棚栽西瓜嫁接栽培技术

栽培要点:嫁接西瓜与自根西瓜栽培技术有所不同,表现在嫁接西瓜前期需肥量比自根西瓜少、发生的主要病害有所不同,而且整枝方式也与自根苗有所差异。

果园套种紫云英好处多

一、紫云英的根瘤菌具有固氧作用,能吸收空气中的氮素,从而转化为果树所吸收的营养成份。压青后可增加土壤肥力,改良土壤团粒结构。根瘤根还能促进土壤微生物活动,平衡菌群结构,初产果园每年可节省施座果肥1—2次。

Experimental Study on the Resistance of a Transport Ship Navigating in Level Ice

This study investigates the resistance of a transport ship navigating in level ice by conducting a series of model tests in an ice tank at Tianjin University. The laboratory-scale model ship was mounted on a rigid carriage using a one-directional load cell and then towed through an ice sheet at different speeds. We observed the ice-breaking process at different parts of the ship and motion of the ice floes and measured the resistances under different speeds to determine the relationship between the ice-breaking process and ice resistance. The bending failure at the shoulder area was found to cause maximum resistance. Furthermore, we introduced the analytical method of Lindqvist （1989） for estimating ice resistance and then compared these calculated results with those from our model tests. The results indicate that the calculated total resistances are higher than those we determined in the model tests.

Uncontrolled hypertension in older patients： markers and associated factors to masked and white-coat effect

Background Hypertension is the main risk factor for cardiovascular diseases, affecting more than half the elderly population. It is essential to know if they have proper control of hypertension. The aim of this study was to identify the associated factors to masked uncon- trolled hypertension and false uncontrolled hypertension in older patients. Methods Two-hundred seventy-three individuals （70.1±6.7 years-old） had blood pressure （BP） measured at the office and by ambulatory BP monitoring （ABPM）, with the definition of controlled group （C）, individuals with high office BP and adequate ABPM, called white-coat effect group （WCE）, uncontrolled （UC）, and subjects with ap- propriate office BP and elevated ABPM denominated masked effect group （ME）. Age, body mass index, diabetes, pulse pressure （PP） and BP dipping during sleep were evaluated （Kruskal-Wallis test and logistic regression models）. Results Age was higher in UC than in C and ME （P 〈 0.01）, and 24-h ABPM PP was lower in C （48± 7 mmHg） and WCE （51±6 mmHg） than in UC （67±12 mmHg） and ME （59±8 mmHg） （P 〈 0.01）. Sleep systolic BP dipping was lower in ME than in C （P = 0.03）. Female gender was associated with a greater chance of being of ME group, which showed a higher PP and lower BP dipping during sleep. Conclusions In older individuals, office BP measure- ments did not allow the detection of associated factors that would permit to differentiate WCE from UC group and C from ME group. ABPM favored the identification of a higher PP and a lower BP dipping during sleep in the masked effect and uncontrolled groups.

The Mulching Effect of the Olives Mill Wastewaters on the Soil Cohesion Improvement and Wind Erosion Reduction in the Southern Tunisian Arid Zones

In the Tunisian arid zones, where the soils are sandy and very poor in organic and mineral matters, wind erosion process is very active and triggered the departure of the thinnest elements of the soil and the apparition of dune building. Facing to these situations, many simple and efficient practices for combating desertification had been tested since many years in the Tunisian arid zones. The mulching of the olive mill wastewaters is one of these techniques. Otherwise, an olive mill wastewaters spray experimental device, with these respective doses of 50 m3/ha, 100 m3/ha and 200 m3/ha next to a witness parcel without OMW, has been putted in place since 1995 in the Chammakh-Zarzis, Tunisia. The mulching of the OMW, in the southern Tunisian regions constitutes an interesting alternative for the controlled and rational evacuation of this polluting sewage on the one hand and for the soil cohesion improvement by： （i） the increase of the organic matter rate which raised, in proportion to the dose, from 0.06% to 1.27% after 10 years of OMW mulching, and （ii） the improvement of the soil structural stability or ~＇the mean weight diameter＂ where the aggregation rate superior to 2 mm is increased until 34% with the dose of 200 m3/ha. Therefore, that treatment will bind the sand particles and thereof control of sandstorms is gained. Indeed, the results in wind tunnel tests on the soil treated with these different doses of OMW showed that the threshold friction velocity u,t was raised from 8.5 m/s to 12 m/s for 50 m3/ha and 200 m3/ha, respectively.

