Author: A. A. L. Amerasinghe
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 310
Book Description
Purple nutsedge [Cyperus rotundas L.) has been recognized as one of the most troublesome perennial weeds of agricultural lands in tropical and some temperate regions. This research sought to determine the effects of timing of herbicides, shading, and soil moisture on plant population growth and tuber production of purple nutsedge through field and greenhouse experiments. The results of these experiments were used to validate a purple nutsedge population matrix model constructed with observed and reported data. Purple nutsedge control options were evaluated with model simulations. Glyphosate reduced shoot number, tuber number, and tuber viability of purple nutsedge, and the herbicide efficacy was higher when applied from 2 to 4 weeks after shoot emergence as compared to the first 2-week growth period. The more effective period for the herbicide coincided with the tuber initiation phase of purple nutsedge growth. Metolachlor caused only temporary suppression of purple nutsedsge. Sunlight intensity by 30%, 47%, 63%, and 90% caused in successively greater reductions in shoot number, tuber number, leaf area, and total dry weight of purple nutsedge. Shading decreased partitioning of plant biomass into tubers and increased partitioning into leaves. These responses remained essentially the same irrespective of timing of shading from early emergence through the first 4 weeks of plant growth. Depletion of available soil moisture from 25% to 75% also reduced the number and dry weights of shoots and tubers produced. However, proportional biomass allocation to shoots, leaves, and tubers and relative growth and net assimilation rates remained unaltered with soil moisture depletion, suggesting that purple nutsedge is fairly well adapted to low soil moisture levels. The importance of intraspecific competition on population regulation of purple nutsedge was evident from model simulations. Model predictions of maximum population size closely agreed with reported plant and tuber densities of purple nutsedge. Model simulations of proportional changes in population size of purple nutsedge, as influenced by soil moisture depletion or shading, also closely followed the field results. Model simulations indicated that seasonal application of herbicides resulting in 90% shoot kill will provide a successful level of control and that herbicide efficiency will be higher when shoots are killed during the second to fourth week of the growing period than from earlier applications. However, model simulations showed that a better strategy than using a highly effective, short duration herbicide is to provide a moderate level of purple nutsedge control extending through the growing season.
Modeling Purple Nutsedge (Cyperus Rotundus L.) Growth
Author: A. A. L. Amerasinghe
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 310
Book Description
Purple nutsedge [Cyperus rotundas L.) has been recognized as one of the most troublesome perennial weeds of agricultural lands in tropical and some temperate regions. This research sought to determine the effects of timing of herbicides, shading, and soil moisture on plant population growth and tuber production of purple nutsedge through field and greenhouse experiments. The results of these experiments were used to validate a purple nutsedge population matrix model constructed with observed and reported data. Purple nutsedge control options were evaluated with model simulations. Glyphosate reduced shoot number, tuber number, and tuber viability of purple nutsedge, and the herbicide efficacy was higher when applied from 2 to 4 weeks after shoot emergence as compared to the first 2-week growth period. The more effective period for the herbicide coincided with the tuber initiation phase of purple nutsedge growth. Metolachlor caused only temporary suppression of purple nutsedsge. Sunlight intensity by 30%, 47%, 63%, and 90% caused in successively greater reductions in shoot number, tuber number, leaf area, and total dry weight of purple nutsedge. Shading decreased partitioning of plant biomass into tubers and increased partitioning into leaves. These responses remained essentially the same irrespective of timing of shading from early emergence through the first 4 weeks of plant growth. Depletion of available soil moisture from 25% to 75% also reduced the number and dry weights of shoots and tubers produced. However, proportional biomass allocation to shoots, leaves, and tubers and relative growth and net assimilation rates remained unaltered with soil moisture depletion, suggesting that purple nutsedge is fairly well adapted to low soil moisture levels. The importance of intraspecific competition on population regulation of purple nutsedge was evident from model simulations. Model predictions of maximum population size closely agreed with reported plant and tuber densities of purple nutsedge. Model simulations of proportional changes in population size of purple nutsedge, as influenced by soil moisture depletion or shading, also closely followed the field results. Model simulations indicated that seasonal application of herbicides resulting in 90% shoot kill will provide a successful level of control and that herbicide efficiency will be higher when shoots are killed during the second to fourth week of the growing period than from earlier applications. However, model simulations showed that a better strategy than using a highly effective, short duration herbicide is to provide a moderate level of purple nutsedge control extending through the growing season.
