An approach to modelling the effect of environmental and physiological factors upon biomass accumulation in winter wheat

2001 ◽  
Vol 136 (4) ◽  
pp. 369-381 ◽  
Author(s):  
A. G. GILLETT ◽  
N. M. J. CROUT ◽  
D. T. STOKES ◽  
R. SYLVESTER-BRADLEY ◽  
R. K. SCOTT

Six sites of variable soil type and environments in England and Scotland were sown with winter wheat (Triticum aestivum L. cv. Mercia) in the autumns of 1992 and 1993 with optimum inputs for growth. Crop monitoring between February and grain maturity provided data to investigate environmental and physiological factors important in controlling biomass accumulation.With increasing use of crop modelling as a tool for interpreting experiments and as crop management decision support systems, it is important that all influences on crop productivity are understood. The ‘radiation use efficiency’ or radiation conversion coefficient provides a convenient basis to study these influences.Significant differences in seasonal radiation conversion coefficients were observed between sites (P < 0·001), ranging from 2·82 to 3·87 g total dry matter/MJ absorbed photosynthetically active radiation. A series of simple dry matter models were developed to help explain biomass accumulation in relation to a number of environmental variables (using the measured green area index as an input) with correlation coefficients [ges ] 0·98 obtained across all sites. Apart from sunlight, differences in the canopy's ability to accumulate nitrogen and maintenance respiration costs were the most significant factors (P < 0·001). The nitrogen effect suggests changes in the conversion of assimilates with nitrogen availability, despite relatively high nutrition levels ([ges ] 180 kg N/ha).Over all sites the canopy extinction coefficient could be described as a linear function of the site spring time plant population (P < 0·01). A more detailed model considered canopy light attenuation to vary between sites according to sowing date and autumn/winter plant establishment and environment.

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 232
Author(s):  
Nangial Khan ◽  
Fangfang Xing ◽  
Lu Feng ◽  
Zhanbiao Wang ◽  
Minghua Xin ◽  
...  

The number of cotton plants grown per unit area has recently gained attention due to technology expense, high input, and seed cost. Yield consistency across a series of plant populations is an attractive cost-saving option. Field experiments were conducted to compare biomass accumulation, fiber quality, leaf area index, yield and yield components of cotton planted at various densities (D1, 1.5; D2, 3.3; D3, 5.1; D4, 6.9; D5, 8.7; and D6, 10.5 plants m−2). High planting density (D5) produced 21% and 28% more lint yield as compared to low planting density (D1) during both years, respectively. The highest seed cotton yield (4662 kg/ha) and lint yield (1763 kg/ha) were produced by high plant density (D5) while the further increase in the plant population (D6) decreased the yield. The increase in yield of D5 was due to more biomass accumulation in reproductive organs as compared to other treatments. The highest average (19.2 VA gm m−2 d−1) and maximum (21.8 VM gm m−2 d−1) rates of biomass were accumulated in reproductive structures. High boll load per leaf area and leaf area index were observed in high planting density as compared to low, while high dry matter partitioning was recorded in the lowest planting density as compared to other treatments. Plants with low density had 5% greater fiber length as compared to the highest plant density, while the fiber strength and micronaire value were 10% and 15% greater than the lowest plant density. Conclusively, plant density of 8.7 plants m−2 is a promising option for enhanced yield, biomass, and uniform fiber quality of cotton.


2009 ◽  
Vol 55 (No. 2) ◽  
pp. 85-91 ◽  
Author(s):  
Q. Li ◽  
M. Liu ◽  
J. Zhang ◽  
B. Dong ◽  
Q. Bai

To better understand the potential for improving biomass accumulation and radiation use efficiency (RUE) of winter wheat under deficit irrigation regimes, in 2006–2007 and 2007–2008, an experiment was conducted at the Luancheng Experimental Station of Chinese Academy of Science to study the effects of deficit irrigation regimes on the photosynthetic active radiation (PAR), biomass accumulation, grain yield, and RUE of winter wheat. In this experiment, field experiment involving winter wheat with 1, 2 and 3 irrigation applications at sowing, jointing, or heading stages was conducted, and total irrigation water was all controlled at 120 mm. The results indicate that irrigation 2 or 3 times could help to increase the PAR capture ratio in the later growing season of winter wheat; this result was mainly due to the changes in the vertical distributions of leaf area index (LAI) and a significant increase of the LAI at 0–20 cm above the ground surface (LSD, <i>P</i> < 0.05). Compared with irrigation only once during the growing season of winter wheat, irrigation 2 times significantly (LSD, <i>P</i> < 0.05) increased aboveground dry matter at maturity; irrigation at sowing and heading or jointing and heading stages significantly (LSD, <i>P</i> < 0.05) improved the grain yield, and irrigation at jointing and heading stages provided the highest RUE (0.56 g/mol). Combining the grain yield and RUE, it can be concluded that irrigation at jointing and heading stages has higher grain yield and RUE, which will offer a sound measurement for developing deficit irrigation regimes in North China.


