Use of Spent Mushroom Substrate (SMS) for Corn (Maize) Production and its Effect on Surface Water Quality

Abstract

Mushroom farmers have large quantities of spent mushroom substrate after their crops are harvested. This material is used for a variety of purposes including the growth of field crops. SMS was incorporated into a poor quality soil before planting 90-day corn. Field plots were established where spent mushroom substrate (SMS) was incorporated at 22.5, 45.0 or 90.0 kg m−1, plus an untreated control on each of three years. Analysis of SMS indicates its nutrient level was 0.9-0.6-1.0 (N-P-K). Starter fertilizer was applied at planting along with an insecticide, but no herbicide. No additional fertilizer was used. Corn yields were significantly higher in SMS amended plots and the nitrogen content of both grain and stover was significantly higher than the control. Surface runoff water quality values from SMS amended soil were in the same range as those from the control treatments, the plots that received no SMS. Annual incorporation of up to 90 kg m−2 of SMS into land planted to corn did not degrade the quality of surface water. Nutrients were retained in the SMS soil matrix and were, apparently, used as nutrients by the corn plants. Surface runoff was very low in ammonia nitrogen, CBOD, and chlorides. Use of SMS as an exclusive soil nutrient/soil ameliorant in corn production resulted is exceptionally good yields and quality.