scholarly journals The critical period of weed interference in upland rice in northern Guinea savanna: Field measurement and model prediction

2013 ◽  
Vol 8 (17) ◽  
pp. 1748-1759 ◽  
Author(s):  
Toureacute Amadou ◽  
Mianikpo Sogbedji Jean ◽  
Mawuena Dieudonneacute Yawovi
Keyword(s):  
Model Prediction ◽  
Field Measurement ◽  
Critical Period ◽  
Upland Rice ◽  
Weed Interference ◽  
Northern Guinea Savanna ◽  
Guinea Savanna

Variation of soil properties under different landscape positions and land use in Hunkuyi, Northern Guinea savanna of Nigeria

2021 ◽  
Vol 193 (4) ◽  
Author(s):  
Fatihu Kabir Sadiq ◽  
Lemuel Musa Maniyunda ◽  
Abdulraheem Okehi Anumah ◽  
Kayode Adesina Adegoke
Keyword(s):  
Land Use ◽  
Soil Properties ◽  
Northern Guinea Savanna ◽  
Guinea Savanna

scholarly journals Integrating Economics in the Critical Period for Weed Control Concept in Corn

Weed Science ◽  
2014 ◽  
Vol 62 (4) ◽  
pp. 608-618 ◽  
Author(s):  
Martina Keller ◽  
Geoffroy Gantoli ◽  
Jens Möhring ◽  
Christoph Gutjahr ◽  
Roland Gerhards ◽  
...  
Keyword(s):  
Weed Control ◽  
Critical Period ◽  
Logistic Models ◽  
Crop Growth ◽  
Growth Stages ◽  
Corn Yield ◽  
Leaf Stage ◽  
Weed Interference ◽  
Free Interval ◽  
Crop Growth Stages

The effect of weed interference on corn yield and the critical period for weed control (CPWC) were determined in Germany and Benin. Treatments with weed control starting at different crop growth stages and continuously kept weed-free until harvest represented the “weed-infested interval.” Treatments that were kept weed-free from sowing until different crop growth stages represented the “weed-free interval.” Michaelis–Menten, Gompertz, logistic and log–logistic models were employed to model the weed interference on yield. Cross-validation revealed that the log–logistic model fitted the weed-infested interval data equally well as the logistic and slightly better than the Gompertz model fitted the weed-free interval. For Benin, economic calculations considered yield revenue and cost increase due to mechanical weeding operations. Weeding once at the ten-leaf stage of corn resulted already profitable in three out of four cases. One additional weeding operation may optimize and assure profit. Economic calculations for Germany determined a CPWC starting earlier than the four-leaf stage, challenging the decade-long propagated CPWC for corn. Differences between Germany and Benin are probably due to the higher yields and high costs in Germany. This study provides a straightforward method to implement economic data in the determination of the CPWC for chemical and nonchemical weed control strategies.

Critical Period of Weed Interference in Transplanted Tomatoes (Lycopersicon esculentum): Growth Analysis

Weed Science ◽  
1983 ◽  
Vol 31 (4) ◽  
pp. 476-481 ◽  
Author(s):  
Susan E. Weaver ◽  
Chin S. Tan
Keyword(s):  
Lycopersicon Esculentum ◽  
Critical Period ◽  
Growth Analysis ◽  
Canopy Temperature ◽  
Dry Weight ◽  
Pressure Potential ◽  
Xylem Pressure ◽  
Fruit Number ◽  
Weed Interference ◽  
Xylem Pressure Potential

The critical period of weed interference in transplanted tomatoes (Lycopersicon esculentumMill. 'Springset’) was from 28 to 35 days after transplanting. A single weeding during this period was sufficient to prevent yield reductions. A growth analysis revealed that significant differences in plant dry weight and fruit number between tomatoes from weed-free and weed-infested plots were not apparent until 56 to 70 days after transplanting. The shorter the initial weed-free period, or the longer weeds were allowed to remain in the plots before removal, the earlier reductions in tomato dry weight and fruit number appeared. Weed interference was due primarily to shading rather than water stress. Tomatoes from weed-infested plots had significantly lower stomatal conductances than those from weed-free plots, but did not differ in xylem-pressure potential or in canopy temperature. If tomatoes were kept weed-free for more than 28 days, or when weeds were present for less than 28 days after transplanting, stomatal conductances were not significantly reduced.

scholarly journals Weed interference capacity on soybean yield

2021 ◽  
Vol 74 (2) ◽  
Author(s):  
Eduardo Carlos Rüdell ◽  
Iuri Dalla Santa Petrolli ◽  
Fernando Machado dos Santos ◽  
Dieferson Frandaloso ◽  
Diécson Ruy Orsolin da Silva
Keyword(s):  
Critical Period ◽  
Chemical Method ◽  
Crop Yields ◽  
Production Costs ◽  
Limiting Factor ◽  
Biological Factors ◽  
Mechanical Method ◽  
Total Period ◽  
Weed Interference ◽  
Mechanical Methods

Among biological factors, weeds are the most important limiting factor for crop yields, as well as increasing production costs. The aim was to determine the influence of control and coexistence of weed community on soybean crop yield and to define the period before interference, the critical period of interference prevention and the total period of interference prevention, with the comparative use of chemical and mechanical methods for weed eradication. The study was conducted in an experimental field in the 2018/2019 harvest. A randomized block with four replications was implemented as experimental design, using two methods for control. The evaluated periods were 0-10, 0-20, 0-30, 0-40, 0-50, 0-60 and 130 days after crop emergence. It was possible to observe that the use of the chemical method generated a higher yield compared to mechanical method. The period before the interference in both chemical and mechanical management was similar, approaching 20 days after crop emergence. The critical period of interference prevention was between 20-50 and 40.5 days after crop emergence in chemical and mechanical methods, respectively. The total period of interference prevention was extended to 50 and 40.5 days after crop emergence in chemical and mechanical methods, respectively. The reduction in productivity due to weed interference was 1639 kg ha-1 (55%)and 947 kg ha-1 (34.6%) in chemical and mechanical methods, respectively.

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