The interactive effects of phosphorus, potassium, lime and molybdenum on the growth and morphology of white clover (Trifolium repens L.) at establishment

Abstract

The effects of simultaneously varying P, K, lime and Mo supplies on the growth and shoot morphology of white clover (Trifolium repens) at establishment were investigated in a factorially designed glasshouse experiment. Phosphorus and lime applications had almost identical, additive, effects on dry‐matter (DM) production, and it was clear that the benefit of both treatments lay in the resultant improvements in plant available P. The adverse effects of P deficiency on young plants resulted, immediately, in a large decrease in stolon branch numbers, but only when the deficiency became acute did similar declines in the dimensions of leaves and petioles occur. It was suggested that this preferential maintenance of leaf and petiole expansion processes under moderate P deficiency, by enabling white clover to retain favourable upper canopy positions, could be an ecological adaptation to maximize its chances of survival in mixed grass–clover swards. Unlike P, K had little effect on clover growth or shoot morphology. However, there was some evidence that plants suffering from acute K deficiency preferentially partitioned resources to organs associated with exploratory growth, i.e. to stolons, at the expense of the plant's photosynthetic capability. Molybdenum application had no effect on DM production or shoot morphology, but did improve the N status of shoots, presumably by enhancing N2 fixation. It was concluded that the survival of white clover in swards at establishment is critically dependent on P supply, and that one of the main benefits of liming is the resultant improvement in P availability.

A Novel Approach to Grass–Legume Management

“…Turner (1990) suggested that clover has poor stomatal control of leaf hydration and water loss, and stomatal closure may be incomplete even when turgor is low, thus verifying white clover susceptibility to water deficits. Bailey and Laidlaw (1999) reported that soil pH < 6.0 and adverse effects of phosphorous (P) deficiency on young plants resulted immediately in a large reduction in stolon branch numbers. Thus, survival of white clover in swards at establishment is critically dependent on P supply, and that one of the main benefits of liming is the resultant improvement in P availability.…”

Effects of sodium fertiliser on the distribution of trace elements, toxic metals and water-soluble carbohydrates in grass and clover fractions

“…Increasing soil pH improves molybdenum availability and encourages better clover performance, since molybdenum is required for nodulation in clover. 36 Speci®cally, clover nodules require molybdenum as a component of nitrogenase enzymes. 37 The greater concentration of iron, manganese, cadmium, aluminium and nickel in grass compared with clover (Table 1) may derive from the reduced competitiveness of clover in grass±clover mixtures, which is due primarily to its uncompetitive root morphology.…”

Peanut response to lime and molybdenum application in low pH soils

“…Molybdenum, which constitutes part of the enzyme nitrogenase, is also essential for symbiotic nitrogen fixation; Mo deficiencies are therefore much more pronounced in legumes (Bailey & Laidlaw, 1999). Since peanut is a legume, it is highly susceptible to Mo deficiency when grown in acidic soils.…”

“…Since peanut is a legume, it is highly susceptible to Mo deficiency when grown in acidic soils. This affects its ability to nodulate and symbiotically fix atmospheric nitrogen (Simbajon & Duque, 1987;Bailey & Laidlaw, 1999). This study, therefore, investigated the effect of lime and molybdenum and their interaction on peanut yields on a low pH soil.…”