Recovery dynamics of rainfed winter wheat after livestock grazing 2. Light interception, radiation-use efficiency and dry-matter partitioning

2011 ◽  
Vol 62 (11) ◽  
pp. 960 ◽  
Author(s):  
Matthew T. Harrison ◽  
John R. Evans ◽  
Hugh Dove ◽  
Andrew D. Moore
Keyword(s):  
Winter Wheat ◽  
Dry Matter ◽  
Light Interception ◽  
Livestock Grazing ◽  
Radiation Use Efficiency ◽  
Dry Matter Accumulation ◽  
Dry Matter Partitioning ◽  
Grain Yields ◽  
Use Efficiency ◽  
Radiation Use

Grazing of cereal crops reduces canopy light interception and could potentially reduce biomass production and grain yields. Alternatively, defoliation after canopy closure may increase light penetration and enhance radiation-use efficiency (RUE, shoot dry matter produced per unit light intercepted). Changes in dry matter partitioning following grazing may also ameliorate grain yield penalties. Experiments with rainfed winter wheat were conducted near Canberra, Australia, to investigate the effect of different intensity or duration of grazing on two cultivars. Grazing reduced leaf area index (LAI), light interception and growth rates by up to 90% but did not affect overall RUE. Although grazing caused significant reductions in cumulative light interception and total dry matter accumulation, it did not affect grain yields because grazed crops had delayed phenological development, allowing increased partitioning of shoot dry matter to spikes. Grazing reduced stem dry matter accumulation and consequently decreased the amount of stem assimilate available for retranslocation to kernels by up to 75%. However, by delaying crop ontogeny, grazing prolonged green area duration after anthesis and thereby increased the supply of assimilates from current photosynthesis to developing kernels, mitigating potential yield penalties caused by defoliation.

Single Leaf Carbon Exchange and Canopy Radiation Use Efficiency of Four Peanut Cultivars1

1993 ◽  
Vol 20 (1) ◽  
pp. 1-5 ◽  
Author(s):  
J. M. Bennett ◽  
T. R. Sinclair ◽  
Li Ma ◽  
K. J. Boote
Keyword(s):  
Solar Radiation ◽  
Dry Matter ◽  
Radiation Use Efficiency ◽  
Dry Matter Accumulation ◽  
Radiation Interception ◽  
Single Leaf ◽  
Seed Harvest ◽  
Use Efficiency ◽  
Total Crop ◽  
Radiation Use

Abstract Knowledge of the interception of solar radiation by crop canopies and the use of that radiation for carbon assimilation is essential for understanding crop growth and yield as a function of the environment. A field experiment was conducted in 1990 at Gainesville, FL to determine if differences in single leaf carbon exchange rate (CER), canopy radiation interception, radiation use efficiency (g dry matter produced per unit of solar radiation intercepted), and increase in seed harvest index with time exist among several commonly grown peanut (Arachis hypogaea L.) cultivars. Four cultivars (Early Bunch, Florunner, Marc I, and Southern Runner) were grown in field plots on a Kendrick fine sand (a loamy, siliceous, hyperthermic Arenic Paleudult) under fully irrigated, intensive management. Total crop and seed dry matter accumulation were determined, and canopy radiation interception measured at weekly intervals. CER of uppermost, fully expanded sunlit leaves were determined at midday at 2-wk intervals. Single leaf CER's were similar among cultivars (25 to 35 μmol CO2 m-2 s-1) and relatively stable throughout most of the season, before declining during late seed filling. Although interception of radiation differed somewhat among cultivars during early canopy development, total crop dry matter accumulation was linearly related to the cumulative amount of radiation intercepted by all four cultivars (r2=≥0.99). Radiation use efficiency was similar among all cultivars with a mean of 1.00 g dry matter accumulated per MJ of intercepted solar radiation. The increase in seed harvest index with time was linear (r2≤0.94) and the rates of increase were similar among the Early Bunch, Florunner, and Marc I cultivars (0.0058 d-1), but lower (0.0043 d-1) for the later maturing Southern Runner cultivar. Results from this study indicated that the primary differences among these four cultivars were in early-season development of the leaf canopy and resultant radiation interception and the rate of seed growth, rather than the capacity to assimilate carbon dioxide.

scholarly journals Responses of Young Tea (Camellia sinensis) Clones to Drought and Temperature. II. Dry Matter Production and Partitioning

1996 ◽  
Vol 32 (4) ◽  
pp. 377-394 ◽  
Author(s):  
P. J. Burgess ◽  
M. K. V. Carr
Keyword(s):  
Dry Matter ◽  
Light Interception ◽  
Radiation Use Efficiency ◽  
Dry Matter Production ◽  
Wave Radiation ◽  
Physiological Basis ◽  
Matter Production ◽  
Use Efficiency ◽  
The Mean ◽  
Radiation Use

