Effect of Flooding and Air-drying on Nutrition Content of Soil in Embankment WLFZ of Chaohu Lake

Organic matter （OM）, total nitrogen （TN）, organic phosphorous （OP） and total phosphorous （TP）content of soil in northwest water-level fluctuating zone （WLFZ） of Lake Chaohu under natural and different artificial conditions were ana- lyzed to study the variation of OM, TN, OP and TP. It showed： Flooding and air- drying help to increase soil OM content in study area. Process of flooding and air- drying is conducive to soil adsorption of nitrogen and it can enhance spatial hetero- geneity of soil OM, TN, OP, process of flooding and air-drying also can reduce the difference of TP contents among different points. Riprap embankment is not con- ducive to maintaining soil organic matter under flooded conditions, emergent plants are conducive to maintaining soil organic matter under flooded conditions. Soil with high nitrogen content will release nitrogen to overlying water under flooded condi- tions. Under drying after flooding conditions, demand for phosphorus of vegetation growth will reduce TP content in soil, bare area will enrich phosphorus, when the next flood cover up a greater release of phosphorus will happen

Effects of Air-Drying on the Inorganic Phosphorus Forms in Soils

After 90 days cultivation of five different plants (rye grass, lupin, buckwheat, rape and amaranth) in three soils (Yellowbrown soil, Paddy soil and Red soil), fresh soil samples were collected and inorganic phosphorus (Pi) fractions weremeasured before and after air-drying. The results clearly indicated that the total Pi and their composition differed significantlyamong soil types. The air-drying process increased the total Pi in yellow brown soil and in paddy soil, while decreased thatin red soil. The total Pi could vary to 70% of that before air-drying. The Pi forms in different soils changed to differentextent after air-drying. As to yellow brown soil, Al-P decreased, while O-P and Ca-P increased; as to paddy soil, Al-P andCa-P increased, while Fe-P and O-P remained; as to red soil, Al-P and Fe-P increased, Ca-P remained and O-P reducedobviously. Growth of different plants in soils had effects on Pi forms during the process of air-drying. Therefore, forchemical study of soil phosphorus, application of fresh soil samples can provide more reliable results.

Effect of Seed Drying on Germination Behavior and Seedling Growth of Sweetsop （Annona squamosa）

An experiment was conducted at the Department of Horticulture, College of Agriculture and Natural Resources, Kwame Nkrumah University of Science and Technology, Kumasi （KNUST） Ghana from September, 2009 to April, 2010, to determine the most appropriate drying method, as a post harvest practice, that would ensure high percentage germination ofAnnona squamosa seeds and its subsequent effect on seedling growth. The seeds were sun-dried, air-dried under shade or kept in the fresh state. Five treatments were used, namely, Freshly Sown seeds （Treatment 1, control）, Seeds Air-Dried under Shade for one day （Treatment 2）; Seeds Sun-Dried for one day （Treatment 3）; Seeds Air-Dried under Shade for three consecutive days （Treatment 4）; Seeds Sun-Dried for three consecutive days （Treatment 5）. The experiment was arranged in a Completely Randomized Design （CRD） and replicated three times. Drying of Annona squamosa seeds had significant effect on earliness and number of seeds germinated. Air drying under shade and sun-drying for three consecutive days improved earliness to germination （26 days after sowing） and percent total germination but air-drying under shade had better effect on total seed germination, achieving 90% germination in 42 days after sowing. Furthermore, the prevailing ambient temperature of 30 ℃-32 ℃ enhanced germination of Annona squamosa seeds. The study concluded that for optimum germination, seeds of Annona squamosa should be either air-dried or sun-dried for three consecutive days and be incubated in an ambient temperature range of 30 ℃-32 ℃. In terms of growth, seedling growth in leaf production was better from seeds sun-dried for three consecutive days.

Effect of Land Use History on Methane Emission and Methanogenic Flora in Flooded Soils

The characteristics of methane emission were compared among six types of upland and paddy soils developed from different parent materials with distinct physics and chemical properties after planting rice. The fluxes of methane emission in submerged soils from the upland were obviously lower than those from the paddy rice field. The flux of methane emission in the paddy soil developed from fluvo-aquic soil was the largest among all the types of soils. Planting of rice was helpful to emission of methane in soils. The amounts of various groups of methanogenic flora were conformed with the deferences among the fluxes of methane emission in various types of soils. Methane formation was observed in each type Of air-dried soils stored for a long time after addition of water and incubation at 35℃.

Effects of soil moisture and temperature on CH_4 oxidation and N_2O emission of forest soil

Soil samples were taken from depth of 0-12cm in the virgin broad- leaved/Korean pine mixed forest in Changbai Mountain in April, 2000. 20 μL·L-1 and 200 μL·L-1 CH4 and N2O concentration were supplied for analysis. Laboratory study on CH4 oxidation and N2O emission in forest soil showed that fresh soil sample could oxidize atmospheric methane and product N2O. Air-dried soil sample could not oxidize atmospheric methane, but could produCt N2O. However, it could oxidize the supplied methane quickly when its concentration was higher than 20 μL·L-1. The oxidation rate of methane was increased with its initial concentration. An addition of water to dry soil caused large pulse of N2O emissions within 2 hours. There were curvilinear correlations between N2O emission and temperature (r2=0.706, p <0.05), and between N2O emission andtwater content (r2=0.2968. p <0.05). These suggested temperature and water content were important factors controlling N2O emission. The correlation between CH4 oxidization and temperature was also found while CH4 was supplied 200 μL·L-1 (r2 =0.3573, p<0.05). Temperature was an important f8Ctor controlling CH4 oxidation. However, when 20 μL·L-1 CH4 was supplied, there was no correlation among CH4 oxidization, N2O emission, temperature and water content.

