Competition between maize and Rottboellia exaltata

1975 ◽  
Vol 84 (2) ◽  
pp. 305-312 ◽  
Author(s):  
P. E. L. Thomas ◽  
J. C. S. Allison
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Field Experiments ◽  
Plant Density ◽  
Seedling Emergence ◽  
Total Yield ◽  
Dry Weight ◽  
Maize Yield ◽  
One Pot ◽  
Maize Grain

SUMMARYOne pot and five field experiments were made to study different aspects of the competition between R. exaltata and maize.The growth of young maize plants was not inhibited by being grown together in pots with young R. exaltata plants. In the field the soil tended to be somewhat wetter when the two species were grown together than when maize was grown alone, and was wettest with R. exaltata grown alone. Maize grain and total yield decreased and shoot yield of R. exaltata increased with R. exaltata plant density on both irrigated and unirrigated blocks of land, but yields were not much affected on either block by increase in plant density of maize or in nitrogen supply; maize yield was increased by irrigation but that of R. exaltata was not. Maize plant arrangement did not greatly affect maize grain and total yield or R. exaltata shoot yield, nor did arrangement of R. exaltata plants have much influence on their depression of maize yield, but R. exaltata caused a greater decrease in the grain yield of a short than of a tall maize cultivar.R. exaltata plants germinating at the same time as the crop plants did not have much effect on maize grain yield if they were removed by 8 weeks after the seedlings emerged, but decreased it considerably if allowed to remain for 12 weeks or more; weeds sown 2 or more weeks after the maize emerged hardly grew and had little effect on maize yield. When maize and R. exaltata were grown together leaf area of the maize was little affected up to the time of flowering, but was decreased after flowering, while leaf area of the weed was greatly depressed. Up to 7–8 weeks after seedling emergence more of the ground area was covered by foliage when maize was grown with R. exaltata than when it was grown alone, but later the ground was completely covered by foliage in both cases. Dry weight of grain and shoot of maize increased and that of shoot of R. exaltata decreased when the weed plants were shortened with growth regulators.

scholarly journals Leaf Removal Affects Maize Morphology and Grain Yield

Agronomy ◽  
2020 ◽  
Vol 10 (2) ◽  
pp. 269 ◽  
Author(s):  
Guangzhou Liu ◽  
Yunshan Yang ◽  
Wanmao Liu ◽  
Xiaoxia Guo ◽  
Jun Xue ◽  
...  
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Field Experiments ◽  
Photosynthetic Capacity ◽  
Maize Yield ◽  
Light Distribution ◽  
Planting Density ◽  
Leaf Removal ◽  
Area Index ◽  
Source Sink

Increasing planting density is an important practice associated with increases in maize yield, but densely planted maize can suffer from poor light conditions. In our two-year field experiments, two morphologically different cultivars, ZD958 (less compact) and DH618 (more compact), were planted at 120,000 plants ha−1 and 135,000 plants ha−1, respectively. We established different leaf area index (LAI) treatments by removing leaves three days after silking: (1) control, no leaves removed (D0); (2) the two uppermost leaves removed (D1); (3) the four uppermost leaves removed (D2); (4) the leaves below the third leaf below the ear removed (D3); (5) the leaves of D1 and D3 removed (D4); (6) the leaves of D2 and D3 removed (D5). Optimal leaf removal improved light distribution, increased photosynthetic capacity and the post-silking source-sink ratio, and thus the grain yield, with an average LAI of 5.9 (5.6 and 6.2 for ZD958 and DH618, respectively) for the highest yields in each year. Therefore, less-compact cultivars should have smaller or fewer topmost leaves or leaves below the ear that quickly senesce post-silking, so as to decrease leaf area and thus improve light distribution and photosynthetic capacity in the canopy under dense planting conditions. However, for more compact cultivars, leaves below the ear should senesce quickly after silking to reduce leaf respiration and improve the photosynthetic capacity of the remaining top residual leaves. In future maize cultivation, compact cultivars with optimal post-silking LAI should be adopted when planting densely.

