No abstract

Senescent sugarbeet leaves were collected at about two-week intervals through the growing season and analyzed for seven nutrients: Na, K, Ca, Mg, N, S, and P. These nutrients also were determined at harvest in leaves of four ages, and in crowns and roots. As the season progressed, average concentrations of Na, Ca, and Mg in senescent leaves decreased, whereas K and S remained approximately constant; N and P de creased early but increased later, probably due to in creased soil availability of these nutrients. Increasing N fertilization increased Nand Mg and decreased P concentrations in senescent leaves, but planting date had little effect. Nitrogen fertilization resulted in in creased Na, Mg, N, and S, but decreased Ca in the six plant parts at harvest. With increasing leaf age, Ca, Mg, Na, and S concentrations increased, whereas those of Nand P decreased. In general, the seven nutrients ocurred in lowest concentration in the root, in highest concentration in the leaves, and at intermediate levels in the crown. Increasing N fertilization levels resulted in increased Na, Mg, and N and decreased Ca in" roots and crowns at harvest. Relative to total crop uptake, leaf senescence resulted in greater proportional loss of the less mobile nutrients (Na, Ca, Mg, S) than of the more mobile Nand P, or of K, which was relatively uniformly distributed in leaves of each age.

No abstract

In soils that can range in pH from the low 4's to 7, depending on the location and liming history, deficiency of Zn, B, and Mo coupled with the soil acidity complex of Mn toxicity had been previously identified as severe limiting factors in producing quality Brassica crops. Fertility studies on fall and spring planted Brassicas focused on the effect of including/not including micronutrients during various phases of growth when NPK preplant fertilizer was reduced. Differential responses to reduction in preplant NPK and applications of micronutrients was found to be dependent on planting time (fall or spring), species of Brassica planted and cultivar. Nutrient uptake in leaf blades and petioles was followed. In broccoli timing of micronutrient applications significantly affected the harvest period length. Broccoli final yields of the B, Zn and Mg treatments were found to contribute ≈75% to 80% of the final yield of a full range micronutrient solution.

Soil fertility studies conducted in commercial vegetable fields to examine alternative uses of mid-south agricultural wastes as soil amendments included work with poultry litter, cotton gin trash, and rice hulls. Poultry litter applications ranging from 0.3 to 0.9 Mg·ha–1 resulted in significant increases in spinach, cabbage, turnip greens, and collard yields grown in soils damaged by precision leveling or in sandy soils with low organic matter; however, positive yield response to litter applied to undamaged soils was variable. Raw rice hulls applied at rates ranging from 2 to 44 Mg·ha–1 resulted in reduced cabbage yield. Trials with cotton gin trash and cover crops on yield of cabbage, broccoli, southern pea, snap bean, and cucumber indicate significant problems with weeds following use of raw gin trash. Composting alleviated most weed problems, but no yield response was apparent at composted gin trash rates ≤9.6 Mg·ha–1. High rates (60 Mg·ha–1) of composted gin trash on damaged soil significantly improved cabbage yield. There were increases in soil pH and Ca levels. Research was supported by a SAREIACE grant.