Effect of Sowing Dates and Amount of Nitrogen Fertilizer at Sowing on Fixation Activity and Different Attributes of Lupinus albus L. cv. Kievskij Mutant

Abstract

Lupinus albus. Cv. Kievskij Mutant was sown on two sowing dates, 17 march 1978 and 6 April 1978 respectively. The early-sown crop was shorter, less branched, senesced several weeks earlier and gave seed yield only half of the late-sown. The early-sown crop produced 33 percent of its seed yield on the branches compared with 47 percent in the late sown. Delaying in sowing more than doubled the seed yield of the branches whilst the main shoot seed yield increased by 50 percent. These differences are probably due in large part to the ‘excessive vernalization’ which The early-sown crop experienced and which was greatly reduced by a three-week delay in sowing. The late-sown crop showed no significant response to nitrogen fertilizer although the 20 and 80 kg treatment yields almost certainly gave some advantage. The earlier senescence which the early-sown exhibited may have been a major factor in reduced nodule growth after the end of June and for the fact that fixation activity reached only a quarter of the level attained by the late-sown crop. Senesced leaves contributed a small portion to total dry matter, they were 7.34 and 4.66 percent for the early and late-sown crop respectively.