scholarly journals Effects of various nitrogen regimes on the ability of rapeseed (Brassica napus L.) to suppress littleseed canarygrass (Phalaris minor Retz.)

2021 ◽  
Author(s):  
Gaofeng Xu ◽  
Shicai Shen ◽  
Yun Zhang ◽  
David Roy Clements ◽  
Shaosong Yang ◽  
...  
Keyword(s):  
Weed Control ◽  
Competitive Ability ◽  
Photosynthetic Characteristics ◽  
Growth Stages ◽  
Invasive Weeds ◽  
Control Efficacy ◽  
N Application ◽  
Phalaris Minor ◽  
N Rates ◽  
Nitrogen Rates

Abstract Background: Littleseed canarygrass (Phalaris minor Retz.) is one of the most troublesome invasive weeds infesting winter crops in Yunnan Province, China. Our previous study found that rapeseed (Bassica napus L.) was a logical candidate crop to control littleseed canarygrass in agroecosystems. Nitrogen (N) could impact plant community composition by altering competitive interactions, however, the effects of different N regimes on weed control efficacy of rapeseed were unknown. Here, we report the effects of different N regimes on the competitiveness of rapeseed with littleseed canarygrass and accompanying differences in photosynthetic characteristics. Results: The results showed that the rapeseed yield and its control efficacy on littleseed canarygrass were significantly affected (P<0.05) under different N regimes, and the control efficacy of littleseed canarygrass by rapeseed increased first and then decreased with the increase of basal nitrogen rates, while increasing topdressing N rates increased control efficacy of littleseed canarygrass by rapeseed. In fact, yield and weed control efficacy of rapeseed was most ideal when both basal and top-dressing N was 90 kg·ha-1. We also found that N significantly impacted the competitive ability of rapeseed to littleseed canarygrass and rapeseed had the highest competitive ability when both basal and top-dressing N was 90 kg·ha-1. With the increase of basal nitrogen rates, competitive balance index (CB) of rapeseed increased initially but decreased beyond an optimal level. CB continually increased with increasing of topdressing N rates. Our research also showed level and period of N application had a significant effect (P<0.01) on the photosynthetic rate (Pn) and chlorophyll content (Chl) of both rapeseed and littleseed canarygrass. Under the same N application regime, the Pn and Chl of littleseed canarygrass were higher than that of rapeseed in December, while the Pn and Chl of rapeseed was higher than that of littleseed canarygrass in February. Our study indicated that photosynthetic characteristics of rapeseed and littleseed canarygrass in different growth stages differ in their sensitivity to N regimes, creating a dynamic competitive relationship. Conclusions: Together, our results demonstrated that optimal application of fertilizer N could help rapeseed produce higher yields and greater weed control efficacy, suggesting that future modeling or experimental studies on utilizing crops to control invasive weeds should carefully consider both timing and placement of N.

scholarly journals Effects of various nitrogen regimes on the ability of rapeseed (Brassica napus L.) to suppress littleseed canarygrass (Phalaris minor Retz.)

2020 ◽  
Author(s):  
Gaofeng Xu ◽  
Shicai Shen ◽  
Yun Zhang ◽  
David Roy Clements ◽  
Shaosong Yang ◽  
...  
Keyword(s):  
Weed Control ◽  
Competitive Ability ◽  
Photosynthetic Characteristics ◽  
Growth Stages ◽  
Invasive Weeds ◽  
Control Efficacy ◽  
N Application ◽  
Phalaris Minor ◽  
N Rates ◽  
Nitrogen Rates

