Nutrient Interactions and Deficiency Diagnosis in the Lettuce II. Effects of Nutrition on Water Content

Abstract

In a sand� culture experiment with lettuces, the water content (as per cent. of dry matter) of the aerial portions was studied in plants subjected to five levels of nitrogen, phosphorus, and potassium supply in all combinations.

Nutrient Interactions and Deficiency Diagnosis in the Lettuce IV. Phosphorus Content and Response to Phosphorus

“…Lundegardh (1941Lundegardh ( , 1951 found this to be true in oats-a given phosphorus content indicated smaller responses to phosphorus if associated with low nitrogen figures than with higher ones. It was shown (Slater and Goodall 1957) that the relationship between nitrogen response and leaf composition was curvilinear; in oats, Lundegardh (1941Lundegardh ( , 1951 found the same to be true for phosphorus responses. The possibility that the relationship between phosphorus responses and phosphorus content was also curvilinear in the present data was likewise tested.…”

“…Whereas an efficient forecast of the response to supplementary nitrogen required data for leaf phosphorus as well as nitrogen (Slater and Goodall 1957), phosphorus content alone formed an adequate basis for forecasting the response to supplementary phosphorus. In considering this difference, however, it must be remembered that phosphorus effects were preponderant throughout the investigation; one may surmise that, if the nitrogen treatments had covered a wider range, information on the nitrogen content of the leaves might well have added to the precision with which responses to phosphorus could be forecast.…”

“…Regression methods were then used to study the extent to which analytical data could be used to predict the responses to the phosphorus subtreatment. Besides the figures for phosphorus content reported in this paper, data on nitrogen (Slater and Goodall 1957) and potassium (Grant Lipp 1952) were also available.…”

“…Previous papers have dealt with the results in terms of dry weight (Goodall et al 1955), water content (Goodall, Slater, and Grant Lipp 1957) and nitrogen relations (Slater and Goodall 1957). The present paper covers the uptake of phosphorus and its concentration in the plant tissues, and the relation between the responses to additional supplies of this element on the one hand, and the com position of the plants on the other.…”

Nutrient Interactions and Deficiency Diagnosis in the Lettuce V. Potassium Content and Response to Potassium

“…These plants were sampled for analysis, and the growth responses to further applications of fixed amounts of the nutrients were determined. Previous papers have dealt with the effects of nutrient treatments on dry weight (Goodall, Grant Lipp, and Slater 1955) and water content (Goodall, Slater, and Grant Lipp 1957), and with the content of nitrogen and phosphorus particularly in relation to the response to these nutrients (Slater and Goodall 1957;Grant Lipp and Goodall 1958). The present paper will deal similarly with the potassium data.…”