Effect of varying soil water stress regimes on nutrient uptake and biomass production in Dalbergia sissoo seedlings in Indian desert

One-year-old seedlings of Dalbergia sissoo from a single provenance were planted in non-weighing lysimeter tanks in July 1998 with a view to provide optimize irrigation parameters in desert areas. Varying water regimes were maintained by re-irrigating the seedlings at 36.2 mm （W1）, 26.5 mm （W2）, 20.2 mm （W3） and 18.1 mm （W4） treatments when the soil water content decreased to 7.56%, 5.79%, 4.44%, 3.23% in the respective treatments. Height, collar diameter, number of leaves and leaf area were highest （p 〈 0.01） for the seedlings irrigated at W1 levek Above-mentioned growth parameters did not differ between W1 and W2 treatments but the seedlings in W2 level had highest biomass per liter of water use （i.e., water use efficiency, WUE）. Irrigation levels of W3 to W5 negatively affected seedling growth, biomass production and nutrient accumulation. Soil water availability below W2 level （i.e., 5.79%） caused an increase in percentage of root biomass to the total biomass of the seedling. However, there was a decrease in percentage of leaf dry biomass in W3 and W4 treatments and in percentage of stem dry biomass in the seedlings of W5 treatment. Seedlings in W5 treatment survived till at soil water potential of-1.96 MPa. Limitation of soil water availability in W3 and W4 treatments affected growth and biomass production of D. sissoo seedlings. W： level was best for growth and biomass production in which water use efficiency was highest. Therefore, better growth and biomass production of D. sissoo seedlings could be obtained by irrigating the seedlings at soil water content of≥5.79% in the loamy sand soil.

Effects of rainwater harvesting on herbage diversity and productivity in degraded Aravalli hills in western India

Over-exploitation and rural growth have severely damaged native vegetations of Aravalli hills in Rajasthan, India. This study was conducted to evaluate the effects of different restoration practices （i.e., rainwater harvesting （RWH） and planting of tree seedlings） on improve- ment in soil water and nutrients and growth and biomass of herbaceous vegetation. Contour trench （CT）, Gradonie （G）, Box trench （BT）, V-ditch （VD） and a control were imposed on 75 plots （each of 700 m 2 ） in natural slope gradient defined as 10%, 10% 20% and 20% slopes in 2005. Each plot had three micro-sites of 1-m 2 at up （USP）, middle （MSP） and lower （LSP） part of the plot for observation in 2008. The existed gradient （due to soil texture and topographic features） of soil pH, EC, SOC, NH 4 - N, NO 3 -N and PO 4 -P in June 2005 between 20% to 10% slopes were decreased in 2008 after applying RWH techniques. Such improvement in soil status promoted vegetation growth and biomass in higher slope gra- dients. Soil water, species diversity and herbage biomass increased from USP to LSP, and RWH techniques had positive role in improving SOC, nutrients, vegetation population, evenness and growth at MSP. Despite of lowest SWC, regular rain and greater soil water usage enhanced green and dry herbage biomasses in 10% 20% and 20% slopes, compared with 10% slope. The highest diversity in CT treatment was related to herbage biomass, which was enhanced further by highest concentrations of SOC and PO 4 -P. Further, CT treatment was found to be the best treat- ment in minimizing biomass variance in different slopes. Conclusively, soil texture and topographic features controlled soil water and nutrients availability. Rainwater harvesting techniques increased soil water storage and nutrient retention and also enhanced vegetation status and biomass by minimizing the effects of hillslopes. Thus depending upon the site conditions, suitable RWH technique could be adopted to increase herb- age biomass while rehabilitating the degraded hills.

Microstrip Antennas Loaded with Shorting Post

In this paper, a technical review with recent advances of the microstrip antennas loaded with shorting posts is presented. The overall size of the antenna is significantly reduced by a single shorting posts and the effect of the various parameters of shorting posts on short-circuit microstrip antenna is also discussed.

Comparative productivity of Prosopis cineraria and Tecomella undulata based agroforestry systems in degraded lands of Indian Desert

Tree-crop interactions were monitored by measuring tree growth characters of Prosopis cineraria L. and Tecomella undulata L. and yields of Vigna radiata （L） in agroforestry systems in degraded lands of Indian Desert. Potential competition for resource between the trees and associated crop was analyzed by measuring soil water contents, soil organic matters and NH4-N at different depths of soil layers i.e., 0-25 cm, 25-50 cm and 50-75 cm in the experimental plots. The plots size were 16 m × 18 m （D1）, 20 m × 18 m （D2） and 32 m × 18 m （D3） with tree densities of 208, 138 and 104 trees.ha^-1 after June 2002, respectively. Results showed that tree height increased by 3% to 7% during June 2002 to June 2004. Collar diameter increased by 30% and 11% in D1, 23% and 19% in D2 and 18% and 36% in D3 plots, respectively, in P. cineraria and T. undulata in two years period. The increase in crown diameter was 9% to 18% in P. cineraria and 11% to 16% in T. undulata. Tree growth was relatively greater in 2002 than in 2003. Yield of V. radiata increased linearly from D1 to D3 plots. Lowest soil water content at 1 m distance from tree base indicated greater utilization of soil water within the tree rooting zone. Concentrations of soil organic matters and NH4-N were the highest （p〈0.05） in 0-25 cm soil layer. P. cineraria was more beneficial than T. undulata in improving soil conditions and increasing crop yield by 11.1% and thus more suitable for its integration in agricultural land. The yield of agricultural crop increased when density of tree species was appropriate （i.e., optimum tree density）, though it varied with tree size and depended upon resource availability. The result indicated bio-economic benefits of optimum density of P. cineraria and T. undulata over traditional practices of maintaining random trees in farming system in arid zones.