Abstract Background: Littleseed canarygrass (Phalaris minor Retz.) is one of the most troublesome invasive weeds infesting winter crops in Yunnan Province, China. Our previous study found that rapeseed (Bassica napus L.) was a logical candidate crop to control littleseed canarygrass in agroecosystems. Nitrogen (N) could impact plant community composition by altering competitive interactions, however, the effects of different N regimes on weed control efficacy of rapeseed were unknown. Here, we report the effects of different N regimes on the control efficacy of littleseed canarygrass by rapeseed and their competitive effects and photosynthetic characteristics. Results: The results showed that the rapeseed yield and its control efficacy on littleseed canarygrass were significantly affected (P<0.05) under different N regimes, and the control efficacy of littleseed canarygrass by rapeseed increased first and then decreased with the increase of basal nitrogen rates, while increasing topdressing N rates increased control efficacy of littleseed canarygrass by rapeseed only. In fact, yield and weed control efficacy of rapeseed was most ideal when both basal and top-dressing N was 90 kg·ha-1. We also found that N significantly impacted the competitive ability of rapeseed to littleseed canarygrass and rapeseed had a highest competitive ability when both basal and top-dressing N was 90 kg·ha-1. With the increase of basal nitrogen rates, competitive balance index (CB) of rapeseed increased first and then decreased, but which gradually increased with increasing of topdressing N rates. Our research also showed level and period of N application had a significant effect (P<0.01) on the photosynthetic rate (Pn) and chlorophyll content (Chl) of both rapeseed and littleseed canarygrass. Under the same N application regime, the Pn and Chl of littleseed canarygrass were higher than that of rapeseed in December, while the Pn and Chl of rapeseed was higher than that of littleseed canarygrass in February. Our study indicated that photosynthetic characteristics of rapeseed and littleseed canarygrass in different growth stages differ in their sensitivity to N regimes, creating a dynamic competitive relationship. Conclusions: Together, our results demonstrated that rational application of fertilizer N could help rapeseed produce higher yields and greater weed control efficacy, suggesting that future modeling or experimental studies on utilizing crops to control invasive weeds should carefully consider both timing and placement of N.

Influence of Nitrogen Rates and Wheat (Triticum aestivum) Cultivars on Weed Control

Weed Science ◽  
1992 ◽  
Vol 40 (1) ◽  
pp. 115-121 ◽  
Author(s):  
Stephen A. Valenti ◽  
Gail A. Wicks
Keyword(s):  
Winter Wheat ◽  
Weed Control ◽  
Grain Sorghum ◽  
Wheat Crop ◽  
Green Foxtail ◽  
Before And After ◽  
Winter Wheat Cultivars ◽  
N Fertility ◽  
N Rates ◽  
Nitrogen Rates

Experiments were conducted to determine the influence of nitrogen (N) fertility and winter wheat cultivars on weed infestations in a winter wheat-ecofallow sorghum-fallow rotation near North Platte, NE. Centurk 78 and Lancota winter wheat suppressed density and growth of barnyardgrass and green foxtail significantly more than Eagle winter wheat before and after wheat harvest. Increasing N rates applied to winter wheat decreased annual grass weed population and weed yields. However, 67 and 101 kg N ha−1reduced winter wheat grain yields compared to 34 kg N ha−1. Plots treated at 2.8 plus 0.3 kg ai ha−1of atrazine plus paraquat 31 d after wheat harvest had more barnyardgrass before grain sorghum planting in 1983 than plots treated 17 d after wheat harvest but the reverse was true for green foxtail after grain sorghum emergence in 1984. Increasing N rates from 34 kg ha−1to 67 and 101 kg ha−1in the previous wheat crop decreased weed density before and after grain sorghum planting. There was no advantage in weed control in the grain sorghum from applying N to winter wheat in the fall vs. spring.

Weed Control Efficacy and Pinto Bean (Phaseolus vulgaris) Tolerance to Early Season Mechanical Weeding

1995 ◽  
Vol 9 (3) ◽  
pp. 531-534 ◽  
Author(s):  
Mark J. Vangessel ◽  
Lori J. Wiles ◽  
Edward E. Schweizer ◽  
Phil Westra
Keyword(s):  
Phaseolus Vulgaris ◽  
Weed Control ◽  
Weed Management ◽  
Seed Weight ◽  
Growth Stage ◽  
Integrated Approach ◽  
Growth Stages ◽  
Weed Species ◽  
Control Efficacy ◽  
Pinto Bean

An integrated approach to weed management in pinto bean is needed since available herbicides seldom adequately control all weed species present in a field. A two-year study was conducted to assess weed control efficacy and pinto bean tolerance to mechanical weeding from a rotary hoe or flex-tine harrow at crook, unifoliolate, and trifoliolate stages of bean development. Weed control was similar for both implements and all timings in 1993. In 1994, mechanical weeding at trifoliolate and both crook and trifoliolate stages controlled more weeds than at other growth stages, regardless of type of implement. Using the flex-tine harrow reduced pinto bean stand, but results based on growth stage were not consistent each year. Damage to pinto bean hypocotyls and stems was observed with the flex-tine harrow used at both crook and trifoliolate stages in 1994. Rotary hoeing did not reduce pinto bean stand or cause injury. Yield and seed weight did not differ among treatments in either year.

