Calcium magnesium imbalance in clovers: A cause of negative yield response to liming
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Three pot experiments, in which causes of negative yield responses to liming were investigated, are reported. The soil used, Waimumu silt loam (Fragiochrept), differed from others that have been reported to show negative yield response to liming, in that it is only moderately weathered and leached, only moderately acid and has previously shown positive yield responses to liming. Deficiencies of Zn and Mg were identified, but limed (pH 6.8) soils still showed a 40% yield depression even where all nutrients were supplied daily. Phosphorus availability was little affected by liming, and despite Mg and Zn addition, yields were depressed at high lime (pH 6.4) and high P while plants showed leaf symptoms of Mg deficiency. Neither plant nor soil analyses indicated low Mg levels but Ca: Mg ratios in soil were 22:1. When a pH range 5.2–6.1 was produced by liming with CaCO3 and MgCO3 at ratios between 100:0, and 50:50 on an equivalent basis, negative yield response was eliminated at Ca:Mg of 50:50. There was no evidence that Mg was fixed or rendered unavailable at the higher pH levels. A Ca induced Mg deficiency arising when exchangeable Ca:Mg>20 is suggested as the cause. The role of variable surface charge in converting soils that respond positively to lime to a negative response condition is discussed.
Key wordscalcium carbonate Mg deficiency Trifolium repens Trifolium subterraneum variable surface change
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- Davis M R 1981 Growth and nutrition of legumes on a highly country yellow-brown earth subsoil. N. Z. J. Agric. Res. 24, 339–348.Google Scholar
- During C 1984 Fertilizers and Soils in New Zealand Farming. P.D. Hasselberg, Government Printer, Wellington, New Zealand. 361 p.Google Scholar
- Edmeades D C, Smart C E, Wheeler D M and Rhys G 1983 Effects of lime on the chemical composition of ryegrass and white clover grown on a yellow-brown loam. N. Z. J. Agric. Res. 26, 473–481.Google Scholar
- Floate M G S and Cossens G C 1985 Pasture responses to lime in the South Island, New Zealand. In Proceedings of Workshop on Lime in New Zealand Agriculture. Eds. B L J Jackson and D CEdmeades. pp 7–9. New Zealand Ministry of Agriculture and Fisheries, Hamilton, New Zealand.Google Scholar
- Lowther W L and Adams A F R 1970 The interaction of lime and phosphorus on the nodulation and growth of white clover. N. Z. J. Agric. 13, 252–262.Google Scholar
- McNaught K J 1970 Diagnosis of mineral deficiencies in grass-legume pasture by plant analysis. In Proceedings of the Eleventh International Grassland Congress. Ed. M J J Norman. pp 334–338. University of Queensland Press, St. Lucia, Queensland, Australia.Google Scholar
- Metson A J 1974 Magnesium in New Zealand soils. I. Some factors governing the availability of soil magnesium. N. Z. J. Exp. Agric. 2, 277–319.Google Scholar
- Muchovej R M C, Borges A C, Novais R F and Thiebaut J T L 1986 Effect of liming levels and Ca:Mg ratios on yield, nitrogen content and nodulation of soybeans grown in acid Cerrado soil. J. Soil Sci. 37, 235–240.Google Scholar
- Pleysier J L and Juo A S R 1980 A single-extraction method using silver-thiourea for measuring exchangeable cations and effective CEC in soils with variable charges. Soil Sci. 129, 205–211.Google Scholar
- Pringle R M, Edmeades D C, Shannon P W and Mansell G P 1985 Predicting lime response on pastures. In Proceedings of a Workshop on Lime in New Zealand Agriculture. Eds. B L TJackson and D CEdmeades. pp 20–22. New Zealand Ministry of Agriculture and Fisheries, Hamilton, New Zealand.Google Scholar
- Wallace T 1944 The Diagnosis of Mineral Deficiencies in Plants by Visual Symptoms: A Colour Atlas and Guide. HMSO, London.Google Scholar