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Crop Sequence and Nitrogen Fertilization Effects on Soil Properties in the Western Corn Belt
- Liebig, M. A., Varvel, G. E., Doran, J. W., Wienhold, B. J.
- Soil Science Society of America journal 2002 v.66 no.2 pp. 596
- Zea mays, continuous cropping, crop rotation, Glycine max, Avena sativa, Trifolium pratense, soil organic matter, soil fertility, nitrogen, soil chemistry, soil microorganisms, application rate, soil organic carbon, Nebraska
- Understanding long-term management effects on soil properties is necessary to determine the relative sustainability of cropping systems. Soil physical, chemical, and biological properties were measured in a long-term cropping system study in the Western Corn Belt. Properties were evaluated after 16 yr in four crop sequences [continuous corn (L.) (CC), corn–soybean [Glycine max. (L.)] (C–SB), corn–oat (L.) + clover (80% sweet clover [ L.] and 20% red clover [ L.])–grain sorghum [((L.) Moench)–soybean (C–OCL–SG–SB), and corn–soybean-grain sorghum–oat + clover (C–SB–SG–OCL)] each at three N fertilization rates (ZERO, LOW, and HIGH) to a soil depth of 30.5 cm on a Sharpsburg silty clay loam (fine, smectitic, mesic Typic Argiudolls). Nitrogen fertilization had a greater impact on soil properties than crop sequence, with management effects most pronounced at 0 to 7.6 cm. Increased N rate resulted in greater organic C, total N, and particulate organic matter (POM), but lower soil pH. Increased N rate also reduced microbial biomass by ∼20% between the HIGH and ZERO N-rate treatments. The C–SB–SG–OCL sequence possessed more potentially mineralizable N (PMN) (57 vs. 46 kg ha for average of CC and C–SB) and a higher percentage of POM present as soil organic matter (17.1% for the C–SB–SG–OCL sequence vs. 13.9% for other sequences). Within the context of soil functions and cropping system performance, results from this study indicate the C–SB–SB–OCL sequence enhanced nutrient cycling efficiency, while N fertilization resulted in a trade-off between its positive effect on biological productivity and negative effect on nutrient cycling efficiency.