Effect of soil type and vermicompost applications on tomato growth

Background Vermicomposts (VC) improve plant growthand development beyond that normally observed from justsoil nutrient transformation and availability. These increasesin plant productivity have been attributed to improvedsoil structure and soil microbial populations thathave higher levels of activity and greater production ofbiological metabolites, such as plant growth regulators.Although there have been many studies on the benefits ofVC as a fertilizer source, little research has focused on theeffects and/or interactions of soil type and VC applicationrates on vegetable crop productivity. This paper identifiesoptimum application rate(s) of VC on tomato growth responsesfor three different textural classes of soils (loamysand, silt loam, and silty clay).Results Soils with high VC rates (0.4 and 0.8 g/g) producedtaller plants with more leaf and flower numbers,higher leaf chlorophyll content, greater plant biomass, andmore total leaf area compared to soils with low VC rates(0.05, 0.1, and 0.2 g/g). Tomato growth increases were alsoobserved at the low VC soil amendment rates compared tothe nontreated control. Tomatoes grown in the sandy soilamended with VC generally had the greatest growth responses(plant height, leaf and flower number, and leafchlorophyll content) compared to the clay or silt loam soils,with the silt loam soil generally providing the leastresponse.Conclusions This research indicated that VC is a suitablealternative fertilizer for tomato, with approximately0.5–0.6 g/g VC added to soil resulting in optimal tomatoplant growth. Moreover, this rate provided tomato growthresults similar to the standard inorganic fertility program.The sandy soil with VC amendments generally increasedtomato plant growth parameters the most compared to theclay and loam soils, with the loam soil generally providingthe least.