scholarly journals YIELD OF POTATO CULTIVARS AS A FUNCTION OF NITROGEN RATES

2020 ◽  
Vol 33 (4) ◽  
pp. 954-963
Author(s):  
ROBERTA CAMARGOS OLIVEIRA ◽  
JOSÉ MAGNO QUEIROZ LUZ ◽  
REGINA MARIA QUINTÃO LANA ◽  
JOÃO RICARDO RODRIGUES DA SILVA ◽  
RENATA CASTOLDI
Keyword(s):  
Crop Yields ◽  
Growth Cycle ◽  
Exchange Capacity ◽  
Potato Cultivars ◽  
N Application ◽  
Climate Conditions ◽  
Random Block ◽  
Cationic Exchange ◽  
N Rates ◽  
Nitrogen Rates

ABSTRACT The use of fertilizers at appropriate doses positively impacts the production and the environment. Therefore, we aimed to evaluate the influence of nitrogen (N) rates on the crop yields of the potato cultivars, Ágata and Atlantic in Unaí, Minas Gerais (MG), and Ágata in Mucugê, Bahia (BA), Brazil. The cultivation of Ágata and Atlantic was conducted in MG from May to August and June to September 2014, respectively. In BA, Ágata was cultivated between September and December 2014. A random block experimental design was used with treatment rates of 0, 30, 70, 120, and 280 kg ha-1 of N. The macro and micronutrient concentrations in potato leaves were evaluated. At the end of the growth cycle, the production of tubers was also evaluated. In the absence of N application, it was observed that P, K, S, and B were below the adequate levels in Atlantic-MG, the S and Zn levels were lower than the adequate levels in Ágata -MG, and the N, K, Mg, and S levels were less than the adequate levels in Ágata-BA. The other nutrients met the needs of the potato, with the N increase being favorable to the levels of most nutrients in all experiments. The maximum rates of N varied between 138 and 194 kg ha-1 in the high and low cationic exchange capacity (CEC) regions, respectively. The knowledge of the interaction among soil attributes, climate conditions and crop specificities allows for the improved prediction of the dosage of N and a reduction in the optimum amount without affecting yields.

scholarly journals Modified split application of nitrogen with biochar improved grain yield and nitrogen use efficiency in rainfed maize grown in Vertisols of India

2020 ◽  
Author(s):  
Bharat Prakash Meena ◽  
Pramod Jha ◽  
K. Ramesh ◽  
A.K. Biswas ◽  
R. Elanchezhian ◽  
...  
Keyword(s):  
Grain Yield ◽  
N Uptake ◽  
Growth Stages ◽  
N Losses ◽  
N Application ◽  
Soil P ◽  
Agronomic Management ◽  
Use Efficiency ◽  
Maize Grain ◽  
N Rates

AbstractConventionally, non-judicious and blanket fertilizer nitrogen (N) used in rainfed maize lead to higher N losses, low N use efficiency (NUEs) and poor yields due to substandard agronomic management practices. To avoid such N losses, fertilizer additions are synchronized with plant uptake requirements. In this context, agronomic based management focused on optimizing N rates and biochar application is essential for improved NUEs and crop productivity. Keeping this in view, a field experiment was conducted during 2014, 2015 and 2016 in rainfed maize (Zea mays L.) grown in Vertisols of India. In this study, twelve treatments that comprised of N omission plot (N0), skipping of basal rate, multi-split topdressing at varying time as broadcast and band placement, soil test crop response (STCR) based NPK with target yield 6.0 t ha-1 in maize and biochar application (10 t ha−1) were investigated. The experiment was conducted following a Randomized Complete Block Design (RCBD) set up with three replications. Pooled analysis of three years data revealed that the application of N rates (120 kg Nha−1) in 2 equal splits (60 kg Nha−1) at knee high (V8) and tasseling (VT) stages with skipped basal N rate, achieved higher maize grain yield (5.29 t ha−1) ascribed to the greater growth parameters, yield components and N uptake compared to the recommended practices. Biochar application (10 t ha−1) as soil amendments along with multi top dressed N (120 kg N ha−1) into 3 splits also increased the grain yield. Delayed N application at V8 and VT growth stages, resulted in higher N uptake, agronomy efficiency (AE), partial factor productivity (PFP), physiology efficiency (PE) and recovery efficiency (RE). Biochar along with N fertilizer also improved the soil organic carbon (5.47g kg−1), ammonium-N (2.40 mg kg−1) and nitrate-N (0.52 mg kg−1) concentration in soil (P<0.05) as compared to non-biochar treatments. Application of biochar along with chemical fertilizer (120 kg Nha−1) significantly increased the concentration of ammonium (2.40 mg kg−1) and nitrate (0.52 mg kg−1) in soil (P<0.05) as compared to non-biochar treatments. The perfect positive linear relationship illustrated that the grain yield of rainfed maize was highly dependent (R2=0.99 at p<0.0001) on N availability, as indicated by the fitted regression line of maize grain yield on N uptake. On the other hand, factor analysis revealed, the one to one positive function relationship of biomass with N uptake at V8 and VT growth stages. Principal Component Regression (PCR) analysis showed that PC1 acted as a major predictor variable for total dry matter yield (TDMY) and dominated by LAI and N uptake. Consequently, these results expressed that the agronomic management based multi-top dressed N application and biochar application to achieve higher yield and greater NUEs in rainfed maize is strongly linked with N application into splits.