Management of Cogongrass (Imperata cylindrica) with Velvetbean (Mucuna pruriens var. utilis) and Herbicides

1999 ◽  
Vol 13 (2) ◽  
pp. 201-208 ◽  
Author(s):  
Udensi E. Udensi ◽  
I. Okezie Akobundu ◽  
Albert O. Ayeni ◽  
David Chikoye
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Maize Yield ◽  
Imperata Cylindrica ◽  
Mucuna Pruriens ◽  
Maize Grain Yield ◽  
Maize Grain ◽  
Herbicide Effects ◽  
Density And Biomass ◽  
Annual Weeds

Field experiments were conducted in 1992 to 1993 and in 1995 to 1996 in Ibadan, Nigeria, to assess the effect of velvetbean and herbicides on maize (corn) and cogongrass growth and to assess regrowth of the weed 1 yr after treatment. In 1992 and 1995 cover cropping with velvetbean and imazapyr and glyphosate application reduced cogongrass density as much as the handweeded control. The smothering effect of velvetbean was equivalent to that of glyphosate at 1.8 kg/ha but was less than imazapyr even at the lowest rate of 0.5 kg/ha. Addition of adjuvant did not improve the efficacy of either herbicide. Maize grain yield was higher in velvetbean plots than in fallow plots dominated by cogongrass. Velvetbean and herbicide effects on cogongrass 1 yr later (1993 and 1996) followed a similar trend as observed in the year of application. Annual weed density was highest in glyphosate plots, followed by imazapyr, and least in plots previously seeded to velvetbean. Maize grain yield was higher in herbicide plots (average yield of 3,170 and 1,920 kg/ha in 1993 and 1996, respectively) than in velvetbean plots (2,800 to 1,180 kg/ha in 1993 and 1996, respectively) and handweeded plots (2,890 and 723 kg/ha in 1993 and 1996, respectively). In 1996 the lowest maize yield was in handweeded plots without velvetbean, suggesting that weeding four times suppressed cogongrass density and biomass, but was not sufficient to minimize the subsequent competition from annual weeds. Uncontrolled cogongrass reduced maize yield to zero. These studies suggest that planting velvetbean for cogongrass control may be a better alternative for farmers without the resources to purchase herbicides.

scholarly journals Influence of seed priming and water stress on selected physiological traits of borage

2015 ◽  
Vol 27 (2) ◽  
pp. 151-159 ◽  
Author(s):  
Soheila Dastborhan ◽  
Kazem Ghassemi-Golezani
Keyword(s):  
Medicinal Plant ◽  
Grain Yield ◽  
Leaf Area Index ◽  
Leaf Area ◽  
Field Experiments ◽  
Seedling Emergence ◽  
Field Performance ◽  
Stability Index ◽  
Seed Priming ◽  
Area Index

Abstract Borage is a valuable medicinal plant with various constituents in leaves, flowers and seeds. Hence, it is important to improve the performance of this medicinal plant under different environmental conditions. Thus, two field experiments were arranged as split-plots based on a RCB design with three replications in 2012 and 2013, to evaluate the effects of seed priming and different irrigation intervals on selected physiological properties of borage leaves. Irrigation intervals (irrigation after 60, 90, 120, 150 mm evaporation from Class A pans, respectively) and priming treatments (control, water, KNO3 and KH2PO4) were allocated to the main and sub plots, respectively. The chlorophyll content index was enhanced under limited irrigation treatments, mainly due to a decrease in leaf area index and intercepting more radiation. However, the membrane stability index was stable under different irrigation intervals. Decreased relative water content and leaf area index and increased leaf temperature under lower water availability led to some reductions in the grain yield of borage. All of the priming techniques, particularly hydro-priming, enhanced the seedling emergence rate, leaf area index and consequently grain yield per unit area. Therefore, seed hydro-priming can be used to improve the field performance of borage, particularly when sufficient water is available.

