Is partial root-zone drying an effective irrigation technique to improve water use efficiency and fruit quality in field-grown wine grapes under semiarid conditions?     

M.L. De la Hera  P. Romero  E. Gómez-Plaza  A. Martinez 《Agricultural Water Management》2007

We investigated the effects of partial root-zone drying (PRD) applied at different periods on leaf water relations, vegetative development, fruit yield, must and wine quality in wine grapes (Vitis vinifera L. cv. Monastrell) during a 3-year field experiment in order to determine the importance of the timing of PRD application on physiological and agronomical vine response under semiarid conditions. Two irrigation treatments were applied: conventional drip irrigation (CI) and PRD. Both treatments received the same annual water quantity. Each year the PRD treatment was applied at different periods of the growth cycle. In 1999 PRD was applied from veraison to harvest (end July–early September); in 2000 from fruit set to harvest (mid June–early September); and in 2001 PRD from budburst to harvest (mid April–early September). Leaf water relations and gas exchange during the experimental period were not significantly affected by PRD treatment. In 1999 and 2000 there was no significant treatment effect on vegetative development, yield or fruit quality. However, in 2001 (when PRD was applied from budburst to harvest), reproductive and vegetative development was clearly altered in PRD vines. Fruit set percentage and vegetative development (shoot length, pruning weight and primary and lateral leaf area) were significantly increased in PRD vines compared to CI. This resulted in both higher yield (kg per vine) (43%) and water use efficiency (40%) compared to CI vines. Berry number per cluster and cluster weight were also significantly increased in PRD vines. Notwithstanding higher yield in PRD vines and a similar berry size, the must and wine quality was not significantly altered, indicating a higher synthesis and accumulation of photoassimilates and metabolites in the berries of PRD vines. We conclude that there was an positive effect on vegetative and reproductive growth when long-term PRD was applied from the beginning of growing season (budburst), suggesting that early onset of PRD is desirable to intensify PRD response under these semiarid conditions. Nevertheless from these results we need to further investigate the long- and short-term effects of PRD, with moderate water amounts, on vegetative and reproductive development such as flowering and fruit set processes in wine grapes.  相似文献   

Impact of land-use changes and sedimentation on the Muhammad Nur Reservoir, South Kalimantan, Indonesia   总被引：1，自引：0，他引：1  

Haji Moehansyah  Basant L. Maheshwari  Jim Armstrong 《Journal of Soils and Sediments》2002,2(1):9-18

The Muhammad Nur Reservoir (MNR) is a major multipurpose reservoir located on the Riam Kanan River in the Indonesian Province of South Kalimantan. The MNR has a high sediment trap efficiency and there is concern that accelerated erosion in the catchment, resulting from inappropriate land use, poses a significant threat to the storage capacity and effective life span of the reservoir. Furthermore, on-going deforestation of large parts of the catchment may have changed the inflow pattern to the reservoir. This paper uses data from fieldwork and published information from different sources to examine the extent of erosion and sedimentation in the catchment and the sediment delivery to the reservoir. Water level variations in the reservoir over a 22-year period are examined for changes that might indicate an alteration of the hydrologic balance in the catchment.  相似文献   

Field Evaluation of Selected Soil Erosion Models for Catchment Management in Indonesia   总被引：1，自引：1，他引：1  

H. Moehansyah  B.L. Maheshwari  J. Armstrong 《Biosystems Engineering》2004,88(4):491-506

Three models, viz., areal non-point source watershed environment response simulation (ANSWERS), universal soil loss equation (USLE) and adapted universal soil loss equation (AUSLE) are evaluated for their performance under the field conditions of the Riam Kanan catchment in South Kalimantan province of Indonesia. While ANSWERS is evaluated for its accuracy to predict both runoff and soil loss, USLE and AUSLE are evaluated for soil loss only. The study was carried out in the context of sedimentation concerns for the Muhammad Nur Reservoir—an important source of drinking and irrigation water supply for the catchment. The models are evaluated using field data collected under four different land uses and during 2 years of field experiments. The land uses considered are cropland with minimum tillage, cropland with conventional tillage, grassland and areas reforested with rubber trees. The ANSWERS model in general has a tendency to overpredict runoff values. The ANSWERS model also was relatively better for predicting soil loss followed by the AUSLE and USLE models. Overall, the ANSWERS model proved superior for predicting soil loss in the Riam Kanan catchment. However, given that the AUSLE model produced sufficiently reliable results and is relatively easy to use, the AUSLE model would also appear to be a useful tool for predicting soil erosion in the catchment.  相似文献   

In vitro Culture of Excised Ovules of Papaver somniferum     

Maheshwari N 《Science (New York, N.Y.)》1958,127(3294):342

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Water and nutrient use efficiency of a low-cost hydroponic greenhouse for a cucumber crop: An Australian case study   总被引：3，自引：0，他引：3  

Harsharn S. GrewalBasant Maheshwari  Sophie E. Parks 《Agricultural Water Management》2011,98(5):841-846

