scholarly journals Interference Periods of Weeds Infesting Maize Crop

2018 ◽  
Vol 10 (10) ◽  
pp. 197 ◽  
Author(s):  
Leandro Galon ◽  
Maico André Michelon Bagnara ◽  
Ricardo Luis Gabiatti ◽  
Francisco Wilson Reichert Júnior ◽  
Felipe José Menin Basso ◽  
...  

When competing with crops, weeds interfere with their growth and consequently reduce grain yield. The purpose of this research was to determine the periods of interference; PIP (pre-interference period), TPWC (total period of weed control), and CPWC (critical period of weed control) of the weeds Alexandergrass (Urochloa plantaginea) and southern crabgrass (Digitaria ciliares) in maize. The experiment was conducted in a randomized complete block design with four replications, in a no-tillage system. The treatments consisted in maintaining maize in the presence and absence of Alexandergrass and southern crabgrass for increasing periods of 0, 7, 14, 21, 28, 35 and 42 days after emergence (DAE). Southern crabgrass and Alexandergrass weeds originated from the soil seed bank with an average density of 215 and 87 plants m-2, respectively. At the end of each period, PIP or TPWC, the weed and crop dry biomass was determined. At 42 DAE, the height and stem diameter of maize plants were evaluated. At harvest 10 maize plants per experimental unit were evaluated for length of ears, number of rows per ear, and number of grains per row. Yield was measured by taking three central rows from each experimental unit. The results indicate that the PIP was 17 DAE, the TPWC was 32 DAE, and the CPWC was 17 to 32 DAE.

2018 ◽  
Vol 53 (4) ◽  
pp. 435-442 ◽  
Author(s):  
Cesar Tiago Forte ◽  
Leandro Galon ◽  
Amauri Nelson Beutler ◽  
Felipe José Menin Basso ◽  
Felipe Nonemacher ◽  
...  

Abstract: The objective of this work was to evaluate the density and composition of the soil weed seed bank when bean, corn, and soybean are cultivated in the no-tillage system (NTS) in rotation with winter cover crop species and in the conventional tillage system (CTS). The experiment was installed in a complete randomized block design with three replicates. The evaluation of the seed bank was performed on soil samples (0-10 and 10-20 cm) in four points of each experimental unit, at 15, 30, 60, and 90 days of cultivation. Bean, corn, and soybean crops were sown in the NTS with different soil cover crops in rotation, as well as in the CTS. The NTS provided a more dense and abundant soil seed bank of the species Gnaphalium spicatum and Oxalis corniculata when corn, soybean, and bean were cultivated. The species Lolium multiflorum showed lower density and less seeds in the soil seed bank when the NTS was adopted. The use of the winter cover crops black oat and cow vetch, cultivated individually or in consortium, resulted in a lower density of weed species, especially of L. multiflorum. The NTS provides a lower density of weed species in the soil seed bank than the CTS.


2016 ◽  
Vol 51 (9) ◽  
pp. 1633-1642 ◽  
Author(s):  
Claudio Hideo Martins da Costa ◽  
Carlos Alexandre Costa Crusciol ◽  
Jayme Ferrari Neto ◽  
Gustavo Spadotti Amaral Castro

Abstract The objective of this work was to evaluate the long-term effects of the surface application of lime on soil fertility and on the mineral nutrition and grain yield of soybean, and of black oat and sorghum in crop succession. The experiment was carried out on a clayey Oxisol, in a randomized complete block design, with four replicates. Treatments consisted of lime the rates of 0, 1,000, 2,000, and 4,000 kg ha-1, applied in October 2002 and November 2004. Soil samples were collected at five soil layers, down to 0.60-m depth. Surface liming was effective in reducing soil acidity and increasing Ca2+ and Mg2+ contents in the subsurface. Moreover, it increased available phosphorus contents and soil organic matter in the long term (48 to 60 months after the last lime application). Surface liming improved plant nutrition, mainly for N, Ca, and Mg, and increased dry matter production and grain yield of the crops, even in years with regular distribution of rainfall. The greatest productivities of soybean, black oat, and sorghum were obtained with the respective estimated lime doses of 4,000, 2,333, and 3,281 kg ha-1, for shoot dry matter, and of 2,550, 3,555, and over 4,000 kg ha-1, for grain yield.


