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1.
Comparative study of conventional and artificial neural network-based ETo estimation models 总被引:1,自引:3,他引:1
Accurate estimation of reference crop evapotranspiration (ETo) is required for several hydrological studies and thus, in the
past, a number of ETo estimation methods have been developed with different degree of complexity and data requirement. The
present study was carried out to develop artificial neural network (ANN) based reference crop evapotranspiration models corresponding
to the ASCE’s best ranking conventional ETo estimation methods (Jensen et al. ASCE Manual and Rep. on Engrg. Pract. no. 70,
1990). Among the radiation methods, FAO-24 radiation (or Rad) method for arid and Turc method for humid region, and among
the temperature methods, FAO-24 Blaney–Criddle (or BC) method were studied. The ANN architectures corresponding to the above
three less data-intensive methods were developed for four CIMIS (California Irrigation Management Information System) stations,
namely, Davis, Castroville, Mulberry, and West Side Field station. The comprehensive ANN architecture developed by Kumar et
al. (J Irrig Drain Eng 128(4):224–233, 2002) corresponding to Penman–Monteith (PM) ETo for Davis was also tried for the other
three stations. Daily meteorological data for a period of more than 10 years (01 January 1990 to 30 June 2000) were collected
from these stations and were used to train, test, and validate the ANN models. Two learning schemes, namely, standard back-propagation
with learning rate of 0.2 and standard back-propagation with momentum having learning rate of 0.2 and momentum term of 0.95
were considered. ETo estimation performance of the ANN models was compared with the FAO-56 PM method. It was found that the
ANN models gave better closeness to FAO-56 PM ETo than the best ranking method in each category (radiation and temperature).
Thus these models can be used for ETo estimation in agreement with climatic data availability, when not all required climatic
variables are observed. 相似文献
2.
A field experiment was conducted with a bunched variety of peanut (Arachis hypogaea L.) cv. JL-24 during the summer seasons (March–June) of 1992 and 1993 in the humid tropical canal command area at the University Experimental Farm, Memari (23°1 N, 88°5 E and 21.34 m a.s.l) in West Bengal of eastern India. The soil at the site is of sandy loam (Typic Fluvaquent) texture and the area has a shallow water table. Weekly and seasonal field water balance components of actual evapotranspiration (ETa) including the capillary contribution into root zone were determined. Peanut yield and water productivity were determined for three ratios of irrigation water and cumulative pan evaporation (CPE) of 0.9, 0.7 and 0.5. Mean crop coefficients were determined for each 7-day period of growth and were related to leaf area index and growing degree-days. Average seasonal values of ETa of peanut were 434, 391 and 356 mm for the three treatments, respectively, for 115 days of growth. The total pod yield and WP were significantly higher in 0.9 IW:CPE treatment in the 1992 season. On an average, 0.9 IW:CPE treatment had 7 and 11% higher yields in 1992 and 1993, respectively, over treatments 0.7 and 0.5 IW:CPE. The maximum average Kc of 1.19 occurred about 9 weeks after sowing relative to grass reference ET (ETo). 相似文献
3.
Bandyopadhyay S Lodh C Sarkar M Ghosh MK Bera AK Bhattacharyya D Mondal DK Baruah KK 《Tropical animal health and production》2012,44(5):1063-1072
Of 273 samples (rectal swab) collected from free-ranging yaks of Tawang district, Arunachal Pradesh, 42 Shiga toxin-producing
Escherichia coli (STEC), six enteropathogenic E. coli (EPEC) and 27 enterotoxigenic E. coli (ETEC) strains were isolated. All the STEC and EPEC strains were further investigated for respective stx variants (for STEC only) and additional putative virulence factors. The 27 ETEC strains were also screened for characteristic
enterotoxin gene(s) and colonization factors. Occurrence of ETEC was significantly (p < 0.05) higher in the diarrheic yaks and yaks of less than 1 year of age. Majority of enterovirulent E. coli isolates were resistant to amikacin, azithromycin, chloramphenicol, colistin, doxycycline, furazolidone, nalidixic acid,
nitrofurantoin, streptomycin and tetracycline. Dendrogram, constructed with molecular fingerprinting profiles obtained from
RAPD (Randomly Amplified Polymorphic DNA) and ERIC (Enterobacterial Repetitive Intergenic Consensus) PCR, placed the isolates
in different clusters irrespective of their serotypes, virulence gene and drug resistance pattern. Collectively, the study
indicates that yaks, being a potential reservoir of multidrug resistant STEC and EPEC, may represent significant risk to public
health in this region. Higher recovery of ETEC isolates from yaks with diarrhea points out that ETEC may be a major determinant
for repeated occurrence of diarrhea in yaks. 相似文献
4.
R. C. Joshi B. Sharma S. K. Bandyopadhyay R. P. Bansal 《Tropical animal health and production》1984,16(3):167-170
Rinderpest antibodies were detected by employing the fluorescent antibody test (FAT) and the immunoperoxidase test (IPT) and the results were compared with the counterimmuno electrophoresis test (CIE). FAT was found to be the most sensitive in detecting post-vaccinal antibodies followed by IPT and CIE tests. 相似文献
5.
6.
Changes in carbon pools and biological activities of a sandy loam soil under medium‐term conservation agriculture and diversified cropping systems 下载免费PDF全文
7.
