2019 ASHS Annual Conference

Strip-till vegetable systems offer benefits unavailable from standard ones featuring raised beds topped with plastic mulch. However, so far, comparable or superior yield is not among these benefits as the productivity of standard systems continues to exceed that of reduced or strip-till ones. That said, previous strip-till research did not include grafted plants or microbe-containing crop biostimulants. In separate literatures, grafted plants and biostimulants have been shown to possess characteristics and activities potentially important in strip-till settings when used alone or in combination. Informed by these literatures and preliminary experiments completed 2014-2017, we began documenting grafting (rootstock; RS) and inoculation(ant) effects on the yield and quality of tomato fruit taken from a strip-till system. Individual and potentially additive effects of planting stock and inoculation(ant) remain our focus. Winter wheat sown in Fall-2017 was green-chopped on May 24, 2018, leaving residue approximately 15 cm in height. One day later, a PTO-driven roto-tiller with one pair of tines was used to create 25-cm wide by 15-cm deep strips on 1.8-m centers throughout the field. On May 29, the ten-treatment, double-control, eight-replicate experiment was initiated by setting ungrafted and grafted ‘BHN589’ plants into the strips at 76 cm intervals, with individual plots containing eight plants of one type and RS and arranged in a randomized complete block design. Estamino, Maxifort, and Submarine RSs were chosen for their reported moderate, high, and low vigor, respectively. All plants in individual selected plots were inoculated by delivering the labeled rate of either iNvigorate (Agrinos) or LC+LT (Lallemand) directly to the soil at the base of each plant as a drench using distilled water as the diluent (inoculation at 2, 4, 6, and 8 weeks after transplanting). Fruit at the blush or more advanced stages of ripening were collected from the center four plants of each plot six times August 8 to September 25 and weighed, sorted, counted, and subsampled for measures of °Brix, pH, and titratable acidity. The experiment was repeated in two replicates of a standard system established at the same time in the center of the same field; crop drip-fertigation and protection practices were identical throughout the field. The work is being repeated in 2019. In the strip-till system, total cumulative yield was unaffected by inoculation regardless of planting stock but increased eighteen percent by grafting (across all RSs and regardless of inoculation). Also, total cumulative yield correlated with reported values of RS vigor.