scholarly journals Spatial variability of soil phosphorus of a low productivity Brachiaria brizantha pasture

2003 ◽  
Vol 60 (3) ◽  
pp. 559-564 ◽  
Author(s):  
Edemar Joaquim Corazza ◽  
Michel Brossard ◽  
Takashi MuraokaI ◽  
Maurício Antonio Coelho Filho

Studies on soil phosphorus (P) of low productivity cultivated pastures in Cerrado (Brazilian Savanna) areas and surveys on other possible problems related to P are scarce. The spatial variability of soil phosphorus content of a Rhodic Ferralsol was studied in a low productivity pasture of Brachiaria brizantha (BB) grown for 10 years, without fertilizer application, in an experimental area at Planaltina (GO), Brazil. Soil samplings were performed on a regular grid of 10 by 10 meters, with 98 sampling points before (between tussocks and under tussocks) and after the establishment of the experiment (after fertilizing). On the same grid, forage plants were collected and separated into fractions for N and P content analyses. Soil available phosphate was determined by the resin method (Pr) and complemented by the 32P isotopic exchange kinetics analysis. Descriptive statistical and geostatistical analyses were utilized to describe the spatial variability. The Pr content on soil samples under tussocks presented mean and median values 45% larger than in soil samples taken between tussocks. The higher variation is probably related to the greater concentration of BB roots, soil organic matter content and soil P recycled through the plants tussocks. The spatial variability of Pr in this soil was high especially after fertilizer application. This variable did not present spatial dependence for the regular 10 m sampling. The generated knowledge on P variability of soils under low productivity cultivated pastures revealed problems related to the sampling methodology traditionally utilized and to P application.

Soil Research ◽  
2007 ◽  
Vol 45 (3) ◽  
pp. 190 ◽  
Author(s):  
Terrence A. Short ◽  
Peter M. Kopittke ◽  
David R. Mulligan ◽  
Neal W. Menzies

As observed with many soils, much of the P in the Brown Kandosol soils of Weipa (Australia) is associated with organic matter. However, following bauxite mining, much of this organic matter is either lost due to mineralisation, or is ‘diluted’ by the mixing of the soil profile. Using a sequential P extraction, the partitioning of P following fertiliser application was examined in an ‘undisturbed’ (Surface) soil and a Mixed soil. In addition, the effect of split-P applications on the growth of 2 native Eucalyptus species was examined. Following its addition to the soil, much of the P was converted comparatively rapidly to forms with reduced availability; by the time of the first measurement (4 weeks) only approximately 10% of the added P remained as the readily available AER-P. For the Surface soil, much of this added P was initially converted to organic P (Po) (measured as hydroxide-Po), before progressively moving into the hydroxide-Pi fraction. In comparison, in the mixed soil, competition for P from microbial biomass was lower (due to a lower organic matter content) and the P was rapidly converted to the hydroxide-Pi fraction before moving to unavailable forms (residual P). Although the use of split-P applications was expected to increase plant growth, maximum growth of Eucalyptus tetrodonta and Eucalyptus leptophleba was generally achieved when all P fertiliser was applied in the first few weeks of growth. Indeed, splitting the P application beyond 16 weeks caused a significant reduction in growth.


Author(s):  
Cássio Ricardo Gonçalves da Costa ◽  
Stella Silva Prazeres ◽  
Patricia Venâncio da Silva ◽  
Kilmer Oliveira Soares ◽  
Ailson de Lima Marques ◽  
...  

The study evaluated the effect of the cultivation of five species of grasses of the genus Brachiaria (B. decumbens, B. ruziziensis, B. brizantha, B. humidicola and B. brizantha CV MG-5) in physical and chemical properties and in the formation and stabilization of aggregates of a Yellow Oxisol. The test with the grasses in the absence and presence of fertilization was conducted in the Chã de Jardim area, belonging to the Centro de Ciências Agrárias-UFPB, located in the county Areia-PB. The experimental design was in randomized blocks, with subdivided parcels, in factorial scheme 5 × 2 × 4, with four repetitions, being: five species of Grass (Braquiarias), two conditions of mineral fertilization with NPK (absence or presence) and four depths of soil samples collection (0-5, 5-10, 10-20, 20-30 cm), totaling 40 subplots of 5.0 × 5.0 m, with 3 repetitions, totaling 120 sampling points. The grasses favored the formation of aggregates and contributed to their stability. Brachiaria brizantha is the most suitable grass to raise the organic matter content of an Oxisol without mineral fertilization.


