In an effort to reduce application costs and to integrate plant health management strategies in soybean, growers may combine POST herbicides with foliar fertilizers or cytokinin mixtures. Field experiments were conducted at the Delta Research and Extension Center in Stoneville, MS in 2015 and 2016 to evaluate soybean [Glycine max (L.) Merr.] injury, weed control, and agronomic performance when combining blended or single-nutrient foliar fertilizers with POST herbicide applications. Field experiments were also conducted at the Delta Research and Extension Center in Stoneville, MS in 2015 and 2016 to evaluate the influence of cytokinin mixtures on soybean injury and weed control when combined with common POST soybean herbicides.

Doctor of Philosophy / Department of Agronomy / Dorivar Ruiz Diaz / Winter annual weeds (WAW) could affect nitrogen supply for corn production. The objectives of first study were to determine the diversity and abundance of WAW and to evaluate the effect of delaying herbicide applications on nitrogen supply and no-till corn response. Research was conducted in 2010 and 2011 at 14 sites in eastern Kansas. A factorial arrangement of three herbicide application dates (Nov.-Mar., April, and May) and five N rates were used. The three most abundant WAW across sites were henbit, purslane speedwell, and horseweed. Delaying herbicide application until April significantly reduced early corn N uptake by 52 mg N plant-1, chlorophyll meter readings at silking by 3.4%, and grain yield by 0.48 Mg ha-1 across sites. An additional 16 to 17 kg N ha-1 was needed to maintain yield if herbicide application was delayed until April. Starter and foliar micronutrient fertilization can potentially increase corn and soybean yield. The objectives of the second study were to evaluate crop response from combinations of starter and foliar fertilizers that contain N-P-K mixtures with and without a blend of micronutrients at four sites for each crop under irrigated conditions. No early corn growth or yield increase was attributed to application of micronutrients (Fe, Mn, Zn, Cu, and B) beyond what was achieved with N-P-K starter fertilization. There was an increase in soybean height (8 cm) and yield (293 kg ha-1) with starter fertilizer containing N-P-K plus micronutrients over the control. No increase in corn or soybean yield was obtained with foliar fertilization. The objective of the third study was to compare soil mobility and changes in soybean nutrient concentration in the leaf and seed from Mn and Zn sources (EDTA and oxysulfate) at two sites. Zinc sources were more mobile in the soil. Both Zn sources increased seed Zn concentration. Manganese oxysulfate increased seed Mn concentration. However, soybean trifoliolate leaf and seed Mn concentration decreased with soil-applied Na2EDTA and MnEDTA. This response was attributed to formation of FeEDTA and increased Fe supply that reduced root Mn absorption. Manganese EDTA is not recommended for soil application.

High-input management practices are often heavily marketed to producers to increase soybean [Glycine max (L) Merr.] yield in already high-yielding environments. Field research was conducted in three locations within 6 states (Arkansas, Iowa, Kentucky, Louisiana, Michigan, and Minnesota) in 2009 to determine the effect of seed treatment, inoculant, foliar fungicide, additional soil fertility beyond state recommendations, foliar fertilizer, increased population over state recommendations, and narrow row spacing on yield. The high-input system (combination of the management practices) yielded higher than standard-input system (University recommended management practices) in only 8 of the 18 locations. Narrow rows, in both the high and standard-input systems, only increased yield in 4 locations. Inoculant did not increase yield at any location. Foliar fertilizer application and seed treatment increased yield in one location each. The additional soil fertility and fungicide application increased yield in two locations each. The increased population increased yields in 3 of the 18 locations; while an additional fungicide application at R5 only increased yield in 1 location. Foliar fertilizers at rates above commercial use did not increase soybean yield in Kentucky in 2008 or 2009. High-input production practices were largely unsuccessful at increasing soybean yield in these studies.

The aim of the study was to evaluate the impact of the application of foliar fertilizers on starch production at potato growing. The literary review contains a general introduction to the topic and furthermore there is a summary of the existing development and production of potatoes both in the Czech Republic and abroad. The results were obtained from the one-year field experiment, during which two potato varieties with different lengths of the growing seasons were planted. It was a medium-early ripening variety Priamos and the late variety Dominator. In 2014 the one-year field experiment was established, during which the effect of the application of the solution of urea, Lignohumate and Energen Fulhum was evaluated compared with the variant without the application of foliar fertilizers. The tuber yield, number of tubers per plant, weight of tubers per plant, average weight of 1 tuber, starch yield and starch content were evaluated. The annual results indicated that the foliar fertilizers had on this year the positive effect on tuber yield, but the impact on the starch yield and content has not been confirmed. Both monitored potato varieties responded positively to the application of Lignohumate - by tuber enlarging. The Priamos Variety had an average tuber yield of 50.3 t/ha and the average starch content of 20.3%. In contrast the variety Dominator had the average tuber yield of 59.8 t/ha but lower starch content, in the average by 17.6%.

The aim of the study was to evaluate the effect of foliar nitrogen nutrition on yield and starch content and protein varieties of potatoes for starch with different length of the growing season. The literary review contains a general introduction to the topic and furthermore there is a summary of the existing development and production of potatoes both in the Czech Republic and abroad. In 2015 it was established one-year field experiment, where the effect was evaluated by 8% urea solution in variations in one application time and application in terms of solution 2 compared to the variant without the application of the urea solution. There were three sorts of potatoes with different vegetation period. It was a medium late variety Zuzanna and semi-late to late varieties Eurogrand and Eurostarch . At very specific 2015 to both precipitation and temperature be best evaluated albeit to a small extent, by the urea solution in the first term. Applications for the 2nd deadline had no significant effect on the production of starch and nitrogen compounds .