Xiao Hou Shao

Water Consumption Characteristics and Water Use Efficiency of Flue-Cured Tobacco under Different Conditions of Irrigation

The experiments were carried out in lysimeters to study water consumption characteristics and water use efficiency of flue-cured tobacco under different conditions of irrigation. By comparing the T and the invalid E of the tobacco K326, it is concluded that in the period of root extending most of the irrigation water is used for the E, in the early vigorous period, plants with all of the treatments show a T higher than the E, in the late vigorous period and the maturity, this ratio remains at 50%. Based on measured data, it was shown that the amount of irrigation water in the vigorous period had the most important influence on the yield of the tobacco.The nonlinear equation of the yield and WUE is Y=-2531.3X2+6113.8X-624.49,R2=0.7324; the equation of the yield and ET is Y=4E-0.7X3-0.0032X2+8.8458X-4806.7, suggesting that the WUE is not maximized at the highest yield of flue-cured tobacco. In the high-yield range, reducing irrigation appropriately could reach the harmonization of high production and water saving.

Study on Soil Evaporation of Flue-Cured Tobacco and its Main Driving Factors under Water and Nitrogen Coupling Condition

A pot experiment was conducted on soil evaporation of flue-cured tobaccounder water and nitrogen fertilizers coupling treatmentsin this study. Soil evaporation at each growth stage of tobacco were analyzed, so did ratio of average soil evaporation (AEa) to mean water consumption (AET). Some factors impacting soil evaporation were also investigated. The results showed that average daily soil evaporation was positively correlated with soil temperature (p<0.01), the equation between daily soil evaporation and surface soil moisture (θ) was AEa=0.058e0.048θ (R2=0.717), while relationship between the ratio of evaporation to water consumption (AEa/AET) and leaf area index (LAI ) was functioned as AEa/AET=0.201 LAI-0.912(R2=0.658). It also suggested that the best effects to decrease soil evaporation of flue-cured tobacco appeared in treatment of 6g N per plant combined with the irrigation amount and frequency at 4.5kg and 9 times, 18kg and 18 times, 13kg and 26 times at root spreading stage, vigorous growing stage and the maturing stage respectively.

Effect of Wastewater Treated by EM Reused for Irrigation on Shallow Groundwater Quality

In allusion to environmental pollution brought about by wastewater irrigation, EM technology was introduced to study the feasibility of EM application in wastewater irrigation. The results show that EC, NO3--N and TN value of EM treatment in shallow groundwater are all less than those of WW treatment as a whole. In all samples, 59.3% NO3--N values are in the alert status, and when irrigation amount reaches 360mm, treatment WW has caused shallow groundwater pollution. TN concentration in treatment WW-3 on June 27 and July 9 is more than 110 mg/L. It suggests that NO3--N can easily penetrate into shallow groundwater with wastewater irrigation and there is insurance of groundwater pollution in the long-term wastewater irrigation. It also indicates that application of wastewater treated by EM reused for irrigation is feasible. TP values are all very low and suggest the pollution of P does not happen.

Experimental Study on the Nozzle of High-Pressure Fog Cooling Systems in Greenhouses

This paper describes a designed new nozzle and provides experimental studies on the nozzle used in high-pressure fog cooling system in Greenhouses. Fogging droplet sizes of the nozzle is measured by MPA Malvern Particle Analyzer. The diameter of droplet sizes (VMD, Dv10, Dv50, Dv90) which is 500 mm far from the nozzle is measured and analyzed when the pump pressure is 2, 3, 4, 5, 6,7MPa.The experimental results shows: the nozzle has fine fogging performance, and its droplet sizes (VMD) are small and less than 30 microns when operating pressure is more than 5MPa.

Studies on Salt and Water Movement in Secondary Salinized Greenhouse Soil under Subsurface Drainage

The secondary salinized greenhouse soil was provided with subsurface pipe drainage system with drainage spacing 6 m and drain depth 0.4m to study the movement of salt and water. The field investigations indicated that the resalination rates of the surface soil with subsurface drainage system were lower than those with non-drained system (CK) in an irrigation circle of the crop. The resalination rate of the surface soil right above the drainage tubes (T1) was significantly lower than that between the two drainage tubes (T2). At the 5th day after irrigation, the soil volumetric moisture contents of different treatments were significantly decreased and the resalination of surface soil were obvious. The results showed a considerable increase of resalination rate after irrigation that was varied at the 5th day as following sequence: CK(10.6%) > T2(8%) > T1(7%).

Fermentation Production of EM Active Calcium and its Performance for the Prevention on Blossom-End Rot in Facility Tomato Cultivation

The blossom-end rot (BER) induced by calcium deficiency will cause a great impact on tomato yield and quality. Aimed at the tomato physical barriers caused by calcium deficiency, the composite micro-organisms (EM) fermentation technology was applied to configure biological active calcium preparations of different calcium concentrations, with raw materials of calcium sulfate, lime and gypsum. The active calcium preparation with calcium concentration of 1 ‰ was sprayed on the fruits during the fruit development period in the field experiment. The results show that lime with highest solubility is the best raw material for the fermentation of EM active calcium preparations with the consideration of higher calcium concentration, reasonable pH and EC value, and the lowest cost. It also shows the incidence of blossom-end rot of the experimental group is 35.36 % lower than that of CK.

Effects of Different Nitrogen Levels on the Yield and Water Use Efficiency of Tobacco

Based on field experiment, the yield and water use efficiency (WUE) of tobacco under different nitrogen levels were studied in Hunan province, China. The results show that the evaportranspiration (ET) of flue-cured tobacco dealt with N2 (90kg N fertilizers per ha) gets to the maximum. In addition, the vigorous period has the maximum ET due to the critical period of water requirement. The linear relationship is established among fertilization, yield and water use efficiency. Reasonable fertilizer application can increase water use efficiency and flue-cured tobacco yield.

Use of Impact Testing to Assess the Softness of Bedding Materials

Bedding materials are very important for cows in freestalls, because they can provide a high degree of comfort to these cows. But techniques of assessing their surface comfort on in the field still remain rather subjective. The objective of this study was to assess softness of bedding materials for use in cow free-stall bases in China. The Clegg Impact values of rubber-coated slatted floor, Solid wood floor and concrete floor are measured in order to compare with the value of pasture. The softest bedding material was the wood (40.43CIV/L) followed by rubber-coated slatted floor (64.23 CIV/L). The hardest material was the concrete floor (132.21 CIV/L).Clegg Impact Tester with a 1-kg hammer was used in this study. The impact of the hammer on bedding materials results in a digital display based on peak deceleration of the hammer’s impact with the free-stall base in tens of gravities (CIV/L). The CIV/L value, as measured by the Clegg Impact hammer, is based on peak deceleration of the 1-kg hammer’s impact with the surface, from a height of 30 cm. The reasonable suggestions of bedding materials used as the free-stall bases are recommended for the farmer in China.