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91.
Comparisons of energy balance and evapotranspiration between flooded and aerobic rice fields in the Philippines 总被引:3,自引:0,他引:3
Ma. Carmelita R. Alberto Reiner Wassmann Takashi HiranoAkira Miyata Ryusuke HatanoArvind Kumar Agnes PadreModesto Amante 《Agricultural Water Management》2011,98(9):1417-1430
The seasonal and annual variability of sensible heat flux (H), latent heat flux (LE), evapotranspiration (ET), crop coefficient (Kc) and crop water productivity (WPET) were investigated under two different rice environments, flooded and aerobic soil conditions, using the eddy covariance (EC) technique during 2008-2009 cropping periods. Since we had only one EC system for monitoring two rice environments, we had to move the system from one location to the other every week. In total, we had to gap-fill an average of 50-60% of the missing weekly data as well as those values rejected by the quality control tests in each rice field in all four cropping seasons. Although the EC method provides a direct measurement of LE, which is the energy used for ET, we needed to correct the values of H and LE to close the energy balance using the Bowen ratio closure method before we used LE to estimate ET. On average, the energy balance closure before correction was 0.72 ± 0.06 and it increased to 0.99 ± 0.01 after correction. The G in both flooded and aerobic fields was very low. Likewise, the energy involved in miscellaneous processes such as photosynthesis, respiration and heat storage in the rice canopy was not taken into consideration.Average for four cropping seasons, flooded rice fields had 19% more LE than aerobic fields whereas aerobic rice fields had 45% more H than flooded fields. This resulted in a lower Bowen ratio in flooded fields (0.14 ± 0.03) than in aerobic fields (0.24 ± 0.01). For our study sites, evapotranspiration was primarily controlled by net radiation. The aerobic rice fields had lower growing season ET rates (3.81 ± 0.21 mm d−1) than the flooded rice fields (4.29 ± 0.23 mm d−1), most probably due to the absence of ponded water and lower leaf area index of aerobic rice. Likewise, the crop coefficient, Kc, of aerobic rice was significantly lower than that of flooded rice. For aerobic rice, Kc values were 0.95 ± 0.01 for the vegetative stage, 1.00 ± 0.01 for the reproductive stage, 0.97 ± 0.04 for the ripening stage and 0.88 ± 0.03 for the fallow period, whereas, for flooded rice, Kc values were 1.04 ± 0.04 for the vegetative stage, 1.11 ± 0.05 for the reproductive stage, 1.04 ± 0.05 for the ripening stage and 0.93 ± 0.06 for the fallow period. The average annual ET was 1301 mm for aerobic rice and 1440 mm for flooded rice. This corresponds to about 11% lower total evapotranspiration in aerobic fields than in flooded fields. However, the crop water productivity (WPET) of aerobic rice (0.42 ± 0.03 g grain kg−1 water) was significantly lower than that of flooded rice (1.26 ± 0.26 g grain kg−1 water) because the grain yields of aerobic rice were very low since they were subjected to water stress.The results of this investigation showed significant differences in energy balance and evapotranspiration between flooded and aerobic rice ecosystems. Aerobic rice is one of the promising water-saving technologies being developed to lower the water requirements of the rice crop to address the issues of water scarcity. This information should be taken into consideration in evaluating alternative water-saving technologies for environmentally sustainable rice production systems. 相似文献
92.
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
93.
Amaresh Kumar NAYAK Rahul TRIPATHI Manish DEBNATH Chinmaya Kumar SWAIN Biswaranjan DHAL Shanmugam VIJAYKUMAR Anshuman Debasis NAYAK Sangita MOHANTY Mohammad SHAHID Anjani KUMAR Manoj RAJAK Khitish Chandra MOHARANA Dibyendu CHATTERJEE Susmita MUNDA Pravat GURU Rubina KHANAM Banwari LAL Priyanka GAUTAM Suschismita PATTANAIK Arvind Kumar SHUKLA Nuala FITTON Pete SMITH Himanshu PATHAK 《土壤圈》2023,33(3):448-462
Scarcity of water and emission of greenhouse gases (GHGs) are the two key environmental issues affecting crop production in India.Reducing the carbon footprint (CF) and water footprint (WF) of crop production can help to mitigate the environmental hazards that stem from GHG emissions and water scarcity.The CFs and WFs of three major cereal crops,rice,wheat,and maize,were estimated for the year 2014 under the environmental conditions in India,based on national statistics and other data sources.To... 相似文献
94.
