Mean Nitrate Research Articles

The Movement of Nitrate Nitrogen Through Columns of Coarse‐Textured Soil Materials

AbstractA laboratory investigation was undertaken in which the movement of nitrate nitrogen through columns of coarse‐textured soil materials was studied. Eight soil materials from the Coastal Plain region of North Carolina were used, and the movement of added nitrates as a function of the porosity of these soils and the quantity of water added to the columns was determined. A multiple regression equation was developed which permitted an estimate of the mean nitrate movement from a knowledge of the value of these two variables.

The Effects of Summer Green Manures on the ammonia and Nitrate Contents of soils Cropped for Winter Wheat. An Examination of the Woburn Green Manure Plots

1. The Woburn field experiments on wheat after green manures are briefly reviewed. Contrary to the original expectations the wheat was less good after two summer crops of tares than after two mustard crops. This result was obtained many times and in recent years the wheat yields were extremely low after both green manures.2. Regular soil analyses for nitrate and ammonia through 1928 and 1929 showed that the mean nitrate content was extremely low (1·2 parts of nitric nitrogen per million of soil). During the cold dry winter of 1928–9 the ammonia nitrogen was several times greater than the nitrate nitrogen.3. Further evidence of an acute nitrogen deficiency during the critical period for the wheat plant in May and June was afforded by the large responses to top dressings of sodium nitrate both in the 1929 and the 1930 wheat crop.