Integration of nitrate cover crops into sugarbeet (Beta vulgaris) rotations. I. Management and effectiveness of nitrate cover crops

Abstract

Between 1989 and 1993, 17 experiments tested the effect of cover crop species, sowing date and destruction date on cover crop dry matter (DM) yield, N uptake and on soil mineral nitrogen (SMN) content. All the experiments were carried out in Suffolk, Norfolk, Lincolnshire and Yorkshire on sandy-loam textured soils after crops of cereals or oilseed rape had been harvested. The largest DM yields were obtained with early sowings and averaged 1·6 t/ha. Cover crop N uptake was less dependent upon sowing date and averaged 35 kg N/ha. The average reduction in SMN was from 46 to 32 kg N/ha. Differences between cover crop species were small when compared with season/site variations.Cereal cover crop DM yields were closely related to the thermal time accumulated from the first significant rainfall after sowing, whilst the yields of non-cereal cover crops were more affected by the moisture content of the soil at sowing. The amount of SMN in the soil at sowing had little or no effect on cover crop yield. The yields of cereal cover crops were much more predictable than those of non-cereal cover crops. Water usage by cover crops was estimated to be 20 mm/t DM and large cover crops delayed the onset of leaching and reduced the amount of water leached. However, even in dry autumns and winters, soils are likely to reach field capacity before the following beet crop is sown. Due to their large C[ratio ]N ratio (20[ratio ]1) little N would be mineralized after cover crop destruction. Cover crops comprising volunteer cereals and weeds often performed as well as the other cover crops and in most cases will be the most cost-effective cover crops.

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

“…Moreover, the earlier harvest of pea and cover crop planting in our system compared with wheat (Vyn et al 2000), resulted in more growing degree days for more cover crop growth (Table 2 and 3). Earlier sown cover crops tend to have higher N content in the fall than later sown covers (Allison et al 1998). Plant N content in cover crops in the spring was consistent with Schomberg et al (2006).…”

Investigation of the Biomass and Nutrient Content of Green Manuring Plants as Second Crops in Hungary

“…As an average over the 2008-2009 period one kilogram of nitrogen resulted in the uptake of 1.4 kg, 3.0 kg and 2.1 kg of additional nitrogen in P. tanacecifolia, S. alba and R. sativus. Accordingly, the intermediate catch crops did play a major role in the nitrogen transports (Allison et al, 1998a(Allison et al, , 1998bThorup-Kristensen et al, 2003). This is an all the more important finding in view of the poor nitrogen supply of the site of the experiment.…”

“…Crops take up the nutrients (primarily nitrogen) leached out of the soil and retain them for the next crop (Allison et al, 1998a(Allison et al, , 1998bBreland, 1995;Thorup-Kristensen et al, 2003). Moreover, they improve the soil's condition, alleviate soil compaction along with damage caused by erosion or deflation (Muller et al, 1989;Smith et al, 1987;Unger and Vigil, 1998).…”

Effect of Different N Nutrient Contents on Biomass of Green Manure as Second Crop, Under Unfavorable Climate Conditions in Hungary

“…The C:N ratio in the soil after the incorporation of the green manure plant depends on when it is worked into the soil, the type, moisture content and temperature of the soil (Cadisch and Giller, 1997). These are some of the parameters on which it depends whether the impact on the next crop is positive (Derpsch et al, 1986;Catt et al, 1992; Thorup-Kristensen, 1993; Kara and Penezoglu, 2000;Zhang and Fang, 2007;Collins, 2007), neutral (Allison et al, 1998a(Allison et al, , 1998bRichards et al, 1996), or negative (Allison and Armstrong, 1992;Clark et al, 1997aClark et al, , 1997bVaughan and Evanylo, 1998).…”