Phosphorus content of the soil influences the growth and productivity of Themeda triandra Forssk. and Microlaena stipoides (Labill.) R.Br.

2014 ◽  
Vol 36 (3) ◽  
pp. 233 ◽  
Author(s):  
Cameron E. F. Clark ◽  
Meredith L. Mitchell ◽  
Mohammed R. Islam ◽  
Brent Jacobs

Despite native grasses occupying a large area of land in Australia, there has been limited work on the responses of these species to the addition of phosphorus (P). The main objective of this study was to investigate the effect of the addition of P to create a range of P contents in the soil on the productivity and morphology of two native grasses at two times of harvests. Two contrasting perennial native grasses, namely kangaroo grass (Themeda triandra Forssk. syn. T. australis R. Br. Stapf) and weeping grass [Microlaena stipoides var. stipoides (Labill.) R. Br.] were grown in a glasshouse with the addition of P to create five contents of P in the soil (7, 17, 32, 107 and 307 mg kg–1 soil) using a completely randomised design with four replicates per treatment. Grasses were harvested to 5 cm above the substrate surface, and the number of tillers and leaf area were recorded on Day 84 (harvest 1) and Day 112 (harvest 2) of the experiment. Dry matter production for kangaroo and weeping grass increased with P contents of the soil of 32 mg and ≥107 mg P kg–1 soil, respectively. Increased dry matter production for both species was the result of increased leaf area, tiller number and root growth. These results provide data that help to understand the disappearance sequence of kangaroo grass from more fertile soils and an increase in weeping grass, particularly in soils with greater fertility. Further research is required to determine if these results hold for other grass ecotypes.

2010 ◽  
Vol 39 (8) ◽  
pp. 1666-1675 ◽  
Author(s):  
Marcio Mahmoud Megda ◽  
Francisco Antonio Monteiro

The objective of this work was to study morphogenic characteristics, and dry matter production of roots and shoots of marandu palisadegrass (Brachiaria brizantha cv. Marandu) submitted to combinations of nitrogen and potassium, in a nutritive solution, employing silica as substrate. The experiment was carried out in a greenhouse during the summer. It was used a 5² fractionated factorial scheme with 13 combinations of nitrogen and potassium, which were distributed in a randomized block design, with four replications. The nitrogen × potassium interaction was significant for the number of tillers and leaves, for leaf area, for shoots and root section dry mass, for total length and surface and specific length and surface in the roots. Production of aerial part dry mass positively correlated with the number of tillers and leaves and grass leaf area. Nitrogen rates modulated the root system development, and the root specific length and surface decreased when high rates of nitrogen and potassium were supllied. Nitrogen and potassium influence Marandu palisadegrass morphogenic characteristics, which are determinant for grass dry matter production.


1980 ◽  
Vol 31 (6) ◽  
pp. 1103 ◽  
Author(s):  
WC Morgan ◽  
DG Parbery

As well as reducing dry matter production of lucerne, infection of 15 % of the leaf area by Pseucbpeziza medicaginis reduced digestibility by 14% and crude protein content by 16%. Infection caused oestrogenic activity in green lucerne.


1982 ◽  
Vol 22 (115) ◽  
pp. 76 ◽  
Author(s):  
KA Boundy ◽  
TG Reeves ◽  
HD Brooke

The effect of serial planting on dry matter production, leaf area, grain yield and yield components cf Lupinus angustifoiius (cvv. Uniwhite, Uniharvest and Unicrop) and L. albus (cv. Ultra) was investigated in field plots at Rutherglen in 1973 and 1974. Delayed planting reduced dry matter production of all cultivars, and leaf area for Ultra. Differences in dry matter partitioning were observed between the late flowering Uniharvest, and the early flowering Unicrop and Ultra. In Uniharvest, delayed plantings resulted in a greater proportion of total dry matter being produced during the flowering phase, whereas the reverse was true for Unicrop and Ultra. The later flowering cultivars showed marked grain yield and yield component reduction with later sowing. Yields were reduced by 160.6 kg/ha and 222.5 kg/ha for each week's delay in sowing Uniharvest and Uniwhite, respectively. This effect was offset in the early flowering cultivars by greater development of lateral branches. In addition, when Unicrop and Ultra were planted in April, pod and flower abortion on the main stem resulted from low temperatures at flowering time. Optimum sowing time was early April for Uniwhite and Uniharvest, and early May for Unicrop and Ultra. Excellent vegetative growth under ideal moisture conditions highlighted the poor harvest indices of lupins and the scope for genetic improvement in the genus.