EFFECT OF VARYING MAIZE DENSITIES ON INTERCROPPED MAIZE AND SOYBEAN IN NEPAL

2005 ◽  
Vol 41 (3) ◽  
pp. 365-382 ◽  
Author(s):  
R. B. PRASAD ◽  
R. M. BROOK
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Field Experiments ◽  
Light Transmission ◽  
Maize Yield ◽  
Row Spacing ◽  
Area Index ◽  
The University ◽  
On Farm ◽  
Photosynthetic Adaptation

Maize and soybean are commonly intercropped in the drier zones of the western mid-hills in Nepal, but farmers report that productivity of soybean has been declining in recent years. Two researcher managed on-farm field experiments were conducted in the mid-hills environment of Nepal during 2001 and 2002, and one glasshouse experiment at the University of Wales, Bangor during 2003, to determine whether varying densities of maize and soybean influenced productivity of the system and to what extent soybean exhibited adaptation to shade. In neither season was maize yield affected by the presence of soybean, but grain yield of soybean was reduced in mixture by means of 59 and 53% during 2001 and 2002 respectively. Biomass and grain yield of maize were greatest at 53×103 plants ha−1 and least at the lowest density, whilst conversely biomass and grain yield of soybean increased. With increasing maize density, rates of accumulation of dry matter and leaf area index also increased, the latter resulting in decreasing transmission of light to the intercropped soybean. Soybean exhibited no photosynthetic adaptation to shade, but the specific leaf area was greater in artificially shaded and intercropped plants. Land equivalent ratios of all intercrops were greater than unity (1.30 to 1.45), indicating higher efficiency of intercropping compared to sole crops. Given the low plasticity in response of the maize canopy to variations in density, it is suggested that soybean could be better grown under maize by increasing between-row spacing of maize from 0.75 to 1.0 m to improve light transmission to the understorey, resulting in higher overall productivity of the intercropping system, and also that soybean germplasm be screened for adaptation to shade.

Physiology of Grain Yield in Groundnuts (Arachis hypogea)

1977 ◽  
Vol 13 (1) ◽  
pp. 101-110 ◽  
Author(s):  
B. A. C. Enyi
Keyword(s):  
Growth Rate ◽  
Grain Yield ◽  
Leaf Area ◽  
Land Surface ◽  
Plant Density ◽  
Dry Weight ◽  
Crop Growth ◽  
Crop Growth Rate ◽  
Arachis Hypogea ◽  
Leaf Area Duration

SUMMARYDodoma Edible outyielded Natal Common groundnut, due to varietal effects associated with differences in pod number, leaf area duration, crop growth rate, number of grains/pod and m2, and weight of individual grain. Increase in plant density led to an increase in grain yield. There was a close and positive relation between stem and pod dry weight; grain yield and leaf area duration; and crop growth rate, grain yield and grain number/m2 of land surface. A greater proportion of total dry matter was diverted into the stems of Dodoma Edible than Natal Common.

Effect of applying nitrogen to cereals in the spring or at ear emergence

1962 ◽  
Vol 58 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Gillian N. Thorne
Keyword(s):  
Grain Yield ◽  
Leaf Area ◽  
Field Experiments ◽  
Spring Barley ◽  
Dry Weight ◽  
Early Application ◽  
Low Efficiency ◽  
Total Dry Weight ◽  
Effect On Yield ◽  
Ear Number

Nitrogen applied at ear emergence to winter wheat or spring barley grown in pots with various levels of basal nitrogen fertilizer, increased grain and total dry weight much less than similar amounts of nitrogen applied in March or April. No nitrogen was absorbed after ear emergence from unfertilized soil, or from the early application, and at maturity equal amounts of nitrogen had been absorbed from early and late applications.Early nitrogen increased final ear number by increasing the number at emergence and also increased grain size. Late nitrogen had negligible effect on yield of ears present when it was applied and caused the production of new shoots with small ears. Nitrogen applied at both times increased leaf area duration after ear emergence similarly; early nitrogen by increasing area at ear emergence and late nitrogen by delaying senescence of existing shoots and causing production of new shoots. The efficiency in grain production of the leaf area present after ear emergence was less with late than with early nitrogen, mainly because of the low efficiency of the shoots produced after ear emergence.These results differed from those of field experiments in which early and late nitrogen usually increased grain yield similarly, probably because in the field there were no late unproductive tillers and all the late nitrogen was utilized in increasing grain yield of existing shoots. Another difference was that nitrogen uptake from soil in the field continued until maturity.