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 310
Book Description
Purple nutsedge [Cyperus rotundas L.) has been recognized as one of the most troublesome perennial weeds of agricultural lands in tropical and some temperate regions. This research sought to determine the effects of timing of herbicides, shading, and soil moisture on plant population growth and tuber production of purple nutsedge through field and greenhouse experiments. The results of these experiments were used to validate a purple nutsedge population matrix model constructed with observed and reported data. Purple nutsedge control options were evaluated with model simulations. Glyphosate reduced shoot number, tuber number, and tuber viability of purple nutsedge, and the herbicide efficacy was higher when applied from 2 to 4 weeks after shoot emergence as compared to the first 2-week growth period. The more effective period for the herbicide coincided with the tuber initiation phase of purple nutsedge growth. Metolachlor caused only temporary suppression of purple nutsedsge. Sunlight intensity by 30%, 47%, 63%, and 90% caused in successively greater reductions in shoot number, tuber number, leaf area, and total dry weight of purple nutsedge. Shading decreased partitioning of plant biomass into tubers and increased partitioning into leaves. These responses remained essentially the same irrespective of timing of shading from early emergence through the first 4 weeks of plant growth. Depletion of available soil moisture from 25% to 75% also reduced the number and dry weights of shoots and tubers produced. However, proportional biomass allocation to shoots, leaves, and tubers and relative growth and net assimilation rates remained unaltered with soil moisture depletion, suggesting that purple nutsedge is fairly well adapted to low soil moisture levels. The importance of intraspecific competition on population regulation of purple nutsedge was evident from model simulations. Model predictions of maximum population size closely agreed with reported plant and tuber densities of purple nutsedge. Model simulations of proportional changes in population size of purple nutsedge, as influenced by soil moisture depletion or shading, also closely followed the field results. Model simulations indicated that seasonal application of herbicides resulting in 90% shoot kill will provide a successful level of control and that herbicide efficiency will be higher when shoots are killed during the second to fourth week of the growing period than from earlier applications. However, model simulations showed that a better strategy than using a highly effective, short duration herbicide is to provide a moderate level of purple nutsedge control extending through the growing season.
Studies on the Growth and Development of Purple Nutsedge (Cyperus Rotundus).
Author: Mohamed Elhassan Fadl Alla Mohamed
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Studies on the Control of Purple Nutsedge (Cyperus Rotundus L.) with Organic Arsenicals
Author: James L. Faubion
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 112
Book Description
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 112
Book Description
Purple Nutsedge (Cyperus Rotundus L.) and Yellow Nutsedge (Cyperus Esculentus L.) Management with Tillage and the Herbicides Imazapic and Imazethapyr
Author: Derek Duane Horrall
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Alternating tillage operations with glyphosate applications resulted in the greatest reduction in tuber number, weight, and viability at mid- and late-season sampling dates. In an herbicide screening study conducted for both purple and yellow nutsedge in the field, imazapic applied at the rate of 71g ha-1 early postemergence (EPOST) resulted in the greatest reduction of tuber numbers and tuber dry weights by July and September. Greenhouse studies indicated that EPOST applications of imazapic and imazethapyr 2 weeks after emergence (WAE) were more effective than those applied to purple and yellow nutsedge 4 and 6 WAE. Foliar-only treatments of purple and yellow nutsedge 2, 4, and 6 WAE provided better shoot control than soil-applied treatments. The greatest control of nutsedge, however, regardless of plant age, was obtained by treating both the foliage and soil. It was determined at the conclusion of a year-long greenhouse study that soil-applied imazapic provided better residual control of purple nutsedge than imazethapyr.
Publisher:
ISBN:
Category :
Languages : en
Pages :
Book Description
Alternating tillage operations with glyphosate applications resulted in the greatest reduction in tuber number, weight, and viability at mid- and late-season sampling dates. In an herbicide screening study conducted for both purple and yellow nutsedge in the field, imazapic applied at the rate of 71g ha-1 early postemergence (EPOST) resulted in the greatest reduction of tuber numbers and tuber dry weights by July and September. Greenhouse studies indicated that EPOST applications of imazapic and imazethapyr 2 weeks after emergence (WAE) were more effective than those applied to purple and yellow nutsedge 4 and 6 WAE. Foliar-only treatments of purple and yellow nutsedge 2, 4, and 6 WAE provided better shoot control than soil-applied treatments. The greatest control of nutsedge, however, regardless of plant age, was obtained by treating both the foliage and soil. It was determined at the conclusion of a year-long greenhouse study that soil-applied imazapic provided better residual control of purple nutsedge than imazethapyr.
Propagules of Purple Nutsedge (Cyperus Rotundus) in Soil
Author: Gamini Siriwardana
Publisher:
ISBN:
Category :
Languages : en
Pages : 4
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 4
Book Description
Influence of Crop Interference and Allelochemicals from Plant Litters on Growth of Purple Nutsedge (Cyperus Rotundus L.)
Author: MAHADEV MURTHY M
Publisher:
ISBN:
Category :
Languages : en
Pages : 91
Book Description
Publisher:
ISBN:
Category :
Languages : en
Pages : 91
Book Description
Dormancy, Growth Inhibition, and Tuberization of Nutsedge (Cyperus Rotundus L.) as Affected by Photoperiods
Author: Gideon Berger
Publisher:
ISBN:
Category : Cyperacae
Languages : en
Pages : 256
Book Description
Publisher:
ISBN:
Category : Cyperacae
Languages : en
Pages : 256
Book Description
Integrated Strategies for Purple (Cyperus Rotundus L.) and Yellow Nutsedge (Cyperus Esculentus L.) Management in Tomato and Bell Pepper
Author: Sanjeev Kumar Bangarwa
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 444
Book Description
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 444
Book Description
Some Effects of EPTC and Temperature on Sprouting of Purple Nutsedge (Cyperus Rotundus L.) Tubers
Author: Shirland Augustus Daniels
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 112
Book Description
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 112
Book Description
Modeling the Sprouting of Cyperus Rotundus L. Tubers in Response to Soil Temperatures Under Soil Solarization
Author: Joel Edward Miles
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 458
Book Description
Publisher:
ISBN:
Category : Nutgrass
Languages : en
Pages : 458
Book Description