Comparative productivity of Prosopis cineraria and Tecomella undulata based agroforestry systems in degraded lands of Indian Desert

Tree-crop interactions were monitored by measuring tree growth characters of Prosopis cineraria L.and Tecomella undulata L.and yields of Vigna radiata(L) in agroforestry systems in degraded lands of Indian Desert.Potential competition for resource between the trees and associated crop was analyzed by measuring soil water contents, soil organic matters and NH4-N at different depths of soil layers i.e., 0-25 cm, 25-50 cm and 50-75 cm in the experimental plots.The plots size were 16 m × 18 m(D1), 20 m × 18 m(D2) and 32 m × 18 m(D3) with tree densities of 208, 138 and 104 trees·ha-1 after June 2002, respectively.Results showed that tree height increased by 3% to 7% during June 2002 to June 2004.Collar diameter increased by 30% and 11% in D1, 23% and 19% in D2 and 18% and 36% in D3 plots, respectively, in P.cineraria and T.undulata in two years period.The increase in crown diameter was 9% to 18% in P.cineraria and 11% to 16% in T.undulata.Tree growth was relatively greater in 2002 than in 2003.Yield of V.radiata increased linearly from D1 to D3 plots.Lowest soil water content at 1 m distance from tree base indicated greater utilization of soil water within the tree rooting zone.Concentrations of soil organic matters and NH4-N were the highest(p<0.05) in 0-25 cm soil layer.P.cineraria was more beneficial than T.undulata in improving soil conditions and increasing crop yield by 11.1% and thus more suitable for its integration in agricultural land.The yield of agricultural crop increased when density of tree species was appropriate(i.e., optimum tree density), though it varied with tree size and depended upon resource availability.The result indicated bio-economic benefits of optimum density of P.cineraria and T.undulata over traditional practices of maintaining random trees in farming system in arid zones.

Double Negative Left-Handed Metamaterials for Miniaturization of Rectangular Microstrip Antenna

In this paper, I have explored a significant concept for the miniaturization of microstrip patch antenna configuration by using the double negative (DNG) left-handed Metamaterials, which have dielectric permittivity and magnetic permeability both negative, simultaneously. It is achieved through the concept of phase-compensation by thin slab consist of the double positive (DPS) material, which have dielectric permittivity and magnetic permeability both positive, simultaneously and DNG metamaterials as a substrate of the microstrip patch antenna. By combining the DNG metamaterial slab with the slab made of DPS materials form a cavity resonator whose dispersion relation is independent of the sum of thickness of the slabs filling this cavity but it depends on the ratio of their thicknesses. This cavity constitutes by DPS and DNG material is used as substrate of the microstrip antennas and the DNG material slab is behave as phase compensator.

Numerical Computation of Resonant Frequency of Shorting Post Loaded Gap-Coupled Circular Microstrip Patch Antennas

In this paper, the numerical computation of resonant frequency of the two gap-coupled circular microstrip patch antenna loaded with shorting post by using cavity model is presented. The numerically computed results are compared with simulated results. The two gap-coupled circular microstrip patch antenna loaded with shorting post miniaturize the cross-sectional dimension of the radiating patch at the microwave frequency, which is useful for short range communications or contactless identification systems. The simulation has been performed using method-of-moments based commercially available simulator IE3D.

Designing Parameters for RF CMOS Cells

In this paper, we have investigated the design parameters of RF CMOS cells which will be used for switch in the wireless telecommunication systems. This RF switch is capable to select the data streams from the two antennas for both the transmitting and receiving processes. The results for the development of a cell-library which includes the basics of the circuit elements required for the radio frequency sub-systems of the integrated circuits such as V-I characteristics at low-voltages, contact resistance which is present in the switches and the potential barrier with contacts available in devices has been discussed.

Measurement Process of MOSFET Device Parameters with VEE Pro Software for DP4T RF Switch

To design a Double-Pole Four-Throw (DP4T) RF switch, measurement of device parameters is required. In this DP4T RF switch CMOS is a unit cell, so with a thin oxide layer of thickness 628 ? which is measured optically. Some of the material parameters were found by the curve drawn between Capacitance versus Voltage (C-V) and Capacitance versus Frequency (C-F) with the application of Visual Engineering Environment Programming (VEE Pro). To perform the measurement processing at a distance, from the hazardous room, we use VEE Pro software. In this research, to acquire a fine result for RF MOSFET, we vary the voltage with minor increments and perform the measurements by vary the applying voltage from +5 V to –5 V and then back to +5 V again and then save this result in a data sheet with respect to temperature, voltage and frequency using this program. We have investigated the characteristics of RF MOSFET, which will be used for the wireless telecommunication systems.