Partha Sarathi Ghorai Sunanda Biswas Tapan Jyoti Purakayastha Nayan Ahmed Tapas Kumar Das Radha Prasanna Bharat Hanamant Gawade Kallol Bhattacharyya Kanchan Sinha Priya Singh Sujit Das 《Soil Use and Management》2023,39(1):503-520
Deterioration of soil quality under resource-intensive modern agriculture in the face of global climate change poses a huge risk to food security. Because of the complex nature, estimators of soil quality often rely upon a limited set of soil attributes, along with statistical data reduction techniques, for developing quality indices, whilst overlooking biological aspects and regional climatic variability. This study screened the most suitable soil quality indexing approaches for a rice-oilseed-based cropping system in the lower Indo-Gangetic plains (IGP). For this, surface soil samples (0–15 cm) were collected from an ongoing long-term fertilizer experiment with a rice-mustard-sesame cropping system in the IGP. The following treatments were assessed for their effect on soil quality: T1-control, T2-NPK (recommended NPK doses), T3-NPKG (NPK + in situ green manuring), T4-NPKGB (NPK + in situ green manuring + biofertilizer) and T5-NPKF (NPK + farm yard manure FYM). We found that total organic carbon (TOC), β-glucosidase, CaCl2 extractable S, alkaline KMnO4 oxidizable N, activity of urease, amidase enzyme and mean weight diameter (MWD) were sensitive key indicators of soil quality. The NPKF treatment maintained the highest soil quality status (0.80–0.91), both under productivity and environmental protection goals, owing to the availability of decomposable carbon. Regression analysis showed a better agreement of equivalent rice yield with expert opinion (EO; R2 = 0.89) than principal component analysis (PCA; R2 = 0.76). Finally, we found that the expert opinion approach with the nonlinear scoring function was the best tool for soil quality assessment of the region. 相似文献
95.
Transplanting of rice seedling in puddled soil is one of the most widely used cultivation practices. The present research is aimed at determining what specific implements are needed to obtain optimal puddle bed for transplantating. Puddling experiments were carried out by the use of pair of bullocks with traditional country plough (T1), pair of bullocks with lug wheel puddler (T2), power tiller with rotary puddler (T3), tractor with cage wheel and 9-tine cultivator (T4) and tractor with cage wheel and rotavator (T5). One summer ploughing was done at friable moisture condition (18.6% db) and then tilled soil was flooded to saturation (24 h) for preparation of puddled bed. Weeding efficiency, puddling depth, percentage increase in bulk density, puddling index, percolation rate and grain yield of paddy were studied for the above treatments. Puddling performance by different implements in comparison to the traditional animal drawn country plough (T1) shows that there is a definite reduction in time requirement for field preparation. Increase in weeding efficiency, bulk density, grain yield and puddling index were also observed. The highest values of weeding efficiency and puddling index were found 98.6% and 79.3, respectively, for rotavator (T5). The total time requirement for preparation of puddle field for treatment T4 (tractor with cultivator) was found to be the lowest (9.4 h ha−1) with 67% weeding efficiency and 62.7 puddling index as compared to all other alternatives tested. Energy requirement for preparation of puddle field was found highest (2390 MJ ha−1) for rotavator (T5) followed by T3, T4, T1, and T2 treatments. 相似文献
96.
Kasturikasen Beura Mahendra Singh Amit Kumar Pradhan Rajiv Rakshit Manohar Lal 《Communications in Soil Science and Plant Analysis》2019,50(3):287-294
We investigated the effects of Arbuscular Mycorrhiza (AM) fungi and various phosphorus (P) levels on the distribution and availability of P in dominant soils of Bihar, India. Potassium chloride (KCl)-P (labile P), sodium hydroxide (NaOH)-P (Fe-Al-bound P), hydrochloric acid (HCl)-P (Ca-bound P), and residual P (Res-P) fractions were analyzed in the soils under maize plant. Ca-bound P was the most abundant P fraction in the alkaline soils (65% of the total P) followed by neutral soil (35% of the total P), whereas it was less abundant (<4%) in the acidic soil type. Fe-Al-bound P was found to be highest for acidic soil (65% of the total P). Soils under the inoculation with Glomus mossae and control gave the highest and lowest values (15.63 mg kg?1 and 10.74 mg kg?1 respectively) for the labile fraction which was similar to the organically bound residual fractions of P (200.17 mg kg?1 and 193.66 mg kg?1 respectively. Inoculation of the soils with AM fungi leads to the redistribution of P fractions in different soils which consequently helps in improvement of available P in soil conducive for plant uptake. 相似文献
97.
