How does a stone mulch increase transpiration and grain yield in wheat under soil water deficit stress?

2012 ◽  
Vol 40 (4) ◽  
pp. 486-493
Author(s):  
M. Inagaki
1978 ◽  
Vol 91 (3) ◽  
pp. 599-623 ◽  
Author(s):  
W. Day ◽  
B. J. Legg ◽  
B. K. French ◽  
A. E. Johnston ◽  
D. W. Lawlor ◽  
...  

SummaryAutomatic mobile shelters were used to keep rain off a barley crop in a drought experiment. The treatments ranged from no water during the growing season to regular weekly irrigation. This paper reports the effect of drought on the harvest yield and its components, on water use and nutrient uptake.Drought caused large decreases in yield, and affected each component of the grain yield. The magnitude of each component varied by up to 25% between treatments, and much of the variation could be accounted for by linear regression against the mean soil water deficit in one of three periods. For the number of grains per ear, the relevant period included tillering and ear formation; for the number of ears per unit ground area, the period included stem extension and tiller death; for grain mass, the period included grain filling.The harvest yields were linearly related to water use, with no indication of a critical period of drought sensitivity. The relation of grain yield to the maximum potential soil water deficit did show that a prolonged early drought had an exceptionally large effect on both yield and water use.Two unsheltered irrigation experiments, also on barley, were made in the same year on a nearby site. The effects of drought on yield in these experiments were in good agreement with the effects observed on the mobile shelter site.When fully irrigated, the small plots under the mobile shelters used water 11% faster than larger areas of crop, because of advection. The maximum depth from which water was extracted was unaffected by the drought treatment. When 50% of the available soil water had been used the uptake rate decreased, but the maximum depth of uptake continued to increase.Measurements of crop nutrients at harvest showed that nitrogen uptake was large, because of site history, and that phosphate uptake was decreased by drought to such an extent that phosphate shortage may have limited yield.


1990 ◽  
Vol 41 (2) ◽  
pp. 267 ◽  
Author(s):  
CS Tan ◽  
WS Meyer ◽  
RCG Smith ◽  
HD Barrs

The effect of soil modification on changing the availability of water and the onset of crop water deficit stress in wheat was assessed during 2 drying periods. The different methods of determining the onset of stress generally agreed with each other. Differences were either related to the different parts of the canopy measured or to different physiological processes measured. Because foliage temp. was continuously monitored, the dynamic development of stress in relation to increasing soil water deficit and root growth became evident. The allowable soil water deficit at the onset of stress varied widely between soil treatments and the stage of crop growth at which deficit stress occurred. Physically modifying the soil increased plant available water by 80%. This resulted from both changes in amount of soil water stored and through a more uniformly distributed root system. Wheat growing in undisturbed soil was unable to adapt to post-anthesis stress, as frequent irrigations prior to anthesis concentrated root distribution in the upper layers.


1994 ◽  
Vol 63 (2) ◽  
pp. 339-344 ◽  
Author(s):  
Michihiro WADA ◽  
Luiz J.C.B. CARVALHO ◽  
Gustavo C. RODRIGUES ◽  
Ryuichi ISHII

2018 ◽  
Vol 21 (1) ◽  
pp. 1-12
Author(s):  
S Parveen ◽  
E Humphreys ◽  
M Ahmed

