MHJJFG9C

3232

15 janvier 2021 10:05

12 avril 2021 16:14

As the demand for organic grain is on the rise in recent years, organic dryland winter wheat (Triticum aestivum) farmers in the intermountain west are searching for soil management practices that will improve soil health, sustain or increase crop yield while economically and environmentally sustainable. Understanding the sole and synergistic effects of soil management options may contribute to sustainable management in organic dryland agriculture. The objective was to understand the effects of different rates of manure compost and the inclusion of cover crops on soil health in two organic dryland soils of varying characteristics, one at Snowville and the other at Blue Creek. Six rates of compost: 0, 12.5, 25 50 Mg DW ha-1 composted feedlot manure, 2 Mg chicken composted manure and 25 Mg DW ha-1 composted feedlot manure plus 45 kg N ha-1 of chicken feather meal were applied before a cover crop mix of Austrian winter pea (Pisum sativum) and hairy vetch (Vicia villosa) were planted on one half of all amended plots in the fallow phase. Responses of physical, biological and chemical soil health indices were assessed. Changes in soil organic matter (SOM) and phosphorus pools were also examined. The one-time application of the highest rate of composted feedlot manure had greater effects on all the soil health indices measured compared with the inclusion of cover crops versus fallow. Some impact of cover crops on soil health was observed with increased dehydrogenase enzyme activity and readily mineralizable carbon only at Snowville, suggesting that cover crops had minimal effects on the overall soil health. The more fertile soil (Mollisols) enhanced compost P mineralization while immobilization and sorption of compost P increased in the less fertile soil (Inceptisols). Both short- and long-term effects of compost on organic carbon were observed in the particulate organic matter and mineral-associated organic matter pools suggesting that organic carbon dynamics in the two pools are relevant to understanding compost effects in dryland soils. These findings suggest that applications of compost (25-50 Mg DW ha-1) may be a more sustainable option for organic dryland farmers in the intermountain west than including cover crops.

None

• AB - Spécifique
• FREDO biologie et travail du sol
• GEO Etats-Unis
• céréale

2020

1 janvier 2020