Winter Cover Crop Effects on Soil Organic Carbon and Carbohydrate in Soil

Abstract

Winter cover crops may increase soil organic carbon (SOC) levels or reduce their rate of depletion. Selection of appropriate cover crops to increase SOC requires an adequate knowledge of the quality and quantity of plant biomass produced and its rate of decomposition in soil. This study examined the SOC and carbohydrate concentrations in soil as affected by several leguminous and nonleguminous cover crops after 6 yr of a corn (Zea mays L.) cover crop double cropping system in a temperate, humid region. The vegetation in the control treatment without cover crops was primarily shepherd's‐purse [Capsella bursa‐pastoris (L.) Medikus]. The cover crops had a variable effect on SOC and soil carbohydrate concentrations due to a significant difference in total organic C and carbohydrate produced by the cover crops. The buried bag technique showed that the biomass C from the aboveground biomass of the cover crops decomposed rapidly in the soil with a half‐life averaging 30.9 ± 9.4 (SD) d in 1992 and 55.2 ± 7.8 (SD) d in 1993. The decomposition of carbohydrate in the aboveground biomass in the soil was also rapid with an average half‐life of 40.0 ± 13.1 (SD) d in 1992 and 50.5 ± 11.8 (SD) d in 1993. The overriding cover crop effect on SOC and carbohydrate was due to the magnitude of the C inputs from the cover crops. With more than 4 Mg ha−1 of top biomass, cereal rye (Secale cereale L.) and annual ryegrass (Lolium multiflorum Lam.) were better suited as winter cover crops for building SOC levels in this region than Austrian winter pea (Lathyrus hirsutus L.), hairy vetch (Vicia villosa Roth), and canola (Brassica napus L.).

Cover crops and nitrogen fertilization effects on soil carbon and nitrogen and tomato yield

“…However, the difference in organic C between treatments in April 1996 (Fig. 2) suggests that cover crops have significantly influenced organic C levels in the soil after 1 yr. Kuo et al (1997a) also observed greater increases in organic C with rye than with hairy vetch in western Washington. In contrast, Hargrove (1986) observed greater increases in organic C with hairy vetch than with rye in northern Georgia.…”

“…Belowground biomass was not measured in this experiment but could be as much as 40% of the aboveground biomass (Kuo et al 1997a). Therefore, the level of organic C in the soil can be increased with cover crops in the southern USA, with nonlegume cover crops being more effective than legume cover crops.…”

“…Carbon concentration in the cover crop and weed samples was determined by the Walkley-Black method (Nelson and Sommers 1996), assuming that all plant C was oxidized during digestion (Kuo et al 1997a). Carbon and N accumulations in the cover crops and weeds and N uptake in tomato biomass (leaves + stems + fruits dry wt.)…”

Nitrogen use efficiency and fertiliser fate in a long-term experiment with winter cover crops

“…Cover crops reduce nitrate leaching in many humid (Hargrove, 1991;McCracken et al, 1994;Thorup-Kristensen et al, 2003) and semiarid regions (Salmerón et al, 2010;Gabriel et al 2012b) and they are an important tool to reduce the risk of diffused water pollution (Thorup-Kristensen et al, 2003). Moreover, cover crops increase organic matter (Kuo et al, 1997), water retention capacity (Quemada and Cabrera, 2002), soil aggregate stability (Roberson et al, 1991) and nutrient supply (Gabriel and Quemada, 2011), and the mulch provided by the residue contributes to soil erosion control (Hargrove, 1991).…”

Effects of Cover Plants on Soil Microbial Community in a Organic Pear Orchard

“…또한 재배 후 녹비로 토양에 혼합하면 토양의 양 분과 유기물을 증진시키는 중요한 역할을 한다 (Duxbury et al, 1989;Eo et al, 2010;McGill et al, 1986;Sakamoto & Oba, 1993). (Cardina, 1995;Kuo and Sainju, 1997). 전작물로 콩과작물 재배시 후작물 은 콩과작물이 생산한 질소의 30~60%를 흡수할 수 있어 질 소비료 시용을 줄일 수 있다고 알려져 있다 (Celette et al, 2009;Evans & Terashima, 1987;Fisk & Hesterman, 2001).…”