Irrigation Residue Removal Study for Greenhouse gas Reduction through Agricultural Carbon Enhancement network and Resilient Economic Agricultural Practices in Lincoln, Nebraska

USDA-ARS REAP Study (Ithaca, NE) - NEMEIRR Sustainable intensification of high-yielding production systems may help meet increasing demands for food, fuel, and fiber worldwide. Specifically, corn stover is being removed by producers for livestock purposes, and stover is also targeted as a primary 2nd generation biofuel feedstock. The NEMEIRR experimental objectives are to quantify how stover removal (no removal, moderate removal, high removal) and tillage management (no-till, disk) affect crop yields, soil organic carbon, soil greenhouse gas emissions, and other soil responses (microbial community structure, function; soil health). This experiment is conducted in a fully irrigated continuous corn system in the western Corn Belt, and soil and plant measurements have been taken since study establishment in 2001. By: V.L. Jin (1 Sep 2016). (41 9 43.3 N. 96 14 41.4 W; 349 m asl). Thc soil is Tomck silt loam (a fine, smectitic. mesic Pachic Argiudoll) and Filbert silt loam (a fine, smectitie. mesie Verne Argialboll). Long-term (1981-2010) mean annual precipitation is 74 cm and tempera¬ture is 9.8°C The study has been in continuous corn since 2000. Thc experimental design is a randomized complete block with factorial treatments arranged in split plots. The whole-plot factor is tillage treatment (NT or CT) and the subplot factor is none (0%). medium (•35%). and high (40%) stover removal calcu¬lated on a mass basis. Nitrogen fertilizer was applied at 202 kg N ha-I yr I in 2001. 2002. 2004. 2007. 2008. 2009, and 2010.190 kg N hi t yr-I in 2003. and 168 kg N ha 1 yr- I in 2005 and 2006. Treatments (tillage) and subplot treatments (residue re¬moval levels) were randomly assigned in a factorial arrangement to whole-plot experimental units (9 by 45.6 m) and subplots within the whole plots (9 by 15.2 m) in six blocks. The previous crop for the entire area in 2000 was corn under rainfcd conditions. Before 2000. the study site was historically cropped with corn, soybean [Glycinc max (L.) Merr.). oat (Arena JoIliM L.), and alfalfa (Maid-ago saliva L). In the spring of 2001, residue was removed from the medium and high stover removal treatments using a flail chopper. The entire study was then disked to remove ridges formed during the previous crop year. In each successive year of the study, only the disk treatment area was tilled to a depth of 15 to 20 cm. usually in the spring before plant¬ing. Irrigation was conducted with a solid set sprinkler system in 2001, then supplemental water applications from 2002 to 2010 were made using a linear-move irrigation system. Irrigation treat¬ments were applied when deemed necessary, with annual rates averaging 12.5 ± 7.0 cm from 2001-2010 (Table I). Glyphosatc-tolerant corn hybrids adapted to eastern Nebraska have been used throughout the study. Corn was plant¬ed with a six-row planter in 76-cm rows at a rate *174.000 viable seeds ha 1, typically during the first week of May. Weed control was accomplished using glyphosate EN-(phosphonomethyl)gly¬eine] and atrazine (6.chloro-N-ethyl-AP-(1-methylethyl)-1.3.5- triazine-2.4-diamine) applications along with in-season cultiva.