Threshold values for sulphur in soils of the main maize-producing areas of South Africa

Biljon, J. J. van; Fouche, D.S.; Botha, A. D.P.

doi:10.1080/02571862.2004.10635041

Cited by 10 publications

(4 citation statements)

References 15 publications

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“…In recent past, crop deficiencies of S have been reported in cropping systems that have reduced anthropogenic S input and failure to replenishment S through fertilizer input to compensate exportation [53]. In line with this, continuous application of Sulphur-free fertilizers may also induce S deficiency [54] such as the case in this study. All the nutrient sources were S-free except for the negligible content contained in FYM (NPK2) and Mavuno fertilizer, used in the NPK3 treatment [55].…”

Section: Maize Agronomic Response Clusterssupporting

confidence: 77%

Maize (Zea mays L.) Response to Secondary and Micronutrients for Profitable N, P and K Fertilizer Use in Poorly Responsive Soils

et al. 2018

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Deficiencies of secondary and micronutrients (SMNs) are major causes of low maize yields in poorly responsive soils. This phenomenon minimizes the agronomic efficiency of N, P and K fertilizers and consequently result in a dwindling economic benefit associated with their use. Therefore, 18 on-farm trials were conducted in western Kenya during two cropping seasons to assess maize response to three NPK amendments; (i) N, P, K, Ca, Zn and Cu (inorganic and organic); (ii) N, P, K, Ca, Zn and Cu (inorganic) and (iii) N, P K, Zn and Cu (inorganic) and evaluate the profitability of their use compared to additions of only N, P and K fertilizers. In this set of experiments, maize response to any amendment refers to a yield increase of ≥2 t ha −1 above control and could be categorized in three clusters. Cluster 1, comprising of nine sites, maize responded to all amendments. Cluster 2, holding six sites, maize responded only to one amendment, N, P, K, Ca, Zn and Cu (inorganic). In this cluster, (2), emerging S, Mg and Cu deficiencies may still limit maize production. Cluster 3; consisting of three sites, maize responded poorly to all amendments due to relatively high soil fertility (≥17 mg P kg −1). Profitability of using NPK amendments is limited to Cluster 1 and 2 and the largest Value Cost Ratio (VCR) of 3.1 is attainable only when soil available P is below 4.72 mg kg −1. These variable responses indicate the need for developing site-specific fertilizer recommendations for improved maize production and profitability of fertilizer use in poorly responsive soils.

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Section: Maize Agronomic Response Clusterssupporting

confidence: 77%

Maize (Zea mays L.) Response to Secondary and Micronutrients for Profitable N, P and K Fertilizer Use in Poorly Responsive Soils

et al. 2018

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“…The RY concept described and applied in K research by Bray (1944) and recently by Van Biljon et al (2004) to evaluate the threshold levels for S, was used. The advantages and shortcomings of the RY concept were discussed by the latter authors who decided to apply RY to their field data because it enabled them to include results from different climatic zones, soil types, maize cultivars, plant spacing and seasons.…”

Section: Methodsmentioning

confidence: 99%

Threshold values and sufficiency levels for potassium in maize producing sandy soils of South Africa

Biljon

Fouche

Botha³

2008

South African Journal of Plant and Soil

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South African maize farmers apply only two thirds of the potassium (K) which is annually removed in the grain, causing a deficit of more than 13 000 tons K per season. It is expected that these maize fields will gradually become depleted and more K will be required to maintain or improve yields. Research goals were set for sandy soils in the main maize producing areas of South Africa to determine the lower & upper threshold values and sufficiency levels for soil K, the K status of these soils and to evaluate the sufficiency level concept for K at the various localities in the Free State Province. Field experiments were conducted at nine localities during four consecutive seasons. The experimental data included the soil K extracted with NH 4 OAc and the relative maize yields (RY) of the treatments, +K which received macro, secondary and micro nutrients and 0K which received the same nutrients but K was omitted. The results indicated a lower threshold value of 125 mg K kg -1 below which maize is expected to respond positively and an upper threshold value of 190 mg K kg -1 above which maize is expected not respond to additional K. The extractable K from 25 000 sandy soil samples received from maize farmers indicated that approximately 50% of these samples contained less K than the lower threshold value, approximately 30% was between the lower and upper threshold values and the remaining 20% was above the upper threshold value. The sufficiency levels obtained with the Mitscherlich model at 98% RY, ranged from 109-340 mg K kg -1 . The difference between the sufficiency values and the extractable soil K at any of these localities, gives an unbiased measurement of the K fertilizer to be recommended.

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“…The RY concept described and applied by Bray (1944) and recently by Van Biljon et al (2004) to evaluate the threshold levels for S, was used. The advantages and shortcomings of the RY concept were discussed by the latter authors who decided to apply RY to their field data because it enabled them to include results from different climatic zones, soil types, maize cultivars, plant spacing and seasons.…”

Section: Methodsmentioning

confidence: 99%

“…Field experiments previously described by Van Biljon et al (2004), with nine treatments replicated three times in randomized blocks were conducted in the main maize growing area of South Africa. Representative soil profiles were selected at each locality, described, classified, analyzed and results presented in Table 1.…”

Section: Methodsmentioning

confidence: 99%

The lower and upper threshold values, biological optimum and mineralization of nitrogen in the main maize producing soils of South Africa

Biljon

Fouche

Botha³

2008

South African Journal of Plant and Soil

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There is still no consensus in South Africa on the parameters used to advise maize farmers on the quantity of N needed for optimum yields. In order to determine the lower and upper threshold values for nitrogen (N), the biological optimum and the mineralization of organic N in the main maize growing areas of South Africa, field trials were carried out at seven localities over three years. The treatments were full fertilization as reference (Ref), with the comparative treatment being where N was omitted (0N). Relative maize yields (RY) were determined and composite soil samples were taken. Bulk density (t m -3 ) and the NO 3 -N extracted with K 2 SO 4 -solution were determined in the laboratory and the kg NO 3 -N ha -1 calculated. The RY responded to N with a lower threshold value in the soil stratum (0-600 mm) of 70 kg NO 3 -N ha -1 (8 mg NO 3 -N kg -1 ), an upper threshold value of 161 kg NO 3 -N ha -1 , a biological optimum of 280 kg NO 3 -N ha -1 and an estimated N mineralization during the growing season of 40 kg NO 3 -N ha -1 .

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Threshold values for sulphur in soils of the main maize-producing areas of South Africa

Cited by 10 publications

References 15 publications

Maize (Zea mays L.) Response to Secondary and Micronutrients for Profitable N, P and K Fertilizer Use in Poorly Responsive Soils

Maize (Zea mays L.) Response to Secondary and Micronutrients for Profitable N, P and K Fertilizer Use in Poorly Responsive Soils

Threshold values and sufficiency levels for potassium in maize producing sandy soils of South Africa

The lower and upper threshold values, biological optimum and mineralization of nitrogen in the main maize producing soils of South Africa

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