4336 Future Direction and Research Needs
Attaining food security for an increasing population while minimizing soil degrada-
tion is a major global challenge facing agriculture. Dryland cropping systems play
a very important role in food, feed, and fiber production in North America.
Improving soil health is critical for sustaining dryland crop production. Soil organic
matter, through the provision of ecosystems services such as increased water and
nutrient holding capacity, increased microbial diversity and function, and increased
soil aggregation and improved soil structure, underpins agricultural production.
Management practices that maintain or improve SOM improve soil health and agri-
cultural sustainability. The WF system in the dryland regions of the INPW and
Great Plains have lost more than 60 % of SOC from topsoil in the last century
Fig. 6 Mean net returns of summer crops in a wheat-summer crop-fallow rotation based on output
from the RZWQM2 model in response to 25, 50, 75 and 100 % plant available water (PAW) at
planting. Summer grain crops were maize, canola, and proso millet, and summer forage crops were
foxtail millet and triticale. The model was based on two locations in the U.S. Great Plains, Akron,
Colorado and Sydney, Nebraska
Dryland Agriculture in North America