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.

Prediction of yield responses to phosphorus by established Greenleaf desmodium/grass pastures in south-east Queensland using chemical tests

1980 ◽  
Vol 20 (105) ◽  
pp. 477
Author(s):  
GE Rayment ◽  
RC Bruce ◽  
BG Cook
Keyword(s):  
Soil Phosphorus ◽  
Residual Variance ◽  
Total Soil ◽  
Plant Chemical ◽  
Diagnostic Samples ◽  
Total Soil Phosphorus ◽  
Independent Variable ◽  
Phosphorus Status ◽  
Yield Responses ◽  
Phosphorus Levels

Phosphorus topdressing experiments (rates to 60 kg P ha-1) on 18 commercial Desmodium intortum cv. Greenleaf/grass pastures were conducted over a 4-year period in south-east Queensland. The aim was to determine whether yield responses, which occurred only in the Greenleaf component at six sites, could be predicted using soil or plant chemical tests. Acid-(0.005 M H2SO4) and bicarbonate-(0.5 M NaHCO3) extractable tests of phosphorus status in 0-10 cm soil samples each explained about 60% of the variance in Greenleaf relative yields. The residual variance was not significantly reduced by the inclusion of terms for total soil nitrogen, total soil phosphorus, exchangeable calcium and pH into the independent variable. These empirical soil phosphorus tests had higher predictive value than plant tests based on phosphorus concentrations in tops and diagnostic samples of Greenleaf. With both acid- and bicarbonate-extractable phosphorus, yield responses are likely in the Greenleaf component when phosphorus levels in most soils are below 22 ppm. Above 29 ppm, no response would be expected

Relationship between phosphorus concentration in surface runoff and a novel soil phosphorus test procedure (DGT) under simulated rainfall

Soil Research ◽  
2011 ◽  
Vol 49 (6) ◽  
pp. 523 ◽  
Author(s):  
W. J. Dougherty ◽  
S. D. Mason ◽  
L. L. Burkitt ◽  
P. J. Milham
Keyword(s):  
Soil Phosphorus ◽  
Test Procedure ◽  
Rainfall Simulation ◽  
Phosphorus Concentration ◽  
Diverse Range ◽  
Soil P ◽  
Wide Range ◽  
High Concentrations ◽  
Curvilinear Relationships ◽  
The Relationship

There is a need to be able to identify soils with the potential to generate high concentrations of phosphorus (P) in runoff, and a need to predict these concentrations for modelling and risk-assessment purposes. Attempts to use agronomic soil tests such as Colwell P for such purposes have met with limited success. In this research, we examined the relationships between a novel soil P test (diffuse gradients in thin films, DGT), Colwell P, P buffering index (PBI), and runoff P concentrations. Soils were collected from six sites with a diverse range of soil P buffering properties, incubated for 9 months with a wide range of P additions, and then subjected to rainfall simulation in repacked trays growing pasture. For all soil and P treatment combinations, the relationship between DGT (0–10 mm) and runoff P was highly significant (P < 0.001, r2 = 0.84). Although there were significant curvilinear relationships between Colwell P and runoff P for individual soils, there were large differences in these relationships between soils. However, the inclusion of a P buffering measure (PBI) as an explanatory variable resulted in a highly significant model (P < 0.001, R2 = 0.82) that explained between-soil variability. We conclude that either DGT, or Colwell P and PBI, can be used to provide a relative measure of runoff P concentration.

The effect of fertilizer nitrogen, phosphorus and potassium on the calcium, magnesium and phosphorus status of pasture cut for silage

1982 ◽  
Vol 99 (1) ◽  
pp. 199-205 ◽  
Author(s):  
J. B. A. Rodger
Keyword(s):  
Calcium Concentration ◽  
Soil Phosphorus ◽  
Magnesium Concentration ◽  
Phosphorus Concentration ◽  
Nitrogen And Phosphorus ◽  
Calcium Phosphorus ◽  
Calcium Magnesium ◽  
Phosphorus Status ◽  
Phosphorus And Potassium ◽  
Clover Content