Author(s):  
Katherine D Vande Pol ◽  
Austin L Laudwig ◽  
Aaron M Gaines ◽  
Beau A Peterson ◽  
Caleb M Shull ◽  
...  

Abstract Litter sizes in commercial pig production have increased substantially over recent years; however, farrowing pen sizes have generally not changed over the same time period. The objective of this study was to evaluate the effect of farrowing pen size on piglet pre-weaning growth and mortality. Differences in pen size were created by varying the width of pens of the same length, increasing the creep area available to the piglets. The study used a total of 1,786 litters in a randomized complete block design to compare two Farrowing Pen Size treatments (FPS): Standard (pen width 1.52 m) and Increased (pen width 1.68 m). Litter sizes were equalized across treatments (12.9 ± 1.95 piglets) at 24 h after birth using cross-fostering. Litter weights were collected at birth and weaning (21.3 ± 2.08 d); pre-weaning mortality was recorded. The experimental unit was the litter; models included FPS and replicate. Farrowing Pen Size had no effect (P > 0.05) on litter size at birth (12.8 and 13.0 for the Standard and Increased FPS, respectively), after cross-fostering (12.9 for both treatments), or at weaning (11.2 and 11.3, respectively). There was no effect (P > 0.05) of FPS on total litter or average piglet weight at birth, after cross-fostering, and at weaning. These results suggest no benefit in piglet performance from increasing the width of farrowing pens. As litter sizes continue to increase in commercial production, further research is warranted to re-evaluate the impact of farrowing pen size on pre-weaning mortality.


2021 ◽  
Vol 27 (1) ◽  
pp. 51-66
Author(s):  
Haseeb Ahmad

An experiment entitled: Maize yield as affected by methods of tillage and weed control methods was conducted at Agronomy Research Farms, The University of Agriculture Peshawar during summer 2016. The study was conducted in randomized complete block design (RCBD) with split plot arrangement having four replications. Tillage practices 1) Chisel plough + rotavator 2) Mouldboard plough + rotavator 3) Cultivator + rotavator and 4) Rotavator were assigned to main plots. Weed management practices included 1) Control, 2) Hoeing 15 days after sowing 3) Hoeing 15 and 30 days after sowing 4) Hoeing 15, 30 and 45 days after sowing, and 4) Herbicide (nicosulfuron) were kept into the subplots. The results revealed that chisel plough + rotavator has significantly reduced weeds m-2 (122, 101 and 125 weeds m-2), weeds fresh weight (19.73 g m-2, 116.35 g m-2 and 252.56 g m-2) and weeds dry weight (6.83 g m-2, 38.69 g m-2 and 80.61 g m-2) at 30, 45 and 60 days after sowing, respectively. The operation of chisel plough + rotavator has produced tallest plants (221.22 cm) with maximum grain rows ear-1 (16), grain yield (3586 kg ha-1) and shelling percentage (78.14%). Among weed control methods, hoeing 15, 30 and 45 days after sowing revealed maximum plant height (226.41 cm), grain rows ear-1 (16), grain yield (3604 kg ha-1) and shelling percentage (79.11%). All weed control methods have showed significant reduction in weeds m-2, weeds fresh weight and weeds dry weight. Interaction was also found significant for weeds m-2 at 60 DAS and grain yield of maize. Lowest weeds (56 weeds m-2) at 60 DAS and highest grain yield (4569 kg ha-1) was recorded when seedbed was prepared with chisel plough + rotavator with 3 hoeings (hoeing 15, 30 and 45 days after sowing). It is concluded that treatment of chisel plough + rotavator and hoeing 15, 30 and 45 days after sowing has significantly produced maximum grain yield of maize crop.


