Crop improvement influences on water quantity and quality processes in an agricultural watershed

Dongyang Ren; Bernard Engel; Mitchell R Tuinstra

doi:10.1016/j.watres.2022.118353

Crop improvement influences on water quantity and quality processes in an agricultural watershed

Water Res. 2022 Jun 15:217:118353. doi: 10.1016/j.watres.2022.118353. Epub 2022 Mar 23.

Authors

Dongyang Ren¹, Bernard Engel², Mitchell R Tuinstra³

Affiliations

¹ Department of Agricultural and Biological Engineering, Purdue University, 225 S University St, West Lafayette, IN 47907, USA; Chinese-Israeli International Center for Research and Training in Agriculture, China Agricultural University, Beijing 100083, P. R. China. Electronic address: ren156@purdue.edu.
² Department of Agricultural and Biological Engineering, Purdue University, 225 S University St, West Lafayette, IN 47907, USA. Electronic address: engelb@purdue.edu.
³ Department of Agronomy, Purdue University, 915W State St, West Lafayette, IN 47907, USA. Electronic address: drmitch@purdue.edu.

PMID: 35405549
DOI: 10.1016/j.watres.2022.118353

Abstract

Field crop traits have and are experiencing significant changes due to genetic and agronomic improvements. How these changes affect regional water quantity and quality processes has not been clarified. The St. Joseph River Watershed (SJRW) located in the U.S. Corn Belt was selected as a case study area. Crop (corn and soybean) trait improvements in the past decades were reviewed and summarized and include changes of growing degree days (GDD), leaf area index (LAI), light utilization (LU), drought tolerance (DT), nutrient content (NC), and harvest index (HI). Based on a calibrated 9-year (from 2011 to 2019) SWAT (Soil and Water Assessment Tool) simulation in SJRW, sensitivities of the above crop traits to yield, ET_a, stream flow, tile flow, surface runoff, and nutrient loads (NO₃N, TN, soluble-P, and TP) were analyzed. Crop traits and their corresponding SWAT parameters for the 2010s were obtained from model calibration and used as the baseline/current scenario; for the 1980s, they were summarized from literature review and used as an historical scenario, while those for the 2040s were determined by assuming crop traits are changing linearly with time and projected as the future scenario. Water quantity and quality changes under the historical and future crop scenarios were compared with the baseline/current simulation. Results showed LU and DT were the most sensitive crop traits to water quantity (i.e., ET_a, stream flow, tile flow, and surface runoff), while HI was the most sensitive to nutrient loads. The impacts of crop improvements on nutrient loads were more significant than on water budgets. Compared with the baseline, the historical and future scenarios resulted in 1.5 - 2.0% changes of stream flow, 6.8 - 18.6% changes of nitrogen loads (NO₃N and TN) and 2.6 - 3.9% changes of phosphorus loads (soluble-P, and TP) in the stream flow, annually. Moreover, in certain months, these changes can reach about 12% for stream flow, 42% for nitrogen loads, and 12% for phosphorus loads. Nitrogen losses by tile drainage and percolation, and phosphorus losses by surface runoff and tile drainage were most significantly affected by the crop improvements. Future work should consider expected crop improvements when studying long-term hydrology and nutrient cycles in agricultural watersheds.

Keywords: Crop traits; Nitrogen load; Phosphorus load; Stream flow; Tile drainage.

MeSH terms

Agriculture*
Nitrogen / analysis
Phosphorus / analysis
Rivers / chemistry
Water Quality
Water*
Zea mays

Substances

Water
Phosphorus
Nitrogen