Effect of Nitrogen Fertilizer Rate and Harvest Season on Forage Yield, Quality, and Macronutrient Concentrations in Midland Bermuda Grass
Bermuda grass [Cynodon dactylon (L.) Pers.] is a major forage for grazing and hay production in the southern United States. The objectives of this study were to determine effects of nitrogen (N) fertilization rate (0, 112, 224, 336, and 448 kg ha−1), split spring and summer applications of N at the 224 and 448 kg ha−1 rates, and harvest periods (spring and summer) on forage yield, crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), total digestible nutrients (TDN), and concentrations of phosphorus (P), potassium (K), magnesium (Mg), and calcium (Ca in Midland Bermuda grass. Data were collected from 2002 to 2008 as part of an ongoing, long-term soil fertility experiment in southern Oklahoma. Repeated measures analysis of these long-term data showed that forage yield responses to N rate varied with year and harvest time with up to 2.5-fold yield differences among years. Nitrogen fertilization increased CP, TDN, and macronutrient P and Mg and decreased ADF and NDF. Crude protein was increased by ≥50%, and ADF and NDF dropped by up to 25% with the greatest N rate. In general, split N applications did not affect forage yield but produced low-quality forage compared to single N application in spring. Split application of 448 kg N ha−1 gave forage with CP, TDN, ADF, and NDF similar to the Bermuda grass receiving 336 or 448 kg N ha−1 as a single application. Spring forage had better forage quality than summer harvests. While N fertilization increased forage Mg and P concentrations by more than 50% during both spring and summer, it had no effect or slight increased K and Ca concentrations. In the southern Great Plains, despite the weather-dependent variability in forage yield of Bermuda grass, N application increase forage quality.
Yield and quality attributes with seasonal variation in Napier Bajra hybrid (Pennisetum purpureum Ã— Pennisetum glaucum) under different nitrogen environments
Field experiment was conducted during kharif season of 2013 in randomized block design using three nitrogen doses (50, 75 and 100 kgN/ha) with three replications for Napier Bajra hybrid. Three nitrogen fertilizers, potassium nitrate (KNO3), urea [CO(NH2)2] and ammonium sulphate [(NH4)2SO4] were used in divided doses. The crop was harvested four times in different seasons. Growth attributes viz. plant height (72.6cm), number of tillers per plant (20.1) and leaf length (91.2) found highest at 100 kgN/ha doses and maximum values were recorded in monsoon season. Green fodder yield (321.0 q/ha) and dry fodder yield (79.6 q/ha) were recorded highest with KNO3 fertilization and found maximum in monsoon season. Among all the harvest seasons, crude protein yield (19.1 q/ha) was observed maximum in summer season. Quality attributes viz. ether extract (2.6%), ash content (12.9%) and in vitro dry matter digestibility (62.6%) were observed highest in summer season. Crude fibre, neutral detergent fibre and acid detergent fibre decreased with increased level of nitrogen doses and observed maximum in monsoon season.
Career Choice Inclination of the College Graduates——under the Analytic Framework on the Basis of LMS Theory
Employment difficulty of college graduates has become a social problem in China today.The research group has found that college graduates have a strong inclination in career choice considering units and regions.In terms of China's manpower market and the segmented labor market theory,it is found that their inclination is caused by the great income gap of different regions,the high cost of job transfer,and the sharp differences in social welfare.It is thus obvious that solution to the problem lies with the gradual breakdown of the institutional segment of labor market.