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United States Department of Agriculture

Agricultural Research Service

Title: Peanut Yield Response to Conservation Tillage, Winter Cover Crop, Peanut Cultivar, and Fungicide Applications

Authors
item Sorensen, Ronald
item Brenneman, Timothy - UNIVERSITY OF GA
item Lamb, Marshall

Submitted to: Peanut Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 1, 2009
Publication Date: June 1, 2009
Citation: Sorensen, R.B., Brenneman, T.B., Lamb, M.C. 2009. Peanut Yield Response to Conservation Tillage, Winter Cover Crop, Peanut Cultivar, and Fungicide Rate. Peanut Science. 37(1):44-51.

Interpretive Summary: Strip tillage can be an effective management tool to reduce peanut production costs. However, the acceptance of strip-tillage has been slowed due to the fear of increased yield loss from soil born diseases and ultimately loss of yield. In peanut, yield and disease response due to conservation tillage practices are not consistent from study to study because of different peanut varieties, various cover crops, management procedures, and different disease pressures. In addition, new peanut varieties have been released with better disease resistance than older varieties. Winter cover crops are planted for animal production, erosion control, or part of a normal crop management system. There is no clear answer as to which is better, conventional or strip tillage, as yield results have been mixed depending on the year and selected management techniques. Various researchers have shown disease reductions or no effect on stem rot (Sclerotium rolfsii), Rhizoctonia limb rot (Rhizoctonia solani), and TSWV with strip tillage and associated cover crops. Disease control with fungicide applications, up to seven applications in one year, can be quite costly to the grower at approximately 20% of the total variable costs. Reducing fungicide applications without loss of yield would be beneficial to the grower. The use of strip tillage in a peanut/cotton rotation irrigated with subsurface drip irrigation (SDI) could be of major interest in conserving water, reducing agronomic inputs, and possibly increasing on-farm revenue. The objectives were to determine the effects of winter cover crop, peanut cultivar, and fungicide rates on peanut diseases, pod yield, grade, and kernel size distribution when irrigated with subsurface drip irrigation. This two year project was conducted at Shellman, GA on a soil as a Greenville sandy loam. This experiment was a split plot (fungicide programs), randomized complete block design (tillage/cover crops) with six crop covers, and three peanut varieties planted within each cover crop replicated three times. The main plots were fungicide applications perpendicular to tillage and peanut cultivar treatments. The six cover crops were: no cover (conventional tillage), wheat (\AGS2000), rye (Abruzzi), two oat cultivars (Horizon 474, and Soil Saver/Black Oats), and triticale (Triticale 314). The peanut cultivars were Georgia Green (GG), DP1, and GA01R. Fungicide rates were fully recommended (1R), half of recommended (0.5R), and none (0R). Fungicide rate and application schedule for the 1R plots consisted of seven fungicide spray applications following manufacturers’ rate and timing recommendations. The 0.5R had two chlorothalonil (Bravo) and two tebuconazole (Folicur) matching alternate applications timings of the 1R regimen. Peanut yield and grade were determined following official federal/state inspection guidelines. Within peanut cultivars, leaf spot (Cercospora arachidicola) intensity decreased as fungicide increased; however, stem rot (Sclerotium rolfsii) incidence was the same for the 1.0R and 0.5R fungicide rate but increased at the 0R fungicide rate. Conventional tillage had more leaf spot than strip tillage, but, there was no difference within winter crop covers. There was no difference in stem rot incidence with tillage or winter cover crop. There was no yield difference with peanut cultivar. Pod yield was the same for the 1.0R and 0.5R fungicide rate (3441 lbs/ac) but decreased at the 0R fungicide rate (2438 lbs/ac). Pod yield was greater with conventional tillage and strip tillage with black oats (Avena sativa) (3298 lbs/ac) compared with strip tillage of other winter crop cover treatments (2988 lbs/ac). Conventional tillage had more leaf spot, equal incidence of stem rot, and higher yield compared with strip tillage. The 0.5R fungicide program had the same yield compared with the 1.0R fungicide program implying a

Technical Abstract: Strip tillage with various crop covers in peanut (Arachis hypogaea, L.) production has not shown a clear yield advantage over conventional tillage, but has been found to reduce yield losses from some diseases. This study was conducted to determine pod yield and disease incidence between two tillage practices, five winter cover crops, three peanut cultivars with different levels of disease resistance, and three fungicide rates. Conventional and strip tillage treatments were implemented on a Greenville sandy loam (fine, kaolinitic, thermic Rhodic Kandiudults) near Shellman, GA. Five winter cereal grain cover crops (strip tillage) and a no cover treatment were sprayed at full (1.0R), half (0.5R) or none (0.0R) fungicide programs. Within peanut cultivars, leaf spot (Cercospora arachidicola) intensity decreased as fungicide increased; however, stem rot (Sclerotium rolfsii) incidence was the same for the 1.0R and 0.5R fungicide rate but increased at the 0R fungicide rate. Conventional tillage had more leaf spot than strip tillage, but, there was no difference within winter crop covers. There was no difference in stem rot incidence with tillage or winter cover crop. There was no yield difference with peanut cultivar. Pod yield was the same for the 1.0R and 0.5R fungicide rate (3867 kg/ha) but decreased at the 0R fungicide rate (2740 kg/ha). Pod yield was greater with conventional tillage and strip tillage with black oats (Avena sativa) (3706 kg/ha) compared with strip tillage of other winter crop cover treatments (3358 kg/ha). Conventional tillage had more leaf spot, equal incidence of stem rot, and higher yield compared with strip tillage. The 0.5R fungicide program had the same yield compared with the 1.0R fungicide program implying a possible 50% savings on fungicide applications on well rotated fields with lower disease risk.

Last Modified: 9/2/2014
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