WSU Tree Fruit Research & Extension Center

Organic & Integrated Tree Fruit Production

Tuesday, January 23, 2018


Browse on keywords: fertility variable fertilizer application

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Search results on 01/23/18

493. Arthur, Tom. Feb. 1989. Precision application with Spud-Tech.. American Vegetable Grower, p. 14-17..
A Wisconsin company has developed a computer software system and variable fertilizer applicator for use on farm fields. Soil samples are taken for every 2.3 acres to generate a nutrient map, which is loaded into a PROM chip. The chip is inserted into the on-board computer on the Spud-Nik applicator rig, which can vary the rates of six different materials. Both fertilizer and pesticides can be varied according to soil parameters.

2385. Hammond, M.W. and D.J. Mulla. 1989. Field variation in soil fertility: its assessment and management for potato production.. Presentation at 28th annual WA Potato Conference.
Spatial variability in potato fields for P and K is common and can lead to yield and quality reductions. The potential for variable fertilizer application allows for an efficient solution to the problem, both from an economic and environmental standpoint. The paper presents an example from an irrigated circle in the Columbia Basin. Fertility maps of the field are presented, showing the spatial variability. This information is used to delineate fertility management zones, which receive different rates. Fertilizer efficiency is shown for both the conventional and variable methods. The variable method increased fertilizer costs about $10/ac. on a 200' grid system, where both P and K were mapped. The program will normally increase profits well beyond this expense.

2396. Hammond, M.W. and D.J. Mulla. 1989. Intensive soil sampling and its use in fertilizer programs.. Presentation at 1989 Irrigated Agr. Fertilizer Conference.
Intensive soil sampling on a small grid in farm fields allows one to determine the spatial variability of nutrient levels and to adjust fertilizer applications accordingly. Data from 100, 200, and 400 ft. grids indicates that results from a 200' grid are adequate, but detail is lost at 400'. Soil information can be put on a computer chip for a given field and then used to drive variable fertilizer and pesticide application equipment.

7231. Veseth, R.. 1987. Variable fertilizer application improves profits and conservation.. STEEP Conservation Farming Update, Spring 1989, p. 7.
This is a report on work being undertaken by Dr. David Malla, of WSU. Mulla proposes that soil, water and fertilizer resources can be used most efficiently with a variable fertilizer management strategy matched to spatially variable crop yield potentials within the field. Extensive testing was done at two sites. Mean yields with variable fertilizer were slightly greater than those with the uniform rates. However, significantly lower fertilizer inputs were used with the variable rates, costing $14 less per acre. The work shows that potential yields are related to landscape position. T:Graphs of available soil water, estimated winter wheat yield, phosphorus, nitrogen, and organic matter are shown in relation to topographic position across a sharply rolling field.

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