Influence of Phosphorous and Foliar Nitrogen on the Growth, Quality and Yield of Kasuri Methi (Trigonella corniculata L.)

Background: Nitrogen and phosphorus are amongst fundamental macronutrients, which are crucial for the growth and development of plant. Soils of dry land of central Rajasthan are deficit in nitrogen and phosphorus content which leads to lower productivity of kasuri methi. Therefore, adequate supply of nitrogen (foliar spray) and phosphorus could enhance productivity of kasuri methi. Methods: The experiment consisted of sixteen treatment combinations including four levels of phosphorus (control, 20, 40 and 60 kg/ha) and four levels of foliar application of nitrogen (control, 1.0, 1.5 and 2.0%). They were under taken in FRBD with three replications. Result: Growth parameters and yield of fresh and dried leaves of the crop increased almost linearly with increasing levels of phosphorus and foliar application of nitrogen. The result indicated that application of phosphorus 60 kg/ha and foliar nitrogen @ 2.0% to the kasuri methi crop significantly increased the plant height (cm) and leaf area per plant (cm2) at each harvest, number of nodules per plant (58.17 and 53.33, respectively) and chlorophyll content (2.32 and 2.39 mg/100 g, respectively), fresh leaves yield (139.1 and 141.66 q/ha, respectively), dry leaves yield (20.01 and 22.38 q/ha, respectively), protein content in leaves (5.28 and 5.75%, respectively) and ascorbic acid in leaves (218.15 and 222.42 mg/100 g, respectively).

Variability in weed biological control : effects of foliar nitrogen on larval development and dispersal of the alligatorweed flea beetle, Agasicles hygrophila

Host quality can have dramatic effects on performance of biological control agents but its importance is understudied. We used a combination of field measurements and laboratory experiments to determine the range of foliar nitrogen (FN) that larvae of the alligatorweed flea beetle (Agasicles hygrophila) are exposed to in the field and its importance to larval development and dispersal. Seasonal variability in FN was assessed at field sites spanning southern to northern Louisiana every 2–3 weeks during the growing season for four years. In a series of laboratory experiments, alligatorweed FN was manipulated to examine its influence on larval development and survival (under different temperature regimes), adult biomass, and dispersal of the biological control agent, A. hygrophila. Foliar nitrogen and rearing temperature had strong independent effects on larval development rate. We demonstrated that increasing nitrogen in leaf tissues shortens larval A. hygrophila developmental time and increases survival to adulthood, regardless of exposure temperature during development. It also suggests that foliar nitrogen may have important effects on biological control of alligatorweed, particularly as a result of seasonal variation in temperature and plant nutrition at field sites and could contribute to observed variation in A. hygrophila efficacy in the field.

Productivity and Profitability of Poplars on Fertile and Marginal Sandy Soils under Different Density and Fertilization Treatments

We evaluated the productivity and profitability of four highly productive poplars including Populus deltoides × P. deltoides (DD ‘140’ and ‘356’), P. deltoides × P. maximowiczii (DM ‘230’), and P. trichocarpa × P. deltoides (TD ‘185’) under two densities (2500 and 5000 trees ha−1), and three fertilization treatments (0, 113, 225 kg nitrogen ha−1) at three sandy coastal sites varying in soil quality. Green stem biomass (GSB) was estimated from the sixth-year stem diameter. Leaf-rust (Melampsora castagne) and beetle damage (by Chrysomela scripta Fabricius), the leaf area index (LAI) and foliar nitrogen, were measured in year two. At all sites, DD and DM had higher survival (>93%) than TD (62–83%). DD produced greater GSB (92.5–219.1 Mg ha−1) than DM (54–60.2 Mg ha−1) and TD (16.5–48.9 Mg ha−1), and this was greater under the higher density (85.9–148.6 Mg ha−1 vs. 55.9–124.9 Mg ha−1). Fertilization significantly increased GSB on fertile soil but not marginal soils; a higher rate did not significantly enhance GSB. Leaf rust was higher for fertile soil (82%) than marginal soils (20–22%), and TD ‘185’ (51% vs. others 34%). C. scripta damage was higher for the higher density (+42%) than lower density, and TD ‘185’ (50% vs. others >38%). LAI was higher on fertile soil (1.85 m2 m−2) than marginal soils (1.35–1.64 m2 m−2), and under the lower density (1.67 m2 m−2 vs. 1.56 m2 m−2). The high GSB producer DD ‘356’ had the lowest LAI (1.39 m2 m−2 vs. 1.80 m2 m−2). Foliar nitrogen varied among genomic groups (DD ‘140’ 1.95%; TD ‘185’ 1.80%). Our plots were unprofitable at a 27 USD Mg−1 delivered price; the biggest profitability barriers were the high costs of higher density establishment and weed control. The best-case treatment combinations of DD (‘140’, ‘356’) would be cost-effective if the price increased by 50% (USD 37.54 Mg−1) or rotations were 12 years (fertile-soil) and longer (marginal soils). The requirement for cost-effectiveness of poplars includes stringent and site-specific weed control which are more important than fertilizer applications.

Effect of Salinization by NaCl on the Growth of African Palm (Elaeis guineensis Jacq)

It is necessary to know the effect of excessive salinity in the soil on the growth of the African palm crop. The objective of the work was to evaluate the effect of salinity caused by NaCl on the growth and absorption of nutrients in the oil palm crop in early growth stage. The research was carried out in the laboratories of the University of Cordoba, where the 16 kg experimental units were made up of a mixture of alluvium and rice husk in a ratio of 4: 1. A complete randomized design was used with six treatments and a control (0.0, 0.5, 1.0, 1.5, 2.5, 3.6, and 6.1 cmolc kg-1 Na) and four repetitions. The data were statistically analyzed by analysis of variance and regression. The results report that the salinity in the soil that originates with the application of 2.5 cmolc kg-1 of Na produces in the soil an electrical conductivity (EC) of 1.96 dS m-1. Consequently, a drastic reduction in the quantified biomass of dry mass of stem, leaf, roots, rachis and leaf area originates, and the models that express this trend were adjusted to decreasing linear regressions with their highly significant parameters. Salinity interferes with the absorption of nutritional elements, such as N, K+ and Mg2+, and foliar nitrogen is the nutrient with the highest sensitivity to variations in EC in the soil. Foliar phosphorus (P) and calcium (Ca) concentrations were not affected by salinity levels.