• Authors:
    • Larson, W. E.
    • Moldenhauer, W. C.
    • Morachan, Y. B.
  • Source: Agronomy Journal
  • Volume: 64
  • Issue: 2
  • Year: 1972
  • Summary: When well-fertilized corn (Zea mays L.) monocultures with large amounts of residues returned to the soil became common, the question was asked as to whether soil tilth and corn yields could be maintained at satisfactory levels in Corn Belt soils. To answer this question corn growth and soil physical properties were determined in a field experiment in which different types (alfalfa (Medicago sativa L.), cornstalks, sawdust, oatstraw (Avena sativa L.) and bromegrass (Bromus inermis Leyss)) and amounts (from O to 16 tons/ha/yr) of plant residues were added to Marshall silty clay loam (Typic Hapludoll) for 13 consecutive years. The soil was cropped to corn and large amounts of N were added. For approximately the first 9 years grain yields were lower from the check and sawdust treatments than from all others. During the last 4 years grain yields declined sharply with rate of addition of cornstalk residues and slightly from additions of alfalfa. It is suggested that the yield decline in the cornstalk treatments was due to a lowering of pH and an Al-induced Ca deficiency in the plant. An alternative explanation is that the cation balance was upset as evidenced by K/Ca and K/Ca + Mg ratios in the plant. The C content of the soil was progressively increased, as was the wet aggregate stability and water retention with rate of addition of organic material. Energy of aggregate rupture, energy to initial runoff, erosion, and infiltration were not significantly influenced. It was not visually evident that significant changes occurred in soil tilth because of treatment differences. Marshall soils are well aggregated, have favorable physical and chemical properties, and although erosive, physical problems are not usually observable in the field. Corn grain yields averaged near 7,000 kg/ha (112 bu/acre) in the later years of the experiment, again suggesting that the physical properties of the soil on all treatments were favorable.
  • Authors:
    • Fetter, J. C.
    • Brown, R. N.
    • Gorres, J. H.
    • Lee, C.
    • Amador, J. A.
  • Source: Water, Air, & Soil Po9llution
  • Volume: 223
  • Issue: 4
  • Year: 0201
  • Summary: Consumer demand for cleaned squid generates a substantial amount of waste that must be properly disposed of, creating an economic burden on processors. A potential solution to this problem involves converting squid by-products into an organic fertilizer, for which there is growing demand. Because fertilizer application to lawns can increase the risk of nutrient contamination of groundwater, we quantified leaching of NO 3-N and PO 4-P from perennial ryegrass turf ( Lolium perenne L.) amended with two types of fertilizer: squid-based (SQ) and synthetic (SY). Field plots were established on an Enfield silt loam, and liquid (L) and granular (G) fertilizer formulations of squid and synthetic fertilizers were applied at 0, 48, 146, and 292 kg Nha -1 year -1. Levels of NO 3-N and PO 4-P in soil pore water from a depth of 60 cm were determined periodically during the growing season in 2008 and 2009. Pore water NO 3-N levels were not significantly different among fertilizer type or formulation within an application rate throughout the course of the study. The concentration of NO 3-N remained below the maximum contaminant level (MCL) of 10 mg L -1 until midSeptember 2009, when values above the MCL were observed for SQG at all application rates, and for SYL at the high application rate. Annual mass losses of NO 3-N were below the estimated inputs (10 kg Nha -1 year -1) from atmospheric deposition except for the SQG and SYL treatments applied at 292 kg Nha -1 year -1, which had losses of 13.2 and 14.9 kg Nha -1 year -1, respectively. Pore water PO 4-P levels ranged from 0 to 1.5 mg PL -1 and were not significantly different among fertilizer type or formulation within an application rate. Our results indicate that N and P losses from turf amended with squid-based fertilizer do not differ from those amended with synthetic fertilizers or unfertilized turf. Although organic in nature, squid-based fertilizer does not appear to be more-or less-environmentally benign than synthetic fertilizers.