Responses of maize (Zea mays L.) hybrids to sowing date, N fertiliser and plant density in different years

2005 ◽  
Vol 53 (2) ◽  
pp. 119-131 ◽  
Author(s):  
Z. Berzsenyi ◽  
D. Q. Lap
Keyword(s):  
Grain Yield ◽  
Field Experiments ◽  
Plant Density ◽  
Maximum Yield ◽  
Quadratic Function ◽  
Sowing Date ◽  
Yield Response ◽  
Maize Hybrids ◽  
Grain Moisture ◽  
Maize Grain

The responses of Hungarian-bred maize hybrids with different vegetation periods to sowing date, N fertiliser and plant density were studied in small-plot field experiments between 2002 and 2004. The maize grain yield was highest in the early and optimum sowing date treatments (8.563 and 8.325 t ha-1) and significantly less in the late and very late treatments (7.908 and 7.279 t ha-1). The year had a substantial effect on both the yield and the grain moisture content. In a long-term maize monoculture experiment set up in 1961, the N fertiliser responses of 6 maize hybrids with different vegetation periods were investigated. Averaged over the years 2002 and 2004 the maize grain yields in the N treatments were as follows (t ha-1): N0: 4.780, N80: 7.479, N160: 8.577, N240: 8.226. The grain yield and yield stability of maize were greatest at a N rate of 160 kg ha-1. The yield response was similar in both years, but the year had a considerable effect on the yield level. The N supplies to maize plants during the vegetation period could be well characterised using a SPAD 502 chlorophyll meter in the R3 phenological stage (18-22 days after silking). The plant density responses of maize hybrids were described by fitting a quadratic function to the data of 19-22 hybrids in the years 2002-2004. The optimum plant density averaged over the hybrids was between 67,483 and 70,161 plants ha-1. The maximum yield associated with optimum plant density was 7.978 t ha-1 in 2002, 6.60 t ha-1 in 2003 and 9.37 t ha-1 in 2004. The annual patterns of plant density responses for the maize hybrids exhibited considerable differences.

Brown manuring optimization in maize: impacts on weeds, crop productivity and profitability

2019 ◽  
Vol 157 (7-8) ◽  
pp. 599-610
Author(s):  
T. K. Das ◽  
S. Ghosh ◽  
C. P. Nath
Keyword(s):  
Grain Yield ◽  
Weed Management ◽  
Field Experiments ◽  
Dry Weight ◽  
Crop Productivity ◽  
Cyperus Rotundus ◽  
Seed Rate ◽  
Maize Productivity ◽  
Maize Grain Yield ◽  
Maize Grain

AbstractField experiments were carried out in order to investigate if brown manuring (BM) using Sesbania plants can be used to control weeds in maize, especially Cyperus rotundus (Experiment I), and further to optimize the BM technology through appropriate Sesbania seed rate (S), 2,4-D application time (T) and dose (D) (Experiment II). Each BM treatment received a pre-emergence application of pendimethalin 1.0 kg a.i./ha. Experiment I showed that the BM practice using 15 kg/ha Sesbania seed and 2,4-D 0.50 kg a.i./ha applied at 25 DAS led to better control of weeds, especially C. rotundus and higher maize grain yield. Further optimization studies (Experiment II) indicated that among the factors S, T and D, the BM combination S~25 kg/ha, D~0.50 kg a.i./ha and T~25 DAS (i.e. S25T25D0.50) resulted in lowest weed density (3.1/m2) and dry weight (3.8 g/m2) and highest weed control index (89.2%) at 60 days after sowing (DAS) which was at par with another BM practice S15T25D0.50. However, the later BM combination led to significantly higher maize productivity (5.25 t/ha) and profitability (net returns (NR) $878/ha), which were 103 and 280% higher, respectively, than the weedy check (WC). The Sesbania seed rate S~15 kg/ha gave 7% higher maize grain yield and 12% higher NR than its corresponding level S~25 kg/ha. Therefore, Sesbania BM with 15 kg seeds/ha and 2,4-D at 0.50 kg a.i/ha applied at 25 DAS can be recommended for effective and eco-friendly weed management in maize, which would provide higher maize grain yield and enhance farmers' profitability.

