Nitrogen availability in a Darling Downs soil following cereal, oilseed and grain legume crops. 1. Soil nitrogen accumulation

Abstract

Available soil mineral nitrogen (N) was determined in a Darling Downs clay at intervals of 4-6 weeks throughout summer and autumn after harvest of two cereals (wheat and oats), two oilseeds (rapeseed and linseed), and four grain legumes (chickpea, fieldpea, lupin and lathyrus). Soil mineral N (0-1.2 m) at 40,68, 107, 150 and 185 days after harvest was affected (P < 0.05) by the prior crop. At 40 days it was generally higher following grain legumes (34-76 kg/ha N) than following oilseeds or cereals (16-30 kg/ha N). Net increase during the next 145 days was in the order of cereals (2 1-27 kg/ha N) < oilseeds (40 kg/ha N) <grain legumes (53-85 kg/ha N). These differences are partly accounted for by differences in the quantities of N removed in the grain of these crops. However, a large quantity of mineral N accumulated following lupin even though a large quantity (80 kg/ha) was removed in the grain.

Biological nitrogen fixation: An efficient source of nitrogen for sustainable agricultural production?

“…The levels of P~x observed tended to be inversely related to the age of the cover-crop, and presumably reflected the change in light penetration through the plantation canopy and the accumulation of organic N in the interrow space between the trees. Strong et al, 1986;Herridge and Doyle, 1988;Doyle et ai., 1988;McDonald, 1992).…”

Influence of agronomic management of legume crops on soil accumulation with nitrate

“…Legume crops are valuable in cereal cropping systems because they increase soil concentration of plant available N (Jones 1974;Reeves et al 1984;Strong et al 1986;Evans et al , 1991Rowland et al 1988;Campbell et al 1992), from processes occurring during the growth of a legume crop and after it is harvested. In the pre-harvest phase, Evans et al (1985Evans et al ( , 1989 and Evans and Taylor (1987) predicted that nitrate derived from pre-existing soil N may accumulate under legume crops, relative to cereals: nitrate they termed 'spared N' or 'conserved N'.…”

Effects of eight years of crop rotation and tillage on nitrogen availability and budget of a sandy loam soil

“…Residual N in the soil was generally higher following pulses such as peas and beans (Vicia faba) than following cereals (Strong et al 1986;McEwen et al 1989). Winter rape (Brassica sp.)…”

“…Available soil N can be influenced by crop rotation and tillage (Strong et al 1986;Dowdell et al 1983;Eck and Jones 1992). Residual N in the soil was generally higher following pulses such as peas and beans (Vicia faba) than following cereals (Strong et al 1986;McEwen et al 1989).…”

“…The red clover rotation resulted in net N import in each rotation cycle of approximately 25 kg ha -1 under CT and 37 kg ha -1 under NT; net N export from the fallow rotation was 30 kg ha -1 under NT and 46 kg ha -1 under CT. Mots clés: Pois de grande culture, jachère, trèfle rouge, bilan azoté, travail du sol, blé Available soil N can be influenced by crop rotation and tillage (Strong et al 1986;Dowdell et al 1983;Eck and Jones 1992). Residual N in the soil was generally higher following pulses such as peas and beans (Vicia faba) than following cereals (Strong et al 1986;McEwen et al 1989). Winter rape (Brassica sp.)…”