Within-field soil heterogeneity effects on herbicide-mediated crop injury and weed biomass

Weed Science ◽  
2001 ◽  
Vol 49 (6) ◽  
pp. 798-805 ◽  
Author(s):  
Martin M. Williams II ◽  
David A. Mortensen ◽  
Alex R. Martin ◽  
David B. Marx
2013 ◽  
Vol 27 (3) ◽  
pp. 538-546 ◽  
Author(s):  
Ryan C. Holmes ◽  
Christy L. Sprague

Field studies were conducted in 2010 and 2011 at two locations in Michigan to examine the effect of row width and herbicide combination on weed suppression and yield in the new Type II black bean variety ‘Zorro.' Black bean was planted in 38- and 76-cm rows. Six weed control strategies were examined:S-metolachlor + halosulfuron (PRE),S-metolachlor (PRE) followed by (fb) bentazon + fomesafen (POST), halosulfuron (PRE) fb clethodim (+ fomesafen at one site in one year) (POST), imazamox + bentazon (POST), a weed-free control, and a nontreated control. Weed control and crop injury were evaluated throughout the growing season. In addition, weeds were counted by species in late July, and weed biomass was harvested and weighed at the end of the season. Black bean yield was obtained by direct harvest. Narrow rows reduced weed populations in two of the four site–year combinations (referred to hereafter as site–years), reduced weed biomass in three of the four site–years, and often improved control of upright broadleaf weeds. All herbicide combinations generally reduced weed populations and biomass, but control of specific weeds was variable. Crop injury was generally slight and transient. Yield was greater in narrow rows in two of the four site–years. All herbicide combinations increased yield compared with the nontreated control and resulted in similar yields to one another. Yield and weed suppression was often maximized in narrow rows, while herbicide performance varied by year and weed spectrum.


Author(s):  
Muhammad Habib-ur-Rahman ◽  
Ahsan Raza ◽  
Hella Ellen Ahrends ◽  
Hubert Hüging ◽  
Thomas Gaiser

AbstractCrop cultivation provides ecosystem services on increasingly large fields. However, the effects of in-field spatial heterogeneity on crop yields, in particular triticale, have rarely been considered. The study assess the effects of in-field soil heterogeneity and elevation on triticale grown in an intensively cropped hummocky landscape. The field was classified into three soil classes: C1, C2, and C3, based on soil texture and available water capacity (AWC), which had high, moderate, and low yield potential, respectively. Three elevations (downslope (DS), midslope (MS), and upslope (US)) were considered as the second study factor. An unbalanced experimental design was adopted with a factorial analysis of variance for data analysis. Temporal growth analysis showed that soil classes and elevation had significant effects. Generally, better growth was observed in C1 compared to that of C3. DS had a lower yield potential than that of MS and US. In addition, the interactive effect was confirmed, as triticale had poor growth and yield in C3 on the DS, but not on US. Crop physiological parameters also confirmed the differences between soil classes and elevation. Similarly, soil moisture (SM) content in the plow layer measured at different points in time and AWC over the soil profile had a positive association with growth and yield. The results confirmed that spatial differences in AWC and SM can explain spatial variability in growth and yield. The mapping approach combining soil auguring techniques with a digital elevation model could be used to subdivide fields in hummocky landscapes for determining sub-field input intensities to guide precision farming.


1991 ◽  
Vol 5 (1) ◽  
pp. 154-158 ◽  
Author(s):  
R. Gordon Harvey

Preplant-incorporated (PPI) herbicides were applied to suppress annual weeds in new seedings of alfalfa, then additional annual weed control and crop tolerance from selected bentazon treatments were evaluated. Bentazon applied at 0.8 kg ai ha-1without an adjuvant caused an average of 8% visual injury to newly seeded alfalfa but did not reduce first-harvest alfalfa yields. Bentazon improved common lambsquarters control in newly seeded alfalfa and reduced weed biomass in first-harvest forage. No significant difference in crop injury, weed control, alfalfa yield, or weed yield was observed when bentazon was applied at 0.6, 0.8, or 1.1 kg ha-1. Greater alfalfa injury occurred when bentazon was applied with 1.25% v/v oil-emulsifier mixture, than when applied alone or with 5% v/v 28% liquid nitrogen fertilizer (28% N). Ten alfalfa cultivars did not differ in sensitivity to bentazon applied early postemergence (POST) or POST.


2004 ◽  
Vol 18 (4) ◽  
pp. 968-976 ◽  
Author(s):  
Farzin Abdollahi ◽  
Hossein Ghadiri

Field studies were conducted to investigate the effects of different rates of herbicides on weed control, agronomic characteristics, and quality of sugar beet at Shiraz, Iran, in 2000 and 2001. Separate and combined applications of herbicides, including 14 combinations and different rates of grass and broadleaf herbicides, at two rates were used. Herbicides reduced weed biomass compared with the weedy check. In both years, maximum reduction in weed biomass was observed with desmedipham plus phenmedipham plus ethofumesate at 0.23 + 0.23 + 0.23 kg ai/ha and desmedipham plus phenmedipham plus propaquizafop at 0.46 + 0.46 + 0.1 kg ai/ha. Efficacy of grass herbicides was reduced when they were combined with pyrazon. Highest crop injury in both years was observed with desmedipham plus phenmedipham plus ethofumesate at 0.23 + 0.23 + 0.23 kg/ ha. Highest and lowest root yields in both years were produced in weed-free and weedy check plots, respectively. All herbicide treatments produced lower sugar beet yields than the hand-weeded check. Of the herbicide treatments evaluated, the highest sugar beet yields were with desmedipham plus phenmedipham plus propaquizafop at 0.46 + 0.46 + 0.1 kg/ha in 2001 and with desmedipham plus phenmedipham plus ethofumesate at 0.23 + 0.23 + 0.23 kg/ha in 2000. Sucrose content and other sugar beet brei characteristics were not affected by the herbicide treatments.


2007 ◽  
Vol 13 (1) ◽  
pp. 121-134 ◽  
Author(s):  
Kei Nakagawa ◽  
Shin-Ichiro Wada ◽  
Kazuro Momii ◽  
Ronny Berndtsson

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