Capturing Sunlight: Using Row Orientation to Maximize Photosynthesis, Soil Moisture, and Weed Suppression in Cover Crop-Based Systems

Project Overview

Project Type: Research Only
Funds awarded in 2023: $248,033.00
Projected End Date: 02/28/2026
Grant Recipient: University of New Hampshire
Region: Northeast
State: New Hampshire
Project Leader:
Natalie Lounsbury
University of New Hampshire


  • Agronomic: annual ryegrass, clovers, corn, radish (oilseed, daikon, forage), rye, soybeans, vetches


  • Crop Production: catch crops, cover crops, intercropping, water management
  • Education and Training: demonstration, on-farm/ranch research
  • Pest Management: mulches - living, weed ecology
  • Production Systems: agroecosystems
  • Soil Management: soil quality/health

    Proposal abstract:

    This project will investigate the concept of strategic manipulation of row orientation (N-S vs. E-W) to improve climate adaptation and interseeded cover crop success in silage corn and soybeans in the Northeast. Row orientation modulates the amount of sunlight that reaches the interrows and subsequently influences soil moisture and the growth of plants between crop rows (weeds or cover crops). We hypothesize that optimal row orientation will differ in non-interseeded and interseeded systems. By providing more interrow shading, E-W orientation will lead to higher soil moisture, greater weed suppression, and higher yields under most conditions in the Northeast. Conversely, by allowing more light to reach the interrow, N-S orientation will lead to greater interseeded cover crop performance without negatively affecting crop yields, which will benefit from the soil shading of the interseeded cover crop. To test these hypotheses, we will conduct research across a latitudinal and environmental gradient in Pennsylvania, New Hampshire, and Vermont. Both research station and on-farm research will investigate the effects of row orientation on crop and cover crop performance in interseeded and non-interseeded systems and will elucidate mechanisms behind the observed results, including the effects of row orientation on light, soil moisture, and weed dynamics. Cover cropping in the Northeast is rapidly expanding, but is implemented on <20% of annual crop acres in the three states where research will be conducted. Farmers have expressed interest in interseeding as a way to expand the diversity of cover crop species that can be grown in short growing seasons, but have reservations about inconsistent performance of interseeding. This project will provide critical data on how intentional row orientation can be used to reduce variability in interseeded cover crop performance, eliminating some of the barriers to adopting the practice. In addition, it will provide data on a free climate adaptive practice on acreage that is not interseeded. This makes the project unique in that it meets farmers “where they are” with respect to climate adaptation. Farmers will be engaged throughout the project with interactive field days and demonstrations, and on-farm research trials in the third year of the project. 


    Project objectives from proposal:

    Strategic manipulation of crop row orientation (N-S vs. E-W) holds promise as a way to enhance interseeded cover crop performance and as a standalone practice to conserve soil moisture and suppress weeds, but it has not been systematically investigated. The objective of this project is to quantify the effects of row orientation on yields, soil moisture, light, weeds, and interseeded cover crops in silage corn and soybean systems. Our research has potential to improve the reliability and therefore adoption of interseeded cover crops while also providing a climate adaptive technique on acreage where interseeding is not practiced.   

    Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.