Plant Pathogens at Work: Progress and Possibilities for Weed Biocontrol Classical versus Bioherbicidal Approach

2007 ◽  
Vol 8 (1) ◽  
pp. 32 ◽  
Author(s):  
C. B. Yandoc-Ables ◽  
E. N. Rosskopf ◽  
R. Charudattan
Keyword(s):  
Biological Control ◽  
Weed Control ◽  
Plant Pathogens ◽  
Classical Biological Control ◽  
Invasive Weeds ◽  
Biological Control Agents ◽  
Weed Biological Control ◽  
Application Technology ◽  
Control Efficacy ◽  
Weed Biocontrol

Weed biological control using plant pathogens has been successfully implemented for a number of important invasive weeds. Both the classical and bioherbicide approaches have shown promise depending on the characteristics of the target weed. Bioherbicidal activity can be improved with research on formulation and application technology. Other approaches that have improved weed control efficacy for both classical biological control agents and bioherbicides include using a combination of pathogens and insects. Accepted for publication 9 April 2007. Published 22 August 2007.

scholarly journals Nitrogen doses and weed control via intercropping with gliricidia for corn production

2010 ◽  
Vol 28 (3) ◽  
pp. 531-539 ◽  
Author(s):  
P.S.L. Silva ◽  
J.D. Braga ◽  
M.S.S. Ribeiro ◽  
O.F. Oliveira ◽  
T.S. Santos
Keyword(s):  
Grain Yield ◽  
Weed Control ◽  
Competitive Ability ◽  
Control Strategies ◽  
Agricultural Practices ◽  
Gliricidia Sepium ◽  
Corn Production ◽  
Yield Values ◽  
Nitrogen Rates ◽  
Weight Number

Many studies have demonstrated the beneficial influence of nitrogen doses on corn dry grain yield and green ear yield. Due to a growing concern with environmental degradation, many agricultural practices, adopted in the past, are being reexamined. With regard to weed control, strategies that employ mechanical control, including intercrops, are being the object of renewed interest. The purpose of this study was to evaluate the effects of the application of nitrogen doses (0, 40, 80, and 120 kg N ha-1; as ammonium sulfate) and weed control on the growth, green ear yield, and grain yield of the AG 1051 corn cultivar. A randomized block experimental design with split-plots and nine replications was adopted. In addition to nitrogen rates, the AG 1051 cultivar was submitted to the following treatments, applied to subplots: no weeding, two hoeings (at 20 and 40 days after sowing), and intercropping with gliricídia (Gliricidia sepium). Gliricidia was sowed at corn planting, between the corn rows, using two seedlings per pit, in pits spaced 0.30 m apart. Gliricidia did not provide weed control, and gave plant growth, green ear yield and grain yield values similar to the no weeding treatment. However, regarding the number of mature ears got, intercropping with gliricidia did not differ from the two-hoeing treatment. Weed control did not have an effect on plant height and number of marketable, husked green ears, with the application of 120 kg N ha-1; indicating that nitrogen improved the corn's competitive ability. The two-hoeing treatment provided the best means for total green ears weight, number of marketable husked ears, both unhusked and husked marketable ear weight, grain yield and its components than the other treatments. Nitrogen application increased corn growth, green ear yield, and grain yield, as well as weed green biomass, but reduced the stand and growth of gliricidia.

Responses of Rice (Oryza sativa L.) Nitrogen Status Indicators to Nitrogen Rates during the Different Rice Growth Stages

2013 ◽  
Vol 726-731 ◽  
pp. 4411-4417 ◽  
Author(s):  
Qing Wen Zhang ◽  
Zheng Li Yang ◽  
Ai Ping Zhang ◽  
Ming Wang
Keyword(s):  
N Uptake ◽  
Nutrition Status ◽  
Growth Stages ◽  
N Availability ◽  
Regression Equations ◽  
N Application ◽  
N Nutrition ◽  
Application Rates ◽  
Significant Regression ◽  
Nitrogen Rates

The SPAD was shown as a diagnostic tool to assess the nitrogen (N) nutrition status. The objective of this study is to evaluate the performance of SPAD as N nutrition status for rice. We conducted two years field experiment in the Ningxia irrigation area. Five N application rates were applied to rice to obtain contrasting conditions of N availability. The leaves N concentrations, SPAD and N uptake by rice were assessed. The results showed that response of SPAD to N uptake rate depends on the developmental stage of the rice. The peak periods for N uptake by rice were the jointing-booting stage to the flowering stage. Significant regression equations were established between SPAD and N uptake. The SPAD meter was demonstrated to be a useful nondestructive system to aid in the evaluation of N nutrition status in rice. However, consistency in sample seasonal timing may necessitate to correlate SPAD values.

