Effect of exchangeable base content in the soil on the yield and base balance of Italian ryegrass [Lolium multiflorum]
1999
Ikeda, K. (Kagoshima-ken. Agricultural Experiment Station (Japan)) | Nonoyama, Y. | Ichiki, M.
In proportion to the heavy application of farmyard manure, the exchangeable bases, especially potassium, are found to be accumulated in the soil. As the result, it was recognized that the mineral content can be used to elucidate effect of the base contents in the soil on the yield and K/(Ca + Mg) ratio of the crop. The results are follows: 1) The effect of exchangeable K content on the dry weight was significantly different, larger above the 0.5 cmol(+) kg-1 K level. But no significance of the total dry-weight was found among the three levels above 0.5 cmol(+) kg-1 K, two levels each of Ca and Mg. 2) The K/(Ca + Mg) ratio of the crop was affected most strongly by exchangeable K content in the soil. According to the relationship between exchangeable K content in the soil and K/(Ca + Mg) ratio of the crop, it seemed to be necessary that exchangeable K content be kept lower than 0.5 cmol(+) kg-1 in the soil under K fertilizer non-application, in order to keep the K/(Ca + Mg) ratio less than 3.0. No significant difference in the K/(Ca + Mg) ratio was found between the two levels of Ca and Mg contents in the soil. 3) Under K fertilizer non-application, exchangeable K content decreased by less than 0.1 cmol(+) kg-1 at the time of fourth clipping, though it was 1.0 cmol(+) kg-1 at the start of the experiment
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