TALL FESCUE GROWTH IN GREENHOUSE, GROWTH CHAMBER, AND FIELD PLOTS AMENDED WITH SEWAGE SLUDGE COMPOST AND FERTILIZER

Abstract

Recommendations for using sewage sludge compost to satisfy the N requirement of crops, which resulted from greenhouse and controlled environmental growth chamber studies, have not been sufficiently validated with field trials. Studies were conducted to evaluate the effects of sewage sludge compost and complete fertilizer amendments on yields and N content of ‘Kentucky 31’ tall fescue (Festuca arundinacea Schreb.) grown on Evesboro loamy sand (mesic, coated Typic Quartzipsamments) in different environments. Compost was applied at rates of either 0, 45, 90, or 135 Mg ha-1 in greenhouse and growth chamber pot studies and 0, 60, 120, and 240 Mg ha-1 in field trials. Fertilizer (N,P,K) was applied at 0 and 200 kg ha-1 where indicated. Compost amendment increased the yields of fescue linearly in all three growth environments. For the second crop, yields were 50% of those for the first crop in the growth chamber and 60% of those for the first crop in the field. A conservative estimate for compost N utilization by the fescue crop was 8% for the initial cropping season and 5% for the second season (determined from the entire plant uptake in the greenhouse and growth chamber). These estimates may be low because the average utilization of compost N by the tall fescue in the field plots was 7% for the first year clippings alone (roots and stubble not analyzed). Equivalent dry matter yields were obtained for the 135 Mg ha-1 compost amendment and complete fertilizer for greenhouse grown fescue; however, equivalent yields for the field-grown fescue were realized by the 60 Mg ha-1 compost amendment. Model equations were derived for estimating fescue yield from compost-amended soil.