Organic Fertilizers for Greenhouse Tomatoes: Productivity and Substrate Microbiology

Abstract

<jats:p>Organic fertilizer regimens consisting of combinations of composts (yard waste, swine manure, or spent mushroom substrate) and liquid fertilizers (fish- or plant-based) were evaluated against conventional hydroponic fertilizers in two experiments with greenhouse tomatoes grown in peat-based substrate. Crop yield and fruit quality were evaluated and several assays of substrate microbial activity and community profiles (fluorescein diacetate analysis and EcoLog, values, nematode counts) were conducted. Crops grown in 20% to 40% compost (yard waste or yard waste plus swine manure) plus a continuously applied liquid source of organic potassium (K), calcium (Ca), magnesium (Mg), and sulphate (SO<jats:sub>4</jats:sub>) could not be sustained more than 1 month before nutrient deficiencies became visible. Supplementation with a nitrogen (N)- and phosphorus (P)-containing plant-based liquid fertilizer at the point when plant deficiencies became apparent subsequently produced yields ≈80% that of the hydroponic control. In a second experiment, the proportion of mushroom or yard waste compost was increased to 50% of the mix, and liquid delivery of K, Ca, Mg and SO<jats:sub>4</jats:sub> plus either plant-based or fish-based N- and P-containing liquid feeds was started at the date of transplanting. In this case, organic yields equal to that of the hydroponic control (8.5 kg/plant) were observed in some treatments. The most productive organic treatment was the mushroom compost supplemented with a low concentration of the plant-based liquid fertilizer. In general, organic tomatoes had a lower postharvest decay index (better shelf life) than did the hydroponic controls, possibly as an indirect consequence of overall reduced yield in those treatments. High concentrations of both organic liquid feeds resulted in lower yields as a result of treatment-induced fusarium crown and root rot. In contrast to some previous studies, those treatments showing fusarium crown and root rot also had the highest gross microbial activity. Measures of gross microbial activity and numbers of microbivorous nematodes were higher (average of 37% and 6.7 times, respectively) in compost/organic feed treatments than in the hydroponic control. Community physiological profiles of the bacterial populations, on the other hand, did not differ between organic and hydroponic treatments. Nematode populations were significantly correlated with gross microbial activity in the organic treatments.</jats:p>

Study of fat compost from dairy industry wastewater as a new substrate for pepper (Capsicum annuum L.) crop

“…have shown that the interactions between heavy metals and essential elements may supply the plants with significant quantities of nutrient elements as well as heavy metals and may thereby affect plant growth positively or negatively, depending on the type of interaction (synergistic or antagonistic). Like other vegetable crops, peppers (Capsicum annuum L.) can be cultivated on conventional substrates such as perlite, rockwool, sand, and other soilless systems, which have replaced the traditional crop grown in agricultural soil in the greenhouse (Zhai et al, 2009;Díaz-Pérez and Camacho-Ferre, 2010). Increasing awareness of the adverse economic and environmental impacts of conventional substrates has stimulated the interest in using organic wastes and agricultural by-products as substrates in soilless culture (Del Amor and Gómez-López, 2009;Lin et al, 2009).…”

Effect of Municipal Solid Waste Compost and Compost Tea as Fertility Amendments on Growth and Tissue Element Concentration in Container-Grown Tomato

“…The stated goal of Rippy et al (2004) also was "to develop a certifiable organic regimen for growing greenhouse tomatoes that would be comparable with those grown conventionally with regard to production methods as well as nutritional status in leaf tissue, plant development, and harvest yields." In the present study, the compost tea, a liquid fertility amendment, had much lower macronutrient concentrations, with the exception of Mg, than the liquid organic fertilizer used by Zhai et al (2009), which was applied every 4 to 6 h. While the N content of tea was not measured in the present study, Hargreaves, Adl, and Warman (2009), using a similar compost from the same Lunenburg facility and the same steeping method, found 106 and 1.70 mg L −1 of nitrate (NO 3 -) and ammonium (NH 4 + ), respectively, which is much lower than NO 3 -content in liquid fertilizer (190 mg L −1 ) used by Zhai et al (2009). When obvious N and P deficiency symptoms were seen in the present study, no attempt was made to allay the deficiency; experimental protocol was maintained to examine availability of nutrients from MSW compost in a container environment and to attempt to verify or refute claims of compost tea benefits, whether applied to soil or foliage.…”

“…These leaf tissue concentrations were of a similar order as in the present study. Zhai et al (2009) grew tomatoes in the greenhouse using a peat-based substrate amended with various composts and with both liquid organic and conventional hydroponic fertilizers. They found in their first year's experiment that after 1 month their organically treated plants, which had received steady organic liquid supplement of K, Ca, Mg, and S from the time of transplanting, displayed N and P deficiency symptoms.…”

The horticultural potential of wastewater-grown algae fertilizers

“…Examples of each include blood meal, bone meal, milled poultry feathers, digested sewage sludge, and algae; and soybean oil, guanos, worm compost tea, and fish emulsion, respectively (Bi et al, 2010;Burger et al, 1997;Eaton et al, 2013;Gagnon and Berrouard, 1994;Gravel et al, 2012;Hartz and Johnstone, 2006;Montagu and Goh, 1990;Zhai et al, 2009). Commercially available bio-based fertilizers contain these materials, or more commonly, combinations of multiple components .…”

“…Furthermore, breakdown and release of nutrients happen more quickly as fertilizer particle size is decreased and occur quickest when fertilizers are applied as liquids (Montagu and Goh, 1990;Gravel et al, 2012). Liquid organic fertilizers rapidly release nutrients upon application, but possess limited sustained nutrient release (Hartz et al, 2010;Zhai et al, 2009). This necessitates consistent and repeated applications of liquid fertilizer for adequate plant nutrition if they are not used in conjunction with a slower-releasing fertilizer (Gravel et al, 2012).…”