Potato Grower

44 POTATO GROWER | MARCH 2017 Diggin' In Diggin' In Diggin' In Diggin' In Diggin' In Diggin' In SOILS | Industry Report Combating hydrophobic soils for improved disease control Breaking Through Recognizing the presence of hydrophobic soils in your fields is not difficult. During a good rain or irrigation period, seeing puddles or runoff is a pretty good indication there is a problem with the infiltration of water in a field. Even patchy crop emergence can be a clue that you have hydrophobic soils. While runoff and a poor crop stand are serious issues that need to be remedied, what is happening below the soil surface can be just as serious and have a direct effect on the health, yield and economic return of a potato crop. The main cause of hydrophobicity or water-repellent soil is the coating of soil particles with waxy organic compounds that result from the breakdown of plant residue or other organic compounds such as manure. Typically, coarse-textured, sandy soils with low clay content (below 5 percent) are more susceptible to becoming water-repellent. It has been found that water repellency only occurs in soils with less than 10 percent clay and that repellency is most extreme in soils with less than 5 percent clay. Below the surface, pockets of the aforementioned wax-covered, water-repellent soil particles can cause uneven infiltration of rainfall and irrigation, resulting in poor germination, emergence, growth and, ultimately, yield. Similarly, a hydrophobic soil pocket UNTREATED CONTROL OF SOIL-BORNE PATHOGENS ORO-RZ MIXED WITH FUNGICIDES PROVIDES IMPROVED INFILTRATION AND PENETRATION OF HYDROPHOBIC SOIL FOR BETTER CONTROL OF SOIL-BORNE DISEASES. SOIL-APPLIED FUNGICIDES MAY MISS PATHOGENS DUE TO POCKETS OF HYDROPHOBIC SOIL. fig. 1 fig. 2 fig. 3

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