A study on the merits of separating tropical soils into groups and using different chemical extractants for different groups in the routine measurement of available soil phosphorus

1983 ◽  
Vol 14 (6) ◽  
pp. 521-539 ◽  
Author(s):  
S.K. Muriuki ◽  
R.G. Barber
2019 ◽  
Vol 103 (1) ◽  
pp. 43-45 ◽  
Author(s):  
Carlos Crusciol ◽  
João Rigon ◽  
Juliano Calonego ◽  
Rogério Soratto

Some crop species could be used inside a cropping system as part of a strategy to increase soil P availability due to their capacity to recycle P and shift the equilibrium between soil P fractions to benefit the main crop. The release of P by crop residue decomposition, and mobilization and uptake of otherwise recalcitrant P are important mechanisms capable of increasing P availability and crop yields.


2013 ◽  
Vol 44 (13) ◽  
pp. 1992-2007
Author(s):  
K. A. Cassida ◽  
J. G. Foster ◽  
J. M. Gonzalez ◽  
R. W. Zobel ◽  
M. A. Sanderson

2014 ◽  
Vol 38 (5) ◽  
pp. 1487-1495 ◽  
Author(s):  
Ciro Antonio Rosolem ◽  
Alexandre Merlin

Phosphorus fixation in tropical soils may decrease under no-till. In this case, P fertilizer could be surface-spread, which would improve farm operations by decreasing the time spend in reloading the planter with fertilizers. In the long term, less soluble P sources could be viable. In this experiment, the effect of surface-broadcast P fertilization with both soluble and reactive phosphates on soil P forms and availability to soybean was studied with or without fertilization with soluble P in the planting furrow in a long-term experiment in which soybean was grown in rotation with Ruzigrass (Brachiaria ruziziensis). No P or 80 kg ha-1 of P2O5 in the form of triple superphosphate or Arad reactive rock phosphate was applied on the surface of a soil with variable P fertilization history. Soil samples were taken to a depth of 60 cm and soil P was fractionated. Soybean was grown with 0, 30, and 60 kg ha-1 of P2O5 in the form of triple phosphate applied in the seed furrow. Both fertilizers applied increased available P in the uppermost soil layers and the moderately labile organic and inorganic forms of P in the soil profile, probably as result of root decay. Soybean responded to phosphates applied on the soil surface or in the seed furrow; however, application of soluble P in the seed furrow should not be discarded. In tropical soils with a history of P fertilization, soluble P sources may be substituted for natural reactive phosphates broadcast on the surface. The planting operation may be facilitated through reduction in the rate of P applied in the planting furrow in relation to the rates currently applied.


2012 ◽  
Vol 359 (1-2) ◽  
pp. 267-279 ◽  
Author(s):  
Laetitia Six ◽  
Pieter Pypers ◽  
Fien Degryse ◽  
Erik Smolders ◽  
Roel Merckx

2021 ◽  
Vol 905 (1) ◽  
pp. 012001
Author(s):  
A K Salam ◽  
M Milanti ◽  
G Silva ◽  
F Rachman ◽  
I M T D Santa ◽  
...  

Abstract This study compared N HNO3 to other methods to determine plant available heavy metals in heavy-metal polluted soils. Soil samples were obtained from an experimental field treated with industrial waste after 22 years of the amendment and employed to conduct the comparative and correlation study. Soil samples were analyzed for Cu using various methods, planted in a glass house with several plants, and analyzed for soil and plant Cu and Zn. The relative strength of the chemical extractants followed the order of N HNO3 ≈ N HCl > Buffered DTPA ≈ Unbuffered DTPA > M CaCl2 ≈ N NH4OAc pH 7. A high correlation was observed for soil extracted Cu by M CaCl2 or N NH4OAc pH 7 or N HCl vs. Buffered DTPA and N HNO3 or N NH4OAc pH 7 vs. N HCl. High correlations of plant and soil Cu extracted by N HNO3 were shown by caisim, water spinach, land spinach, and corn, while plant and soil Zn were shown by caisim, water spinach, land spinach, and lettuce.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
C. Nobile ◽  
D. Houben ◽  
E. Michel ◽  
S. Firmin ◽  
H. Lambers ◽  
...  

Abstract Crops have different strategies to acquire poorly-available soil phosphorus (P) which are dependent on their architectural, morphological, and physiological root traits, but their capacity to enhance P acquisition varies with the type of fertilizer applied. The objective of this study was to examine how P-acquisition strategies of three main crops are affected by the application of sewage sludges, compared with a mineral P fertilizer. We carried out a 3-months greenhouse pot experiment and compared the response of P-acquisition traits among wheat, barley and canola in a soil amended with three sludges or a mineral P fertilizer. Results showed that the P-acquisition strategy differed among crops. Compared with canola, wheat and barley had a higher specific root length and a greater root carboxylate release and they acquired as much P from sludge as from mineral P. By contrast, canola shoot P content was greater with sludge than with mineral P. This was attributed to a higher root-released acid phosphatase activity which promoted the mineralization of sludge-derived P-organic. This study showed that contrasted P-acquisition strategies of crops allows increased use of renewable P resources by optimizing combinations of crop and the type of P fertilizer applied within the cropping system.


1999 ◽  
Vol 132 (4) ◽  
pp. 399-405 ◽  
Author(s):  
A. E. OSMAN ◽  
A. K. SALKINI ◽  
F. GHASSALI

The effects of residual phosphate (P) fertilizer were monitored for six seasons on Mediterranean grassland. The phosphate fertilizer was originally applied annually at three rates (0, 25 and 60 kg P2O5/ha) for 7 years (1984–1990) to phosphate-deficient grassland at Tel Hadya, northern Syria. The herbage biomass productivity, botanical composition and the seed bank in the soil were monitored for six seasons (1991/92–1996/97). The experiment was grazed at two annual stocking rates (1·1 sheep/ha (low) and 2·3 sheep/ha (high)). The experimental site was typical of native grassland within the cereal zone of west Asia, where cropping is not possible because of shallow, stony soils and steep slopes.Available soil phosphorus in May 1991 was 6·5, 20·8 and 40·1 mg P/kg under the 0, 25 and 60 kg P2O5/ha treatments and 6·6, 13·4 and 14·8 mg P/kg respectively, in May 1997. Yields of both legumes and total herbage (legume+grass+other species) were significantly influenced by the residual phosphate. Legume yields were between 6- and 7-times the control yield in the first two years of the study. This decreased with time but was still in the range of 1·5 to 1·9 times the yield of the control in 1997, six years later. Total herbage yield was consistently higher on the plots previously fertilized with P, which ranged between 1·5- and 2·5-times the control. Both legume seed and grass seeds were significantly larger with residual P, which ranged between 5·4- and 2·0-times the control for the legume and 2·5- and 1·4-times for the grasses. All these factors have practical implications for the use of P fertilizer on grassland which could help control soil erosion and improve livestock production on marginal lands on which farming communities largely depend.


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