|Siri-Prieto, G -|
Submitted to: Agronomy Journal
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 11, 2009
Publication Date: July 15, 2009
Citation: Siri-Prieto, G., Reeves, D.W., Raper, R.L. 2009. Tillage Requirments for integrating winter-annual grazing in peanut production: Plant water status and productivity. Agronomy Journal. 101(6):1400-1408. Interpretive Summary: Our study shows that integration of winter-annual grazing in peanut production can enhance profitability for Southeastern producers. Data suggested that peanut following oat improved plant populations and increased rooting and soil water extraction compared with peanut following annual ryegrass (possibly associated with more N uptake later in the cycle, root restriction, and some allelopathic effect by ryegrass). We found no clear effect of forage species or tillage system on peanut leaf stomatal conductance. Strict no-till resulted in lower plant populations, reduced soil water extraction, and lowered peanut yields (47, 15, and 42%, respectively) when compared with the other seven tillage systems. Oat appears to be a better choice than ryegrass for peanut grown following winter-annual grazing, and deep tillage was necessary to maximize yields in no-tillage. Deep tillage in conventional surface tillage systems did not increase peanut yield. Within no-tillage systems, peanut yields were greater with in-row subsoil using the narrow-shanked implement compared to paratill (4.13 vs. 3.84 Mg ha-1, respectively). Oat, together with in-row subsoil for peanut production, had the greatest total annual net return [$462 ha-1, and net returns from animal production represented 40% of the total return ($185 ha-1)]. In conclusion, integrating winter-annual grazing with peanut using noninversion deep tillage in conservation tillage systems can increase profitability for producers without sacrificing peanut yields. We believe that integrating winter-annual grazing with peanut production can be an effective means to help Southern farmers increase income.
Technical Abstract: The use of crop rotation systems involving winter-annual grazing can help peanut (Arachis hypogaea L.) producers increase profitability, although winter-annual grazing could result in excessive soil compaction, which can severely limit yields. We conducted a 3-yr field study on a Dothan loamy sand in southeastern Alabama to develop a conservation tillage system for integrating peanut with winter-annual grazing of stocker cattle under dryland conditions. Winter-annual forages and tillage systems were evaluated in a strip-plot design, where winter forages were oat (Avena sativa L.) and annual ryegrass (Lolium mutiflorum L.). Tillage systems included moldboard and chisel plowing, and combinations of noninversion deep tillage (none, in-row subsoil, or paratill) with/without disking. We evaluated soil water content, peanut leaf stomatal conductance, plant density, peanut yield, peanut net return, and total system annual net return. Peanut following oat increased soil water extraction (15%), stands (12%), and yields (21%) compared with peanut following ryegrass. Strict no-till resulted in the lowest yields (2.29 Mg ha-1, 42% less than the mean) and noninversion deep tillage (especially in-row subsoil) was required to maximize water use and yields with conservation tillage. Net return from annual grazing ($185 ha-1, USD) represented 40% of the total return for the best treatment (no-tillage with in-row subsoil following oat = $462 ha-1). Integrating winter-annual grazing in this region using noninversion deep tillage following oat in a conservation tillage system can benefit peanut growers, allowing extra income without sacrificing peanut yields. Abbreviations: AAES, Alabama Agricultural Experiment Station; ACES, Alabama Cooperative Extension System; DOY, day of year; DWG, daily weight gain; SMK, sound mature kernels.