Nirmala Sehrawat Mukesh Yadav Anil Kumar Sharma Vikas Kumar Kangila Venkataraman Bhat 《Archives of Agronomy and Soil Science》2019,65(9):1287-1301
Mungbean is an important food grain legume with high economic status. It has an excellent source of dietary protein and nutritional health benefits, particularly for the vegetarians. It increases soil fertility and also plays an imperative role in major cropping systems due to its short life span. Production of mungbean is still decreasing due to its susceptibility towards various environmental stress factors. Salt stress is one of the most prevailing abiotic stress imposing threats for agriculture food crops along with increasing world population and limited natural resources. Fewer efforts have been made to develop an improved variety of mungbean. The present review summarizes the adverse effects of salt stress and mungbean response at the physiological and molecular level. It covers recent studies on introgression of useful traits in mungbean for its better adaptability and survival under stressed conditions. Modern biotechnological approaches and traditional breeding methods may assist the development of salt-tolerant cultivars of mungbean for salinity-affected area in arid and semi-arid regions. Researchers involved in this area should keep this goal on priority for sustainable mungbean production. Availability of protein-rich food may help to reduce the problem of malnutrition in poor families and national food security issue for a continuous rising population. 相似文献
98.
99.
An efficient method for the purification and characterization of nematicidal azadirachtins A,B, and H,using MPLC and ESIMS 总被引:2,自引:0,他引:2
Sharma V Walia S Kumar J Nair MG Parmar BS 《Journal of agricultural and food chemistry》2003,51(14):3966-3972
Azadirachtin A enriched concentrate containing 60% active ingredient (a.i.) was prepared from the methanolic extract of the de-fatted neem (Azadirachta indica A. Juss) seed kernels. Azadirachtins A, B, and H, the three major bioactive constituents of neem seed kernel, were purified from this methanolic concentrate by employing reverse phase medium-pressure liquid chromatography (MPLC), using methanol-water solvent system as an eluant. The three pure azadirachtin congeners thus obtained were characterized by their unique mass spectral fragmentation, using electrospray probe in positive ion mode (ESI). All three azadirachtins exhibited nematicidal and antifungal activities. Azadirachtin B was the most effective against the reniform nematode Rotylenchulus reniformis (EC(50) 96.6 ppm), followed by Azadirachtin A (119.1 ppm) and H (141.2 ppm). At 200-ppm concentration, the test compounds caused 50-65% mortality of Caenorhabditis elegans nematode. Azadirachtin H showed the highest activity against the phytophagous fungi Rhizoctonia solani (EC(50) 63.7 ppm) and Sclerotium rolfsii (EC(50) 43.9 ppm), followed by B and A. The isolation of pure azadirachtins A, B, and H directly by MPLC purification from its concentrate and their characterization by ESIMS are unique and less time-consuming. 相似文献
100.
In plants exposed to high metal concentrations, mechanisms to counteract the oxidative burst are crucial for its survival. To investigate the temporal sequence of physiological reactions of peanut seedlings (Arachis hypogaea L.) to cadmium exposure, seeds were cultured in increasing concentrations of CdCl2, ranging from 50 to 300 μM. Germination frequency was scored, and the distributions of Cd in root, stem, and leaves were determined after 2 and 4 weeks of culture. Lipid peroxidation and activities of antioxidative enzymes including catalase (CAT; EC 1.11.1.6) and guaiacol peroxidase (GPX; EC 1.11.1.7) were estimated in these three parts of the plant. Germination of seedlings was not affected, but the growth of seedlings was severely suppressed with increasing concentrations of CdCl2 and incubation period. Pattern of Cd distribution in the three organs varied with concentration and period of exposure to Cd. Increased lipid peroxidation was detected in all parts of the developing seedlings with increasing metal accumulation. Catalase and guaiacol peroxidase activity varied in the three parts of the seedlings with concentration of Cd and incubation period. Guaiacol peroxidase activity appears to be more active in scavenging the reactive oxygen species in developing peanut seedlings. The results of the present experiment demonstrate the advantages of a tissue‐culture model system in studying the complex network of interactions of various factors in stress tolerance. 相似文献