Interaction of a Foliar Application of Iron HEDTA and Three Postemergence Broadleaf Herbicides with Soybeans Stressed from Chlorosis

Nutrient Accumulation and Photosynthesis in Glyphosate-Resistant Soybeans Is Reduced Under Glyphosate Use

“…Many farmers have noticed that some transgenic soybeans are sensitive to water stress; others have reported visual plant injury in some GR soybean varieties after glyphosate application (Zablotowicz and Reddy, 2007) and also the nutritional status of GR soybeans is strongly affected by glyphosate (Zobiole et al, 2010). Field observations in Brazil and the north central United States have reported that frequent applications of glyphosate induce iron (Fe), zinc (Zn), and manganese (Mn) deficiencies in GR-soybean (Franzen et al, 2003;Johal and Huber, 2009).…”

Acúmulo de nutrientes em soja convencional e soja RR em diferentes tipos de controle de planta daninha

“…(King et al, 2001). O menor acúmulo de biomassa causada pelo glyphosate na soja RR pode ser atribuído ao acúmulo do ácido aminometilfosfônico (AMPA), seu principal metabólito (Reddy et al, 2004), ou às reduções na taxa fotossintética (Zobiole et al, 2010c) (Franzen et al, 2003;Bott et al, 2008;Johal & Huber, 2009;Zobiole et al, 2010a).…”

Nutritional and management related interactions with iron-deficiency stress response mechanisms

“…Another possibility is that the higher root density creates a localized change in environmental conditions such as soil temperature and / or soil moisture that affects the development of Fe deficiency (Fe deficiency begins to develop early when soil temperatures are low and soil moisture is high in the North Central U.S.). A related observation is that applying Fe-EDDHA to the soybean seed reduced chlorosis severity for soybean seeds planted in close proximity in wide rows (Goos and Johnson 200 I) but not for narrow rows with greater interseed spacing (Goos and Johnson 2000).H erbicide applications have also been shown to interact with the occurrence and severity of Fe deficiency in soybean (Franzen et al 2003). Soil applied herbicides can stunt root growth and accelerate the expression of Fe deficiency.…”

“…Soil applied herbicides can stunt root growth and accelerate the expression of Fe deficiency. Post-emergent herbicide applications to soybean already exhibiting Fe deficiency symptoms can exacerbate the problem (Franzen et al 2003 tomato absorbed more Fe when grown in combination with Coker 227 oat than when grown in monoculture, but T203 soybean was prevented from obtaining Fe when grown with oat (Table 5). A follow up study with five soybean cultivars varying from high to low in Fe efficiency showed that even the most efficient soybean tested did not increase Fe uptake in the presence of oat phytosiderophore compared to without phytosiderophore present; yet efficient cultivars obtained more Fe than the inefficient cultivars in the order of their ability to reduce Fe H (Table 5; Hopkins et al I 992a, b, c;Jolley and Brown 1991b).…”