1983 ◽  
Vol 100 (2) ◽  
pp. 351-358 ◽  
Author(s):  
C. F. Green ◽  
L. V. Vaidyanathan ◽  
M. N. Hough

SUMMARYSequential dry-matter measurements for winter wheat crops grown at different sites during different seasons were plotted against accumulated potential evaporation. A relation consisting of two intersecting straight lines represented the observations. Early crop growth had a gentle slope due to an incomplete leaf canopy. Later growth occurred at a rate which depended upon the amount of applied nitrogen, the amount of radiation and the availability of water. The intersection occurred consistently at a leaf area index of 1·25.


2000 ◽  
Vol 134 (1) ◽  
pp. 13-23 ◽  
Author(s):  
J. E. OLESEN ◽  
L. N. JØRGENSEN ◽  
J. V. MORTENSEN

Data from a three factor experiment carried out during two years were used to analyse the effects of drought, nitrogen and disease on light interception (IPAR) and radiation use efficiency (RUE) in winter wheat (Triticum aestivum L.). The factors in the experiment comprised four irrigation strategies including no irrigation, three nitrogen levels providing 67, 83 and 100% of the recommended nitrogen rate, and two strategies for control of leaf diseases (with and without fungicides). Light interception was estimated from weekly measurements of crop spectral reflectance. This method was compared with estimates derived from crop area index measured by plant samples or by using the LAI2000 instrument. There was a good correspondence between the different methods before anthesis, but an overestimation of light interception with the methods using crop area index after anthesis due to an increase in non-photosynthetic active leaf area. Irrigation increased both IPAR and RUE. The relative increase in IPAR for irrigation was greater than the relative increase in RUE in the first year, whereas they were of similar size in the second year. The differences between the years could be attributed to changes in timing of the drought relative to crop ontogenesis. Increasing nitrogen rate increased IPAR, but caused a small decrease in RUE in both years. This reduction in RUE with increasing nitrogen concentration in leaves was also found to be significant when disease levels and drought effects were included in a multiple linear regression. Fungicide application increased IPAR in both years, but RUE was only significantly reduced by disease in the first year, where mildew dominated the trial. The data were also used to estimate the coefficients of partitioning of dry matter to grains before and after anthesis. About 40% of dry matter produced before anthesis and about 60% after anthesis was estimated to contribute to grain yield. The low fraction after anthesis is probably due to the fact that it was not possible to estimate changes in RUE with time, which may lead to biases in the estimation of partitioning coefficients.


2002 ◽  
Vol 74 (2-3) ◽  
pp. 131-149 ◽  
Author(s):  
J.E. Olesen ◽  
B.M. Petersen ◽  
J. Berntsen ◽  
S. Hansen ◽  
P.D. Jamieson ◽  
...  

1986 ◽  
Vol 107 (3) ◽  
pp. 621-627 ◽  
Author(s):  
S. K. Bandyopadhyay ◽  
R. De

SUMMARYField experiments made for 2 years under semi-arid unirrigated conditions of north India examined the physiological factors affecting the growth and yield of sorghum when intercropped with groundnut (Arachis hypogaea), mung (Vigna radiata) or cow pea (V. unguiculata). Dry-matter production and leaf area index of sorghum were increased when intercropped with any of the legumes. The mixture advantage was reflected in delaying the senescence of sorghum leaves. Maximum grain and stover yields of sorghum were obtained in a mixture with mung or cow pea. The higher seed yield resulted from more seeds per panicle and greater panicle and 1000-grain weight.


Author(s):  
A. A. Torop ◽  
V. V. Chaykin ◽  
E. A. Torop ◽  
I. S. Brailova ◽  
S. A. Kuzmenko

We compared peculiarities of the production process of the older and modern(created 80 years after) sorts of winter rye. It is determined that the specific coenotic productivity of a modern sort is 60.6% higher.This increase is due to higher number of productive sprouts per unit area and higher sprout weight. The coenosis of modern sorts is highly resistant to lodging. The modern sort has a 33.5% higher leaf surface index and a 17.7% higher share of the leaves in the upper tier, differing in their erectile orientation in space. As for the content of total chlorophyll in the dry matter of leaves and vagina, the modern sort is inferior to the older by 30.2%during theearing period, and by 17.5%during the milky-wax ripeness period.As for the content of total chlorophyll in the sowing area, the compared sorts were practically the same, but the ratio between chlorophyll a and c was noticeably different. As for the chlorophyll content in stems, in dry matter and in the area of ​​sowing, the modern sort is inferior by1.5 times and more to the older in both observation terms. The sorts differed in the biomass accumulation and its distribution between the parts during the vegetation period. To establish the ear productivity, the older sort used only the current photosynthesis products.In conditions of an unfavorable growth year, the modern sort used previously accumulated by leaves and re-utilized assimilates. The actual and potential productivity of an ear in a modern sort is higher by 77.4 and 68.0%, respectively, but the degree of its vegetative mass supply is lower by 48.6%.Only due to the higher, by 77.4%, utilization of the mass of the sprout, the modern sort binds a greater number of grains in the ear with a higherseparate mass.Since the sharp increase in the ear productivity potential was not accompanied by the same growth of the sprout vegetative mass, the modern sort, in unfavorable conditions for growth, has tensions in the relation system between the sprout vegetative mass and pouring grain. This may be the reason of the unstable achievedyield level.