2019 ◽  
Vol 4 (1) ◽  
pp. 363-375
Author(s):  
Gabriel J Pent ◽  
Scott P Greiner ◽  
John F Munsell ◽  
Benjamin F Tracy ◽  
John H Fike

Abstract Integrating trees into pastures, a practice known as silvopasture, may benefit livestock in the summertime through the provision of shade. The purpose of this project was to compare the behavioral patterns of sheep grazing in silvopastures and open pastures. Black walnut (Juglans nigra L.) and honeylocust (Gleditisia triacanothose L.) based silvopasture systems were compared with open pastures in a randomized complete block design with three blocks over two summers. Behavior measures were recorded within a replicate within a week, and these measures were taken sequentially within three experimental periods. Ewe lambs (n = 3) within each experimental unit were equipped with a wideband audio-recording device to detect prehension events. Time-lapse cameras documented sheep behavior every 60 s. In the silvopastures, the lambs spent over 90% of daylight hours within shade from trees. Lambs in silvopastures spent more time lying down than animals in the open pastures (P ≤ 0.01), while lambs in the open pastures spent more than 2 h longer each day standing (P < 0.0001). Lambs in the black walnut silvopastures spent more time grazing (488 ± 14 min · d−1) than lambs in the honeylocust silvopastures (438 ± 14 min · d−1; P = 0.0493) and lambs in the open pastures (417 ± 14 min · d−1; P = 0.0026). There was no difference in grazing time for lambs in the latter two systems (P = 0.5597). Spectral analysis of the imagery revealed that the lambs in the black walnut silvopastures grazed more frequently than the lambs in the other systems for both years. The acoustic analysis, though limited by recorder durability to 47 complete recordings, revealed no difference in total bites taken per day (P ≥ 0.7222) or in the morning (P ≥ 0.2069), afternoon (P ≥ 0.5816), and evening periods (P ≥ 0.9337). Silvopastures provide an opportunity to improve lamb comfort in the summer.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 188-189
Author(s):  
Michael Coelho ◽  
Peter Ader

Abstract This study examined the effect of 1-monoglycerides and 1,2-diglycerides of butyric-, caproic- and caprylic acid (SILOHealth™ 104L [monoglycerides]) and avilamycin on day 14 and 21 post weaning performance of E. coli (GN-Ent and O157:H7) day 5 challenged piglets fed corn/soy diets that met or exceeded current NRC (2012) recommendations. A total of 96, Choice Genetics CG32, piglets were used in a randomized complete block design with pen as the experimental unit, treatment as the fixed effect, and block as the random effect (4 piglets/pen x 3 treatments x 8 replications). Pigs were blocked by sex and weight and were orally dosed with 5 ml (1x109 CFU/g, strain GN-Ent and O157:H7) E. coli d 5 after weaning (Ec). The treatment were: NC with Ec; T1=NC + 3 kg/MT monoglycerides; T2=NC+ 80 ppm avilamycin. Least significant difference was used to compare means of treatment. Mortalities and pen removals were weighed and recorded. The E. coli infection model was effective in causing E. coli mortality of 25% at d14 post weaning and 33% at d21 post weaning in NC. T1 and T2 reduced mortality versus NC at d14 (25, 3 and 0%, P < 0.05) and d21 (33, 4 and 0%, P < 0.05), increased ADG at d14 (203, 255 and 259 g, P < 0.05) and d21 (456, 511 and 515 g, P < 0.05), decreased FCR at d21 (1.90, 1.85 and 1.83, P < 0.05), and decreased intestinal E. coli, log 10 of CFU/g, versus NC (4.1, 2.2 and 2.1, P < 0.05). Monoglycerides and avilamycin performance, mortality and intestinal E. coli log 10 were not significantly different at P < 0.05. In conclusion, the use of monoglycerides improved ADG, reduced FCR, reduced mortality and reduced intestinal E. coli log 10 at day 14 and 21 post weaning versus NC and monoglycerides were not significant different (P < 0.05) than avilamycin.


