Prohexadione calcium, a plant growth regulator, is commonly used on virginia market type peanut ( Arachis hypogaea L.) cultivars to manage excessive vine growth and improve digging efficiency.  However, use of prohexadione calcium on runner market type cultivars has been minimal.  The objective of this research was to evaluate prohexadione calcium on virginia and runner market type peanut cultivars at multiple rates in small-plot (17 site years) and on-farm (5 site years) experiments.  Applications of prohexadione calcium were at the manufacturer’s recommended use rate of 140 g/ha (1x), 105 g/ha (0.75x), and 70 g/ha (0.5x) rates.  A non-treated control was also included in all experiments.  Cultivar and treatment responses were evaluated based on mainstem height, yield, total sound mature kernels, and return on investment. Plants treated with prohexadione calcium had greater row visibility based on a 1-10 row visibility. Plant main stem heights were often shortened when prohexadione calcium was applied compared to the control, although response varied by location and by year.  Average mainstem heights were 26 cm for non-treated plots and 23 cm for prohexadione calcium treated plots across all virginia market type small plot experiments. Prohexadione calcium did not significantly increase yield at any rate in any small plot experiments regardless of rate. Reduced rates of prohexadione calcium significantly increased yield in all the large on-farm experiments compared to the control. Yield increases ranged from 453 to 731 kg/ha for all prohexadione calcium treatments compared to the control across all large plot on-farm experiments. The greatest return on investment was the 0.75x rate resulting in an increase in revenue of $210 ha -1 . With an increase in yield and return on investment in all large plot on-farm experiments and not in small plot experiments no matter the market type, it is assumed that the growth and yield response to prohexadione calcium may be more pronounced where soil variability is greater, affecting growth, digging, and yield potential.  Prohexadione calcium can be beneficial in virginia market type and runner market type peanut cultivars to decrease vine growth and increase yield.

Land preparation method, planting flat or on a raised bed, has no effect on peanut pod yield.• In furrow-irrigated environments, should peanut be irrigated on every furrow or every other furrow?• Irrigating every other furrow, in furrow-irrigated peanut, increased irrigation water use efficiency.

Scheduling irrigations for furrow-irrigated peanut (Arachis hypogea L.) based on soil moisture potential could improve yield and net returns by ensuring adequate season-long soil water availability. This research was conducted to determine if sensor-based irrigation scheduling improves peanut yield, net returns above irrigation costs, and irrigation water use efficiency relative to FAO-56, a water balance irrigation-scheduling method that determines evapotranspiration using meteorological data and crop growth stage. The effects of irrigation scheduling (FAO-56, -50 cbar, -75 cbar, -100 cbar, and non-irrigated) on peanut yield, net returns above irrigation costs, and irrigation water use efficiency were investigated at Stoneville, MS on a Bosket very fine sandy loam (fine-loamy, mixed, active, thermic Mollic Hapludalfs). Relative to non-irrigated and FAO-56, maintaining the soil moisture at -50 cbar improved peanut yield at least 12.7% and either had no effect during wet years or improved net returns above irrigation costs up to 20.7% during dry years (P ≤ 0.0376). Maintaining soil moisture at -50 or -100 cbar either had no effect during wet years or increased irrigation water use efficiency by at least 5.3-fold relative to FAO-56 during dry years (P = 0.0071). Our data indicate that peanut yield, net returns above irrigation costs, and irrigation water use efficiency are more consistently optimized in furrow-irrigated environments by maintaining a season-long irrigation threshold of -50 cbar.

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The University of Georgia Extension recommendation for optimum plant stand in peanut (Arachis hypogaea L.) is 13.1 plants/m, although previous work has shown that yield potential can be maintained at lower plant stands. The unpredictable and often extreme weather and the ubiquity of pathogens in the region often contribute to poor emergence and poor plant stands. When plant stand is adversely affected, replanting the field may be a practical option. The objectives of this study were to determine i) the effect of plant stand on yield, grade and disease incidence, ii) at what plant stand peanut gains an advantage from replanting and iii) the best method for replanting peanut when an adequate stand is not achieved. Field trials took place in