Soil Phosphorus and Potassium Estimation by Reflectance Spectroscopy

2016 ◽  
Vol 59 (1) ◽  
pp. 97-105 ◽  
Keyword(s):  
Soil Phosphorus ◽  
Reflectance Spectroscopy ◽  
Phosphorus And Potassium

Factors Affecting Soil Phosphorus and Potassium Estimation by Reflectance Spectroscopy

2013 ◽  
Author(s):  
Guotian Hu ◽  
Kenneth A. Sudduth ◽  
D Brenton Myers ◽  
Dongjian He ◽  
Manjula V. Nathan
Keyword(s):  
Soil Phosphorus ◽  
Reflectance Spectroscopy ◽  
Factors Affecting ◽  
Phosphorus And Potassium

Effects of primary tillage and soil amendment practices on pearl millet yield and nutrient uptake in the Sahel of West Africa

1999 ◽  
Vol 35 (4) ◽  
pp. 437-448 ◽  
Author(s):  
F. N. IKPE ◽  
J. M. POWELL ◽  
N. O. ISIRIMAH ◽  
T. A. T. WAHUA ◽  
E. M. NGODIGHA
Keyword(s):  
Soil Amendment ◽  
Soil Phosphorus ◽  
Phosphorus Uptake ◽  
Nitrogen Levels ◽  
Tillage Practices ◽  
No Till ◽  
Primary Tillage ◽  
Repeated Applications ◽  
Phosphorus And Potassium ◽  
Millet Yield

The main objective of this study was to determine the best soil amendment and tillage practices for sustainable millet yield and grain and stover quality. The treatments included tillage practices (immediate-, late- and no-till) and soil amendments (sheep manure plus urine, manure, millet stover (stalks, leaf blades and leaf sheaths) and millet stover ash) in factorial combinations with fertilizer nitrogen levels of 0, 15 and 30 kg ha−1 plus controls. Results showed that (i) higher yields were obtained in tilled plots than in no-till plots; (ii) tillage timing may not be a significant yield determining factor; (iii) the application of animal urine resulted in significantly higher yield and greater nitrogen, phosphorus and potassium uptake than the application either of manure alone or of millet stover. Urine application (ruminant urine contains virtually no phosphorus), which elevates soil pH especially during the first week after application, may have resulted in the dissolution of phosphorus from the aluminium–iron complexes of kaolinitic clays. This is corroborated by the significantly higher phosphorus uptake from the manure-plus-urine plots than from plots amended with either manure alone or millet stover. Long-term implications of ‘mining’ soil phosphorus with repeated applications of animal urine in these fragile ecosystems remains unclear.

Age-related morphological and physiological responses of irrigated rice to declined soil phosphorus and potassium availability

2016 ◽  
Vol 15 (3) ◽  
pp. 499-511 ◽  
Author(s):  
K. A. T. N. Somaweera ◽  
D. N. Sirisena ◽  
W. A. J. M. De Costa ◽  
L. D. B. Suriyagoda
Keyword(s):  
Soil Phosphorus ◽  
Physiological Responses ◽  
Irrigated Rice ◽  
Age Related ◽  
Phosphorus And Potassium

Using soil and plant analyses in decisions about fertilisers: a farmer’s perspective

1998 ◽  
Vol 38 (7) ◽  
pp. 745 ◽  
Author(s):  
W. R. Gibson
Keyword(s):  
Soil Phosphorus ◽  
Phosphorus Concentration ◽  
Plant Analysis ◽  
Ph Measurements ◽  
Initial Soil ◽  
Potassium Application ◽  
Phosphorus And Potassium ◽  
Yield Responses ◽  
The Relationship ◽  
Phosphorus Levels

Summary. This paper describes the part played by soil and plant analysis in decisions about fertilisers used on a mixed pastoral and cropping farm at Scone, in the Northern Midlands of Tasmania. Measurements of phosphorus and potassium concentrations in soils provide an essential framework for choosing fertilisers for crops and pastures. Use of lime with certain crops is determined by pH measurements. Neither soil nor plant analysis are used in choosing nitrogenous fertilisers. Fifteen paddocks were tested 7–8 years after initial soil tests (Colwell extracts). Phosphorus concentrations (mean ± s.e.) had risen by 13 ± 5 µg/g (P<0.05) and potassium by 89 ± 19 µg/g (P<0.001). In addition, the relationship between changes in these concentrations and the total phosphorus or potassium applied to individual paddocks was examined. Phosphorus concentration rose (P<0.001) by 5.9 µg/g for each 10 kg/ha additional phosphorus applied over the 7–8 years. Application of phosphorus at 7 kg/ha annually was enough to maintain soil phosphorus levels. No such relationship was detected for potassium. Application of lime at 4 t/ha raised the pH by about 1 unit. These results provide some reassurance about the behaviour of soils on Scone in response to the practices used in commercial mixed farming. The importance for the farmer of analyses being reliable is stressed, as is the need for well-based interpretation of the analytical results in order that the yield responses to fertilisers can be foreseen. Evidence about the financial returns produced by the increased yields is often lacking, especially for grazing enterprises.

Spatial heterogeneity of soil phosphorus and potassium in a mixed evergreen and deciduous broad-leaved forest in karst region of southwest China

2017 ◽  
Vol 37 (24) ◽  
Author(s):  
王华 WANG Hua ◽  
陈莉 CHEN Li ◽  
宋敏 SONG Min ◽  
宋同清 SONG Tongqing ◽  
曾馥平 ZENG Fuping ◽  
...  
Keyword(s):  
Spatial Heterogeneity ◽  
Southwest China ◽  
Soil Phosphorus ◽  
Karst Region ◽  
Broad Leaved Forest ◽  
Phosphorus And Potassium ◽  
Leaved Forest

scholarly journals Soil phosphorus and relationship to phosphorus balance under long-term fertilization

2018 ◽  
Vol 64 (No. 5) ◽  
pp. 214-220 ◽  
Author(s):  
Sun Benhua ◽  
Cui Quanhong ◽  
Guo Yun ◽  
Yang Xueyun ◽  
Zhang Shulan ◽  
...  
Keyword(s):  
Inorganic Nitrogen ◽  
Soil Phosphorus ◽  
Organic Fertilizers ◽  
Available Phosphorus ◽  
Soil P ◽  
Olsen P ◽  
P Fertilizer ◽  
P Balance ◽  
Activation Coefficient ◽  
Phosphorus And Potassium

Temporal changes in the concentrations of plant-available phosphorus (P) in soil (Olsen-P), total soil-P and P activation coefficient (the ratio of Olsen-P to residual-P (i.e. an approximation to total-P)) were measured in plots that received consistent inorganic nitrogen, phosphorus and potassium plus organic fertilizers annually. Maize and winter wheat crops were grown in rotation for 24 years. Olsen-P and P activation coefficient declined significantly in the earlier years (&lt; 12 years) for treatments that did not include any P fertilizer, and increased over the same period for the P-fertilized treatments. The rates of change in the Olsen-P and P activation coefficient values were positively related to P balance. In the later years, the Olsen-P and P activation coefficient plateau values were positively related to the P balance.

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