Dry matter accumulation and water use relationships in wheat crops

1979 ◽  
Vol 30 (5) ◽  
pp. 815 ◽  
Author(s):  
AD Doyle ◽  
RA Fischer

In order to better understand crop growth (dry matter accumulation, DM), crop evapotranspiration (Et), and their interrelationships, we studied dryland crops of wheat (Triticum aestivum L. cv. Timgalen) sown at various dates and seeding densities in each of three years at Tamworth, N.S.W. Soil water stress was minimal before anthesis in each year, but in two years substantial stress arose before maturity. DM was increased consistently by increased plant density, and decreased at anthesis and maturity by later sowing. Crop growth rates determined over 2-week intervals around anthesis ranged from 3 to 20 g m-2 d-1, representing a range in efficiency of utilization of intercepted total solar radiation of 0.48 to 2.35%, variation which was adequately explained (R2 = 0.80) by ontogeny (days from anthesis) and Et / Ep ratio (Ep = class A pan evaporation). Et at anthesis, but not at maturity, was increased slightly by higher seedmg density; crop Et was not consistently affected by sowing date. Et / Ep over 2-week periods around anthesis was related to leaf area index, and to a lesser extent to available soil water and Ep (R2 = 0.58). For the period from the first sowing date in June or July until the middle of October, the relationship of total Et to DM production was linear and close each year, but the slope varied from 6.2 g m-2 mm-1 (cold dry year) to 14.0 g m-2 mm-1 (wet year). This variation could be attributed to annual variation in the soil evaporation component of Et, and in the ratio of DM to crop transpiration (= transpiration efficiency, TE). For 2-week periods around anthesis, TE ranged from 2.9 to 5.4 g m-2 mm-1 and was inversely related to Ep (R2 = 0.56). Provided soil evaporation can be allowed for, since it ranged from 18 to 41% of crop Et from sowing to maturity, it is argued that the crop transpirationtranspiration efficiency approach is particularly useful for analysing the growth and water use of dryland wheat.

HortScience ◽  
2017 ◽  
Vol 52 (3) ◽  
pp. 441-449 ◽  
Author(s):  
Christopher Vincent ◽  
Diane Rowland ◽  
Bruce Schaffer

Primed acclimation (PA) is a regulated deficit irrigation (RDI) strategy designed to improve or maintain yield under subsequent drought stress. A previous study showed photosynthetic increases in papaya in response to a PA treatment. The present study was undertaken to test the duration of the PA effect when papaya plants were challenged with severe drought stress. Potted plants were stressed at 1, 2, and 3 months after conclusion of a PA treatment consisting of 3 weeks at soil water tension (SWT) of −20 kPa. Measurements included leaf gas exchange, root growth, and organ dry mass partitioning. PA did not reduce net CO2 assimilation (A) during the deficit period. At the end of the PA period, total dry matter accumulation per plant and for each organ was unaffected, but proportional dry matter partitioning to roots was favored. After resuming full irrigation, A increased and whole plant water use was more than doubled in PA-treated plants. However, water use and A of PA-treated plants decreased to reconverge with those of control plants by 6 weeks after the PA treatment. Over the course of the study, PA plants maintained lower stem height to stem diameter ratios, and shorter internode lengths. However, these changes did not improve photosynthetic response to any of the water-deficit treatments. We conclude that papaya exhibits some signs of stress memory, but that rapid short-term acclimation responses dominate papaya responses to soil water deficit.