Weed Science ◽  
1999 ◽  
Vol 47 (6) ◽  
pp. 712-719 ◽  
Author(s):  
Anne Légère ◽  
Yuguang Bai

The robustness of competitive attributes of cereals such as rapid and uniform seedling emergence, tillering, early biomass accumulation and canopy closure, and height advantage over weeds have not yet been tested under environmental conditions typical of no-till (NT) cropping systems. Our objective was to evaluate the effects or NT practices on growth and productivity ofAvena sativa, Triticum aestivum, Hordeum vulgare, and associated weeds. The experiment was conducted on a Kamouraska clay at La Pocatière, QC, in 1994, 1995, and 1996.Avena sativa, T. aestivum, andH. vulgarewere grown under tilled and NT practices. Cereal growth parameters were measured six (1994) or seven (1995) times between planting and the 11th week after planting but only once in 1996. Grain yields and yield components were determined at crop maturity.Avena sativaandH. vulgarepopulations were little affected by tillage, whereasT. aestivumpopulations were reduced by 16 to 20% in NT systems. Growth in height in NT systems was either similar or greater than in tilled systems in all three cereals. Cereal leaf area index (LAI) and biomass accumulation was also comparable between tillage systems, except forT. aestivumLAI in 1994, which was greater in tilled plots on two sampling dates. Response of annual dicots to tillage was inconsistent in all crops. Annual monocots dominated in some but not all NT systems. Perennial dicots dominated in NT systems, whereas perennial monocots were more abundant in tilled systems in all three cereals.Avena sativaandT. aestivumyields in NT plots were comparable or greater than in tilled plots, in spite of having either lower test weights (A. sativa) or lower 1,000-grain weights (T. aestivum). NTT. aestivumproductivity was maintained in spite of reduced plant establishment.Hordeum vulgareyields were also similar across tillage systems, except in 1995, when yields in tilled plots were greater than in NT plots. The height advantage observed for NTH. vulgaredid not result in improved yields. All three cereals, and particularlyA. sativa, appeared well suited to NT systems, despite the pressure provided by different weed groups, compared to tilled systems. However, results suggest that NT production of cereals could benefit from improved attention to perennial dicot control and crop seedling establishment, particularly forT. aestivum.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xiaodan Wang ◽  
Yaliang Wang ◽  
Yuping Zhang ◽  
Jing Xiang ◽  
Yikai Zhang ◽  
...  

AbstractDetermination of the optimal fertilization method is crucial to maximize nitrogen use efficiency and yield of different rice cultivars. Side-deep fertilization with controlled-release nitrogen, in conjunction with machine transplanting and subsequent topdressing, was applied to Indica–japonica hybrid rice ‘Yongyou1540’ (YY1540) and indica hybrid rice ‘Tianyouhuazhan’ (TYHZ). Four nitrogen treatments were applied in 2018 and 2019: traditional nitrogen application with quick-release nitrogen (T1), single-dose deep fertilization at transplanting with 100% controlled-release nitrogen (T2), and deep fertilization of 70% controlled-release nitrogen and topdressing of 30% quick nitrogen at tillering (T3), or at panicle initiation (T4). Side-deep fertilization reduced the fertilizer application frequency without causing yield loss, T4 enhanced the yield of YY1540 by increasing the number of productive tillers and number of spikelets per panicle compared with T1, T2 and T3. The yield of TYHZ showed no significant difference among treatments. The T4 treatment decreased the number of tillers at the tilling peak stage and increased the percentage productive tillers and number of differentiated spikelets. Compared with the other treatments, T4 increased dry matter accumulation and leaf area index during panicle initiation and grain ripening, and contributed to enhanced nitrogen uptake and nitrogen utilization in YY1540. On average, nitrogen uptake and utilization in YY1540 were highest in T4, but no significant differences among treatments were observed in TYHZ. Dry matter accumulation and nitrogen uptake from panicle initiation to heading of YY1540 were correlated with number of spikelets per panicle, but no significant correlations were observed for TYHZ. Supplementary topdressing with quick-release nitrogen at the panicle initiation stage was required to increase yield of indica–japonica hybrid rice, whereas single-dose deep fertilization with controlled-release nitrogen is satisfactory for the indica hybrid cultivar.


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