Manure and nitrogen fertilizer effects on corn productivity and soil fertility under drip and furrow irrigation

Abstract

A field experiment was conducted at the Arkansas Valley Research Center in 2005 through 2007 to study the effects of manure and nitrogen fertilizer on corn yield, nutrient uptake, N and P soil tests, and soil salinity under furrow and drip irrigation. Manure or inorganic N was applied in 2005 and 2006 only. There were no significant differences in corn yield between drip and furrow irrigation even though, on average, 42% less water was applied with drip irrigation. Inorganic N or manure application generally increased grain yield, kernel weight, grain and stover N uptake, and grain P uptake. Nitrogen rates above 67 kg ha⁻¹ did not increase grain yield significantly in 2005 or 2006, nor did manure rates in excess of 22 Mg ha⁻¹. High manure rates increased soil salinity early in the season, depressing corn yields in 2005 and 2006, particularly with drip irrigation. Salts tended to accumulate in the lower half of the root zone under drip irrigation. Residual nitrate nitrogen from manure and inorganic N application sustained corn yields above 12.0 Mg ha⁻¹ in 2007. More research is needed to develop best manure and drip irrigation management for corn production in the Arkansas Valley.

Keywords:

• corn
• nitrogen
• water
• soil salinity
• phosphorus

Acknowledgments

This study was funded by the Colorado Department of Public Health and Environment (CDPHE), USDA-NRCS, USDA-ARS, and Colorado State University Agricultural Experiment Station. The authors would like to thank James Valliant for his leadership in applying for and obtaining the CDPHE grant and Michael Bartolo for his valuable support in setting up the drip irrigation system. The authors thank K. Tanabe, C. Reule, P. Norris, Amin Berrada and B. Floyd for their assistance in sample collection and analytical support in processing and analyzing the soil and plant samples. Trade names and company names are included for the benefit of the reader and do not imply any endorsement or preferential treatment of the product by the authors, Colorado State University or USDA-ARS.