Composted Cotton Stalks and Cotton Gin Trash Substrate Amendments and Irrigation/Ground Cover Management I. Effect on Physical and Chemical Properties of Pine Bark and Pine Tree Substrates

This project evaluated two cotton waste products (cotton stalks and cotton gin trash) as amendments to pine bark (PB) and pine tree (PT) substrates for their impact on substrate physical and chemical properties. PB or PT substrates were amended (v/v) with cotton stalks composted with a N source (CSN), cotton stalks composted without an N source (CS), or aged cotton gin trash (CGT) at 4:1 PB:CS (PB:CS), 4:1 PB:CSN (PB:CSN), 9:1 PB:CGT (PB:CGT), 1:1 PT:CS (PT:CS), 1:1 PT:CSN (PT:CSN) and 4:1 PT:CGT (PT:CGT) (by vol). In 2010, PB-amended substrates had larger percentages of coarse (> 2.0 mm) and fine (< 0.5 mm) particles while PT-amended substrates had larger percentages of medium (0.5–2.0 mm) particles. In 2011, PB-amended substrates again had larger percentages of coarse particles, while PT-amended substrates had more medium and fine particles. Generally, most physical properties were within adequate ranges and were better than or comparable to the 100% PB control. Substrate solution pH was generally highe...