The influence of some nutritional conditions on nodulation of and nitrogen fixation by peanut plants

Abstract

The objective of this work was to investigate the effects of nitrogen, phosphorus, calcium and magnesium on the growth and nitrogen fixation process in peanut plants under greenhouse conditions. The results of a series of preliminary experiments conducted to determine satisfactory growing conditions in terms of rooting medium and nutrient solution are reported. Efforts were made to determine a satisfactory ratio between quartz gravel and oyster shells for the rooting medium. Studies were also conducted to determine the stage of growth required for the development of adequate nodules. The effects of the addition of phosphorus and different forms of calcium along with the influence of magnesium on peanut growth and nodulation were studied. The effect of time of application of nitrogen on growth and nodulation also was studied as well as the influence of pH. It was found that the plants could probably be harvested between six and ten weeks of age. The best pH seemed to be about 5.8. Satisfactory levels of phosphorus, calcium and magnesium were determined. Oyster shells worked well as part of the substrate. It might have been better to have supplied the calcium in a form other than oyster shells because of the nutrients other than calcium found in the shells. An experiment was conducted using N isotopic nitrogen as a tracer to determine the effect of nitrogen on total growth, nodulation and nitrogen fixation by peanut plants. Low levels of nitrogen aided nodulation. not inhibit nodulation completely. Very high levels did Results of this experiment indicate that the addition of some nitrogen to some field grown peanut plants may be beneficial and profitable.