scholarly journals Dynamics of deep water and N uptake under varied N and water supply

2021 ◽  
Author(s):  
Guanying Chen ◽  
Camilla R Rasmussen ◽  
Dorte Bodin Dresboell ◽  
Abraham George Smith ◽  
Kristian Thorup-Kristensen
Keyword(s):  
Water Supply ◽  
Water Deficit ◽  
Water Uptake ◽  
Oilseed Rape ◽  
Deep Water ◽  
Water Status ◽  
Soil Column ◽  
N Uptake ◽  
Winter Oilseed Rape ◽  
Soil Layers

Aims: Enhanced nitrogen (N) and water uptake from deep soil layers may increase resource use efficiency whilst maintaining yield under stressed conditions. Winter oilseed rape (Brassica napus L.) can develop deep roots and access deep-stored resources such as N and water, while this potential has large uncertainties in variable environments. In this study, we aimed to evaluate the effects of reduced N and water supply on deep N and water uptake. Methods: Oilseed rape plants grown in outdoor rhizotrons were supplied with 240 and 80 kg N ha-1 respectively in 2019 whereas a well-watered and a water-deficit treatment were established in 2020. To track deep water and N uptake, a mixture of 2H2O and Ca(15NO3)2 was injected into the soil column at 0.5 and 1.7 m depths. δ2H in transpiration water and δ15N in leaves were measured after injection. δ15N in biomass samples was also measured. Results: Differences in N or water supply had little effect on root growth. The low N treatment reduced water uptake throughout the soil profile, but caused a non-significant increment in 15N uptake efficiency at both 0.5 and 1.7 m. Water deficit in the upper soil layers led to compensatory deep water, while N uptake was not altered by soil water status. Conclusion: Our findings demonstrate that for winter oilseed rape, high N application and water deficiency in shallow layers increase deep water uptake and that the efficiency of deep N uptake is mainly sensitive to N supply rather than water supply.

Water and salt movement in soil driven by crop roots: a controlled column study

Biologia ◽  
2009 ◽  
Vol 64 (3) ◽  
Author(s):  
Masaharu Kitano ◽  
Kazuki Urayama ◽  
Yoshinobu Sakata ◽  
Yasutaka Sonoda ◽  
Kenji Ebihara ◽  
...  
Keyword(s):  
Water Content ◽  
Water Deficit ◽  
Time Course ◽  
Soil Column ◽  
Xylem Sap ◽  
Selective Absorption ◽  
Salt Accumulation ◽  
Soil Layers ◽  
Column System ◽  
Root Absorption

AbstractWater deficit and salt accumulation in soil presents serious problems to crop production in semi-arid regions. These problems depend on the active transpiration stream and the selective absorption of ions by crop roots. In this study, a large sized soil column system was used to examine the dynamics of water and ion transport and salt accumulation in soil layers. Special reference was placed on the effects of the active and selective absorption by roots of different crops (i.e., corn plants, sunflower plants and no plants). The column system was equipped with on-line systems for the control of groundwater level. Soil water content sensors enabled time-course evaluations of the volumetric water content and hence upward flux of the groundwater in the soils at different depths. Furthermore, the distribution and accumulation of ions in soil layers, plant organs and xylem sap were analyzed using ion chromatography. In this column experiment, diurnal and longer term changes in water movement and ion accumulation in soil, affected by root absorption characteristics of plants, were evaluated quantitatively. The results demonstrated that the column system was applicable for the quantitative analysis of the effects of root absorption by different crops on water deficit and salinization in soils.

scholarly journals Dynamics of Growth and Nitrogen Capture in Winter Oilseed Rape Hybrid and Line Cultivars under Contrasting N Supply

Agronomy ◽  
2020 ◽  
Vol 10 (8) ◽  
pp. 1183 ◽  
Author(s):  
Yangyang Zhang ◽  
Piaopiao Lu ◽  
Tao Ren ◽  
Jianwei Lu ◽  
Li Wang
Keyword(s):  
Oilseed Rape ◽  
Seed Yield ◽  
Field Experiments ◽  
N Uptake ◽  
Genotypic Variation ◽  
Utilization Efficiency ◽  
Winter Oilseed Rape ◽  
N Accumulation ◽  
N Supply ◽  
Parental Lines

Cultivation of winter oilseed rape hybrids has been introduced as a promising solution to improve the nitrogen use efficiency (NUE) and to reduce the large N balance surpluses in this crop. To achieve a better understanding of the underlying physiological mechanisms, field experiments were conducted over two years to investigate the dynamics of growth and N capture in an oilseed rape hybrid and its parental lines under both low (0 kg ha−1) and high (180 kg ha−1) N supply. The results showed that the dynamic trajectories of crop growth and N capture could be accurately characterized by logistic equation using growing degree days as the independent variable. At both N rates, the oilseed rape hybrid outperformed the parental lines in seed yield and aboveground biomass accumulation, which was more closely associated with the longer duration (td) of the rapid growth period (RGP), than with the higher maximum growth rate (vm). N uptake was the main factor driving genotypic variation in seed yield, with an increasing importance of N utilization efficiency at high N supply. The hybrid had significantly higher N uptake than the parental lines at both low and high N supply, because of larger vm for N accumulation during the RGP, which may present a scope for genetically improving NUE in oilseed rape. High N application enhanced crop biomass production and N accumulation, as a result of prolonged td and larger vm during the RGP. The initiation of RGP for N accumulation occurred after overwinter period, which could not be accelerated by high N supply, suggesting rational distribution of N fertilizer with reduced basal dose. However, larger amounts in spring would be beneficial for a better synchronization to crop N demand with lower environmental risks.