SUMMARYThe physiological basis for differences in yields from well-watered and draughted plants of four contrasting clones of tea was studied in terms of light interception, dry matter production and partitioning at a high altitude site in Southern Tanzania where there are marked seasonal variations in rainfall and temperature. The plant dry weights, including roots, were measured eight months after field planting and subsequently at intervals of three to four months, corresponding to the different seasons, during the following two years. Fully irrigated plants of one clone (S15/10) were also harvested after four years in the field. Clones differed in the rates of canopy spread and hence in their capacity to intercept solar radiation. The ‘radiation use efficiency’ (the net total dry matter production per unit of intercepted short-wave radiation) was similar for the four well-watered clones and ranged from 0.40 to 0.66 g MJ−1, which corresponds closely to values reported for other woody tropical plants. A 16-week drought treatment imposed two years after planting reduced the mean light interception of the four clones by about 25% and the mean radiation use efficiency by 78% to 0.09 g MJ−1. Clone S15/10, a cultivar from Kenya which produces large yields, partitioned a greater proportion of dry matter to leaves and harvested shoots than the other clones, and correspondingly less to large structural roots. This resulted in a maximum harvest index of 24%, substantially greater than other values reported in the literature. There were seasonal differences in partitioning, with more dry matter being diverted to roots and less to shoots during the cool season. Although the drought treatments had no significant effect on root growth, the amount of dry matter partitioned to leaves, stems and harvested shoots declined by 80–95%. The roots of all four clones extended in depth at similar rates (about 2 mm d−1), those of Clone S15/10 reaching 2.8m after four years. The results are discussed in terms of appropriate field cultural practices and possible selection criteria for high yielding clones.

scholarly journals Light interception and radiation use efficiency response to tridimensional uniform sowing in winter wheat

2018 ◽  
Vol 17 (3) ◽  
pp. 566-578 ◽  
Author(s):  
Zhi-qiang TAO ◽  
De-mei WANG ◽  
Shao-kang MA ◽  
Yu-shuang YANG ◽  
Guang-cai ZHAO ◽  
...  
Keyword(s):  
Winter Wheat ◽  
Light Interception ◽  
Radiation Use Efficiency ◽  
Use Efficiency ◽  
Radiation Use

Dry matter accumulation and distribution in five cultivars of maize (Zea mays): relationships and procedures for use in crop modelling

1999 ◽  
Vol 50 (4) ◽  
pp. 513 ◽  
Author(s):  
C. J. Birch ◽  
G. L. Hammer ◽  
K. G. Rickert
Keyword(s):  
Grain Yield ◽  
Harvest Index ◽  
Dry Matter ◽  
Radiation Use Efficiency ◽  
Dry Matter Accumulation ◽  
Degree Days ◽  
Grain Number ◽  
Plant Parts ◽  
Use Efficiency ◽  
Radiation Use

The ability to predict accurately dry matter (DM) accumulation, partitioning, and thus final grain yield is crucial in crop simulation models. The objectives of the study were to measure radiation interception and radiation use efficiency, to quantify the distribution of DM among the various plant parts, and to develop improved methods of modelling DM accumulation and partitioning among plant parts. Five cultivars of maize differing widely in maturity and adaptation were planted in October 1993 in south- eastern Queensland, and grown under non-limiting conditions of water and plant nutrient supplies. Data on DM accumulation, light interception, and canopy development were collected. The light extinction coefficient (k) did not differ among the cultivars. Radiation use efficiency was constant in each cultivar until close to physiological maturity, when a small decline was observed. Partitioning of DM between leaves and stems (until 90% of leaf tips had appeared) was described by a linear relationship between the proportion of DM allocated to leaves and the number of leaves present. Ear growth was described by a thermal-time-dependent equation from 150 degree-days (base temperature 8˚C) before silking to 115 degree-days after silking. Predictions of accumulation of grain yield by either components of yield (grain number per plant and individual grain weight) or daily increase in harvest index were assessed, but neither was entirely satisfactory, the former because of inaccurate prediction of grain number per plant, and the latter because of differences among cultivars in the daily increase in harvest index and terminal harvest index. Thus, the use of genotype-specific coefficients remains necessary. Throughout crop life, DM in stems can be predicted by difference, once DM is allocated to other plant parts. The relationships presented where leaf number mediates DM partitioning before silking simplify modelling of DM accumulation and partitioning in maize.

Estimates of physiological determinants forAmaranthus retroflexus

Weed Science ◽  
1999 ◽  
Vol 47 (3) ◽  
pp. 291-296 ◽  
Author(s):  
Stevan Z. Knezevic ◽  
Michael J. Horak ◽  
Richard L. Vanderlip
Keyword(s):  
Leaf Area ◽  
Specific Leaf Area ◽  
Environmental Conditions ◽  
Dry Matter ◽  
Plant Density ◽  
Light Interception ◽  
Radiation Use Efficiency ◽  
Redroot Pigweed ◽  
Use Efficiency ◽  
Radiation Use

Redroot pigweed is a troublesome weed in the sorghum-growing regions of North America. In 1994 and 1995, field studies were conducted at two locations near Manhattan, KS, to determine the influence of redroot pigweed density and environmental conditions on physiological determinants of redroot pigweed growth: duration of plant growth, light interception, radiation-use efficiency, and dry matter partitioning. In addition, specific leaf area was determined. Redroot pigweed was seeded at monoculture densities of 2, 4, and 12 plants m−1of row each year at each location. Duration of redroot pigweed growth was not influenced by plant density. Light interception was defined as a simple exponential function of leaf area index. Specific leaf area did not change over the season and averaged 135 cm2g−1. Partitioning of redroot pigweed dry matter was not influenced by plant density or environmental conditions but did not change within vegetative and reproductive stages. Radiation-use efficiency was not influenced by redroot pigweed density; the most reliable estimate was 1.74 g dry matter MJ−1of intercepted photosynthetically active radiation. Physiological determinants described were not affected by redroot pigweed density or environmental conditions and therefore provide a starting point for the development of a redroot pigweed growth module. The module could be coupled with available crop growth models (e.g., the sorghum growth model SORKAM) to simulate redroot pigweed–sorghum competition.

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