Growth, Yield and Yield Components of American Cotton (Gossypium hirsutum L.) As Affected by Cultivars and Nitrogen Fertilizer
Nitrogen stress in upland cotton addresses significant and visible shortfalls in plant growth. It is an important element both in nature and agricultural conditions, for cotton plant growth and development. To evaluate the response of different yield and yield component of high yielding upland cotton cultivars to various split applications of nitrogen fertilizer, a two season field research was conducted during 2007 and 2008. Different experimental treatments were comprised on cotton leaf curl virus (CLCV) resistant high yielding cotton cultivars i.e. CIM-496, CIM-506, CIM-534 along with different nitrogen rate of Zero, 60, 110 and 160 kg ha -1 . However, cultivar CIM-534 produced significantly the highest plants, nodes per plant and flowering buds plant -1 . While, CIM-496 showed better potential in relation to leaf area index, crop growth rate, relative growth rate and net assimilation rate (physiological), dry biomass and number of bolls m -2 (reproductive) and seed cotton, cotton seed (yield) parameters during both the seasons. On increasing N rates, vegetative characteristics of cotton like plant height, nodes plant -1 and number of flowering buds per plant significantly gave better response with each cultivar. Advanced cotton cultivars produced significantly higher total dry biomass (TDM), bolls m -2 , seed cotton, cotton seed and GOT % age on each increment in applied nitrogen. The nitrogen fertilizer rate i.e. 160 kg ha -1 proved to be the optimum for the highest cotton yield and yield components. Further fibre characteristics such as staple length, uniformity ratio and maturity ratio significantly influenced by different cultivars.
Effect of Nitrogen Rates and Flowering Dates on Fiber Quality of Cotton (Gossypium hirsutum L.)
Nitrogen (N) supply during boll setting and maturation period of cotton can be critical in determining fiber quality. The study aims to investigate the relationship between N rates and formation of fiber length, strength, maturity and micronaire in bolls with different flowering dates. Field experiments were conducted using two cotton cultivars (Kemian 1 and NuCOTN 33B) and three N fertilization rates (0, 240, and 480 kg N ha -1 ) in Nanjing and Xuzhou in 2005 and in Anyang in 2007, China. The fiber length, strength, maturity, micronaire, and N concentration per unit area (N A) of the subtending leaf of cotton boll were analyzed. N fertilization rates, flowering dates, and N fertilization rates × flowering dates significantly (P ≤ 0.05) affected N A and the formation of fiber length, strength, maturity and micronaire. N fertilization rates affected fiber quality by influencing NA which was significantly related to rate and duration of the fiber quality formation process. The optimal N A for fiber quality formation was varied. For bolls flowering before August 25, when mean daily temperature during boll maturation period (MDT BMP ) was higher than 21°C, NA in the 240 kg N ha -1
Ceramic microwave antennas for mobile applications
Due to their medium to high permittivity values, ceramic microwave materials are attractive as building blocks for miniaturised antenna solutions. Further advantages are low dielectric losses and an excellent temperature stability of standard ceramic materials. Yet, the permittivity of the ceramic material also has a strong influence on the radiation efficiency and bandwidth of the antenna. This implies that in the design process a suitable compromise has to be found between the degree of miniaturisation on the one hand and the antenna efficiency and bandwidth on the other. We describe two approaches towards efficient miniaturised ceramic microwave antennas: the dielectric resonator antenna (DRA) with partial metallisation and the shorting post patch antenna. We focus on design steps taken to ensure both a high degree of miniaturisation and high values of the radiation efficiency, the choice of the ceramic material and the experimental performance of the antennas.