Nitrate and soluble oxalate accumulation in Kikuyugrass (Pennisetum clandestinum).
Tests were carried out to examine the capacity of P. clandestinum to form and accumulate nitrates and soluble oxalates. The av. concn of nitrates (2%) and soluble oxalates (3%) in P. clandestinum plants grown in nutrient solution was not significantly affected by exposure of the plant to Na (as 0.001 and 0.1 smallcap˜M NaCl), K (as 0.01 and 0.1 smallcap˜M KCl) and N (as 100 nmol NH4NO3/litre). A level of 1.5% nitrates in plants is considered toxic to livestock and 0.3-0.4% soluble oxalates in P. clandestinum has caused osteodystrophia fibrosa in horses that grazed the plant over several months. The formation of soluble oxalates in P. clandestinum is largely genetic and is not affected by the presence of Na or the addition of K beyond the normal nutritional requirements of the plant. Therefore, if P. clandestinum grows on fertile soil in which K and N are not limiting, the plant may accumulate toxic concn of both nitrates and soluble oxalates.