Tillage Effects on Availability of Nitrogen to Corn Following a Winter Green Manure Crop

Abstract

Field studies were conducted in 1984 through 1986 to investigate the release of inorganic N to corn (Zea mays L.) following a winter annual green manure crop of hairy vetch (Vicia villosa Roth) that had either been plowed down to 22 cm (conventional tillage, CT), or killed and left on the surface (no‐till, NT). Soil samples were taken regularly throughout the season at three depths (0–7.5 cm, 7.5–22 cm and 22–45 cm) and analyzed for inorganic N. Crop growth and N uptake, as well as various other plant, soil and environmental parameters were also monitored. First year data (1985) show that soil inorganic N concentration in vetch treatments was higher under CT than NT, and it was more evenly distributed throughout the plow layer. Both corn yields and N uptake, however, were significantly higher in the NT system, probably because of higher soil moisture content in a dry summer. Vetch did not stimulate significant yield increases over 0‐N control plots in either tillage system, although there was greater N uptake by corn in vetch treatments. Under NT, 29% of the original N in the above‐ground vetch biomass was measured either as soil inorganic N or corn N. Under CT, 56% of the original vetch N was measured. A repeat of the first experiment was conducted in 1986. Again, higher levels of inorganic N occurred under CT than under NT where vetch had been grown. Contrary to the results of 1985, corn yields were significantly higher in CT treatments than NT treatments at all N levels, and both corn yield and N uptake were significantly higher in vetch treatments than control treatments under both tillage systems. Maximum inorganic N levels were measured in late October in 1986, when 22% and 55% of the original vetch N was measured under NT and CT tillage systems, respectively.

Nitrogen dynamics under growth chamber conditions as influenced by method of alfalfa termination 2. Plant-available N release

“…In addition, because soil-incorporated residues were less prone to desiccation than surficial residues, incorporated residues may have been mineralized more rapidly. Various studies have similarly demonstrated a larger available N supply from soil-incorporated than from surface-applied legume residues (McCalla and Russel 1948;Wilson and Hargrove 1986;Sarrantonio and Scott 1988).…”

“…Tillage has been shown to increase the available N supply from green manure crops compared with herbicide application (Sarrantonio and Scott 1988). However, in field studies with corn, the fertilizer N response following alfalfa was found to be similar whether the previous alfalfa crop had been terminated by herbicide application or by tillage (Triplett et al 1979;Levin et al 1987).…”

Soybean nitrogen contribution to corn and residual nitrate under conventional tillage and no-till

“…Oyer and Touchton (1990) found that inclusion of soybean and clover in cropping systems provided N for corn, and corn yields were greater in rotation than in continuous corn systems. Paré et al (1993a) found only a limited benefit from soybean in rotation with corn in Quebec.The impact of legumes on corn yield and response to N fertilizers may depend on cultivation methods and weather conditions (Sarrantonio and Scott 1988). In a dry year, vetch cover crops contributed much less available N to NT corn than to CT corn, but yield with NT was higher than with CT because of improved water efficiency due to cover crops effects.…”

“…The impact of legumes on corn yield and response to N fertilizers may depend on cultivation methods and weather conditions (Sarrantonio and Scott 1988). In a dry year, vetch cover crops contributed much less available N to NT corn than to CT corn, but yield with NT was higher than with CT because of improved water efficiency due to cover crops effects.…”

Análise econômica do uso de leguminosas estivais intercalares à cultura do milho, na ausência e na presença de adubação nitrogenada, no oeste de Santa Catarina

“…Neste sentido, diversos estudos têm sido realizados, enfocando não só o potencial de plantas de cobertura de ciclo hibernal (Sarrantonio & Scott, 1988;Blevins et al, 1990;Da Ros, 1993;Pavinato et al, 1994;Freitas et al, 1996;Amado et al, 1998), mas também de espécies de ciclo estival (Scherer & Baldissera, 1988;Burle et al, 1992;Wildner & Dadalto, 1992;Araújo & Almeida, 1993;Bayer et al, 1998;Carsky et al, 1998).…”