Summary
Nine vesicular-arbuscular mycorrhizal endophytes were assessed for their infectivity and ability to improve the growth of alpine strawberry seedlings in sterilized, low-phosphate soils (4 and 8 mg kg−1 NaHCO3-soluble P), limed to different pHs. At pH 4, Glomus clarum greatly stimulated plant growth, but the other endophytes except Gigaspora margarita and Glomus fasciculatum‘E3’ had little or no effect. The most efficient endophytes at pH 5 were E3, Acaulospora laevis and G. clarum. The largest plants were those growing at pH 7 and inoculated with Glomus epigaeum; A. laevis and G. clarum were ineffective at this pH. The most effective endophytes at pH 6 and 7 were G. epigaeum, Glomus mosseae, E3, Glomus caledonium and Gigaspora heterogama, although results varied slightly between soils. Most endophytes infected well at all pHs, even where they did not enhance plant growth. In studies of this nature plant growth is affected by different pHs, soil P levels and the inoculum used. Nevertheless these data show clearly that different endophytes vary enormously in their symbiotic effectiveness at different soil pHs. The practical implications of these results are discussed.

https://nph.onlinelibrary.wiley.com/doi/pdf/10.1111/j.1469-8137.1971.tb02504.x

Plant growth responses to vesicular-arbuscular mycorrhiza

Publisher Summary This chapter emphasizes on the effects that lime and phosphate applications have on the soil–plant system. An understanding of such effects is essential for those involved in the development and management of acid, phosphate-fixing soils. The response of crop plants to liming has been reviewed extensively by Pearson. In acid soils with a pH less than 5.0–5.5, initial lime applications result in large increases in crop growth and yield. The positive growth response is because of amelioration of aluminium (Al) toxicity because the soluble and exchangeable soil Al precipitates as hydroxy-Al species as the pH is raised. An understanding of the chemistry of soil A1 is central to the understanding of the fertility of acid soils. Because phytotoxic concentrations of soluble and exchangeable A1 often limits crop production on acid soils, there is increasing interest in basing lime requirements on estimates of exchangeable or reactive pools of soil A1 rather than on the amount required to bring the soil to an arbitrarily defined pH such as 6.5. Phosphate deficiency is common on highly weathered acid soils that often possess a high phosphate fixation capacity. In soils high in organic matter, liming may result in an initial burst of microbial activity and the mineralization of soil organic phosphorus.

Lime and Phosphate in the Soil-Plant System

Plant growth responses to vesicular-arbuscular mycorrhiza. ix. interactions between va mycorrhiza, rock phosphate and symbiotic nitrogen fixation

Soil chemistry and mineral problems in farm livestock. A review

Phosphate Nutrition of Plants-A General Treatise

Nine tropical and one temperate pasture legume species were grown in pots of soil with varying additions of phosphate. Growth responses and chemical conlposition of the plant tops were recorded, and from the latter, critical percentages of phosphorus were established. These were verified by using data from two soils in the pot culture investigation and a total of six field sites. Glycine javanica and Desmodium intortum were the most responsive species in pots, and Stylosanthes humilis and Lotononis bainesii were the least responsive species. The quantity of phosphorus per pot accumulated in the tops of the plants was greatest for Stylosanthes humilis and Lotononis bainesii at all treatment levels. Critical percentages of phosphorus in the tops of Phaseolus Iathyroides, Phaseolus atropurpureus, Stylosanthes humilis, Centrosema pubescens, Glycine javanica, Lotononis bainesii, Medicago sativa, Desmodium uncinatum, Desmodium intortum, and Vigna luteola sampled at the immediate pre-flowering stage of growth were 0.20, 0.24, 0.17, 0.16, 0.23, 0.17, 0.24, 0.23, 0.22, and 0.25% phosphorus respectively.

CS Andrew

Papers

The effect of phosphorus on the growth and chemical composition of some tropical pasture legumes. I. Growth and critical percentages of phosphorus