Relationship between weed density and yield loss in semi- dry rice (Record no. 26663)
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| 000 -LEADER | |
|---|---|
| fixed length control field | 03215nam a2200181Ia 4500 |
| 003 - CONTROL NUMBER IDENTIFIER | |
| control field | OSt |
| 005 - DATE AND TIME OF LATEST TRANSACTION | |
| control field | 20220829104530.0 |
| 008 - FIXED-LENGTH DATA ELEMENTS--GENERAL INFORMATION | |
| fixed length control field | 140128s9999 xx 000 0 und d |
| 082 ## - DEWEY DECIMAL CLASSIFICATION NUMBER | |
| Classification number | 630.31 |
| Item number | SHI/RE |
| 100 ## - MAIN ENTRY--PERSONAL NAME | |
| Personal name | Shiji C P |
| 245 ## - TITLE STATEMENT | |
| Title | Relationship between weed density and yield loss in semi- dry rice |
| 260 ## - PUBLICATION, DISTRIBUTION, ETC. (IMPRINT) | |
| Place of publication, distribution, etc. | Vellanikkara |
| Name of publisher, distributor, etc. | Department of Agricultural Statistics, College of Horticulture |
| Date of publication, distribution, etc. | 2001 |
| 502 ## - DISSERTATION NOTE | |
| Degree type | MSc |
| 520 3# - SUMMARY, ETC. | |
| Summary, etc. | Sacciolepis interrupta and Isachne miliacea are two major problem weeds of rice in Kerala. An investigation on the quantum of crop loss incurred due to different densities of these weeds was undertaken to study the extent of damage inflicted on the crop which would necessitate early control of these weeds. The observations recorded on the various crop and weed characteristics were analysed as a 52 factorial experiment. It was found that crop characteristics like total bio- mass of paddy at harvest, number of tillers of paddy at harvest, number of productive tillers at harvest, grain yield and strain yield. And weed characteristics like number of tillers of S. interrupta at 60 DAS, height of S. interrupta at 60 DAS, number of tillers of S. interrupta at harvest of rice, dry matter production of S. interrupta and drymatter production of 1. miliacea were found to be affected by the weeds. The intra and interspecific competition was also brought to light based on the analysis. Single weed species models like that of Cousens (1985), Hakansson (1983), the first model of Watkinson (1981), Marra and Carlson (1983), Wilson and Cussans (1983), Wilcockson (1977) and Carlson et al. (1981) fitted well to the yield loss - S. interrupta/ 1. miliacea density relationship whereas those models proposed by Ngouajio et al. (1999), Kropff and Spitters (1991), Dew (1972), Zakharenko (1968) and Chisaka (1977) fitted well only to the yield loss- S. interrupta density relationship. The extended version of the Cousens (1985) model by Swinton et al . . (1994a) to a multi-species model was also fitted to the data and the same explained the yield loss - S. interrupta + 1. miliacea densities relationship to a considerable extent. The reduced form of the multispecies model to an equivalent single species model as worked out by Swinton et al. (1994b) also had a good fit. The numerical assessment of yield loss _. S. interrupta + 1. miliacea density relationship as illustrated by Berti and Zanin (1994) revealed the extent of damage on the crop by the weeds. The new curvilinear models tried also explained the yield loss - weed density relationship with the exception that the role of 1. miliacea deterring the yield of crop could not be highlighted due to its peculiar way of growth. The threshold weed densities worked out on a economic loss basis revealed that even the presence of two S. interrupta plants in a square meter area was hazardous for the crop whereas even the presence of 321. miliacea plants in the same stipulated area was not as detrimental as S. interrupta. |
| 700 ## - ADDED ENTRY--PERSONAL NAME | |
| Personal name | Krishnan S (Guide) |
| 856 ## - ELECTRONIC LOCATION AND ACCESS | |
| Uniform Resource Identifier | https://krishikosh.egranth.ac.in/handle/1/5810151236 |
| 942 ## - ADDED ENTRY ELEMENTS (KOHA) | |
| Source of classification or shelving scheme | |
| Koha item type | Theses |
| Withdrawn status | Lost status | Source of classification or shelving scheme | Damaged status | Not for loan | Permanent Location | Current Location | Shelving location | Date acquired | Full call number | Barcode | Date last seen | Price effective from | Koha item type |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| KAU Central Library, Thrissur | KAU Central Library, Thrissur | Theses | 2014-03-18 | 630.31 SHI/RE | 171722 | 2014-03-18 | 2014-03-18 | Theses |