1967 ◽  
Vol 45 (11) ◽  
pp. 2063-2072 ◽  
Author(s):  
Holger Brix

Seedlings of Douglas fir (Pseudotsuga menziesii (Mirb.) Franco) were grown in growth chambers under all combinations of three temperatures (13, 18, and 24 °C) and three light intensities (450, 1000, and 1800 ft-c). Dry matter production of leaves, stem, and roots was determined at 65 and 100 days after germination. The leaf area produced per unit of leaf dry weight and the dry matter distribution to the plant organs was measured. Net assimilation rates between the ages of 65 and 100 days were calculated. Rates of photosynthesis per unit of leaf were determined at different light intensities and temperatures, and rates of respiration of plant top and of roots were found for different temperatures.Increasing light intensity affected dry matter production in two opposing ways: (i) it increased the rate of photosynthesis per unit leaf area, and (ii) it decreased the leaf area added per unit of dry matter produced. A pronounced increase in growth with increase in temperature from 13 to 18 °C was a result of a temperature influence on production of leaf area rather than the effect of photosynthesis per unit of leaf. Net assimilation rates decreased with increase in temperature at all light intensities.


1974 ◽  
Vol 10 (2) ◽  
pp. 87-95 ◽  
Author(s):  
B. A. C. Enyi

SUMMARYApplication of dimecron to cowpea plants increased grain yield, its effect being more pronounced in widely spaced plants and those planted in March. Dimecron increased grain yield by encouraging greater leaf area development, by increasing the number of flowering inflorescences and the number of pods set per inflorescence, and by decreasing the number of shrivelled pods. March planting encouraged greater dry matter production than January and May planting. Dimecron application decreased the number of Ootheca beningseni, reduced the proportion of leaf damaged by these insects, and reduced the number of plants infested with aphids and Acidodis larvae.


1972 ◽  
Vol 8 (4) ◽  
pp. 347-353 ◽  
Author(s):  
R. H. V. Corley ◽  
C. K. Mok

SUMMARYPotassium application appeared to increase dry matter production and yield of oil palms, primarily by increasing leaf area, while nitrogen increased both leaf area and net assimilation rate. Responses to phosphorus and magnesium were harder to interpret. Production of vegetative dry matter attained a fairly constant level at the higher rates of fertilizer application, while the ratio of bunch yield to total dry matter production was little affected by fertilizer treatments. The importance of these results for oil palm breeding, and their possible value in diagnosing fertilizer requirements, are briefly discussed.


Weed Science ◽  
1981 ◽  
Vol 29 (1) ◽  
pp. 53-59 ◽  
Author(s):  
D. T. Patterson

The effects of caffeic acid, chlorogenic acid,t-cinnamic acid,p-coumaric acid, ferulic acid, gallic acid,p-hydroxybenzaldehyde, 5-sulfosalicylic acid, vanillic acid, and vanillin on growth, photosynthesis, water relations, and chlorophyll content of 3-week-old soybeans [Glycine max(L.) Merr. ‘Tracy’] grown in aerated nutrient solution were determined. At concentrations of 10−3M, caffeic,t-cinnamic,p-coumaric, ferulic, gallic, and vanillic acids significantly reduced dry matter production, leaf expansion, height, leaf production, net assimilation rate (rate of dry matter production per unit leaf area), and leaf area duration (total leaf area present during treatment interval). Chlorogenic acid,p-hydroxybenzaldehyde, 5-sulfosalicylic acid, and vanillin at 10−3M did not inhibit growth. None of the 10 compounds at 10−4M inhibited growth. At concentrations of 10−3M, caffeic,t-cinnamic,p-coumaric, ferulic, gallic, and vanillic acids severely reduced net photosynthetic rate and stomatal conductance of single, fully expanded leaves. These same compounds also caused marked reductions in leaf chlorophyll content, with net losses of chlorophyll occurring over an 86-h period after treatment.


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