De betekenis van tweezaadlobbige graslandplanten voor de minerale samenstelling van weidegras

In 169 paddocks of widely different soil fertility three random samples, one of dicotyledons, one of associated grasses and one of the soil were obtained. The mineral compositions of Plantago lanceolata, Trifolium pratense and T.repens and Taraxacum officinale were compared with those of the corresponding grass samples. The variance of their differences was analysed and partial regressions of these differences on stage of growth, temperature and soil conditions were calculated.Clovers and herbs were richest in Na 2 0, CaO and MgO, in cation excess, alkaline earth alkalinity, and to a lesser extent also in alkali alkalinity. These results were discussed from the aspect of mineral requirements for animals. The actual differences between dicotyledons and grasses varied greatly, however. The effects of herbs and clovers on the incidence of grass tetany was often small or absent.This was explained by the observation that the preference K>Na>Mg>Ca was normally greater with cation intake by grasses than by dicotyledons. This might be related to the cation-exchange capacities of plant roots. At higher increments of soil K the effect of the root's cation-exchange capacity on K uptake decreased. Differences between dicotyledons may also be correlated with cation- exchange capacities of plant roots

De betekenis van tweezaadlobbige graslandplanten voor de minerale samenstelling van weidegras

In 169 paddocks of widely different soil fertility three random samples, one of dicotyledons, one of associated grasses and one of the soil were obtained. The mineral compositions of Plantago lanceolata, Trifolium pratense and T.repens and Taraxacum officinale were compared with those of the corresponding grass samples. The variance of their differences was analysed and partial regressions of these differences on stage of growth, temperature and soil conditions were calculated.Clovers and herbs were richest in Na 2 0, CaO and MgO, in cation excess, alkaline earth alkalinity, and to a lesser extent also in alkali alkalinity. These results were discussed from the aspect of mineral requirements for animals. The actual differences between dicotyledons and grasses varied greatly, however. The effects of herbs and clovers on the incidence of grass tetany was often small or absent.This was explained by the observation that the preference K>Na>Mg>Ca was normally greater with cation intake by grasses than by dicotyledons. This might be related to the cation-exchange capacities of plant roots. At higher increments of soil K the effect of the root's cation-exchange capacity on K uptake decreased. Differences between dicotyledons may also be correlated with cation- exchange capacities of plant roots