Worldwide fresh water scarcity and labour unavailability in agriculture are driving researchers and farmers to find management strategies that will increase water productivity and reduce labour requirement. Wet seeding instead of transplanting rice greatly reduces the labour requirement for crop establishment, while use of alternate wetting and drying (AWD) instead of continuous flooding reduces irrigation input. However, the safe threshold for irrigating wet seeded rice (WSR) at different crop stages has not been investigated. Therefore, experiment was conducted to determine the effects of different degrees of water stress during different crop growth stages on yield performance of WSR. This was done in greenhouse experiment in the 2011 wet season 2011 at the International Rice Research Institute, Los Baños, Philippines. In the experiment, water stresses were applied by withholding irrigation until soil water tension increased to 10, 20 or 40 kPa (kilo pascal) at 10 cm below the soil surface. Soil water tension was measured using 30 cm long guage tensiometer installed with the center of the ceramic cup. The stresses were applied during three crop stages: 3-leaf (3L) to panicle initiation (PI), PI to flowering (FL), and FL to physiological maturity (PM). The experiment also included a continuously flooded (CF) treatment. The number of drying events ranged from 8-12 during 3L-PI, 6-10 during PI-FL and 6-10 during FL-PM. There was a consistent trend for a decline in the number of irrigations and irrigation input with increasing irrigation threshold, and thresholds of 20 and 40 kPa resulted in significantly lower input than with CF. There were consistent trends for lower grain yield as the level of water deficit stress increased, and imposition of stresses of 20 and 40 kPa at any or all three stages significantly reduced grain yield compared with CF. There was a trend for the reduction in grain yield to be greater when the stresses were imposed at all three stages compared with a single stage, but the differences were not significant. There was a consistent trend for irrigation water productivity (WPi) to decrease as the irrigation threshold increased, with significantly lower values for a 40 kPa threshold at any stage, in comparison with CF. This was because the decline in water input to the pots was less than the decline in yield as the threshold increased. The results suggest that the optimum threshold for irrigation of WSR is 10 kPa during the vegetative and grain filling stages, and that the soil should be kept at close to saturation during PI-FLBangladesh Rice j. 2017, 21(1): 1-12


2007 ◽  
Vol 35 (4) ◽  
pp. 1603-1608 ◽  
Author(s):  
M. Inagaki ◽  
J. Valkoun ◽  
M. Nachit

HortScience ◽  
2019 ◽  
Vol 54 (12) ◽  
pp. 2249-2256
Author(s):  
Travis Culpepper ◽  
Joseph Young ◽  
David T. Montague ◽  
Dana Sullivan ◽  
Benjamin Wherley

Lawns must be managed increasingly under less frequent or deficit irrigation. Deficit irrigation can reduce gas exchange, carbon assimilation, and physiological function in both warm- (C4) and cool- (C3) season turfgrasses, yet limited research has compared the physiological response to increasing levels of soil water deficit. The objectives of this greenhouse study were to compare three commonly used transition-zone turfgrasses—bermudagrass [Cynodon dactylon (L.) Pers.] (C4), buffalograss [Buchloe dactyloides (Nutt.) Engelm.] (C4), and tall fescue (Festuca arundinacea Schreb.) (C3)—and their ability to maintain quality and physiological function under water deficit stress. Visual turf quality, normalized difference vegetation index (NDVI), reflective canopy temperature, and gross photosynthesis were evaluated initially near field capacity (FC), and subsequent soil water deficit [48% (moderate) and 33% (severe) of plant-available water] conditions. Bermudagrass and tall fescue had similar quality ratings near FC, although the photosynthetic rate was greater for bermudagrass. Compared with other turfgrasses, bermudagrass maintained greater turf quality, NDVI, and photosynthetic rates further into water deficit stress. Tall fescue quality and photosynthetic rates declined most rapidly in both experiments as a result of the combined heat and drought stress. Buffalograss used less water compared with other species, and maintained consistent turf quality, NDVI, and photosynthetic rates under moderate and severe water deficit. These results support the notion that buffalograss and bermudagrass are better adapted than tall fescue at maintaining functional and ecosystem services with shallow soil depths in landscape situations under imposed summertime water restrictions.


1970 ◽  
Vol 40 (2) ◽  
pp. 171-175 ◽  
Author(s):  
Shakil Uddin Ahmed

Soybean leaf Nitrogen (N) status correlated linearly with the amount of chlorophylls and SCMR at flowering stage in response to water deficit levels. In addition, SCMR showed significant positive correlation with chlorophylls at flowering stage. Grain yield significantly correlated to the leaf nitrogen as well as to the chlorophylls and SCMR at flowering stage in response to water deficit levels. These relationships indicated that the water stress decreased leaf nitrogen, chlorophylls and SCMR which in turn caused decreased grain yield of soybean. The results from the study suggest that, flowering stage is the best time for prediction on the adverse effects of water stress on leaf nitrogen assimilation, chlorophylls and SCMR on potential yielding ability of soybean.Key words: Soil water deficit; Leaf nitrogen; Chlorophyll (a+b); Growth stages; Soybean DOI: http://dx.doi.org/10.3329/bjb.v40i2.9773   Bangladesh J. Bot. 40(2): 171-175, 2011 (December)


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