Effects of Mulching Material on the Early Fruit Yield of Tomato （Lycopersicon esculentum Mill.） Varieties under Polyhouse Growing Condition

Tomato is one of the most widely produced and consumed vegetable crops in Ethiopia. It is not produced during the rainy season, mainly due to high disease pressure and low soil temperature. Therefore, an experiment was conducted to study the effect of different types of mulch （black and white plastic mulch as well as grass mulch） on early yield of tomato varieties （Miya ＆ Cochoro） under polyhouse growing condition at Bahir Dar during the rainy season in 2012. Treatments were arranged in 4 - 2 factorial combinations in randomized complete block design with three replications. One month old seedlings were transplanted on 8.4 m2 gross plots size （3 m x 2.8 m） at a spacing of 70 cm x 40 cm between rows and plants, respectively. Data recorded from plants found in the two middle rows of each plot. Di-ammonium phosphate （DAP） and Urea fertilizers were applied at the rate of 200 kg and 100 kg/ha, respectively. Sixteen plants were considered for data collection in each plot. White plastic mulch resulted in significantly （P 〈 0.05） earlier flowering, fruit setting and fruit maturity compared to other mulching materials. Varieties were also significantly different in days required to flowering, fruit setting and fruit maturity. Miya took significantly short period to flower, fruit set and fruit maturity compared to Cochoro variety. The effect of different mulch types on early fruit yield was found statistically significant. The highest early marketable fruit yield of 10.99 ton/ha and 10.54 ton/ha were recorded when Miya variety was grown with white and black plastic mulch, respectively. Therefore, use of white and black plastic mulches recommended for early tomato fruit yield.

Benefiting from providing multi-dimensional view of peers in overlay of P2P streaming system

Most overlay of existing P2P streaming systems just focus on the view point of video content data.An multi-dimensional overlay for the P2P streaming system(MDOPS) is proposed for providing multi-dimensional view including video data,peers' service capability and online stability based on locality sensitive hashing.MDOPS organizes all Live/VoD peers and the above multi-dimensional information in a one-dimensinal DHT,uses range resource information publish/search and introduces multiple load balancing methods.MDOPS maintains an additional candidate coordinating peer list with high qualified peers who own the video data the peer would possibly access currently and in future.This list could speed up the process of searching peers for data scheduling layer.Simulation experiment based on trace of real streaming system has testified that MDOPS can effectively improve the quality of search results and smooth load distribution among peers without increasing the cost of resource publish/search.

Effect of Weed Control on Establishment and Herbage Production in Dwarf Napiergrass

Weed control is a crucial factor for maintaining establishment and herbage production in dwarf variety of late-heading type （DL） napiergrass （Pennisetum purpureum Schumach） in southern Kyushu, Japan. This study was aimed to verify the weeding-effect on dry matter （DM） production in the farm level and to examine the effect of several weed control, i.e. mixed sowing of annual setaria （abbreviated as S）, which has no regrowth ability after stem-elongation, paper-mulching （as P） and hand-weeding （as ＋W）, compared with no-weeding （as -W） on DM yield and quality of DL napiergrass in two years. Weed control practices significantly （P 〈 0.05） promoted several plant growth attributes in DL napiergrass, compared with no-weeding both in the farm and experimental levels. Paper-mulchidng （P-W or P＋S-W） had highest yields among several practices in both years. Setaria-sowing ha a partially mitigating effect of weed damage on DM production of DL napiergrass, while additive DM gain from setaria could compensate the yield decrease in DL napiergrass and reduce herbicide cost. Neither digestibility nor crude protein was affected by any weed control in either year. Thus, paper-mulching and annual setaria-sowing could be effective alternative practices for weed control of this species.

Numerical Simulation of Soil Water Dynamics in a Drip Irrigated Cotton Field Under Plastic Mulch

Drip irrigation under plastic mulch has been widely applied in arid Northwest China as a water-saving irrigation technology. A comprehensive knowledge of the distribution and movement of soil water in root zone is essential for the design and management of irrigation regimes. Simulation models have been proved to be efficient methods for this purpose. In this study, the numerical model Hydrus-2D was used to simulate the temporal variations of soil water content in a drip irrigated cotton field under mulching. A concept of partitioning coefficient, calibrated to be 0.07, was introduced to describe the effect of plastic mulch on prevention of evaporation. The soil hydraulic parameters were optimized by inverse solution using the field data. At the optimized conditions, the model was used to predict soil water content for four field treatments. The agreements between the predictions and observations were evaluated using coefficient of determination （R2） and root mean square error （RMSE）. The results suggested that the model fairly reproduced the variations in soil water content at all locations in four treatments, with R2 ranging from 0.582 to 0.826 and RMSE from 0.029 to 0.050 cm3 cm-3, indicating that the simulations agreed well with the observations.

A Study on the Degree of Barrier Coverage in Wireless Sensor Networks

Recently, the barrier coverage was proposed and received much attention in wireless sensor network (WSN), and the degree of the barrier coverage, one of the critical parameters of WSN, must be re-studied due to the difference between the barrier coverage and blanket coverage. In this paper, we propose two algorithms, namely, local tree based no-way and back (LTNWB) algorithm and sensor minimum cut sets (SMCS) algorithm, for the opened and closed belt regions to determine the degree of the barrier coverage of WSN. Our main objective is to minimize the complexity of these algorithms. For the opened belt region, both algorithms work well, and for the closed belt region, they will still come into existence while some restricted conditions are taken into consideration. Finally, the simulation results demonstrate the feasibility of the proposed algorithms.