Abukari I.A.,Savanna Agricultural Research Institute |
Shankle M.W.,North Mississippi Research and Extension Center |
Reddy K.R.,Mississippi State University
Scientia Horticulturae | Year: 2015
The herbicide S-metolachlor is used to control or suppress annual grasses, nutsedges and several broadleaf weeds in sweetpotato. However, a decline in storage root quality is suspected when an excessive rainfall occurs within 24h after application. A sunlit, controlled environment experiment was conducted to investigate sweetpotato response to five levels of S-metolachlor (0.00, 0.86, 1.72, 2.58 and 3.44kgha-1), and two levels of simulated rainfall (0 and 38mm at 51mmh-1) immediately after application. Sweetpotato slips were transplanted into white polyvinyl chloride pots filled with sandy loam soil. S-metolachlor treatments were applied to slips and a simulated rainfall treatment delivered immediately after transplanting and herbicide treatment. All pots were transferred to sunlit growth chambers that were maintained at 30/22°C, day/night temperatures and ambient carbon dioxide concentration (400μLL-1) for 60 days. An evapotranspiration-based irrigation system was used to supply water and nutrients. Plant biomass components and quality of storage roots were recorded 60 days after transplanting. There was no difference between rainfall treatments across S-metolachlor rates for vine lengths, leaf numbers and leaf area. These parameters, however, declined linearly and significantly with increase in S-metolachlor concentration. Total storage root weight declined linearly with increased S-metolachlor concentration; the decline was steeper with simulated rainfall. Yield of marketable storage roots declined by 18 and 31% in the absence of rainfall and 55 and 79% in the presence of rainfall with S-metolachlor at minimum (0.86kgha-1) and maximum (1.43kgha-1) recommended label rates, respectively, used to control weeds. Yield reduction was directly proportional to the rate of S-metolachlor applied in the absence or presence of rainfall; 77 and 123g fresh weight kg-1ha-1 S-metolachlor for no-rainfall and rainfall treatment, respectively. These results can be used to improve management decisions to optimize yield under field conditions as well as to mitigate risk of injury that could be associated with the use of S-metolachlor in sweetpotato production systems. © 2015 Elsevier B.V.
Bauske E.M.,University of Georgia |
Kelly L.,North Mississippi Research and Extension Center |
Smith K.,Auburn University |
Bradley L.,North Carolina State University |
And 2 more authors.
HortTechnology | Year: 2011
Extension Master Gardener (EMG) volunteers are key to effective dissemination of horticultural information to the public. The goal of this workshop was to identify techniques to increase the capacity and effectiveness of EMG volunteers. The workshop focused on projects and tools that reduce the administrative burden of managing volunteers, increase the scope of issues that volunteers are prepared to address, and pool volunteer efforts and resources across county lines. Two online systems for managing and reporting EMG volunteer activities were described. Both systems are intuitive, user-friendly, and updated without the assistance of web managers. Regional web-based, advanced training on specific topics was used to expand educational messages of EMG volunteers and eliminate the costs associated with face-to-face training. Presentations were made using distance learning technologies and resources were shared online. Hosting agents tailored hands-on supporting activities to meet local needs. Volunteers expanded extension outreach by answering noncommercial landscape and garden telephone questions. Many of the administrative, logistical, and resource burdens associated with the EMG helpline phone service were overcome by working across county lines, standardizing training, centralizing supporting resources, and clustering volunteers into regional telephone helpline offices. Other projects and tools presented in the workshop focused on the need to affirm and/or foster the volunteers' connection with the university and the outreach mission of Cooperative Extension.
Avendano-Reyes L.,Mississippi State University |
Avendano-Reyes L.,Autonomous University of Baja California |
Fuquay J.W.,Mississippi State University |
Moore R.B.,Mississippi State University |
And 4 more authors.
