Long-term rotation with monoculture cover crops increases yield of strawberry, reduces weed populations, and maintains soil chemical, physical, and biological characteristics during strawberry production
Date of Award
Master of Science
Gail R. Nonnecke
Proliferation of weed seeds and pathogenic organisms in the soil can cause a decline of yield of strawberry grown continuously on the same site. Rotations with cover crops or tillage have been found to mitigate this problem, but data are needed on the relative effectiveness of various potential rotations. Conventional management of weeds and soil pathogens in strawberry can cause detrimental effects to the chemical, physical, and biological components of the soil and subsequently reduces plant vigor. Previous research suggests that rotating cover crops with strawberry reduces weeds and soil pathogens and maintains the chemical, physical and biological components of the soil.
We evaluated soil characteristics of seven monoculture cover crops (Panicum virgatum L., Andropogon gerardii Vitman, Lolium perenne L., Sorghastrum nutans (L.) Nash, Rudbeckia hirta L., Sorghum bicolor (L.) Moench, and Tagetes erecta L.), continuous tillage, and continuous `Honeoye' strawberry during treatment establishment and after the rotation of the treatments with strawberry by the chemical, physical, and biological components of the soil. A second objective was to evaluate type and biomass of weeds, density of lesion nematodes, and plant density and yield of strawberry among the rotation of those seven monoculture cover crops, continuous tillage, and continuous `Honeoye' strawberry plots. Plots were established in 1996 and maintained through 2005. In 2005, treatments were tilled and `Honeoye' strawberry plants were planted into the plots and were maintained until 2008.
Chemical analyses of the soil showed minimum effects by treatments. During treatment (1996 - 2005), plots of continuous tillage decreased water infiltration time and bulk density; however soil macro aggregate mass was lowest in plots of continuous tillage. Physical components of the soil were further reduced in the continuous tillage plots during strawberry production (2005 - 2007). Plots rotated with L. perenne showed high carbon utilization and mineralized nitrogen. Plots rotated with T. erecta reduced overall biological activity in the first year after treatment, but effects were less after the second year of strawberry growth. Plots of continuous tillage showed high microbial richness in the second year of strawberry production; however effects were not different after the third year of production.
Monocot weed biomass was lowest in plots of continuous tillage or rotated with A. gerardii, P. virgatum, S. bicolor, and S. nutans. Dicot weed biomass was lowest in plots of continuous tillage or rotated with S. bicolor. Dicot weed biomass was greatest in plots of continuous strawberry and plots rotated with L. perenne. Lesion nematode counts were below the threshold level for all treatments. Strawberry plant density and yield of strawberry were greatest in plots tilled or rotated with A. gerardii, P. virgatum, S. bicolor, S. nutans, or T. erecta.
Continuous tillage reduced organic carbon and nitrogen in the soil, broke down soil aggregate particles and reduced water infiltration, and showed biological variability in the soil. Plots rotated with A. gerardii, L. perenne, P. virgatum, R. hirta, and S. nutans increased organic carbon and nitrogen, increased macro aggregate mass and water infiltration, and showed maintainable biological activity during strawberry production. In addition, strawberry production areas tilled or rotated with A. gerardii, P. virgatum, S. bicolor, S. nutans, or T. erecta had lower weed biomass and greater plant establishment and yield of strawberry.
Dennis Nicklas Portz
Portz, Dennis Nicklas, "Long-term rotation with monoculture cover crops increases yield of strawberry, reduces weed populations, and maintains soil chemical, physical, and biological characteristics during strawberry production" (2008). Graduate Theses and Dissertations. 11137.