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¹

Because of increases in the price of chemical inputsto agriculture, uncertain supplies, and environmentalconcerns, a reduction in pesticide and fertilizer use maybecome increasingly desirable, if it could be achievedwithout a major reduction in output. For this reason,it is of interest to compare yields obtained under presentconventional practice with those obtained at the lowerlimit of chemical intensiveness. This paper reports maize(Zea mays L.) yields on two groups each of 26 commercialmixed grain and livestock farms covering a widerange of soil types in the western Corn Belt. One groupwas managed with conventional fertilization and pestcontrol practices, while no herbicides, insecticides, orstandard commercial fertilizers were used on the other.The mean yield from the convenional fields was 8.5%higher than from the matched fields on which conventionalfertilizers or pesticides were not used. The differencewas not statistically significant (P<90%). Conventionalmaize yields tended to be higher than maize yieldson fields which received no pesticides or fertilizers underfavorable growing conditions and lower when conditionswere adverse. Grain from the fields receiving pesticidesand fertilizers had a significantly higher crude proteincontent. These fields also had a significantly higherincidence of Diplodia stalk rot and lodging. Soils fromfields receiving no pesticides and fertilizers had a significantlyhigher (P>95%) organic C content, as well ashigher total N (P>90%), but lower Pt phosphorus(P>90%). Differences in P2 phosphorus, exchangeableK, C:N ratio, CEC, and pH were not significant (P<90%)

Key Words: Zea maysL. • Organic farming • N fertilizer • Plant population

² Contribution from the Center for the Biology of Natural Systems, Washington Univ., St. Louis, MO 63130. Supported by the NSF, Program of Research Applied to National Needs (Rann), Grant Nos. AER-74-18438 and AER-77-17031. The opinions, findings, conclusions, and recommendations expressed in this paper are those of the authors and do not necessarily reflect the views of NSF.

Received for publication July 28, 1978.

This article has been cited by other articles:

				W. Lockeretz, G. Shearer, and D. H. Kohl Organic Farming in the Corn Belt Science, February 6, 1981; 211(4482): 540 - 547. [Abstract] [PDF]