Tropical Animal Health and Production | Year: 2010
To estimate the relationship between heat stress during the last 60 days prepartum, body condition score and certain reproductive traits in the subsequent lactation of Holstein cows, 564 multiparous cows and 290 primiparous cows from four dairy herds were used in a hot, humid region. Maximum prepartum degree days were estimated to quantify the degree of heat stress. Multiple regressions analyses and logistic regression analysis were performed to determine the effect of prepartum heat stress and body condition change on reproductive parameters, which were obtained from DHIA forms at the end of the lactation. Multiparous and primiparous cows which gained body condition score from calving to 60 d postpartum exhibited 28 and 27 fewer days open (P < 0.05), respectively, than cows not gaining. There was no effect (P > 0.05) of heat stress measurement on days open or services per conception in either multiparous or primiparous cows. During hotter months of calving, multiparous cows showed higher services per conception and primiparous cows showed higher days open and services per conception (P < 0.05). Maximum prepartum degree-days were positively associated (P < 0.05) with calving difficulty score. Multiparous cows with high body condition score at calving were 1.47 times more likely to present a very difficult calving than cows that calved in October (P < 0.05). Collectively, these results suggest that reproductive performance was not affected by cumulative prepartum heat stress although it was associated with very difficult calving score. © Springer Science+Business Media B.V. 2009.
Sloan R.C.,North Mississippi Research and Extension Center |
Sloan R.C.,Mississippi State University
Forest Products Journal | Year: 2010
Steam-pressed scrim lumber (SPSL) involves crushing small diameter trees into mats that are coated with adhesive and pressed into boards. Water from the crushing process contains a high biological oxygen demand (BOD), chemical oxygen demand (COD), and total suspended solids (TSS). This water must be remediated before it can be discharged into public water systems. A 6-month study was conducted to evaluate the effectiveness of co-composting of the process water with wood waste and chicken manure as a method of remediation. Wood waste from the SPSL pilot facility in Shuqualak, Mississippi, was ground into small particles. This material was composted using four treatments: with or without added manure plus deionized (DI) water or process water to adjust moisture content. The compost end products for all treatments were evaluated for relative toxicity, weight loss, maturity, and suitability as a container substrate to grow plants. Additional testing determined the toxicity of compost leachate and evaluated the effects on germination rates of sensitive plant species. Co-composting successfully reduced the bulk and toxicity for all treatments. Treatments containing manure and process water showed over 90 percent emergence rate of sensitive seeds by Day 90. The manure amendments were comparable to the commercial greenhouse substrate in growth. Thus, a bio-based value-added medium that is nontoxic and suitable for potting mix was produced from SPCL wastes, remediating the process waste. © Forest Products Society 2010.
Gajanayake B.,Mississippi State University |
Raja Reddy K.,Mississippi State University |
Shankle M.W.,North Mississippi Research and Extension Center |
Arancibia R.A.,North Mississippi Research and Extension Center
Scientia Horticulturae | Year: 2014
Soil moisture deficit at early season is detrimental for sweetpotato growth and development affecting final yield. This study investigated the effects of different soil moisture regimes on early season growth, developmental, and physiological responses of two sweetpotato cultivars, 'Beauregard' and 'Evangeline', grown in a greenhouse environment. Five levels of soil moisture treatments, 0.256, 0.216, 0.164, 0.107, and 0.058m3m-3 of VWC, were maintained through sensor-based soil moisture monitoring, and semi-automated programmed irrigation. Midday leaf water potential (LWP), gas exchange, and fluorescence were measured weekly from 30 to 50 days after transplanting (DAT). Growth and development of plants were evaluated through harvesting four plants at 5-day intervals from 14 to 50 DAT. Leaf pigments and cell and chlorophyll stability indices were also determined. Midday LWP of sweetpotato declined linearly with decreasing soil moisture levels. The photosynthetic rate also declined linearly in Beauregard and quadratically in Evangeline with decreasing soil moisture. Both cultivars had a close association between photosynthetic rate and stomatal conductance over the soil moisture treatments, suggesting that stomatal closure is a key limitation for the drop in photosynthesis. Chlorophyll concentration was significantly lower at extreme soil moisture deficit conditions. Significant difference was found in water use efficiency between cultivars and among soil moisture treatments. Rates of vine elongation and leaf formation of Evangeline decreased more rapidly than Beauregard with declining soil moisture levels. Also with decreasing soil moisture, the shoot biomass declined more rapidly than root biomass. The results showed that maintaining soil moisture closer to field capacity (0.256m3m-3 of VWC) during early season is beneficial for early development of both root and shoot system and thus better crop performance. The data and the inferences derived from the functional algorithms developed in this study will be useful for crop modelling, field-level irrigation scheduling, and planting decisions. © 2014 Elsevier B.V.