2016 ◽  
Vol 34 (2) ◽  
pp. 357-364 ◽  
Author(s):  
G.A.M. PEREIRA ◽  
L.H. BARCELLOS JR. ◽  
V.A. GONÇALVES ◽  
D.V. SILVA ◽  
A.T. FARIA ◽  
...  

ABSTRACT Knowledge of herbicides sorption by colloids predicts its movement in the soil profile and its effectiveness in controlling weeds and crops poisoning when directly applied to the soil. This knowledge becomes even more important for herbicides which have long persistence in the soil. In this research, clomazone sorption was estimated by the biological method in Brazilian soil samples with different physical and chemical characteristics, cultivated with sugarcane crops. As an indicator of the presence of clomazone in the soil, Sorghum bicolor was used. The data relating to assessments of poisoning and accumulation of dry matter of the plants were subjected to multivariate analysis of similarity among variables. After that, clomazone doses that caused 50% of intoxication in sorghum plants grown (C50) as well as sorption ratio (SR) of the herbicide in different soil types were estimated. There was similarity greater than 80% for data regarding the percentage of intoxication and accumulated dry matter, with the option to use only those related to the first variable. RS and C50 were higher in Organosol and lower in red-yellow Latosol with and without changing the pH. It was concluded that the clomazone dose to be recommended must be differentiated for different soils, since the value of clomazone sorption in the soil is dependent on its attributes, and the organic matter content is of the utmost importance.


2017 ◽  
Vol 14 (8) ◽  
pp. 2055-2068 ◽  
Author(s):  
Jie Zhang ◽  
Arthur H. W. Beusen ◽  
Dirk F. Van Apeldoorn ◽  
José M. Mogollón ◽  
Chaoqing Yu ◽  
...  

Abstract. Phosphorus (P) plays a vital role in global crop production and food security. In this study, we investigate the changes in soil P pool inventories calibrated from historical countrywide crop P uptake, using a 0.5-by-0.5° spatially explicit model for the period 1900–2010. Globally, the total P pool per hectare increased rapidly between 1900 and 2010 in soils of Europe (+31 %), South America (+2 %), North America (+15 %), Asia (+17 %), and Oceania (+17 %), while it has been stable in Africa. Simulated crop P uptake is influenced by both soil properties (available P and the P retention potential) and crop characteristics (maximum uptake). Until 1950, P fertilizer application had a negligible influence on crop uptake, but recently it has become a driving factor for food production in industrialized countries and a number of transition countries like Brazil, Korea, and China. This comprehensive and spatially explicit model can be used to assess how long surplus P fertilization is needed or how long depletions of built-up surplus P can continue without affecting crop yield.


2010 ◽  
Vol 58 (Supplement 1) ◽  
pp. 35-40
Author(s):  
S. Hoffmann ◽  
K. Berecz ◽  
S. Simon

Increasing doses of farmyard manure (FYM) or equivalent mineral NPK fertilizers and their combinations were analysed in a crop rotation with potato, maize and winter wheat with special regard to their long-term influence on soil fertility. The yield-increasing capacity of FYM doses was only 82%, as compared to the equivalent amount of mineral NPK. Fairly high N release (50.9 kg ha −1 ) could be observed on the unfertilized plots. Great differences in N utilization were recorded, depending on the form and dose of fertilizers. The average N utilization from FYM was only 29.3%, while that of the equivalent fertilizer application was 49.8%. The lowest soil reactions were observed without fertilization and at the highest NPK doses. Negative N balances generally resulted in low soil organic matter content. FYM and equivalent NPK fertilizers had a similar influence on the ammonium lactate (AL)-extractable K 2 O content of the soil, while an increase in the AL-P 2 O 5 content could be observed in the case of mineral fertilization.


