Examine the benefits of winter kill Sorghum-Sudan grass (Sudex) as a weed suppressing mulch in tomato production

Project Overview

Project Type: Farmer/Rancher
Funds awarded in 2009: $3,650.00
Projected End Date: 12/31/2010
Region: North Central
State: Minnesota
Project Coordinator:
Katie Cramer
Cramer Organics


  • Agronomic: sorghum (milo)
  • Vegetables: tomatoes


  • Crop Production: conservation tillage
  • Education and Training: demonstration, on-farm/ranch research
  • Production Systems: organic agriculture
  • Soil Management: soil microbiology, organic matter, soil quality/health

    Proposal summary:

    Problem: Over the years, our primary challenge has been weed control. Quackgrass and other perennial grasses have been particularly troublesome, and have required many hours of labor to control. We feel that it is extremely important to control these weeds, to reduce labor, and increase crop quality. Cultivating, both hand and tractor have been our primary means of control. We have also used various form of mulch: Hay, straw, leaves, grass clippings, and plastic. Other organic farming practices, such as crop rotation, have also helped. Proposed Solution: I believe mulch is a superior weed control vehicle, as it provides so many additional benefits. In addition to smothering weeds, it adds organic matter back into the soil, and provides moisture and temperature control. Cover crops mulch adds additional benefits, primarily in labor reduction, as it is very difficult to apply mulch by hand on a farm scale. Bringing in mulch from off farm also adds the risk of the unknown, weeds, chemicals, etc. We chose Sudex in this study, because of its ability to 1) create a large amount of biomass over the summer that would winter kill and provide a thick, dead mulch in the spring to choke weeds. 2) Ability to control nematodes and disease and 3) ability to kill weed with allelopathic compounds Description of Study: Sudex was broadcasted on1/4 acre at the rate of 50#/acre in early summer of 2009. The crop was then mowed when about four feet tall, to allow the roots to penetrate deeper and to increase biomass for the killed mulch and further the allelopathic effects. By late summer a large healthy crop had developed. In December, the Sudex has created a dense, mostly dead, canopy of mulch. About a week prior to planting the tomato plants next spring, the ground for planting will be exposed to allow warming. This can be done in a variety of ways, including ridge or strip tilling using a specially made cultivating shoe, or possibly using Mantis tiller attached to a tractor toolbar. Tomato starts will then be planted with a water wheel planter on 135’ beds spaced 2’ between plants and 10’ between beds. Fish emulsion is added to the water in the planter. 5’ re-bar stakes are then placed 4 feet apart for “weaving”, and drip tape installed. Once the plants are 1 – 2 feet high, twine is used in a “Florida weave” fashion around the plants and stakes to hold them upright. This is done 4 times throughout the season. In addition, the plants will be foliar sprayed with a calcium solution and fish emulsion about 4 times during the season Additional tomatoes will be grown in the same fashion as describe above, but using hay or straw mulch. This will be our comparison group. Detail records & pictures will be kept on a weekly basis to monitor tomato plants, weeds, and the composition of the Sudex mulch.

    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.