Chemical soil test prediction of pasture responses to potassium on recent soils of the South Island west coast

Williams, P. H.; Morton, J. D.; Jackson, B. L. J.

doi:10.1080/03015521.1986.10423057

Cited by 6 publications

(12 citation statements)

References 4 publications

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“…For these sites, the application of fertiliser K had very little effect on soil QTK levels, similar to the results reported by Williams et al (1986) as discussed above, suggesting that most of the fertiliser K was leached below 75 mm within the time frame of the experiments (3 years) from where it was taken up by the pasture. For this subset of trials there was a pasture response up to 40 kg K ha…”

Section: Movement Of Fertiliser Ksupporting

confidence: 76%

“…However, it is predominantly the volcanic soils, which do not normally contain significant amounts of reserve K (Metson 1980), that are non-responsive at low soil QTK and indeed at low TBK levels, suggesting that there must be another explanation for this feature in the data. Williams et al (1986) reported that soilexchangeable K (but not QTK) was more highly correlated to relative yield than TBK on a set of 13 trials under high rainfall (4000Á8000 mm annually) on the West Coast, distinguished by their low and narrow range in soil K levels (QTK B4). They noted that, for these soils, there were significant quantities of reserve K (TBK), but not exchangeable K, at depth (15Á30 cm) that may have accounted for their lack of responsiveness to fertiliser K.…”

Section: Reserve Kmentioning

confidence: 99%

“…Ozanne et al (1965) showed this explicitly using radioactive K, and found that plant K uptake at various depths was related to the quantity of roots present. Williams et al (1986) measured the recovery of K in pasture across 13 sites (mowing trials with 70% return of clippings) on the West Coast on recent and gleyed soils under high rainfall. The recoveries were low: 17, 17 and 19 for fertiliser inputs of 30, 60 and 120 kg K ha…”

Section: Movement Of Fertiliser Kmentioning

confidence: 99%

“…Jackson did note, however, that the TBK test would not predict pasture responses to fertiliser K accurately on soils where the rate of release of reserve K was less than the plant demand and in situations where the plants derived significant amounts of K from below the soil depth tested. In subsequent field work on pastoral soils on the West Coast, it was found that exchangeable K was superior to the TBK method in terms of predicting K responses (Williams et al 1986), but these results were on soils with a narrow range of exchangeable soil K. Campkin (1985) published a model for calculating the potassium requirements for grazed pastures. This model assumed that the soil-pasture-animal system was at a steady state with respect to soil K, and hence the fertiliser K requirements were calculated as the sum of all the losses of K from the system.…”

Section: Introductionmentioning

confidence: 99%

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The diagnosis and correction of potassium deficiency in New Zealand pastoral soils: a review

Edmeades

Morton²,

Waller

et al. 2010

New Zealand Journal of Agricultural Research

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Field-trial data from a database comprising records of 804 potassium (K) fertiliser trials were used to define the production functions relating exchangeable soil K (quick test K (QTK) 0Á75 mm) to the relative response to fertiliser K applications, for the major soil groups in New Zealand. For all soil groups for which there were sufficient data, the production functions were generally flat in the range QTK 5Á10, and thus the estimated relative pasture production at QTK 5 and QTK 10 were similar. The critical QTK levels to achieve 97% maximum production were relatively well defined, being 6 (5Á8) for sedimentary soils (brown and pallic) and brown soils, and 7 (5Á10) for pumice soils. The data for the allophanic soils were unstable and the best estimate was 6 (5Á10). For the remaining soils groups (podzols and raw soils, organic, recent and gley soils) for which there was much less data, the relationships were essentially flat over the range QTK 2Á10. The probability of pasture responses to applied K increased as soil QTK decreased from 10. For the sedimentary and volcanic soils (including both allophanic and pumice) the probability was about 70Á80% at soil QTK B2. The comparable probabilities were 50Á60% for the recent and gley soils, and 30Á43% for the podzols and raw soils. A feature of the response functions was that some trials were not responsive to fertiliser K despite having low soil QTK. In most cases this could not be attributed to soil K reserves as measured by the soil TBK test (sodium tetra-phenol-boron extractable which measures exchangeable K plus plant-available but non-exchangeable K). Other possible reasons for this feature in the data are discussed, including uptake of K from below the soil sampling depth and the temporal effects of clover responses to applied K. Soil K buffer capacities*the amount of fertiliser K over and above maintenance required to increase soil QTK by 1 unit (DK)*ranged from 50 to 150 kg K ha (1 (average 124) for sedimentary soils. For some soils (developed organic soils, gleyed soils and podzols), fertiliser K had very little effect on QTK (0Á75 mm). It is not clear whether these differences are due to differences in leaching of K from the sampling depth, differences between soils in their ability to absorb and retain applied K or indeed the result of errors in the measurement of this parameter. Estimated maintenance K requirements (i.e. the amount of applied K required to maintain soil QTK levels) increased with increasing soil QTK from 4 to 10, from 0Á150 kg K ha(1 yr (1 to 100Á300 kg K ha (1 yr (1 in situations where losses of K were extreme due to the removal of all harvested clippings. Given the uncertainties in predicting K responses and the amount of fertiliser K required to correct K deficiency, practical suggestions are offered as to how best to diagnose and manage soil K deficiency. Areas for future research to improve the prediction of pasture responses to fertiliser K are also included.

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Section: Movement Of Fertiliser Ksupporting

confidence: 76%

Section: Reserve Kmentioning

confidence: 99%

Section: Movement Of Fertiliser Kmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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The diagnosis and correction of potassium deficiency in New Zealand pastoral soils: a review

Edmeades

Morton²,

Waller

et al. 2010

New Zealand Journal of Agricultural Research

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“…They involve treating soil with acid e.g., boiling M HNO 3 , continuous leaching with 0.01M HC1, or treatment with a salt precipitant such as sodium tetraphenyl boron (NaTPB). In New Zealand, Metson & Hurst (1953) and Campkin (1972) used the boiling nitric acid method to measure the K-releasing power of soils whereas Jackson (1985) and Williams et al (1986) used the NaTPB method. Jackson (1985) recommended the NaTPB method for soils which have significant non-exchangeable K and lowmedium exchangeable K in preference to the nitric acid method.…”

Section: Methods Of Assessing Exchangeable Plus Non-exchangeable K-rementioning

confidence: 99%

Potassium in the soils of New Zealand—A review

Kirkman

Basker

Surapaneni

et al. 1994

New Zealand Journal of Agricultural Research

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This paper reviews current information about potassium (K) in the soils of New Zealand, based on work conducted since the 1920s. The forms of K existing in soils are discussed and related to the K status of the genetic soil groups. The methods used in New Zealand to assess Ksupplying power, K-releasing power, and plantavailable K are discussed. The historical development of the methods for computing the K fertiliser requirements of pastures and crops in New Zealand is reviewed with emphasis on the Computerised Fertiliser Advisory Service (CFAS) established in 1984. The CFAS model is discussed and amendments are suggested.

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Variability of clay mineralogy in two New Zealand steep-land topsoils under pasture

et al. 2006

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Chemical soil test prediction of pasture responses to potassium on recent soils of the South Island west coast

Abstract: Pasture yield responses to potassium (K) fertiliser were measured at 13 sites which had low levels of exchangeable K but varying amounts of non-exchangeable K.

Cited by 6 publications

References 4 publications

The diagnosis and correction of potassium deficiency in New Zealand pastoral soils: a review

The diagnosis and correction of potassium deficiency in New Zealand pastoral soils: a review

Potassium in the soils of New Zealand—A review

Variability of clay mineralogy in two New Zealand steep-land topsoils under pasture

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