Growth and water-use characteristics of Romaine lettuce cultivated in Histosol as affected by irrigation management, compaction, and seeding type

2020 ◽  
Vol 100 (3) ◽  
pp. 278-288
Author(s):  
Jacynthe Dessureault-Rompré ◽  
Jean Caron ◽  
Laurie Plamondon ◽  
Linda Gaudreau ◽  
Sylvain Jutras ◽  
...  
Keyword(s):  
Water Use ◽  
Water Uptake ◽  
Soil Column ◽  
Water Productivity ◽  
Direct Seeding ◽  
Column Height ◽  
Rooting Depth ◽  
Organic Soils ◽  
Romaine Lettuce ◽  
Soil Layers

In Canada, most lettuce (Lactuca sativa L.) is produced on cultivated organic soils, which can be very productive but are also very sensitive to degradation and compaction. The objective of this work was to evaluate the effect of soil compaction, irrigation thresholds, and transplant type on the growth and water-use characteristics of Romaine lettuce that is grown in organic soil. The experiments were conducted in greenhouses at Laval University. Tensiometers and time-domain reflectometer probes were used to characterize the water-use characteristics of the Romaine lettuce. Most of the growth characteristics of the Romaine lettuce, with the exception of the dry weight, were significantly influenced by the available rooting depth (soil column height) and by the irrigation threshold used. Lettuce water uptake decreased significantly as the depth increased. In addition, in drier conditions, the deeper soil layers contributed more to the total water uptake than the surface soil layers. The water productivity was lower in the presence of a compacted layer combined with a direct seeding treatment, compared with all of the other treatments. First, it is concluded that the irrigation method should allow a certain degree of dryness by use of a lower irrigation threshold (ideally between −20 and −30 kPa) to stimulate deep rooting. Second, the use of small lettuce plant preseeded in small block of peat substrate instead of direct seeding in the field can compensate for a possible compaction effect.

scholarly journals Importance of deep water uptake in tropical eucalypt forest

2016 ◽  
Vol 31 (2) ◽  
pp. 509-519 ◽  
Author(s):  
Mathias Christina ◽  
Yann Nouvellon ◽  
Jean‐Paul Laclau ◽  
Jose L. Stape ◽  
Jean‐Pierre Bouillet ◽  
...  
Keyword(s):  
Water Uptake ◽  
Deep Water ◽  
Eucalypt Forest

scholarly journals A novel deletion in FLOWERING LOCUS T modulates flowering time in winter oilseed rape

2021 ◽  
Author(s):  
Paul Vollrath ◽  
Harmeet S. Chawla ◽  
Sarah V. Schiessl ◽  
Iulian Gabur ◽  
HueyTyng Lee ◽  
...  
Keyword(s):  
Association Mapping ◽  
Flowering Time ◽  
Oilseed Rape ◽  
Major Effect ◽  
Structural Variants ◽  
Winter Oilseed Rape ◽  
Flowering Locus T ◽  
Winter Type ◽  
Long Read ◽  
Flowering Locus

Abstract Key message A novel structural variant was discovered in the FLOWERING LOCUS T orthologue BnaFT.A02 by long-read sequencing. Nested association mapping in an elite winter oilseed rape population revealed that this 288 bp deletion associates with early flowering, putatively by modification of binding-sites for important flowering regulation genes. Abstract Perfect timing of flowering is crucial for optimal pollination and high seed yield. Extensive previous studies of flowering behavior in Brassica napus (canola, rapeseed) identified mutations in key flowering regulators which differentiate winter, semi-winter and spring ecotypes. However, because these are generally fixed in locally adapted genotypes, they have only limited relevance for fine adjustment of flowering time in elite cultivar gene pools. In crosses between ecotypes, the ecotype-specific major-effect mutations mask minor-effect loci of interest for breeding. Here, we investigated flowering time in a multiparental mapping population derived from seven elite winter oilseed rape cultivars which are fixed for major-effect mutations separating winter-type rapeseed from other ecotypes. Association mapping revealed eight genomic regions on chromosomes A02, C02 and C03 associating with fine modulation of flowering time. Long-read genomic resequencing of the seven parental lines identified seven structural variants coinciding with candidate genes for flowering time within chromosome regions associated with flowering time. Segregation patterns for these variants in the elite multiparental population and a diversity set of winter types using locus-specific assays revealed significant associations with flowering time for three deletions on chromosome A02. One of these was a previously undescribed 288 bp deletion within the second intron of FLOWERING LOCUS T on chromosome A02, emphasizing the advantage of long-read sequencing for detection of structural variants in this size range. Detailed analysis revealed the impact of this specific deletion on flowering-time modulation under extreme environments and varying day lengths in elite, winter-type oilseed rape.

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