2019 ◽  
Vol 20 ◽  
Author(s):  
Angela Maria de Vasconcelos ◽  
Mauricio Cesio Araujo Dutra ◽  
Robson Mateus Freitas Silveira ◽  
Valdson José da Silva ◽  
Luís Alfredo Pinheiro Leal Nunes ◽  
...  

Abstract The objective of this study was to compare and explain the variations in the production and nutritive value of canarana erecta lisa grass (Echinocloa pyramidalis Lam.) at different harvest intervals. The treatments corresponded to the cut intervals of 20, 27, 34, 41, 48, 55, 62, and 69 days. The experimental design was a randomized complete block design with three replications. Each experimental unit had 6m2 (3m ×2m). The variables studied included forage production, canopy height, and nutritive value o harvested forage. Forage production varied from 11517 to 12324 kg ha-1; Plant heights from 48.8 to 234 cm; Neutral detergent fiber (NDF) from 68.8% to 71.13%; Acid detergent fiber (ADF) from 36.20% to 44.15%; Crude protein (CP) from 11.43% to 5.85% and in “in vitro” dry matter digestibility (IVDMD) from 63.30% to 47.42%. These values indicated that the nutritive value of canarana erecta lisa was reduced at longer harvest intervals. It is recommended to harvest the grass at 35 days of regrowth favoring productivity, nutritive value and forage digestibility.


2019 ◽  
Vol 40 (3) ◽  
pp. 1225
Author(s):  
Newton Tavares Escocard de Oliveira ◽  
Paulo Levi de Oliveira Carvalho ◽  
Jansller Luiz Genova ◽  
Eliseu Carlos Cristofori ◽  
Fábio Henrique Rodrigues Silveira ◽  
...  

In this study, we aimed to evaluate the effect of the addition of different probiotics to commercial diets for piglets on diet digestibility, total bacterial count (TBC) of faeces, Clostridium count and growth performance. In the digestibility assay, 24 entire male pigs with an average initial body weight of 18.8 ± 0.87 kg were housed individually in metabolism cages and distributed in a completely randomised experimental design; this consisted of three treatments (probiotic-free commercial feed; commercial feed with the addition of 0.2% probiotic containing a blend of microorganisms; commercial feed with the addition of 0.1% yeast-based probiotic Saccharomyces cerevisiae boulardii) and eight replicates. The digestibility of the feeds was determined. At the end of the experiment, 25 grams of faeces were collected for microbiological analysis. In the subsequent experiment, 150 crossbred piglets (entire males and females), weaned at 21 days of age and having an average initial body weight of 6.81 ± 0.71 kg were distributed in a randomised complete block design, with six treatments repeated twice in the first and thrice in the second block, totaling five replicates and five pigs per experimental unit. The treatments, arranged in a 3 x 2 factorial arrangement, consisted of a combination of the three experimental diets used in the digestibility test and two genders. The growth performance in the nursery was evaluated during the following phases: pre-starter I (21 to 29 days), pre-starter I and II (21 to 40 days) and the total period (21 to 63 days). There was an effect (p < 0.05) of the diets on the digestible protein and the logarithm of the TBC. There was no effect (p > 0.05) of the interaction or the diets on the growth performance of the pigs in any of the phases. Both in the entire experimental period and in the pre-starter I and II phases, male pigs presented better feed conversion (p < 0.05) than females. There was an improvement in the apparent digestibility of the crude protein of the feed when the pigs were fed commercial feed containing probiotics. Pigs fed commercial feed containing probiotics based on yeast Saccharomyces cerevisiae boulardii presented a reduced TBC in their faeces. Commercial feed containing probiotics did not influence the growth performance parameters of nursery phase piglets.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 70-70
Author(s):  
Michael Coelho ◽  
Robert Jones ◽  
Frank Parks

