The effects of soil compaction, form of nitrogen fertiliser, and fertiliser placement on the availability of manganese to barley

Abstract

A study was made of the effects of seedbed compaction and use of fertiliser (application rate, placement, and the choice of ammonium or nitrate forms of nitrogen) on the availability of manganese to barley in light soils in East Scotland. Generally, the uptake of manganese by the plants was increased by increasing the amount of fertiliser applied and by compaction of theseedbed, althoughno significant increase inextractable soil manganese was detected. The increase in uptake from wheel-tracks (where the compression had resulted in an element of fertiliser placement), compared with nonwheeled areas, was much greater than the effect due to overall plot compaction by tractor wheels in the absence of a fertiliser placement effect. Combine-drilling of fertiliser with the seed resulted in large increases in plant uptake of manganese in non-wheeled areas, compared with uptake where the fertiliser had been broadcast, but had no significant effect in the wheel-tracks where growth and uptake were generally better. In some, but not all, experiments, significant reductions in pH occurred in the soil beneath the wheel-tracks which were very closely correlated with increases in extractable manganese. Use of ammonium sulphate as nitrogen source also reduced the pH, compared with calcium nitrate, and this, too, increased extractable manganese and greatly improved plant growth. The probable cause of enhanced manganese availability was soil acidification brought about by nitrification of ammonium fertiliser and/or by H+ ion secretion by roots to balance the uptake of ammonium and other cations. The uptake of manganese by the plant was further improved either through concentration of fertiliser in the root zone by placement, or by soil compaction which resulted in shallow sowing of seed and a closer active relationship between roots and broadcast fertiliser. Other possible factors involved were (a) a greater exudation by roots of compounds able to dissolve insoluble manganese, in compacted soil; (b) contact reduction processes; (c) stimulation of root growth, leading to more efficient uptake by the plant, where higher rates of fertiliser were used or where the fertiliser was concentrated in localised zones in the soil..

Effects of municipal waste compost and nitrogen fertilizer on growth and mineral composition of tomato

“…Macfie and Taylor (1989) stated that ammonium-bearing fertilizers can increase Mn uptake by plants especially due to reduction of soil pH. In another study (Goldberg et al 1983), the influence of N on the enhancement of Mn concentration in barley shoot was attributed to the dissolution of insoluble Mn by chemical compounds secreted by roots and also to the stimulation of root growth and better contact with soil. Soil application of MWC notably raised mean Cu concentration in tomato shoot ( Table 5).…”

Occurrence and Correction of Manganese Deficiency in Plants

“…The latter may make Mn more available to the plant by reducing Mn and improving root-soil contact. Another benefit noted by Goldberg et al (39) and Holmes et al (56) was that compaction forced shallower sowing and brought the roots into closer contact with acid-forming fertilizers which increased the availability of Mn.…”

“…Loose seedbeds produced by tillage of certain organic and coarse textured mineral soils can induce Mn deficiency which may be overcome by compaction of the soil (8,39,56). Compaction can alleviate the deficiency without affecting pH, redox potential, or the amount of exchangeable Mn present in the soil, by increasing root-soil contact and thereby enhancing reduction of Mn at the root-soil interface (110).…”

“…Hence all factors which influence the concentration of divalent Mn at the surface of the root have a potential bearing on the amount of Mn which is available to the plant and thereby on the occurrence and geographic distribution of Mn deficiency. The inability of plants to obtain sufficient Mn may arise from inadequate contact between the root and the soil (39,110) or because adverse soil and environmental conditions have restricted the development of the root system and limited the volume of soil from which the plant may draw Mn. Even where Mn is readily available and accessible in the soil, Mn deficiency may still occur.…”

“…The deficiency is found in Denmark on certain calcareous soils high in organic matter and particularly on coarse textured soils which have been overlimed (144). Podzols and brown forest soils, including some with impeded drainage, were identified as being commonly associated with Mn deficiency in Scotland: low bulk density was specified as an important contributory factor (39). In Australia (22), Mn deficiency occurs on a wide range of soil types including fen soils, sodic soils (solonized brown soils, s010dized solonetz and solods), podzols and podzolic soils of various types, and soils associated with carbonates (calcareous sands, terra ross as and rendzinas).…”