Soil Research ◽  
2016 ◽  
Vol 54 (1) ◽  
pp. 11 ◽  
Author(s):  
Melinda R. S. Moata ◽  
Ashlea L. Doolette ◽  
Ronald J. Smernik ◽  
Ann M. McNeill ◽  
Lynne M. Macdonald

Organic phosphorus (P) plays an important role in the soil P cycle. It is present in various chemical forms, the relative amounts of which vary among soils, due to factors including climate, land use, and soil type. Few studies have investigated co-variation between P types or stoichiometric correlation with the key elemental components of organic matter– carbon (C) and nitrogen (N), both of which may influence P pool structure and dynamics in agricultural soils. In this study we determined the organic P speciation of twenty Australian Red Chromosols soils, a soil type widely used for cropping in Australia. Eight different chemical forms of P were quantified by 31P NMR spectroscopy, with a large majority (>90%) in all soils identified as orthophosphate and humic P. The strongest correlations (r2 = 0.77–0.85, P < 0.001) between P types were found among minor components: (i) between two inositol hexakisphosphate isomers (myo and scyllo) and (ii) between phospholipids and RNA (both detected as their alkaline hydrolysis products). Total soil C and N were correlated with phospholipid and RNA P, but not the most abundant P forms of orthophosphate and humic P. This suggests an influence of organic matter content on the organic P pool consisting of phospholipid and RNA, but not on inositol P or the largest organic P pool in these soils – humic P.


2009 ◽  
Vol 33 (5) ◽  
pp. 1481-1488 ◽  
Author(s):  
Vanusa Maria Feliciano Jacomino ◽  
Kerley Alberto Pereira de Oliveira ◽  
Maria Helena Tirollo Taddei ◽  
Maria Célia Siqueira ◽  
Maria Eleonora Deschamps Pires Carneiro ◽  
...  

Phosphogysum (PG) or agricultural gypsum, a solid waste from the phosphate fertilizer industry, is used as soil amendment, especially on soils in the Cerrado region, in Brazil. This material may however contain natural radionuclides and metals which can be transferred to soils, plants and water sources. This paper presents and discusses the results of physical and chemical analyses that characterized samples of PG and compares them to the results found in two typical soils of the Cerrado, a clayey and sandy one. These analyses included: solid waste classification, evaluation of organic matter content and of P, K, Ca, Mg, and Al concentrations and of the mineralogical composition. Natural radionuclides and metal concentrations in PG and soil samples were also measured. Phosphogypsum was classified as Class II A - Not Dangerous, Not Inert, Not Corrosive and Not Reactive. The organic matter content in the soil samples was low and potential acidity high. In the mean, the specific 226Ra activity in the phosphogypsum samples (252 Bq kg-1) was below the maximum level recommended by USEPA, which is 370 Bq kg-1 for agricultural use. In addition, this study verified that natural radionuclides and metals concentrations in PG were lower than in the clayey Oxisol of Sete Lagoas, Minas Gerais, Brazil. These results indicated that the application of phosphogypsum as soil amendment in agriculture would not cause a significant impact on the environment.


2010 ◽  
Vol 82 (2) ◽  
pp. 267-277 ◽  
Author(s):  
Javier Garcia-Guinea ◽  
Virgilio Correcher ◽  
Lorena Recio-Vazquez ◽  
Elena Crespo-Feo ◽  
Rafael Gonzalez-Martin ◽  
...  

The presence of high level of heavy metals involves a human healthy risk that could induce chronic diseases. This work reports on the metal contamination due to heaps of steel-slag accumulated during more than 40 years in allotments and industrial areas in the southern part of Madrid (Spain). Several slag and soil samples were collected in an area of 10 km² and characterized by different conventional (XRD and XRF) and no so common methods (ESEM, thermoluminescence and EDS-WDS). The analysis reveal the presence of: (i) important amounts of Fe (43%), Mg (26%), Cr (1.1%), Mn (4.6%), S (6.5%) in the form of Fe-rich slag phases (wustite, magnetite...), Si and Ca-rich phases (larnite, ghelenite...), Cr (chromite), Mn (bustamite) and graphite, (ii) traces of some other contaminants such as Cr (7700 ppm), Zn (3500 ppm), Ba (3000 ppm), Pb (700 ppm) or Cu (500 ppm) on pathway soil samples that come from the steel slag, and (iii) Co (13 ppm), Pb (78 ppm) and V (54 ppm) in farmland soil samples. Although the existing heavy metals content is not appropriate for the current use, the extremely high metal contamination of the surrounding areas is more worrying. The properties of the soil farmlands (pH circa 7, 13% of clay, mainly illite, and 1-4% of organic matter content) show suitable conditions for the retention of cationic metals, but further studies on the movilization of these elements have to be performed to determine the possibility of severe human health risks. This sort of study can provide useful information for the politicians regarding the appropriate use of the territory to prevent possible health hazard for the population.


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