Effects of lime and molybdenum on the yield and composition of white clover in a sequence of New Zealand zonal soils

Abstract

Abstract Responses to lime and molybdenum in white clover obtained in a glasshouse experiment have been related to factors associated with acidity in a weathering and leaching sequence of zonal soils derived mainly from greywacke parent materials. On a percentage increase basis the largest dry-matter responses to lime were obtained on the strongly leached and podzolised soils. Yields of limed clover in the soil sequence decreased with increasing weathering and leaching On the weakly leached brown-grey earth Conroy sandy loam, a response to lime was attributed to an increase in molybdenum availability and probably to more effective clover nodulation. Increasing weathering and leaching in moderately and strongly leached yellow-brown earths was accompanied by a decrease in molybdenum availability and was an important factor limiting clover growth. On Cass fine sandy loam, Korokoro silt loam, and Marua clay loam the response to Jime was attributed mainly to an increase in molybdenum uptake. Renata silt loam, a moderately weathered, weakly podzolised yellow-brown earth, was an exception and was well supplied with available molybdenum. Poor growth on this soil was probably caused by insufficient calcium for nodulation. On the weakly and moderately podzolised northern yellow-brown earths Rangiora silty clay loam and Hukerenui silt loam, a severe nitrogen deficiency, resulting from nodulation failure, was a major cause of poor growth. High manganese levels in these clovers were considered to be a consequence of restricted growth rather than the cause. Over all soils, liming increased uptake of nitrogen, increased molybdenum availability, and, with the exception of Renata silt loam, decreased the manganese content of white clover.