Using CERES-Maize model to determine the nitrogen fertilization requirements of early maturing maize in the Sudan Savanna of Nigeria

CERES-Maize model was used to determine nitrogen fertilizer requirements of early maturing maize varieties in the Sudan Savanna. Data were collected from 2013 to 2014 field experiments conducted in Bayero University Kano, (BUK), Kano, Nigeria. The experiments consisted of three nitrogen fertilizer levels (0, 60, and 120 kg N ha^?1) and two early maize varieties (EVDT and 2009 TZEEW). Sensitivity analysis was performed to evaluate the responses of the two maizes to N fertilizers and for economic and strategic responses. The model predicted grain yield and harvest index reasonably well for the two varieties. Increasing N application from 0 to 30 kg N ha^?1 increased grain yield by 105%, when nitrogen (N) rate was increased to 60 kg N ha^?1, grain yield increased by 226%. Yield increases of 364%, 451%, and 461% was observed when N rate increased from 0 to 90, 120, and 150 kg ha^?1, respectively.     

Estimation of simultaneous nitrification and denitrification in grassland soil associated with urea-N using 15N and nitrification inhibitor

 A low efficiency of use of N fertilisers has been observed in mid-Wales on permanent pasture grazed intensively by cattle. Earlier laboratories studies have suggested that heterogeneity in redox conditions at shallow soil depths may allow nitrification and denitrification to occur concurrently resulting in gaseous losses of N from both NH₄ ⁺ and NO₃ ^–. The objective of the investigation was to test the hypothesis that both nitrification and denitrification can occur simultaneously under simulated field capacity conditions (∼5 kPa matric potential). Intact soil cores were taken from grassland subjected to both grazing and amenity use. The fate of applied NH₄ ⁺ was examined during incubation. ¹⁵N was used as a tracer. Nitrapyrin was used as a nitrification inhibitor and acetylene was used to block N₂O reductase. More than 50% of N applied as NH₄ ⁺ disappeared over a period of 42 days from the soil mineral-N pool. Some of this N was evolved as N₂O. Accumulation of NO₃ ^––N in the surface 0–2.5 cm indicated active nitrification. Addition of nitrapyrin increased N recovery by 26% and inhibited both the accumulation of NO₃–N and emission of N₂O. When intact field cores were incubated after addition of ¹⁵N-urea, all of the N₂O evolved was derived from added urea-N. It was concluded that nitrification and denitrification do occur simultaneously in the top 7.5 cm or so, of the silty clay loam grassland topsoils of mid-Wales at moisture contents typical of field capacity. The quantitative importance of these concurrent processes to N loss from grassland systems has not yet been assessed. Received: 15 December 1998     

Growth performance of bath sponge (Spongia officinalis Linnaeus, 1759) farmed on suspended ropes in the Dardanelles (Turkey)

Commercial bath sponge population in the Mediterranean has been recently reduced due to diseases and the depletion of natural banks. The commercial supply is far below the demand on the last 10–15 years. In this study, we aimed to investigate the farming performance of Spongia officinalis in the Dardanelles. Sponges collected from the Dardanelles cut into pieces of different weight. They were divided into two groups depending on the wet weight ranging from 50 to 150 g (mean weight 102.6 ± 4.81 g) and from 160 to 360 g (mean weight 235.8 ± 8.56 g). Three rope systems located parallel to each other with 6–7 m inter‐distance were constructed for the cultivation of sponges. At the end of the study, while small‐sized sponges could reach mean wet weight of 120.7 ± 14.8 g, large‐sized sponges reached mean wet weight of 247.6 ± 22.4 g. Growth rates were estimated 5–17% at 21st month. The survival rates were found 82% and 88%.     

Elucidate Genetic Diversity and Population Structure of Bread Wheat (Triticum Aestivum L.) Cultivars Using IRAP and REMAP Markers

Journal of Crop Science and Biotechnology - Analysis of genetic diversity and population structure in bread wheat is an essential step in their conservation, utilization, and breeding....