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Infiltration runoff measurements were made on nine urban lawns using a sprinkling infiltrometer in conjunction with the application of a complete fertilizer at three rates. The amounts of inorganic N, P, and K removed with the runoff water were determined. Results of the infiltration measurements show that the presence of textural and compaction discontinuities within the soil profile, formed during building and lawn construction, was probably the greatest factor affecting infiltration. Where these discontinuities were distinct, water intake was reduced to about 35% of that for a lawn with an undisturbed profile. For lawns with similar infiltration characteristics, a first order relationship appeared to exist between amounts of fertilizer applied and amounts lost. A second order equation, however, best described the relationship between percent of applied fertilizer in the runoff and 90‐min cumulative infiltration. When the simulated storm was applied immediately after fertilizer application, fertilizer losses averaged 10.6%; however, when fertilizer application was followed by recommended watering before the intense storm, average losses were reduced to 1.7% of the amount applied.

The effect of soil applications of WEX, Basic H, and Amway Spray Adjuvant was evaluated using corn (Zea maysL.), soybean [Glycine max(L.) Merr.], or potato (Solanum tuberosumL.) as test crops at three Wisconsin locations. Each wetting agent is a nonionic surfactant, and claims or has claimed to improve crop yield, quality, and nutrient availability. WEX was evaluated at recommended fertilization levels. Amway and Basic H, in the corn experiments, were evaluated at varying levels of applied N. Basic H was evaluated on potatoes at 30, 50, and 100% of the entire recommended fertilization program. Although crop yield was increased by fertilization in all cases, no yield improvements were observed from the use of any wetting agent at any fertilizer rate. No differences in nutrient availability as evidenced by foliar nutrient content of N, P, and K or crop protein levels were observed in association with the application of a wetting agent.

Calcitic papermill lime‐sludge, a by‐product of the kraft paper process, was evaluated as a liming material and its equivalency with dolomitic agricultural limestone determined. An incubation study involving 10 medium‐ or light‐textured Wisconsin soils demonstrated that lime‐sludge neutralizes soil acidity very rapidly. Maximum soil pH was achieved in less than 1 week after application of the lime‐sludge, while the pH of soils treated with finely‐ground agricultural limestone increased continuously throughout the 24‐week incubation period. In field trials conducted for 3 years on two different soils, corn (Zea maysL.) was followed by alfalfa (Medicago sativaL.) or birdsfoot trefoil (Lotus corniculatusL.). Both legumes responded favorably to liming but not differently to the lime‐sludge and agricultural limestone, whereas a response was not observed for corn. Yield data provided no evidence that use of the calcitic lime‐sludge created Mg stress in any tested crop. Plant tissue analyses and the absence of a yield response to soil‐applied MgSO4•7H2O supported this observation. The liming equivalency of lime‐sludge to agricultural limestone was examined under both laboratory and field conditions. Both suggested that 1 m3of the lime‐sludge has the same liming value as 1.1 metric tons of agricultural limestone with a neutralizing index of 60 to 69. This value is considerably less than the equivalency of 1.5 yd.3of lime‐sludge per ton of 60 to 69 agricultural limestone specified by Wisconsin Administrative Code.

Estimates of N, P, and K availability to corn (Zea maysL.) from injected dairy manure on three field sites in south central Wisconsin were made using a fertilizer equivalence approach. Nutrient uptake from treatments of a control, three rates of manure (approx. 53, 97, and 138 Mg ha−1yr−1on a wet basis), and three rates of broadcast fertilizer were evaluated. Crop nutrient recoveries of fertilizer N, P, and K were generally higher than crop recoveries of manure total N, P, and K. Estimates of first year N, P, and K availability showed substantial variability across rate, location, and year with standard deviations often about 50% of the mean. Ranges for N, P, or K availability were 12 to 63, 12 to 89, and 24 to 153%, respectively. These data do not identify those factors responsible for differences in nutrient availability from one site‐year to another. Biological or chemical availability indices of a 1‐wk anaerobic incubation at 40 °C or a 16‐h autoclaving in 0.01 MCaCl2solution were evaluated as measures of N availability and compared with field results. Correlations between measured changes in NH4‐N from these indices, as well as total Kjeldahl N and inorganic N levels in the top 30 cm of soil 4 to 6 wk after treatment application, and N uptake indicated inorganic N levels to be a better index of N availability than the other indices examined. However, to determine nutrient availability on a routine basis, more reliable biological or chemical indices are necessary. A simple model may help to simulate environmental effects and the contribution of residual nutrients in the soil.