Responses of Potato Plants to Fertilization and Soil Moisture Tension Under Induced Soil Compaction¹

Abstract

Abstract Potato plants were grown 3 different years in noncompacted, moderately compacted, and severely compacted soils. Changes in yield and quality of tubers were measured against different levels of N and P and against soil moisture tension. Total and U. S. No. 1 tuber yields were affected adversely by compacted soil. Tuber deformity was confined to angular development conforming to the shape of adjacent clods. Second growth and growth cracks in tubers were of no consequence. No consistent change in specific gravity was found. Neither yield nor quality of the tubers was enhanced by use of N higher than 180 pounds per acre. Addition of P had no appreciable effect. Soil P reserves were high. Tuber yield and quality in all soils were best when the soil moisture tension was near 0.5 atm. At a lower tension (0.2 atm) enlarged lenticels were more prevalent, and at a higher tension (0.7 atm) the yield and percent of U. S. No. 1 tubers diminished in severely compacted soil. Without proper control of the soil moisture regime in compacted soils, loss in tuber yield and quality could be accentuated. Neither changes in fertilizer nor irrigation practices alleviated the adverse effects of soil compaction on potato yield or quality.