2005 ◽  
Vol 56 (7) ◽  
pp. 743 ◽  
Author(s):  
Heping Zhang ◽  
Neil C. Turner ◽  
Michael L. Poole

Water use of wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), canola (Brassica napus L.), and lucerne (Medicago sativa L.) was measured on a duplex soil in the high rainfall zone (HRZ) of south-western Australia from 2001 to 2003. Rainfall exceeded evapotranspiration in all years, resulting in transient perched watertables, subsurface waterlogging in 2002 and 2003, and loss of water by deep drainage and lateral flow in all years. There was no significant difference in water use among wheat, barley, and canola. Lucerne used water at a similar rate to annual crops during the winter and spring, but continued to extract 80−100 mm more water than the annual crops over the summer and autumn fallow period. This resulted in about 50 mm less drainage past the root-zone than for annual crops in the second and third years after the establishment of the lucerne. Crop water use was fully met by rainfall from sowing to anthesis and a significant amount of water (120−220 mm) was used during the post-anthesis period, resulting in a ratio of pre- to post-anthesis water use (ETa : ETpa) of 1 : 1 to 2 : 1. These ratios were lower than the indicative value of 2 : 1 for limited water supply for grain filling. High water use during the post-anthesis period was attributed to high available soil water at anthesis, a large rooting depth (≥1.4 m), a high proportion (15%) of roots in the clay subsoil, and regular rainfall during grain filling. The pattern of seasonal water use by crops suggested that high dry matter at anthesis did not prematurely exhaust soil water for grain filling and that it is unlikely to affect dry matter accumulation during grain filling and final grain yield under these conditions.


2021 ◽  
Vol 25 (04) ◽  
pp. 751-760
Author(s):  
Weiping Yan

In order to promote the comprehensive production capacity and yield of farmland soil, the effects of subsoil tillage on soil structure, root activity, photosynthetic characteristics, dry matter accumulation, yield and water use through long-term positioning research in semi-arid areas were studied. This study was started in 2011 and investigated in the 2015–2016 research cycle. The experiment was conducted with five treatments including 30 cm subsoiling (SS-30) and 40 cm subsoiling (SS-40) before spring sowing, 30 cm (AS-30) and 40 cm (SS-40) between rows after autumn harvest and no subsoiling (CK). The effects of subsoiling on soil properties, crop growth, yield and water use of maize in semi-arid areas were investigated. The results showed that subsoiling significantly reduced the penetration resistance and bulk density of soil, and significantly increased the soil moisture content from subsoiling to the surface. Subsoiling increased GSand Ci, Tr, Pnand WUE in maize plants, and significantly increased root activity. Subsoiling significantly increased dry weight of aboveground part and root, significantly decreased root shoot ratio, and significantly increased WUE per plant. Subsoiling significantly increased 100 grain weight, yield and WUE of population. Subsoiling can effectively improve the soil structure, enhance the water storage capacity of the soil in arid areas, delay water loss, improve root activity, net photosynthetic rate, dry matter accumulation and WUE, and promote crop growth and yield of maize. Subsoiling in autumn has the best effect on soil improvement. Increasing the subsoiling depth properly can improve their effects, which will gradually less with the passage of time.© 2021 Friends Science Publishers


1998 ◽  
Vol 38 (2) ◽  
pp. 171 ◽  
Author(s):  
J. Mwanamwenge ◽  
S. P. Loss ◽  
K. H. M. Siddique ◽  
P. S. Cocks

Summary. A number of studies conducted in Western Australia have shown that faba bean has considerable potential as a pulse crop in the low to medium rainfall cropping regions (300–450 mm/year). However, its yield is variable and can be low in seasons when rainfall is less than average. Traits associated with the adaptation of 10 diverse faba bean genotypes to low rainfall, Mediterranean-type environments were evaluated at Merredin in south-western Australia over 2 contrasting seasons. Plant density was varied with seed size to ensure all genotypes achieved similar canopy development and dry matter production. Time to flowering appeared to be the most important trait influencing seed yield of faba bean in this environment. Seed yield was significantly correlated with time to 50% first flower in 1994 and 1995 (r2 = 0.61 and 0.82 respectively, P<0.01). In the dry 1994 season, rapid leaf area development in ACC286 allowed a greater absorption of photosynthetically active radiation resulting in more dry matter accumulation than other genotypes. ACC286 also had greater root length density at 20–30 cm depth compared with Icarus and the standard cultivar Fiord. There were no significant differences in total water use between the genotypes examined, although the pattern of water use varied markedly. The ratio of pre- to post-flowering water use was about 1:1 in the early flowering and high yielding ACC286 and 2.6 :1 for the late maturing, low yielding Icarus. Seed yield and harvest index were positively correlated with post-flowering water use (r2 = 0.75 and 0.71 respectively). Above-average rainfall in 1995 resulted in increased yield of all genotypes, particularly ACC286 which again produced the highest yields. Early flowering genotypes with rapid dry matter accumulation in the seedling stages (such as ACC286) could widen the adaptation of faba bean to low rainfall, Mediterranean-type environments and situations where sowing is delayed.


