Yield response and nitrogen uptake of pearl millet (Pennisetum americanum (L.) Leeke) cultivars to nitrogen application in the savanna region of Nigeria

Field experiments were carried out during the wet seasons (May to September) of 1980 and 1981 in order to determine the response of five pearl millet cultivars to nitrogen fertilization in savanna region of Nigeria. There were varietal differences in yield and nitrogen uptake in response to nitrogen rates. Most cultivars responded significantly up to 75 kg N ha^–1. Hybrid outyielded other cultivars at both locations each year. Nitrogen use efficiency was highest with the Hybrid, compared to other cultivars.     

Single superphosphate depresses molybdenum uptake and limits yield response to phosphorus in groundnut (Arachis hypogaea L.) grown on an acid sandy soil in Niger,West Africa

The effect of phosphorus (P) fertilization on dry matter production and nitrogen (N) uptake of groundnut (Arachis hypogaea L.) was studied during the growing seasons of 1989, 1990 and 1991 under rainfed conditions on an acid sandy soil in Niger, West Africa. Annual application of 16 kg P ha^–1 as single superphosphate (SSP) failed to increase the total dry matter production significantly in all three years.Fertilization with SSP increased the concentrations of P and sulfur (S) in shoots from deficiency to sufficiency levels. It decreased the already very low concentrations of molybdenum (Mo), especially in the nodules, and also the N concentration in the shoot dry matter.With SSP application, total N uptake declined over three years. Foliar application of P and soil application of triple superphosphate (TSP) enhanced dry matter production, N and Mo uptake.Although these acid sandy soils are known to be deficient in P and S, care must be taken in using SSP in groundnuts as it may induce Mo deficiency, unless supplementary Mo is applied.ICRISAT Journal Article No. 1230     

The effect of nitrogen,phosphorus and potassium fertilizer applications on the seed yield of sunflower (Helianthus annuus L.) grown on sandy soils and the prediction of phosphorus and potassium responses by soil tests

The nitrogen, phosphorus and potassium requirement of sunflower was evaluated when the crop was grown on siliceous sands overlying clay in the south east of South Australia. Of the seven sites used in the investigation, significant seed yield responses to phosphorus were recorded at two, while at a further two sites seed yields were increased by potassium additions. Nitrogen applications did not significantly increase seed yields at any site but decreased seed yields at two. This lack of nitrogen response was attributed to the sites having been long term legume pastures prior to the sunflower crops.Oil concentrations of sunflower seed ranged from 40.6% to 45.3% between sites, but fertilizer treatment had no significant effect.Critical nutrient ranges for both soil (Colwell) extractable phosphorus and potassium were derived at maximum seed yield. These were 16–20 mg kg^–1 for extractable phosphorus and 70–80 mg kg^–1 for extractable potassium.