Soil fertility management as a factor in weed control: the effect of crimson clover residue, synthetic nitrogen fertilizer, and their interaction on emergence and early growth of lambsquarters and sweet corn

Abstract

Previous experiments have shown that crimson clover (Trifolium incarnatum L.) used as a green manure may supply weed control benefits as well as nitrogen (N) to a subsequent crop of corn (Zea mays L.). In contrast to use of synthetic N fertilizer, use of fresh, incorporated crimson clover residue as an N source has been found to suppress lambsquarters (Chenopodium album L.) aboveground drymatter accumulation but to only temporarily reduce that of sweet corn. One possible cause of the clover's suppressive effect is the initial low availability of N that may occur after residue incorporation in the soil. A factorial treatment combination of +/-crimson clover residue and four rates of N fertilizer was used in two field experiments to further document the clover's influence on early plant growth and development and to test the hypothesis that low initial N availability is responsible for the clover's previously observed suppressive effects. The presence of crimson clover residue was found to reduce total emergence of lambsquarters by 27%, while application of N fertilizer increased lambsquarters emergence by almost 75%. Lambsquarters emergence was also delayed by the residue treatment. Addition of N did not alleviate the clover's suppressive effect on total emergence or emergence rate of lambsquarters. Sweet corn emergence and emergence rate differed by less than 5% in 0 N/+residue and 0 N/-residue treatments. Applications of N to residue plots suppressed rather than enanced sweet corn emergence. Lambsquarters aboveground biomass accumulation was 46% lower in the residue than nouresidue treatments at 23 days after planting (DAP) and remained 26% lower at 53 DAP. Addition of N did not alleviate the suppressive effect of the clover residue on lambsquarters aboveground drymatter accumulation. Sweet corn aboveground biomass accumulation was not affected by the presence of the clover residue. The results of the experiments indicate that the suppressive effect of crimson clover residue on lambsquarters emergence and growth is not attributable to initial low availability of N. However, given the stimulatory effect of N fertilizer on lambsquarters development, use of crimson clover as an N source would appear to provide weed control benefits both as a direct suppressant of weed emergence and growth and as a substitute for fertilizer N.

Interactions between allelochemicals and the microbial community affect weed suppression following cover crop residue incorporation into soil

“…2). Our results agree with previous reports of potent red clover residue affects on wild mustard (Ohno and Doolan 2001) and common lambsquarters emergence (Dyck and Liebman 1994). We found some seed germination in fresh residue treatments starting on day 16 (Fig.…”

Nitrogen cycling, profit margins and sweet corn yield under fall cover crop systems

“…At Ridgetown, N treatment had no effect on sweet corn shoot biomass production at any time during the sweet corn season, likely due to high plant available N over the growing season (data not shown). Other research has also shown that fertilization does not necessarily lead to increased sweet corn biomass or plant populations (Dyck and Liebman 1994;Mullins et al 1999;Teasdale et al 2008). Similarly, others have found that neither cover crops (Teasdale et al 2008;Burgos and Talbert 1996) nor N treatment (Isse et al 1999) had an effect on sweet corn biomass.…”

Cover Crop-Based, Organic Rotational No-Till Corn and Soybean Production Systems in the Mid-Atlantic United States

“…The soil surface is noticeably wetter and warmer under hairy vetch monocultures, and its prostrate growth habit results in rapid decomposition even while the plant is still growing [53]. Since N is known to stimulate both weed germination and growth [54], grass/legume mixtures that delay N release allow producers to address both weed and N management needs. However, as we discuss in greater detail below, grass/legume mixtures decrease the overall N available for a corn crop when compared to a pure legume cover crop and, thus, may require supplemental sources of N.…”