Biologija ◽  
2016 ◽  
Vol 62 (1) ◽  
Author(s):  
Raouf Seyed Sharifi ◽  
Ali Namvar

Crop phenology is one of the most important aspects of crop yield determination and it is essential to predicting physiological responses under varying field conditions. In order to evaluate plant density and intra-row spacing effects on phenology, dry matter accumulation, and leaf area index of maize in second cropping, a factorial experiment based on randomized complete block design was conducted at the research farm of the University of Mohaghegh Ardabili. Experimental factors were: plant population at three levels (7, 9, and 11 plants m–2) with three levels of intra-row spacing (45, 60, and 75 cm). The results showed that the maximum plant height (179.07  cm), total dry matter (592  g  m–2) in 83–91 days after sowing, days to 50% anthesis (45 days), days to 50% silking (50 days), LAI (4.07) in 63–70 days after sowing were observed in the plots with 11 plants m–2 and intra-row spacing of 45 cm. Based on the results, it was concluded that application of 11 plants m–2 with row spacing of 45 cm can be recommended for profitable maize production.


2012 ◽  
Vol 40 (1) ◽  
pp. 183
Author(s):  
Hamid MADANI ◽  
Christos DORDAS ◽  
Ahad MADANI ◽  
Mohammad-Ali MOTASHAREI ◽  
Shima FARRI

Chicory is considered one of the alternatives crops that can be used in crop rotation and contains many phytochemicals that can be used in medicine. In addition, lengthening the growing season by early sowing may increase root chicory yield potential, and thus increase its competitiveness with traditional crops. The objectives of the present study were to determine whether early sowing date risks can be decreased by higher sowing density and also to study the effect of sowing date and sowing density on dry matter accumulation and partitioning of chicory. Growing season did not affect any of the characteristics that were studied. Also plant density affected the flowers biomass, root biomass per plant and the respective yield together with the plant height and essence yield and total yield. The sowing date affected the leaf, flower and stem biomass on a plant basis. However, the interaction between plant density and sowing date affected the total biomass per plant, the flower biomass per plant, the root biomass per plant, the flower yield, the root yield and the essence yield. These results indicate that for higher production it is important to determine the right plant density and sowing date which can affect growth, dry matter accumulation and essence yield.


2020 ◽  
Vol 12 (18) ◽  
pp. 7825 ◽  
Author(s):  
Fang Yang ◽  
Rui Cen ◽  
Weiying Feng ◽  
Jing Liu ◽  
Zhongyi Qu ◽  
...  