Abstract This study evaluated the metabolizable (ME) release of graded levels of phytase when fed to 35 kg pigs on mash corn/soy diets formulated to meet or exceed current NRC (2012) recommendations. A total of 280 male (PIC 337 x Camborough) pigs were used in a randomized complete block design with pen as the experimental unit, treatment as the fixed effect, and block as the random effect (4 pig/pen x 8 treatments x 10 replications). Pigs were blocked by sex and weight. Treatments groups consisted of PC, NC1=PC- 0.17% Ca, - 0.15% aP, -0.02% Na, -200 kcal/kg, T1=NC +1000 FTU/kg phytase+0.15 g/kg NSPase, T2=NC+1500 FTU/kg phytase+0.15 g/kg NSPase, T3=NC+2000 FTU/kg phytase+0.15 g/kg NSPase, T4=NC+2500 FTU/kg phytase+0.15 g/kg NSPase and T5=NC+3000 FTU/kg phytase +0.15 g/kg NSPase. TiO2 was used as the undigestible marker. Feed, rectum grabbed fecal samples were collected at 35 kg pigs. ME was 3407, 3213, 3301, 3329, 3345, 3354 and 3358 Kcal/kg, P < 0.05, respectively. The NC reduced the ME by 194 Kcal/kg versus the PC. 1000, 1500, 2000, 2500 and 3000 FTU/kg released 87, 116, 132, 141 and 145 Kcal/kg, respectively. Least cost formulation reduced net feed costs by $8.63, $9.22, $11.10, $11.90 and $12.39/ton, respectively. In conclusion, Natuphos E by breaking down phytic acid and Natugrain TS by breaking down NSPs released up to 145 Kcal/kg ME in pigs.


2019 ◽  
Vol 97 (Supplement_2) ◽  
pp. 70-71
Author(s):  
Michael Coelho ◽  
Robert Jones ◽  
Frank Parks

Abstract This study presents a novel find of a Feed NSPase Enzyme, Natugrain TS, reducing finish pig hemorrhagic bowel syndrome (HBS) mortality. A total of 3,750 weaned pigs (28 kg), (PIC 337 x Camborough), were used in a randomized complete block design with pen as the experimental unit, treatment as the fixed effect, and block as the random effect (25 pigs/pen x 5 treatments x 30 replications). Pigs were blocked by sex and weight and were fed mash corn/soy/DDGs diets formulated to meet or exceed current NRC (2012) recommendations. Treatments were T1= 0 g/MT Natugrain TS, T2= 100 g/MT Natugrain TS, T3= 150 g/MT Natugrain TS, T4= 200 g/MT Natugrain TS and T5= 250 g/MT Natugrain TS. At the finishing phase, Natugrain TS significantly decreased intestinal E. coli log 10 (7.12, 4.95, 4.02, 3.21 and 3.25 log 10, P < 0.05, respectively), significantly decreased intestinal lesion score (0–5 score) (4.21, 4.02, 2.98, 2.25 and 2.26, P < 0.05, respectively). Microbiota was analyzed in fresh, manually collected, rectum fecal samples. Microbiota was separated into prevalent in Natugrain TS control (0) and 200 g/ton. In the control treatment, there was a prevalence of Desulfoyibrio, Oscillospira, Campylobacter, Anearoctruncus, Mogibacterium and Brachyspirae, etc., while in the 200 g/ton treatment there was a prevalence of Synergistales, Burkolderiales, Dehabacteriaceae, Bifidobacterium, Roseburia, Lactobacillus and Bacilli, etc. Natugrain TS significantly decreased mortality (4.8, 3.6, 2.7, 1.9 and 2.1 %, P < 0.05, respectively), significantly decreased specifically HBS mortality (3.50, 1.98, 0.68, 0.40 and 0.46%, P < 0.05, respectively). In conclusion, Natugrain TS changed the microbiome by breaking down arabinoxylans, decreasing intestinal E. coli and intestinal lesion score, changing the microbiota to prevalent Bifidobacterium, Roseburia, Lactobacillus and Bacilli, and Natugrain TS up to 200 g/ton specifically decreasing hemorrhagic bowel syndrome mortality from 3.5% to 0.5%.


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