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Organic & Integrated Tree Fruit Production

Saturday, June 23, 2018

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Search results on 06/23/18

3249. Huber, D.M.. 1990. Fertilizers and soilborne diseases.. Soil Use and Management 6:168-173.
The influence of fertilizers on diseases has been directly attributed to effects on survival and germination of the pathogen, and/or effects on its penetration and virulence. As plant nutrition is improved, other benefits accrue including enhanced disease resistance, disease escape due to rapid growth rates, and root exudates that support beneficial soil microflora.

8323. Cook, R.J.. 1990. presentation at Palouse Cons. Farm field day. .
A new combination of cropping practices appears to solve some disease problems in continuous wheat culture. Wheat straw is not toxic to wheat plants, but keeps the soil moist and favors disease. Cook suggested the following system: no-till, paired row, fertilizer placed beneath each row. The fertilizer shank disturbs the soil and inhibits certain disease organisms. Each plant has easy access to fertilizer beneath, and the P helps the seedling grow out of disease injury that may occur. P also stimulates root growth. The paired row opens up the canopy to some drying, which stops take-all and Rhizoctonia. This system is working in continuous no-till winter wheat in Pullman, and is also working in continuous no-till spring barley at Lind, WA. Cook suggested its use in the intermediate rainfall area. The fertilizer is placed at 5" depth and the seed at 1.5".

8384. Beus, C., D. Dillman, and J. Carlson. 1990. Palouse agriculture: a survey on production practices, policies, and problems.. unpublished results, Dept. of Rural Sociology, Washington St. Univ., Pullman, WA 99164.
This random survey was done in the Palouse area of eastern WA and northern ID, with a random sample of about 260 farmers. Average farm size was 1392 acres. One-third of the respondents would like to change their current rotation, primarily to reduce disease problems, but consider government programs to be the biggest barrier. Desire to use no-till planting was evenly split. Half the respondents felt they were using most of the available erosion control practices. Large percentages (>60%) felt that contour tillage, surface roughness, no-till, good plant cover, and tilth were very important erosion control factors. Herbicide and fertilizer use trends over the past five years were normally distributed. Use of fungicides on wheat (other than seed treatment) was generally less than 20%. Half the farmers currently use soil testing, and of those, 90% tested for residual N to 4-5 ft. depth. Half the respondents felt they had cut back on pesticide and fertilizer use since their high point, while only 10-20% felt they would do so in the future. About 65% had heard of the LISA program, and 26% indicated opposition to it.

11095. Smiley, R.W. and R.J. Cook. 1973. Relationship between take-all of wheat and rhizosphere pH in soils fertilized with ammonium vs. nitrate nitrogen.. Phytopathology 63:882-890.
Take-all of wheat was reduced by ammonium fertilizer supplemented with N-Serve to slow nitrification, but was severe with no added N, or with calcium nitrate at N rates equivalent to that supplied by ammonium. The addition of lime negated the control of ammonium. A good correlation existed between rhizosphere pH and disease severity, but not with bulk soil pH. The rhizosphere pH dropped with ammonium uptake, increased with nitrate uptake, and remained unchanged with no added N. Disease severity was progressively less as rhizosphere pH dropped below 7, and was greatly reduced below 6.6. In a fumigated soil, disease was controlled only when pH was below 5. Reduced disease severity apparently resulted from direct inhibition of the pathogen at pH less than 5 and indirect inhibition (possibly a biocontrol) above 5.

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