Diurnal variations of chlorophyll and dry matter contents of Senna occidentalis in response to zinc and soil moisture

1997 ◽  
Vol 39 (3) ◽  
pp. 419-424 ◽  
Author(s):  
K.A. Farghali
1969 ◽  
Vol 50 (2) ◽  
pp. 92-112
Author(s):  
R. Vázquez ◽  
A. Eschenwald-Hess ◽  
M. J. Martínez-Luciano

A field experiment was conducted at Lajas Substation in order to study the effects of four irrigation and three nitrogen levels under three different seeding rates on dry-matter yields of White Native sorghum. The following irrigation treatments were tried: High moisture, plots irrigated when the average soil-moisture suction in the active root-zone reached 0.7 atm.; medium moisture, irrigated when the average soil-moisture suction reached 2.0 atm.; low moisture, irrigated when the average soil-moisture suction reached 5.0 atm., and nonirrigated plots were used as check. The nitrogen levels tested were 40, 80, and 120 pounds per acre per harvest. The seeding rates used were 10, 20, and 30 pounds per acre.


1969 ◽  
Vol 72 (2) ◽  
pp. 203-215 ◽  
Author(s):  
Maurice Eddowes

SUMMARYCompetition among maize plants in the vegetative stage of growth was postponed by application of nitrogen to the seed bed and by maintaining soil moisture near field capacity. The amount of available nitrogen was a critical factor in determining the effect of the competitive balance between nitrogen and light on maize yield. The supply of either affected the capacity of the crop to utilize the other, but ultimately light became the dominant factor.Soil moisture deficits of up to 1.0 in from field capacity, in the early stages of vegetative growth, did not reduce dry-matter accumulation and uptake of nitrogen, but in the absence of weed competition and post-planting cultivation soil moisture losses in the early stages of crop growth may be small.In 1966, maize responded quicker to surface applied than to deep-placed nitrogen and utilized the surface applied nitrogen for dry-matter accumulation more effectively.Provided that there was initially an adequate supply of nitrogen in the seed bed, there appeared to be no advantage to total yield from application of nitrogen top dressings to maize. In the West Midlands, under conditions of adequate nutrient and soil moisture supply, the optimum plant population for commercial production of forage maize was about 40000 per acre.


2002 ◽  
Vol 42 (7) ◽  
pp. 945 ◽  
Author(s):  
J. L. Jacobs ◽  
G. N. Ward ◽  
A. M. McDowell ◽  
G. Kearney

Effect of cultivation practice and sowing time on soil moisture retention at sowing, growth rates, dry matter yield, water use efficiency and nutritive characteristics (metabolisable energy, crude protein, neutral detergent fibre, water-soluble carbohydrates and starch) of turnip, pasja and rape was determined on 2 soil types (site A and B) over 2 years. Cultivation treatments were: optimum full inversion, an optimum non-inversion cultivation and over cultivated. At each site, cultivation treatments were imposed at 2 different times (early and late).Results showed few differences in soil moisture at sowing between the 3 cultivation systems. Where seedbeds were prepared earlier rather than later, soil moisture at sowing was higher. Given that there was relatively little difference in soil moisture between cultivation treatments within a sowing time, it is likely that rainfall events may have confounded cultivation effects.Apart from year 2 at site A, the water use efficiency of turnip was higher than for pasja and rape. It is proposed that the lower value in year 2 may be due to root development being retarded by low moisture availability, particularly at the later sowing date, thus leading to a lower dry matter yield.Despite no cultivation effects on soil moisture at sowing, there appeared to be clear advantages for the full inversion technique in terms of subsequent weed germination. Generally, weed numbers post germination were lower for this cultivation method compared with both non-inversion techniques. In conclusion, the cultivation techniques used had little effect on soil moisture at sowing and subsequent dry matter yields, provided the resultant seedbed was well-prepared, fine, firm and weed free. Full inversion cultivation techniques in areas where broad-leaved weeds are a problem may substantially reduce subsequent weed burdens. Early sowing where possible may reduce the likelihood of crop failure through the provision of adequate soil moisture at sowing and increase the incidence of rain during the growing period. Timing of sowing will vary according to paddock requirements during early spring (e.g. grazing or forage conservation), soil type, and trafficability for cultivation.


