across ilr coordinates. Specific varietal nutrient profiles and ilr norms were defined. The nutrient profile of orange varieties could be classified into homogeneous groups to take advantage of fertilizer trials conducted on varieties of the same group. The Aitchison distance and a perturbation vector could be instrumental for diagnostic purposes and nutrient management.     

Effect of iron-quercetin complex on reduction of nitrite in in vitro and in vivo systems

This study investigated whether reducing agents such as quercetin and iron(II) facilitate formation of nitric oxide (NO) gas from orally ingested nitrite in an vivo study. When 3 mg/kg Na (15)NO2 was orally administered to rats with or without iron(II) or quercetin, Hb (15)NO, which is indicative of systemic (15)NO, was detected in the blood, with the maximum blood concentration of Hb (15)NO at 15 min after nitrite or nitrite plus quercetin treatment, whereas after administration of nitrite plus iron(II) or nitrite plus iron(II) and quercetin, the time was shortened to 10 min. Interestingly, iron(II), quercetin, or iron(II) plus quercetin did not affect the total amount of Hb (15)NO generated from orally administered Na (15)NO2. However, the systemic nitrite concentration was significantly decreased in the presence of iron(II) or iron(II) plus quercetin. These results may indicate that iron(II) is critical to the generation of NO gas from nitrite, whereas quercetin contributed little under the in vivo experimental conditions.     

Role of aldehyde oxidase in the hepatic in vitro metabolism of 3-methylindole in pigs

The metabolism of 3-hydroxy-3-methylindolenine (HMI), a recently discovered metabolite of 3-methylindole (3MI, skatole) produced by porcine liver microsomes, was investigated in vitro using porcine liver cytosol. HMI was rapidly metabolized to a single product, 3-hydroxy-3-methyloxindole (HMOI), by porcine cytosol. By the use of the selective inhibitors menadione and quinacrine, it was shown that the enzyme responsible for the oxidation of HMI into HMOI was aldehyde oxidase (AO; aldehyde:oxygen oxidoreductase, EC 1.2.3.1). The activity of AO in the conversion of HMI to HMOI was measured in a population of pigs (n = 30) with a wide range of 3MI levels in back fat (0.07-0.30 mg/kg). AO activity was found to be negatively correlated (r = -0.70; P < 0.001) with the level of 3MI in fat. The results of the present study suggest that AO plays an important role in the metabolism of 3MI in the pig and that its catalytic activity is related to an adequate 3MI clearance.     

Role of hydrocolloids in the creaming of oil in water emulsions

The influence of guar gum and xanthan gum on the creaming of 10% oil in water emulsions has been investigated. The presence of very low concentrations of the polysaccharides (typically < approximately 0.075%) was found to induce depletion flocculation of the emulsion droplets and increased the rate of creaming. However, at higher polysaccharide concentrations (typically > approximately 0.1%) the creaming rate was reduced due to the increased viscosity of the aqueous phase. For most systems a delay period was noted before creaming started, which was found to be dependent on the zero shear viscosity of the continuous phase and independent of polysaccharide type. The delay period increased significantly at zero shear viscosities approaching 1 Pa s. A mathematical model has been used to fit the creaming rate profiles and a simple exponential relationship obtained between delay time and polysaccharide concentration.     

响应面设计法在温室番茄栽培中的应用

为优化温室番茄的栽培条件,试验研究了不同栽培密度、施氮量和施钾量对日光温室番茄产量的影响。通过中心复合试验设计,构建三因素（栽培密度,氮肥,钾肥）五水平的响应面设计方法并建立番茄产量与三因子的二次回归数学模型。结果表明:三因素对温室番茄产量均有显著的影响（p0.01）,影响的大小顺序为栽培密度施钾量施氮量;栽培密度与施氮量、施钾量之间存在显著的交互作用（p0.01）,施氮量与施钾量之间的相互作用对番茄产量影响不显著（p0.05）;多元二次回归分析结果显示,栽培密度、施氮量、施钾量与番茄产量之间的回归模型高度显著（p0.01）。统计分析确定温室番茄的最佳栽培条件为:栽培密度4.83万株/hm2,施氮量262 kg/hm2,施钾量513kg/hm2;在此条件下,温室番茄产量的预测值为119381kg/hm2,验证试验所得产量为121005kg/hm2。本研究为日光温室番茄高产、稳产和优质提供了理论依据。