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ARS Home » Plains Area » Sidney, Montana » Northern Plains Agricultural Research Laboratory » Agricultural Systems Research » Research » Publications at this Location » Publication #343908

Title: Soil total carbon and nitrogen and crop yields after eight years of tillage, crop rotation, and cultural practice

item Sainju, Upendra
item LENSSEN, ANDREW - Iowa State University
item Allen, Brett
item Stevens, William - Bart
item Jabro, Jalal "jay"

Submitted to: Heliyon
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/30/2017
Publication Date: 12/13/2017
Citation: Sainju, U.M., Lenssen, A.W., Allen, B.L., Stevens, W.B., Jabro, J.D. 2017. Soil total carbon and nitrogen and crop yields after eight years of tillage, crop rotation, and cultural practice. Heliyon. 3:e00481.

Interpretive Summary: Soil quality generally improves with increasing soil organic matter content. Enhancing organic matter levels is difficult in semi-arid dryland cropping systems where limited rainfall restricts biomass production potential for annual crops; however, farmers can choose cropping practices that are more likely to improve soil organic matter content. ARS researchers at Sidney, Montana found that crop rotation is an important factor in improving soil quality in northern Great Plains dryland farming areas. They observed that continuous monocropping with a cereal grain like wheat enhances soil organic matter because it returns more crop residue to the soil than other crop rotations. Adding an annual legume such as dry pea in rotation with the cereal grain enhances both soil organic matter and crop yield because the legume adds more of the essential crop nutrient nitrogen than continuous cereal cropping. Crops that are harvested for hay, such as hay barley result in decreased soil organic matter levels. Farmers can increase soil quality and crop yield using cereal-legume crop rotations in dryland cropping systems.

Technical Abstract: Information on the long-term effect of management practices on soil C and N stocks is lacking. An experiment was conducted from 2004 to 2011 in the northern Great Plains, USA to examine the effects of tillage, crop rotation, and cultural practice on annualized crop biomass (stems + leaves) residue returned to the soil and grain yields, and soil total C (STC) and total N (STN) stocks at the 0-120 cm depth. Tillage practices were no-tillage (NT) and conventional tillage (CT) and crop rotations were continuous spring wheat (Triticum aestivum L.) (CW), spring wheat-pea (Pisum sativum L.) (W-P), spring wheat-barley (Hordeum vulgaris L.) hay-pea (W-B-P), and spring wheat-barley hay-corn (Zea mays L.)-pea (W-B-C-P)]. Cultural practices were traditional (conventional seed rates and plant spacing, conventional planting date, broadcast N fertilization, and reduced stubble height) and improved (variable seed rates and plant spacing, delayed planting, banded N fertilization, and increased stubble height). Crop biomass and grain yields were greater with CW and W-P than W-B-P and grain yield was greater with the traditional than the improved practice. The STC at 10-20 cm and 90-120 cm was greater with CW or W-P than other crop rotations in CT and greater with CW than W-B-P in NT. The STN at 20-40 cm was greater with W-P than CW and W-B-P in CT. With NT and the improved cultural practice, STN at 0-5, 5-10, 20-40, and 60-90 cm was greater with W-P and W-B-C-P than other crop rotations. The STN at 0-10 cm correlated with annualized crop biomass and grain yields (r = 0.94-0.97, P = 0.05). Increased crop residue returned to the soil increased soil C stock with CW and W-P and N stock with W-P, but removal of aboveground crop biomass for hay decreased stocks with W-B-P. Increased soil N stock had beneficial effect on crop grain yield.