Changes in the nitrate and sulfate content of the soil solution under orchard conditions

Abstract does not appear. First page follows.

In 1922, the Division of Pomology of the California Agricultural Experiment Station began an investigation on the maintenance of soil fertility in deciduous orchards. For this purpose a field of approximately twelve acres was selected and half of it planted to deciduous fruit trees. This will hereafter be referred to as block A. The following year, 1923, the other half was set out. It will be designated block B. The soil in the field selected varied from a fine sandy loam to a loam of the Yolo series. The water table stood at approximately sixteen feet. The entire volume of soil above the water table was in horizon A. There were some slight modifications in texture before that depth was reached, but neither gravel nor clay was found.

Crop History of the Field Used

The crop history of this field before the planting of the orchard is of interest.† In the summer of 1908, this area was levelled for alfalfa irrigation. Previous to this time it had been in grain for an indefinite period, probably about fifty years. In the spring of 1909, it was planted to alfalfa. From 1909 to 1913, there is no available record as to yields or irrigation frequency, but it is supposed that the entire area had essentially the same treatment.