1971 ◽  
Vol 11 (53) ◽  
pp. 677
Author(s):  
DO Norris

Use was made of a soil, in which the indigenous rhizobia are incapable of nodulating Dolichos lablab, to study nodulation of this species resulting from lime pelleted and rock phosphate pelleted seed after storage for one day and one, two, four, six, and eight weeks at 27�C. Cellofas A was used as sticker and two strains of Rhizobium were compared. From each sowing plants were dug at eight weeks of age, and the treatments compared using the criteria : number of plants in row, per cent plants nodulated, number of nodules per plant, per cent of nodules on the crown and yield of dry matter per row. Rock phosphate pelleting was superior to lime pelleting in survival of inoculant on the seed, survival of plants in the row, and promotion of nodulation. Lime pelleting depressed yield at eight weeks of age but not at four months. Both strains of inoculant survived one month's storage satisfactorily when simply applied with sticker. Total nodule number fluctuated greatly with time of planting, and was inversely related to per cent crown nodulation, suggesting chat soil moisture at planting may have had a significant effect on nodulation. Strong interactions of inoculant strain with pelleting treatment and time of planting stressed the difficulty of interpreting nodulation effects resulting from pel!etinp treatments. Rhizobium strain CB756 was greatly superior to CB159 in survival on stored seed, nodulation criteria, onset of N fixation and yield.


1984 ◽  
Vol 20 (2) ◽  
pp. 161-170
Author(s):  
D. Boobathi Babu ◽  
S. P. Singh

SUMMARYThe effects of irrigation and spraying of transpiration suppressants on growth and nutrient uptake by spring sorghum (CSH 6) have been investigated. Crop growth, measured by plant-height, leaf area index and dry matter production, and uptake of N, P and K increased with more frequent irrigation and in response to the spraying of transpiration suppressants. Foliar applications of atrazine at 200 g ha−1 and CCC at 300 ml ha−1 proved to be the best in this NW Indian location.


2001 ◽  
Vol 49 (3) ◽  
pp. 273-282 ◽  
Author(s):  
M. Long ◽  
H. Eiszner

HALLE-WITTENBERG, HALLE(SAALE), GERMANY Received: 13 June, 2001; accepted: 6 August, 2001 Field experiments were conducted at a high latitude site for sunflower (Helianthus annuus L.) production in central Germany (51 o 24' N, 11 o 53' E) in 1996, 1997 and 1998. The responses of sunflower development to various planting patterns differed in the duration from emergence to the middle of the linear growth period as calculated via a tangent hyperbolic model F(t)=(. +ß)×tanh[. ×(t–.)]. Final dry matter accumulation showed few differences among the planting patterns: 12 plants m –2 at 50 cm row spacing at 75 cm row spacing (RS2PD2) and 4 plants m –2 at 100 cm row spacing (RS3PD1). The actual and simulated values for final dry matter were close to 1200 g m –2 . The responses of soil moisture and temperature to planting patterns changed from the upper to the deep soil layers. In a normal year, e.g. 1997, the soil water to 150 cm depth was sufficient for sunflower growth. In a drought year, e.g. 1998, soil water deeper than 150 cm was used by sunflower crops. The soil temperature was mostly lower in RS1PD3 and RS2PD2 than in RS3PD1, particularly in the upper soil, at depths of 5 and 20 cm. The most important factor defining the responses of soil moisture and temperature to planting patterns seems to be the amount of radiation penetrating the ground, which may depend on latitude, wind and row orientation.


Weed Science ◽  
1979 ◽  
Vol 27 (1) ◽  
pp. 106-109 ◽  
Author(s):  
L. A. Morrow

Studies on the development of leafy spurge (Euphorbia esula L.) were conducted in the field and growth room. Sixteen months after planting in field plots, leafy spurge plants arising from underground bud-producing root segments, transplanted seedlings, or seeds averaged 96, 83, and 136 shoots per plant, respectively, when grown free of interference from other vegetation. A number of plants arising from each source flowered the first year, and all plants flowered and produced seed the second year after planting. When grown in a perennial grass sod consisting of crested wheatgrass [Agropyron desertorum (Fisch. ex Link) Schult.] and smooth brome (Bromus inermis Leyss.), no plant flowered or produced additional shoots. Soil moisture was less where a dense sod was present. In the growth room, total dry matter of tops and roots was greatest at a soil temperature of 18.3 C or higher, and plant height was greatest at 33.3 C. An early emerging crop might suppress leafy spurge by utilizing the available soil moisture early in the growing season.


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