Mechanical Properties of Small Clear Wood Specimens of <i>Pinus patula</i>Planted in Malawi

Pinus patula is one of the major exotic species grown in Malawi mainly for saw-timber production. It is native to Mexico. Little has been reported about the mechanical properties of the wood. The objective of this study was to investigate the mechanical properties of Pinus patula in more detail, in order to provide a basis for utilizing this resource. The mechanical properties of small clear wood specimens of Pinus patula were evaluated using 40 cm logs from 1, 3, 5, 7 and 9 m above the ground. Small clear wood specimens were selected and subjected to a bending test in accordance with Japan Industrial Standards (JIS) air-dry conditions. The growth rate did not affect the mechanical properties measured. There were significant correlations at 1% level between air-dry density and Modulus Of Elasticity (MOE) (R = 0.85) and between air-dry density and Modulus Of Rupture (MOR) (R = 0.83). There was also a significant correlation between MOE and MOR at 1% level (R = 0.90). At about 12% moisture content, the tested five Pinus patula families have average MOR and MOE of 105.17 MPa and 10.93 GPa, respectively.

Effects of applying lactic acid bacteria to the fermentation on a mixture of corn steep liquor and air-dried rice straw

This study was to determine the fermentation quality of a mixture of corn steep liquor(CSL)(178 g/kg wet basis) and air-dried rice straw(356 g/kg wet basis) after being treated with inoculants of different types of lactic acid bacteria(LAB). The treatments included the addition of no LAB additive(control),which was deionized water; homo-fermentative LAB alone(^(ho)LAB), which was Lactobacillus plantarum alone), and a mixture of homo-fermentative and hetero-fermentative LAB(^(he+ho)LAB), which were L. plantarum, Lactobacillus casei, and Lactobacillus buchneri. The results showed that the inoculation of the mixture of CSL and air-dried rice straw with ^(he+ho)LAB significantly increased the concentration of acetic acid and lactic acid compared with the control(P < 0.05). The addition of ^(he+ho)LAB effectively inhibited the growth of yeast in the silage. The concentration of total lactic acid bacteria in the ^(he+ho)LAB-treated silage was significant higher than those obtained in other groups(P < 0.05). The duration of the aerobic stability of the silages increased from 56 h to >372 h. The control group was the first to spoil, whereas the silage treated with ^(he+ho)LAB remained stable throughout the 372 h period of monitoring. The results demonstrated that the ^(he+ho)LAB could effectively improve the fermentation quality and aerobic stability of the silage.

A Comparison of Different Preservation Methods for Nitrogen Isotopes of Soil Extractable NO3^-

Nitrogen(N) isotope ratio(δ^(15)N) of soil extractable NO_3^- plays a pivotal role in the study of N biogeochemical circulation in ecosystems. However, the NO_3^-concentration and its isotope composition of soil samples are unstable, making sample storage critical for preserving the N isotope composition of extracted soil NO_3^-. Nevertheless, studies on the appropriate selection of storage methods after soil sampling are scarce. In this study, we compared two commonly used methods for storing soil samples and investigated the stability of N isotopes of soil NO_3^-. The results demonstrated that no significant changes in the NO_3^-concentration and δ^(15)N value occurred in the samples stored at-18?C. However, the soil NO_3^-concentration markedly increased, and NO_3^-δ^(15)N value significantly changed after air-drying storage. Meanwhile, we also found that NO_3^-and its δ^(15)N were well preserved in the filtered soil extracts after 1 month. In contrast, the NO_3^-concentration gradually decreased and the^(15)N in NO_3^-was gradually enriched in the bactericidal agent-containing soil mixture solution during the storage period. Overall, our results indicated that N isotopes of NO_3^-could be effectively preserved in frozen-stored soil samples or filtered soil extracts. For field investigations conducted in remote areas and continued for a long-time period(and lacking a refrigerant supply), soil extraction/filtration using a CaSO_4-saturated solution may be a superior preparation and storage method for analyzing N isotopes of soil NO_3^-.

Research on Physical and Mechanical Properties of Moso Bamboo

With the increase of the utilization of bamboo, we must find out more in bamboo properties. According to the national standard GB/T15780 -1995, this paper analyzed the air-dried density and mechanical properties of Moso bamboo in different ages and stalk parts. The results showed that both the age and the stalk part have remarkable effects on air-dried density and mechanical properties. The effect of age is much more prominent than that of stalk part. The performance shows: upper > middle > down, which increases with the age, and reaches to the peak values at the age of 4 and show a downward trend at the age of 6. According to the tests, the optimum age of bamboo for cutting is about at 4. Moreover, there is a positive correlation between air-dried density and mechanical properties. The correlation coefficients between air-dried density and crushing strength parallel to the grain, bending strength, modulus of elasticity and tensile strength parallel to the grain are 0.917 3, 0.783 9, 0.745 8 and 0.507 4, respectively. In addition, there is a good relativity among mechanical properties, δt: δc: MOR: MOE = 2.79: 1.00: 2.40: 0.15.