SUMMARYPhysiological problems in some Fife dairy herds were thought to be associated with mineral imbalance in grass cut for silage. Consequently trials at two sites were conducted to study the effects of three levels of nitrogen and phosphorus and two levels of potassium on yield and composition of pasture cut for silage.Nitrogen increased yield of herbage and reduced its clover content whereas phosphorus and potassium had little effect on yield or clover content. Herbage clover content and calcium concentration declined over the period of the experiment. Mean concentrations of calcium, magnesium and phosphorus were 5·8, 1·7 and 3·4 g/kg respectively. Concentrations of these minerals varied more with time of cutting and with season than with level of applied phosphorus and potassium.Nitrogen tended to reduce calcium concentration in mixed herbage and to increase magnesium concentration in the grass component; it did not affect herbage phosphorus concentrations, but narrowed the calcium-phosphorus ratio in the second cuts. Applied phosphorus increased herbage phosphorus concentration only at the site with the lower soil phosphorus status. Potassium tended to reduce magnesium concentration in clover and, at one site, in mixed herbage; it also tended to reduce herbage phosphorus concentrations in second cuts.Mineral uptake was increased by applied nitrogen. Mean annual uptake of calcium magnesium and phosphorus was 34, 10 and 20 kg/ha respectively.The effects of treatments on concentration and balance of these minerals are discussed in relation to ruminant requirements and maintenance of suitable levels of the minerals in the soil.It is concluded that normal applications of NPK fertilizer are not detrimental to satisfactory mineral balance in pasture.

Changes in soil chemical properties in a long-term fertilizer trial in a non-irrigated vineyard

1971 ◽  
Vol 22 (6) ◽  
pp. 931
Author(s):  
MT Seeliger ◽  
RJ French
Keyword(s):  
Chemical Properties ◽  
South Australia ◽  
Available Phosphorus ◽  
Research Station ◽  
Potassium Fertilizer ◽  
Slow Moving ◽  
Phosphorus And Potassium ◽  
Yield Responses ◽  
Phosphorus Levels

Changes in soil properties in a long-term factorial experiment with nitrogen, phosphorus, and potassium fertilizer at the Nuriootpa Viticultural Research Station in South Australia were measured after 23 years of application. The measurements were related to vine yield responses reported earlier. Phosphorus, broadcast as superphosphate, gave excessively high available phosphorus levels in the top 6 in, of soil, but yield responses were delayed for 8 years until the slow-moving phosphorus reached the 6–12 in. layer where the feeder roots occurred. Broadcasting superphosphate was a wasteful and inefficient means of applying phosphorus in this environment. About three-quarters of the phosphorus applied could be measured in the top foot of soil. Nitrogen applied as sulphate of ammonia reduced pH significantly in the top 18 in. of soil, with the biggest reduction of 1.5 units to pH 5.0 in the 6–12 in. layer. As this acidity developed it probably caused the depression in vine vigour and yield. Potassium levels were high and not limiting in the unfertilized soils. The relation between nutrients supplied in the fertilizers and nutrients removed in the grapes is discussed.

Effect of topdressed phosphorus fertilizer on established white clover based pastures in south-east Queensland. 1. Prediction of yield responses using soil tests

1979 ◽  
Vol 19 (99) ◽  
pp. 454 ◽  
Author(s):  
GE Rayment ◽  
RC Bruce
Keyword(s):  
White Clover ◽  
Field Experiments ◽  
Soil Phosphorus ◽  
Relative Yield ◽  
Pasture Production ◽  
Phosphorus Status ◽  
Empirical Tests ◽  
Yield Responses ◽  
Phosphorus Levels ◽  
Term Field

Seventeen short-term field experiments were conducted over a five year period in south-east Queensland in which rates of up to 60 kg P ha-1 as monocalcium phosphate were topdressed onto established, previously grazed, grass-white clover (Trifolium repens) pastures, Increases (P < 0.05) in yields of white clover were obtained at seven sites, but concurrent increases in grass production occurred at only four sites. Higher total pasture production resulted at six of these sites. One quantitative (total) and two empirical (0.005 M H2SO4 and 0.5 M Na HCO3) estimates of phosphorus status in 0-10 cm soil samples, collected prior to topdressing treatments, were separately correlated with relative yield responses of white clover, grass and total pasture components. Although soil phosphorus levels by all methods were statistically intercorrelated (P < 0.01), acid-extractable and total phosphorus tests were generally unsuitable for predictive purposes, having low coefficients of determination for regressions and Cate-Nelson separations of responsive from non-responsive sites. Bicarbonate-extractable phosphorus proved the most suitable soil test. It accounted for 60 and 44% of the variance in relative yields of white clover and total pasture, respectively, but was poorly correlated with relative yields of grass. The suggested critical level of soil phosphorus (bicarbonate extraction) for white clover is 28 ppm P. For total pasture, responses are likely below 22, unlikely above 28 and uncertain between 22 and 28 ppm P, respectively. Percentage variance in relative yields already explained by both empirical tests was not significantly increased by inclusion of terms for pH and exchangeable calcium into the X variable.