The Australian greenhouse industry is primarily dominated by low-cost hydroponic greenhouses for delivery of water and nutrients to plants to grow a variety of vegetable crops including cucumber and tomato. The nutrient rich drainage water from these greenhouses is generally released into the local environment causing pollution concerns. This study was initiated to investigate the opportunities in recycling drainage water to increase water and nutrient-use efficiency of hydroponic greenhouses and reduce the environmental impact of the drainage water discharge. Results indicated that a total of 4.15 ML/ha of irrigation water was applied during the 13 weeks crop growing period of which 2.56 ML/ha was drained off and 1.59 ML/ha was used to meet the crop evapotranspiration demand. The study showed that the recycling of the drainage water resulted in a 33% reduction in potable water used for irrigation in cucumber production. The drainage water contained 59% applied N, 25% applied P and 55% applied K and illustrated the potential for nutrient recovery and production cost savings through the reuse of drainage water. This case study demonstrates that some relatively simple changes in irrigation practices within greenhouse systems to recycle drainage water can considerably improve sustainability of low-cost hydroponic greenhouses and help minimise the environmental footprint of the greenhouse industry.  相似文献   

Agriculture as a source of phosphorus causing eutrophication in Central and Eastern Europe   总被引：5，自引：0，他引：5  

P. Csathó    I. Sisák    L. Radimszky    S. Lushaj    H. Spiegel    M. T. Nikolova    N. Nikolov    P. &#;ermák    J. Klir    A. Astover    A. Karklins    S. Lazauskas    J. Kopi&#;ski    C. Hera    E. Dumitru    M. Manojlovic    D. Bogdanovi&#;    S. Torma    M. Lesko&#;ek  & A. Khristenko 《Soil Use and Management》2007,23(S1):36-56

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Stress distribution over a triangular tillage tool     

C. P. Gupta  R. C. Maheshwari 《Soil & Tillage Research》1992,22(3-4):265-282

To simplify the analysis of stress over a cultivator shovel moving at a certain depth, it was represented by an isosceles triangular plate of uniform thickness. To simulate the boundary conditions to which a cultivator shovel is subjected, the triangular plate was assumed as clamped along one of the edges while the other two edges were assumed as free. These assumptions made it possible to apply the theory of bending of laterally loaded plates for the computation of stresses set up in the tillage tool. This theory involves fundamental equations of elasticity, namely the equations of equilibrium, equations of continuity and surface conditions. The theoretically calculated values of stresses were fairly close to experimentally observed values.  相似文献   

Studies on Jamunapari goats. II. Studies on comparative intake of nutrients by browsing goats     

J S Saxena  M L Maheshwari 《The Indian veterinary journal》1971,48(2):173-175

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Partial characterization and insecticidal properties of Ricinus communis L foliage flavonoids     

Upasani SM  Kotkar HM  Mendki PS  Maheshwari VL 《Pest management science》2003,59(12):1349-1354

Aqueous leaf extract of Ricinus communis L (Euphorbiaceae), a cultivated plant in tropical countries, showed excellent insecticidal activity against Callosobruchus chinensis L (Coleoptera: Bruchidae). We have isolated and tested flavonoids as insecticidal and antimicrobial agents. The isolated flavonoids showed potential insecticidal, ovicidal and oviposition deterrent activities against C chinensis L. However, antimicrobial activity against the common microbial infestants of stored pulses, of which C chinensis is a major pest, was found to be insignificant. Two bands having Rf 0.63 and 0.69 were seen on HPTLC plates using mobile phase benzene + ethyl acetate + methanol + formic acid (12 + 4.5 + 2 + 1.5 by volume) as eluant. The Rf values and scanning of the spectrum in the ultraviolet region, showed identity with the flavonoids quercetin and kaempferol. This was further confirmed using HPLC and IR and UV spectrometry. HPLC and HPTLC chromatograms also suggested quercetin to be the major flavonoid present in the hydrolyzed aqueous leaf extract of R communis.  相似文献   

Participatory Rural Appraisal and Compensation Intervention: Challenges and Protocols While Managing Large Carnivore–Human Conflict     

Aishwarya Maheshwari  Neha Midha  Anil Cherukupalli 《Human Dimensions of Wildlife》2014,19(1):62-71

When large carnivores cause socioeconomic losses in a community, conflict increases, retaliatory killing of the carnivore can occur, and conservation efforts are undermined. We focused on Participatory Rural Appraisal (PRA) and economic compensation schemes as approaches for managing conflict. PRA is a tool for collecting data on the large carnivore–human conflict and economic compensation schemes for those affected negatively by carnivore presence. We reviewed published papers and reports on large carnivore–human conflicts, PRA, and compensation schemes. This article details insights into common pitfalls, key lessons learned, possible solutions including new approaches for compensation and protocols to be followed while managing large carnivore–human conflict. We hope to contribute to a meaningful dialogue between locals, managers, and researchers and help in effective implementation of conservation programs to mitigate large carnivore–human conflict around the protected areas.  相似文献