Weed Management, Training, and Irrigation Practices for Organic Production of Trailing Blackberry: II. Soil and Aboveground Plant Nutrient Concentrations

Abstract

<jats:p>Organic production of blackberries is increasing, but there is relatively little known about how production practices affect plant and soil nutrient status. The impact of cultivar (Black Diamond and Marion), weed management (nonweeded, hand-weeded, and weed mat), primocane training time (August and February), and irrigation (throughout the summer and none postharvest) on plant nutrient status and soil pH, organic matter, and nutrients was evaluated from Oct. 2012 to Dec. 2014 in a mature trailing blackberry (<jats:italic>Rubus</jats:italic> L. subgenus <jats:italic>Rubus</jats:italic> Watson) production system. The study site was certified organic and machine harvested for the processed market. The planting was irrigated by drip and fertigated with fish hydrolysate and fish emulsion fertilizer. Soil pH, organic matter content, and concentrations of soil nutrients, including ammonium-nitrogen (NH<jats:sub>4</jats:sub>-N), potassium (K), calcium (Ca), magnesium (Mg), sulfur (S), copper (Cu), manganese (Mn), and zinc (Zn), were greater under weed mat than in hand-weeded plots. Soil K and boron (B) were below recommended standards during the study, despite a high content of K in the fish fertilizer and supplemental B applications. Primocane leaf nutrient concentrations were below the N, K, Ca, and Mg sufficiency standards in ‘Black Diamond’ and were lower than in ‘Marion’ for N, phosphorus (P), Ca, Mg, S, B, and Zn in at least one year. In contrast, floricane leaves and fruit tended to have higher nutrient concentrations in ‘Black Diamond’ than in ‘Marion’. Weed management strategy affected many nutrients in the soil, leaves, and fruit. Often, use of weed mat led to the highest concentrations. Withholding irrigation postharvest had limited effects on plant nutrient concentrations. Primocane training time affected the nutrients in each plant part differently depending on year.</jats:p>

Seasonal Variation in Mineral Nutrient Concentration of Primocane and Floricane Leaves in Trailing, Erect, and Semierect Blackberry Cultivars

“…'Black Diamond', 'Columbia Star', and 'Onyx' leaf K increased during the last 2 weeks of July just before the onset of senescence. Floricane leaf K concentrations were similar to those reported in other erect cultivars (Pereira et al, 2015) and in 'Black Diamond' (Dixon et al, 2016); however, leaf K for 'Marion' was higher in our study than what was previously reported by Dixon et al (2016). Leaf K declined during fruiting likely because of the relatively high K content of blackberry fruit (Dixon et al, 2016;Harkins et al, 2014).…”

“…The reason for the decline in leaf Ca in the floricanes of erect and semierect cultivars in late August is not clear, but this decline was not observed in 2013 for these cultivars (data not shown). Floricane leaf Ca and Mg concentrations likely increased through the season because these leaves were aging, as has been reported in older leaves of raspberry (Hughes et al, 1979) and blackberry (Strik, 2015), and there are relatively low concentrations of these nutrients in trailing blackberry fruit (Dixon et al, 2016;Harkins et al, 2014).…”

“…Cultivars of blackberry (Fernandez-Salvador et al, 2015a, 2015b, 2015cDixon et al, 2016;Harkins et al, 2014;Strik, 2015) and raspberry (John and Daubeny, 1972;John et al, 1976) differed in primocane leaf nutrient levels when sampled in midseason. By contrast, Clark et al (1988) found no difference among three erect blackberry cultivars in leaf nutrient levels and speculated that this was because of their similar parentage.…”

Changes in Some Soil Chemical and Biological Properties on the Growing Season of Sesame in Çukurova Region

“…Leogrande et al (2014) researched the effects of different irrigations and organic fertilizers (mineral fertilizer, commercial stable manure, anaerobic digestate and municipal solid waste compost) on soil properties of eggplant crop in a three-year field experiment and reported that anaerobic digestate and compost reached the highest levels of soil total organic carbon. Dixon et al (2016) studied that impacts of weed management (nonweeded, hand-weeded, and weed mat) and irrigation (throughout the summer and none postharvest) on soil organic matter and nutrients (potassium, calcium, copper, manganese and zinc) for two years in blackberry (Rubus L. subgenus Rubus Watson) and reported that these nutrients were were higher under higher weed mat than hand-weeded plots. They also indicated that soil K was below recommended standards during the study despite fertilization.…”