scholarly journals Optimizing Grain Yield and Water Use Efficiency Based on the Relationship between Leaf Area Index and Evapotranspiration

Agriculture ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 313
Author(s):  
Guoqiang Zhang ◽  
Bo Ming ◽  
Dongping Shen ◽  
Ruizhi Xie ◽  
Peng Hou ◽  
...  
Keyword(s):  
Grain Yield ◽  
Water Use Efficiency ◽  
Leaf Area Index ◽  
Water Use ◽  
Plant Density ◽  
Maize Yield ◽  
Area Index ◽  
Irrigation Level ◽  
Use Efficiency ◽  
The Relationship

Achieving optimal balance between maize yield and water use efficiency is an important challenge for irrigation maize production in arid areas. In this study, we conducted an experiment in Xinjiang China in 2016 and 2017 to quantify the response of maize yield and water use to plant density and irrigation schedules. The treatments included four irrigation levels: 360 (W1), 480 (W2), 600 (W3), and 720 mm (W4), and five plant densities: 7.5 (D1), 9.0 (D2), 10.5 (D3), 12.0 (D4), and 13.5 plants m−2 (D5). The results showed that increasing the plant density and the irrigation level could both significantly increase the leaf area index (LAI). However, LAI expansion significantly increased evapotranspiration (ETa) under irrigation. The combination of irrigation level 600 mm (W3) and plant density 12.0 plants m−2 (D4) produced the highest maize yield (21.0–21.2 t ha−1), ETa (784.1–797.8 mm), and water use efficiency (WUE) (2.64–2.70 kg m−3), with an LAI of 8.5–8.7 at the silking stage. The relationship between LAI and grain yield and evapotranspiration were quantified, and, based on this, the relationship between water use and maize productivity was analyzed. Moreover, the optimal LAI was established to determine the reasonable irrigation level and coordinate the relationship between the increase in grain yield and the decrease in water use efficiency.

Characteristics of the canopy, root system and grain yield of a crop of Lupinus angustifolius cv. Unicrop

1975 ◽  
Vol 26 (3) ◽  
pp. 497 ◽  
Author(s):  
EAN Greenwood ◽  
P Farrington ◽  
JD Beresford
Keyword(s):  
Carbon Dioxide ◽  
Grain Yield ◽  
Leaf Area ◽  
Time Course ◽  
Dry Weight ◽  
Grain Filling ◽  
Main Axis ◽  
Carbon Dioxide Exchange ◽  
Area Index ◽  
Plant Parts

The time course of development of a lupin crop was studied at Bakers Hill, Western Australia. The aim was to gain insight into the crop factors influencing yield. Weekly measurements were made of numbers and weights of plant parts, and profiles of roots, leaf area and light interception. A profile of carbon dioxide in the crop atmosphere was taken at the time of maximum leaf area, and the net carbon dioxide exchange (NCE) of pods was estimated for three successive weeks. The crop took 10 weeks to attain a leaf area index (LAI) of 1 and a further 9 weeks to reach a maximum LAI of 3.75, at which time only 33% of daylight reached the pods on the main axis. Once the maximum LAI was attained at week 19, leaf fall accelerated and rapid grain filling commenced almost simultaneously on all of the three orders of axes which had formed pods. Measurements of NCE between pods on the main axis and the air suggest that the assimilation of external carbon dioxide by the pods contributed little to grain filling. Grain dry weight was 2100 kg ha-1 of which 30%, 60% and 10% came from the main axis, first and second order apical axes respectively. Only 23% of the flowers set pods and this constitutes an important physiological limitation to grain yield.

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