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J. S. P. Yadav , H. M. Mathur

Abstract

Pot experiments using soil-sand medium and water culture solution were conducted in the laboratory to determine the range of pH tolerated by sal seedlings for their growth. The results obtained in the soil-sand medium indicated that sal seedlings grow freely and luxuriantly in the range of pH 5.6-7.8 and fail to survive beyond this range. However, owing to the large quantities of acid and alkali needed to accomplish the extreme pH values in the soil medium, on the acidic and alkaline side, it is not safe to define exactly the critical pH values unless confirmed by further experiments. It is suggested that while assessing the precise role of pH values in governing the growth and distribution of sal in the field a great consideration should also be given to other soil factors like cation exchange capacity, cationic equilibrium, organic matter content, available nutrients, moisture regime, texture, etc. In water culture experiment, the profuse development of white slimy growth on the ischolar_main system resulted in the early death of sal seedlings in spite of treating the ischolar_mains with copper sulphate solution and providing adequate aeration throughout. It is, therefore, concluded that sal seedlings are particularly susceptible to slimy growth under excessive water accumulation, as in the case during peak rainy season (Aug. & Sept.), and this extraneous growth is primarily responsible for destroying ischolar_main hairs and thus causing the death of plants. Carbon dioxide accumulation in soil water is only the secondary cause in the process of such mortality.

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O. N. Kaul , P. B. L. Srivastava , H. M. Mathur

Abstract

The paper describes the results of an investigation on nitrogen, phospborus and potassium requirements of Eucalyptus hybrid seedlings. The seedlings were grown in pots and supplied with 5 doses of N, P and K equivalent to 0, 100, 200, 300 aad 400 Iba./acre in all combinations. The seedlings showed marked deficiency symptomsin the absence or in some cases at lower levels of N and P. Survival of the plants is decreased with the increase in the dose of N while reverse is true with the increase in the dose of P, K has no significant effect on the survival of the plants. It was found that N and P each had significant effect on the growth of the plants, while reverse is true in the case of K. Interaction of these nutrients is not significant. As regards the uptake and interaction of the nutrients, the results indicate that the supply of K has synergistic effect on the accumulation of nitrogen while varying levels of N appear to show no specific trend in the uptake of K. Phosphorus uptake is not affected by the supply of N and K. The studies clearly indicate that N and P nutrients are of great importance in the growth of this species.

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