Effects of Crop Residue, Soil Temperature, and Sulfur on the Growth of Winter Wheat

Stewart, B. A.; Whitfield, C. J.

Effects of Crop Residue, Soil Temperature, and Sulfur on the Growth of Winter Wheat

1965

Stewart, B. A. | Whitfield, C. J.

The interrelations of wheat straw, fertility levels, and three soil temperatures on the growth and nutrient status of winter wheat were investigated. When only N and P were added, the decomposition of straw incorporated with the soil immobilized a portion of the available S and caused a reduction in yield. When S was added with the N and P, the incorporation of straw had no effect on yield. Ratios of total N to total S and protein N to protein S were determined on the wheat tissue. Indications are that a total N/S ratio of these elements can be used as a very good criterion in assessing the S status of plants. A total N/total-S ratio of about 17:1 or less suggests that S is not limiting, while a greater ratio points out that S is limiting the formation of protein. The N-S relation in soil organic matter is also discussed in relation to its abilities and limitations in supplying S for plant growth.

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