A. Bandyopadhyay P. C. Nautiyal T. Radhakrishnan H. K. Gor 《Journal of Agronomy and Crop Science》1999,182(1):37-41
Experiments were carried out during winter–summer (January–June) season to understand the role of seed testa, cotyledons and embryonic axis in imparting dormancy of some groundnut cultivars belonging to different habit groups. Crop was harvested at four maturity stages; 90, 100, 110 and 121 days after emergence (DAE). After drying the pods in shade for 2 days, the germination of seeds with (GST) and without (GSW) testa in rolled germination towels and seeds, and embryonic axes (GEM) in culture media from individual plants of a cultivar was studied. Seed testa played an important role in imparting dormancy followed by the cotyledons, and embryonic axis. However, the nature of dormancy of embryonic axis appeared to be different from that of the testa and cotyledons. Results suggested that the dormancy in groundnut is regulated mainly by testa (a maternal tissue) in the Spanish type, but by cotyledons, and embryonic axis (both zygotic tissue) as well as testa in Virginia types. Thus the genetic control of seed dormancy in groundnut appears to be quantitative in nature. 相似文献
8.
K. G. Mandal K. M. Hati A. K. Misra K. K. Bandyopadhyay M. Mohanty 《Journal of Agronomy and Crop Science》2005,191(6):416-425
Increasing production of wheat from a limited water supply can result from efficient irrigation and nutrient management. A 3‐year field experiment was conducted at the Indian Institute of Soil Science, Bhopal, to study the growth, yield, seasonal evapotranspiration (ET) and water use efficiency (WUE), and the water–yield relationship of wheat in a soybean–wheat cropping system on vertisols. Three levels of irrigation, viz. I0, no post‐sowing irrigation; I1, two irrigations [crown root initiation (CRI) and flowering stage]; and I2, three irrigations (CRI, maximum tillering and flowering stage) and three nutrient management treatments, viz. F0, control (without fertilizer/manure); F1, 100 % NPK (100–21.5–24.9 kg ha?1); and F2, 100 % NPK + farmyard manure (FYM‐10 t ha?1) were tested in a split‐plot design with three replication. It has been established (through anova ) that the year effect was rather negligible and the interaction effects of irrigation and nutrient management on the growth parameters, ET, yield components, yield and WUE were significant. Plant height, progressive leaf area index, dry matter accumulation and crop growth rate were higher in I2F2, and I2F1 and I1F2 were statistically at par. The seasonal ET increased significantly with the increase in water supply in every nutrient treatment and it was highest in I2F2 and lowest in I0F0. The highest grain yield was obtained in I2F2; and a similar yield was recorded in I3F1 and I2F2. This shows a strong interaction effect between irrigation and nutrients. Yield components, viz. number of ears m?2, number of grains ear?1 and 1000‐grain weight were significant. The higher number of ears m?2 containing greater number of grains with relatively heavier weights appeared to have contributed to the higher yield in I1F2, I2F1 and I2F2. The highest WUE obtained in I0F2 did not correspond to the highest yield and maximum ET, but a WUE of 10.43 kg ha?1 mm?1 in the I2F2 combination corresponded with the highest yield and the seasonal ET requirement was 391.8, which was 137 % greater than the water use at maximum WUE. The ET–grain yield relationship was linear, with a lowest regression slope (i.e. marginal WUE) and elasticity of water production (Ewp) in F0 and a considerably higher slope and Ewp in F1 and F2. As the Ewp is positive and close to one in 100 % NPK treatment, the scope of improving WUE and yield with only inorganic fertilizer is very little, and relatively greater scope exists in the integrated management of organic manure and inorganic fertilizer. The results suggest that integrated nutrient management (100 % NPK + FYM) in conjunction with three irrigations maximized yield of wheat with concomitant improvement in ET and WUE under limited water availability. 相似文献
9.
10.
S. Tripathi A. Chakraborty B. K. Bandyopadhyay K. Chakrabarti 《Archives of Agronomy and Soil Science》2013,59(4):439-450
The studied soils were collected from a 24-year long-term fertilizer experiment with rice (Oryza sativa L.) grown on tropical Typic Endoaquepts during monsoon season only. The organic carbon (OC) and total nitrogen (TN) status of the soils improved with the N100P22K42 treatment than the initial values at the start of the experiment. The available P status of the soils depleted in the N100P11K22 and N0P0K0 treatments than the initial value. Soil microbial biomass carbon (MBC) and basal soil respiration (BSR), activities of urease, acid and alkaline phosphatases as well as fluorescein diacetate hydrolyzing activity (FDHA) were the highest in the N100P22K42 treatment. The highest percentage of MBC in OC in the N100P22K42 treatment revealed the accumulation of organic matter with an overall improvement in nutrient status of soil, since MBC is a labile pool of plant nutrients. Long-term application of fertilizers (N100P22K42) had no deleterious effect on microbial and biochemical soil quality parameters. Rice grain yields were inconsistent with N100P0K0 and N0P0K0 while that of N100P22K42, N100P11K22 and N100P22K0 increased gradually during the course of the experiment for each block period of six years. The grain yield of rice showed high significant correlation with the microbial and biochemical soil parameters. 相似文献