INFLUENCE OF HARVEST SYSTEMS AND NITROGEN RATES ON YIELDS, QUALITY AND PERSISTENCE OF CHAMP TIMOTHY IN THE SEEDING AND POSTSEEDING YEARS

1976 ◽  
Vol 56 (3) ◽  
pp. 715-723 ◽  
Author(s):  
H. T. KUNELIUS ◽  
M. SUZUKI ◽  
K. A. WINTER
Keyword(s):  
Full Range ◽  
Phleum Pratense ◽  
In Vitro Digestibility ◽  
N Application ◽  
System A ◽  
Yield Quality ◽  
N Rates ◽  
Nitrogen Rates ◽  
Phleum Pratense L

The interaction effects of harvest systems and rates of N on yield, quality and persistence of Champ timothy (Phleum pratense L.) were studied in a 4-yr field experiment. In the seeding year, total dry matter (DM) yields were highest (4.41 tons/ha) for the harvest taken 12 wk after seeding. Total DM yields increased with increasing N application up to 148 kg N/ha/yr. During the 3 postseeding yr, timothy was harvested four (system A), three (B) or two (C) times per season. Nitrogen was applied at five rates from 33 to 165 kg/ha; three times for systems A and B and twice per season for system C. Total DM yields showed increases for the full range of N application for systems A and B, but up to 132 kg/ha/application for system C. The tissue N concentrations were increased by increasing rates of fertilizer N while the in vitro digestibility of DM (IVDDM) was not generally changed. Forage with high IVDDM of 68.0 to 72.0% was produced under systems A and B whereas under C, IVDDM ranged from 55.9 to 65.1% during the season. The NO3-N concentrations of tissue frequently exceeded 0.15% levels at N rates above 132 kg/ha/application. High rates of N tended to thin the stand, but weeds were most prevalent where the lowest N rate was used.

scholarly journals Propane Flaming as a New Approach to Control Mediterranean Invasive Weeds

Agronomy ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 187 ◽  
Author(s):  
Alon Horesh ◽  
Yaakov Goldwasser ◽  
Karam Igbariya ◽  
Zvi Peleg ◽  
Ran Nisim Lati
Keyword(s):  
Climate Changes ◽  
Cyperus Rotundus ◽  
Sorghum Halepense ◽  
Effective Control ◽  
Anthropogenic Activity ◽  
Response Analysis ◽  
Growth Stages ◽  
Invasive Weeds ◽  
Control Efficacy ◽  
Invasive Weed

In recent decades, anthropogenic activity and climate changes have reshaped global weed dispersal and establishment in new territories. This study aimed to evaluate the effectiveness of propane flaming approach in the control of perennial invasive and native Mediterranean broadleaf and grass weeds. The invasive weeds, Cyperus rotundus, Sorghum halepense, and Ecballium elaterium, were treated multiple times with a single propane dose (2.5 kg propane km−1), using the broadcast technique. The local annual weeds, Sinapis arvensis, Lavatera trimestris, and Avena sativa, were treated once at five propane doses (0–2.5 kg propane km−1), using the cross-row technique. Dose-response analysis was performed. Three applications provided effective control (up to >90%) for all tested perennials, and affected seed and flower production in Sorghum halepense and Ecballium elaterium, respectively. However, the timing of the sequential application had a significant impact on the degree of control, in terms of dry weight reduction and seed production. Weed density had an impact on control efficacy but was only a significant determinant for Ecballium elaterium. Cross-row application was effective during early growth stages of broadleaf weeds (ED50 < 1.2 kg propane km−1), but was less effective during later growth stages (ED50 > 2.6 kg propane km−1). For grass weeds, both early and late application were ineffective (ED50 > 4.1 kg propane km−1). More research is needed to optimize this weed control tactic for various cropping systems and weed species. Implementation of this novel approach into integrated weed management programs will increase the control efficacy of invasive weed under the projected climate changes and reduce the evolution of herbicide-resistant weeds.

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