The water-retaining and yield-increasing capacity of super-absorbent polymer (SAP) are essential for soil remediation in arid and semi-arid areas. Therefore, it is of great significance to investigate the influencing factors and mechanisms of SAP effects on soil environments and crop growth for the precise management of agricultural water-saving irrigation. In this study, we adopted SAP as a soil conditioner and monitored changes in soil temperature, photosynthetic rate, leaf transpiration rate, chlorophyll, crop growth indexes (plant height, stem diameter, leaf area index, dry matter accumulation), and yield under different SAP doses during the growth stage of maize, on the basis of which the improvement mechanism of SAP in arid and semi-arid soil was analyzed. The results demonstrated the following: (1) 45 kg/hm2 of SAP application could increase the temperature of the soil layer, effectively reduce the diurnal temperature variation of the soil surface, and promote the stable growth of maize; (2) when different SAP doses were applied, the leaf surface temperature of maize increased by 0.95 °C on average. In particular, when 135 kg/hm2 of SAP was applied, the leaf surface temperature increased by 1.55 °C; (3) SAP could promote the photosynthetic rate of maize. In addition, the plant height, leaf area index, and dry matter accumulation of maize gradually increased with an increasing amount of SAP; (4) the application of SAP not only increased the grain row number, ear row number, and average 100-seed weight, but also increased the crop yield by nearly 6%. The application of SAP demonstrated a comprehensive utility (redistribution of soil water and temperature, synergy between SAPs and plants), which suggests that the most basic goal, to ensure socio-economic and ecological sustainability in dryland systems, was obtained.


1973 ◽  
Vol 9 (2) ◽  
pp. 169-180 ◽  
Author(s):  
R. H. V. Corley

SUMMARYCrop growth rate of oil palm increases with leaf area index (LAI) to about 40 tons/ha./yr at the highest LAIs obtained. Net assimilation rate and dry matter production per palm decrease with increasing LAI, but the amount of dry matter per palm incorporated in vegetative tissues is unaffected by density. As a result the optimal LAI for oil yield is considerably below the critical LAI for maximum crop growth rate.


1986 ◽  
Vol 107 (2) ◽  
pp. 405-420 ◽  
Author(s):  
P. D. Jenkins ◽  
D M. H. Leitch

SummaryResults are reported from experiments carried out in three seasons in an environment with mild winters and early springs in which the date of sowing of winter oil-seed rape was varied from early September to early December. Consistently high seed yields were achieved in the late sowings and, in two of the three seasons, delaying sowing beyond early September resulted in significant yield increases. The pattern of dry-matter accumulation and changes in leaf area index were affected to a large extent by sowing date, but no significant effect on total dry-matter production at final harvest was found. Numbers of axillary inflorescences per plant and, in two of the experiments, numbers of fertile pods/m2, were reduced by late sowing, but large increases in numbers of seed per pod were found in each experiment. Mean weight per seed was reduced when sowing was delayed but there was no consistent effect on oil content. Differences were found between cultivars in the extent to which delayed sowing produced increased yields. It is suggested that early spring growth, delayed flowering and reduced reflexion of radiation during flowering were important factors leading to the high yields achieved by late sowings. No interactions were found between sowing date and plant population density for any yield component in one experiment.


2007 ◽  
Vol 55 (4) ◽  
pp. 417-436 ◽  
Author(s):  
Z. Berzsenyi ◽  
Q. Dang

In maize, plant density has a considerable influence on the rate of dry matter accumulation and on its partitioning between vegetative and reproductive sinks. The aim of the present research was to use the first, second and third derivatives of the Richards function (RF) for growth analysis on maize hybrids grown at various densities. In two-factorial split-plot experiments carried out in Martonvásár, Hungary in 1997–1999 the growth analysis method was used to examine the effect of six plant densities (20, 40, 60, 80, 100 and 120 thousand plants ha −1 ) on the growth of three maize hybrids (Mara, Mv 355, Florencia) with different vegetation periods. Plant density had a significant effect on the dynamics of dry matter accumulation, absolute growth rate (AGR) and absolute acceleration rate (AAR). There was a significant reduction in the asymptotic maximum (A) and growth parameters (AGR, AAR) of the whole plant and of the individual plant organs (stalk, leaf, ear and grain yield), while the parameters of the leaf area index (LAI) increased significantly with a rise in the plant density. The usefulness of the RF for approximating the growth processes of maize plants and individual plant parts was confirmed statistically.


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