Phosphorus nutrition of peanut (Arachis hypogaea L.) on Cockatoo Sands of the Ord River Irrigation Area

1985 ◽  
Vol 25 (3) ◽  
pp. 649 ◽  
Author(s):  
MJ Bell
Keyword(s):  
Critical Concentration ◽  
Soil Phosphorus ◽  
Maximum Yield ◽  
Dry Weight ◽  
Yield Response ◽  
Phosphorus Concentration ◽  
Irrigation Area ◽  
Arachis Hypogaea L ◽  
Phosphorus Status ◽  
Phosphorus Levels

Yield response of field-grown Virginia Bunch peanuts to a range of soil phosphorus levels, determined using 0.5M NaHCO3 extractant, in the top 10 cm of the soil profile was evaluated on Cockatoo Sands of the Ord River Irrigation Area. Critical levels of soil phosphorus (required to attain 90% of maximum yield recorded in fertilized plots) was 7.3 ppm for pods and 7.9 ppm for kernels. Yield increases obtained with higher soil phosphorus status were due to increased pod number and kernel size. Trends in tissue phosphorus concentration in uppermost fully expanded leaves were monitored during the season, and critical concentrations for 90% of maximum pod yield were derived. The critical concentration (0.30% P, dry-weight basis) did not change with time during the vegetative phase of development, but declined in a linear fashion over time during reproductive development, from 0.27% P at 60 days after emergence to 0.12% P at 100 days after emergence.

scholarly journals Concentration of Nitrogen, Phosphorus and Potassium in Sorghum Plants Grown at Different Levels of Nitrogen Nutrition

2018 ◽  
Vol 19 (2) ◽  
pp. 127
Author(s):  
Svetla Kostadinova ◽  
Zivko Todorov ◽  
Ivan Velinov
Keyword(s):  
Potassium Concentration ◽  
Nitrogen Nutrition ◽  
Nitrogen Concentration ◽  
Nitrogen Level ◽  
Phosphorus Concentration ◽  
Plant Parts ◽  
Phosphorus And Potassium ◽  
The Relationship ◽  
Nitrogen Phosphorus ◽  
Different Levels

The pot experiment was conducted in a greenhouse to study the effect of nitrogen nutrition of 0, 200, 400, 600 and 800 mg N.kg-1 soil on the concentration of nitrogen, phosphorus and potassium in sorghum plants. The plants were analyzed in 4-5 leaves growth stage by dividing the leaves, stems and roots. It was established that the sorghum plants formed the largest amount of dry biomass when grown at N600 level. Higher levels (N600 and N800) increased the nitrogen content of stems and roots and phosphorus in all plant parts, but they significantly reduced the nitrogen concentration in the leaves. The concentration of potassium in the leaves and stems increased in parallel with the levels of nitrogen from 3.64% K2O and 4.02% K2O at N0 to 4.42% K2O and 5.03% K2O at N800, respectively. The nitrogen level very strongly positively correlated with the nitrogen concentration of roots (r = 0.927**) and the potassium concentration of leaves (r = 0.993**) and stems (r = 0.985**). The relationship between nitrogen fertilization and the nitrogen concentration of leaves was negative (r = - 0.535*). The positive and proven relationship was established between the nitrogen level and the phosphorus concentration of plant organs.

Long-Term (15 Years) Results of NPS Controls in an Agricultural Watershed upon a Receiving Lake's Water Quality

1993 ◽  
Vol 28 (3-5) ◽  
pp. 441-449 ◽  
Author(s):  
Paul J. Garrison ◽  
Timothy R. Asplund
Keyword(s):  
Water Quality ◽  
Structural Changes ◽  
Soil Phosphorus ◽  
Water Clarity ◽  
Management Control ◽  
Agricultural Watershed ◽  
Control Measures ◽  
Phosphorus Loading ◽  
Phosphorus Concentration ◽  
White Clay

Nonpoint source controls were installed in a 1215 ha agricultural watershed in northeastern Wisconsin in the late 1970. Changes were made in handling of animal wastes and cropping practices to reduce runoff of sediment and nutrients. Modelling results predicted a reduction in phosphorus runoff of 30 percent. The water quality of White Clay Lake has worsened since the installation of NPS controls. The lake's phosphorus concentration has increased from a mean of 29 µg L−1 in the late 1970s to 44 µg L−1 in recent years. Water clarity has declined from 2.7 to 2.1 m and the mean summer chlorophyll levels have increased from 9 to 13 µg L−1 with peak values exceeding 40 µg L−1. Increased phosphorus loading is not the result of elevated precipitation but instead the failure of the control measures to sufficiently reduce P loading. Most of the effort was placed on structural changes while most of the P loading comes from cropland runoff. Further, soil phosphorus concentrations have increased because of artificial fertilizers and manure spreading. The White Clay Lake experience is discouraging since the majority of the polluters in this watershed utilized some NPS control practices, including 76 percent of the farms which installed waste management control facilities.

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