Evaluation of Conservation Tillage and Cover Crop Systems for Organic Processing Tomato Production

Abstract

<jats:p>Field experiments were conducted in 2000 and 2001 in Meridian, Calif. to evaluate the effects of cover crop mixtures and reduced tillage on yield, soil nitrogen (N), weed growth, and soil moisture content in organic processing tomato (<jats:italic>Lycopersicum esculentum</jats:italic>) production. The trial was set up as a randomized complete-block design with eight treatments consisting of a 2 × 3 (cover crop × tillage) factorial design, a fallow control (F) and a single strip-till (ST) treatment. Cover crop mixtures were either legumes (L), common vetch (<jats:italic>Vicia sativa</jats:italic>), field pea (<jats:italic>Pisum sativum</jats:italic>) and bell bean (<jats:italic>Vicia faba</jats:italic>), or those legumes with grasses (GL), annual ryegrass/triticale (<jats:italic>Lolium multiflorum</jats:italic>/x<jats:italic>Triticosecale</jats:italic>) in 2000; cereal rye (<jats:italic>Secale cereale</jats:italic>)/triticale in 2001. Tillage treatments included an incorporation of the cover crop at planting (IP), a delayed incorporation (DI) (17 to 19 days after planting), and no-till (NT). Due to regrowth of the annual ryegrass in 2000, tomato fruit yields in 2000 were reduced by 50% to 97% within all GL treatments. However, regrowth of the cover crop was not a problem in 2001 and yields were not different among treatments. Total percent weed cover was 1.6 to 12.5 times higher in NT than IP treatments in 2000 and 2.4 to 7.4 times higher in 2001 as weed pressure was mainly affected by tillage practices and less by cover crop type. In 2000, available soil N was 1.7 to 9.4 times higher in L than GL treatments and was significantly influenced by tillage, but there were no treatment effects in 2001 due to a 60% reduction in weed pressure and minimal or no cover crop regrowth. Soil moisture content did not differ between treatments in either year. These results demonstrate the importance of appropriate selection and termination of cover crops for their successful adoption in organic conservation tillage systems.</jats:p>

Advances and Trends in Organic Fruit and Vegetable Farming Research

“…Although no tillage may limit weed control (Madden et al 2004) and delay the mineralization and nitrification processes of cover crop residue (Qasem 1992;Sainju et al 2002;Khaledian et al 2010), it had a powerful effect on microbial communities, namely fungi, Gram-positive bacteria, actinomycetes, arbuscular mycorrhizal fungi, and total bacteria, in a horticultural field (Yang et al 2012). As a compromise, it has also been shown that long-term strip tillage made a more hospitable environment for earthworm growth and reproduction in comparison with conventional full-width tillage (Overstreet et al 2010).…”

“…As a compromise, it has also been shown that long-term strip tillage made a more hospitable environment for earthworm growth and reproduction in comparison with conventional full-width tillage (Overstreet et al 2010). From a productivity perspective, similar yields in no-tillage and tilled vegetable crops were reported when cover-crop regrowth did not occur and adequate irrigation was provided (Teasdale and Abdul-Baki 1995;Abdul-Baki et al 1996;Creamer et al 1996;Mills et al 2002;Madden et al 2004). For example, a no-tillage roller/crimper system using rye-hairy vetch or wheat-winter pea covers for an irrigated organic tomato crop was found to provide results for plant growth, number of fruits, and yield similar to those achieved in a tilled system (Delate et al 2012).…”

Biomass Production and Carbon/Nitrogen Ratio Influence Ecosystem Services from Cover Crop Mixtures

“…Cover crops are annual species grown for a short time period, while the natural systems in which the diversity productivity relationship has been studied include perennial species and consider productivity over several years (Tilman et al, 2006; Marquard et al, 2009). While cover crop bicultures (Ranells and Wagger, 1997; Lawson et al, 2013; Hayden et al, 2014; Alonso‐Ayuso et al, 2014) and higher order polycultures (Creamer et al, 1997, 2001; Teasdale and Abdul‐Baki, 1998; Madden et al, 2004) have been the subject of previous research, explicit tests for increased biomass production by mixtures (cover crop systems containing three or more species) relative to component monocultures are limited. The only examples of which we are aware (Wortman et al, 2012; Smith et al, 2014) concluded that spring‐sown cover crop mixtures are more productive than monocultures because they exhibited overyielding.…”

Organic Weed Control and Cover Crop Residue Integration Impacts on Weed Control, Quality, Yield and Economics in Conservation Tillage Tomato-A Case Study

“…2 Net returns above variable treatment cost (NRAVTC); standard deviations are shown in parentheses. 3 The control is plastic cover with no weed control. Table 5.…”

“…The goal of organic agriculture includes producing food and fiber products in a manner that increases biodiversity, promoting soil health, and reducing environmental degradation due to agricultural practices. A number of ecological differences have been noted in previous research when comparing conventional and organic agriculture [3,4]. Comparisons of soil properties and pest population dynamics for organic and traditional farming practices note differences between these systems that affect the agroecosystem [3,4].…”