Nitrogen transformation rates and nutrient availability under conventional plough and conservation tillage

2015

Biol Fertil Soils

Effects of fire and post-fire mulching for soil protection on N transformations were evaluated in the laboratory 4, 8 and 12 months after a wildfire in the 0-2-cm layer of a burned soil without (BS) or with straw mulch (BSM) and an unburned soil (US). The relationships between the gross N rates calculated with the FLUAZ model (Mary et al. 1998) and 19 soil characteristics were also explored. The gross N mineralisation (m) and NH 4 + immobilisation rates (ia) were similar and significantly correlated (p<0.001) and decreased during the incubation. Both m and ia were higher in burned than in unburned soils and, despite a reduction with time, differences were still 3-fold at t=12 months. Treatment explained half the variation of gross nitrification (kn), which was always low in US and nil in burned soils. Nitrate immobilisation (in) was the only gross rate that was (a) higher in unburned than in burned soils, (b) higher after 12 months than in previous samplings and (c) negatively affected by mulching. Both m and ia were positively correlated with soil pH, initial inorganic-N pools and extractable-Mn (p<0.05 to p<0.001) and negatively correlated with soil water-holding capacity and contents of total C, total N, extractable Cu and extractable Zn (p<0.05 to p<0.001). Both kn and in were negatively correlated with soil characteristics. Despite the strong correlations of pH and total C and N with the gross N transformations, the former variables were never included in the best multiple linear models for the latter. Besides the initial NH 4 + -N or NO 3 − -N contents, all but one best multiple regressions for m and ia included one or two available nutrients, in particular Cu, K, P and Mn. Multiple regressions of kn were only found for US and they included two nutrients (Ca and K, or K, Zn and electrical conductivity). Considering all samples and incubation intervals together, two thirds of in variance was explained by a model with the initial NO 3 − -N, the available Cu and P content. Mulching of burned soil gave a shortlived stimulation of m and ia and a sustained reduction of in.

Section: Discussioncontrasting

confidence: 60%

mentioning

confidence: 99%

Soil gross N transformation rates after a wildfire and straw mulch application for burned soil emergency stabilisation

Gómez-Rey

2015

Biol Fertil Soils

“…Our results agree with the lack of differences on gross and net N transformation rates found in the same plots by Gómez-Rey et al (2012), although both a reduction (Doran, 1987;Peigné et al, 2007) and a long term increase of N availability to plants (Kandeler and Böhm, 1996;Rice et al, 1986) after the adoption of conservation practices have also been reported.…”

Section: Discussionsupporting

confidence: 91%

“…In the Spanish temperate humid zone, the most common rotation under conservation tillage is the maize-Italian ryegrass due to the economic and timeliness advantages without detrimental effect on yields (Bueno et al, 2007), as also reported for other Atlantic climates (Hansen et al, 2011). For this forage rotation, improvements of the physical, chemical and biological properties in the topsoil layer have been reported after adopting conservation tillage management (Bueno et al, 2006;Díaz-Raviña et al, 2005;Gómez-Rey et al, 2012;Gómez-Rey et al, 2014).…”

Section: Introductionsupporting

confidence: 53%

Fate of 15N-fertilizers in the soil-plant system of a forage rotation under conservation and plough tillage

Couto-Vázquez

Soil and Tillage Research

2016

The long-term effect of conventional plough tillage (PT) and conservation minimum tillage (MT) on soil N (0-5, 5-15, 15-30, 30-45 and 45-60 cm), recovery efficiency of 15 N-fertilizer (REN), plant N concentration and N exported with crops was evaluated during two years in a 14-year-old ryegrass-maize forage rotation. Adjacent PT (n=9) and MT (n=9) plots were randomly assigned in triplicate to three treatments to which

“…For this crop rotation, conservation tillage has economic and timeliness advantages without detrimental effect on forage yields (Bueno et al, 2007). Moreover, conservation practices improved the physical, chemical and biological properties in the topsoil layer under this forage rotation (Bueno et al, 2006;Díaz-Raviña et al, 2005;Gómez-Rey et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

Availability and uptake of trace elements in a forage rotation under conservation and plough tillage

García‐Marco

Gómez-Rey

Soil and Tillage Research

2014

Self Cite

After 14 years under conventional plough tillage (CT) or conservation minimum tillage (MT), the soil available Al, Fe, Mn, Cu and Zn (0-5, 5-15 and 15-30 cm layers) and their plant uptake were evaluated during two years in a ryegrass-maize forage rotation in NW Spain (temperate-humid region). The three-way ANOVA showed that trace element concentrations in soil were mainly influenced by sampling date, followed by soil depth and tillage system (35-73 %, 7-58 % and 3-11 % of variance explained, respectively). Excepting for Fe (CT) and Al (CT and MT), the elemental concentrations decreased with depth, the stratification being stronger under MT. For soil available Al, Fe, Mn and Cu, the concentrations were higher in CT than in MT (5-15 and 15-30 cm layers) or were not affected by tillage system (0-5 cm). In contrast, the available Zn contents were higher in MT than CT at the soil surface and did not differ in deeper layers. The concentration of Al, Fe and Cu in crops were not influenced by tillage system, which explain 22 % of Mn variance in maize (CT > MT in the more humid year) and 18 % of Zn variance in ryegrass (MT > CT in both years). However, in the summer crop (maize) the concentrations of Fe, Mn and Zn tended to be higher in MT than in CT under drought conditions, while the opposite was true in the year without water limitation. Therefore, under the studied conditions of climate, soil, tillage and crop rotation, little influence of tillage system on crop nutritive value would be expected. To minimize the potential deficiency of Zn (maize) and Cu (maize and ryegrass) on crop yields the inclusion of these micro-nutrients in fertilization schedule is recommended, as well as liming to alleviate Al toxicity on maize crops.