scholarly journals Factors affecting the herbage iodine content.

1974 ◽  
Vol 22 (3) ◽  
pp. 195-206 ◽  
Author(s):  
J. Hartmans
Keyword(s):  
Soil Type ◽  
Dry Matter ◽  
Field Experiments ◽  
Iodine Content ◽  
Single Species ◽  
Residual Effects ◽  
Grass Species ◽  
Yield Response ◽  
N Application ◽  
Factors Affecting

In pot and field experiments, N application somewhat increased the I content of the harvested crop, although I concentrations in the herbage decreased considerably (diluting effect of increased dry matter yields). Herbage I contents were not consistently affected by chemical fertilizers which produced no yield response. I contents were up to 13 times higher in dicotyledenous pasture species than in grasses. I contents varied between grass species and to less extent between varieties of a single species. Contrary to earlier New Zealand data, good quality grasses were lower in I content than medium-value and inferior grasses. Small I dressings were less effective than larger amounts in terms of percentage return in the harvested crop; residual effects in later cuts were always small. The effectiveness of I dressings depended on soil type and tended to be lowest on soils of low natural I content. ADDITIONAL ABSTRACT: Studies were with ryegrass in pots and pastures. N dressing increased I uptake by the crop but reduced the I content considerably because of the diluting effect of higher DM yields. Dressing with fertilizers which did increase yield did not affect herbage I content consistently. Dicotyledonous species in pasture had I contents up to 13 times that of grasses. The I content of grasses varied over a 2-fold range but variation was smaller in a given species. Good quality grasses had a lower I content than inferior grasses. Smaller I dressings gave a smaller percentage return in the crop than larger amounts; the efficiency depended on soil type and tended to be less for soils with the lowest natural I content. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Trace element uptake by two British Columbia forages as affected by poultry manure application

1991 ◽  
Vol 71 (3) ◽  
pp. 305-312 ◽  
Author(s):  
A. A. Bomke ◽  
L. E. Lowe
Keyword(s):  
Dry Matter ◽  
Field Experiments ◽  
Clay Soil ◽  
Poultry Manure ◽  
Yield Response ◽  
Silty Clay ◽  
Manure Application ◽  
Deep Pit ◽  
Loam Soil ◽  
Trace Element Uptake

Field experiments evaluated yield response to deep-pit poultry manure application to barley on a clay soil near Prince George and a grass-legume forage on a silty clay loam soil near Chilliwack, B.C. Substantial dry matter yield increases were measured at manure applications up to 20 t ha−1. Subsamples of both crops and the poultry manure were analyzed for Cu, Zn, Mn, Ba, Pb, Ni, Cr, Cd, B and Co. Selenium analyses were made on selected crop samples. There were no indications of toxicity problems even at 40 t ha−1, the highest application. Copper and Zn concentrations in forages were increased by the poultry manure and the Mn/Cu ratio tended to decrease with manure application. Key words: Orchardgrass, ladino clover, barley, micronutrients

Response of Chickpea to Nitrogen, and a Comparison of the Factors Affecting Chickpea Seed Yield with those Affecting Wheat Grain Yield

1995 ◽  
Vol 31 (1) ◽  
pp. 39-47 ◽  
Author(s):  
D. J. Bonfil ◽  
M. J. Pinthus
Keyword(s):  
Seed Development ◽  
Seed Yield ◽  
Dry Matter ◽  
Growth Analysis ◽  
Field Experiments ◽  
Limiting Factors ◽  
Wheat Grain ◽  
Factors Affecting ◽  
Wheat Grains ◽  
Adjacent Field

SummaryChickpea yields in Israel are usually considerably lower than wheat yields under comparable conditions. This study aimed to examine the possible yield limiting factors in chickpeas. Increasing the availability of nitrogen during seed development by a pre-sowing application of nitrate or by nitrogen top dressing at the onset of flowering led to an increase in the percentage of nitrogen in the straw but had no significant effect on seed yield. Growth analysis of chickpeas and wheat grown in two adjacent field experiments revealed that during the fruiting period these crops accumulated similar amounts of dry matter. However, the proportion of total wheat dry matter accumulated in the wheat grains was twice the proportion of total chickpea dry matter accumulated in the chickpea seeds. It was concluded that the main intrinisic factor limiting the seed yield of chickpeas is the continuation of vegetative growth during the period of seed development, which reduces the amount of assimilate allocated to the seeds.Los factores restrictivos del rendimiento en el garbanzo

Irrigation and Nitrogen Studies in s. 23 Ryegrass Grown for Seed: 1. Growth, Development, Seed Yield Components and Seed Yield

1977 ◽  
Vol 88 (3) ◽  
pp. 605-614 ◽  
Author(s):  
P. D. Hebblethwaite
Keyword(s):  
Seed Yield ◽  
Yield Components ◽  
Seed Weight ◽  
Dry Matter ◽  
Field Experiments ◽  
Unit Area ◽  
Yield Response ◽  
Seed Yield Components ◽  
Seed Yields ◽  
Number Of Seeds

SUMMARYThe effects of irrigation and nitrogen on S. 23 perennial ryegrass grown for seed were investigated in a series of field experiments from 1972 to 1974. Irrigation significantly increased seed yield by 16% in 1972 and 52% in 1974 but had no effect in the wet year of 1973. In 1972 maximum deficit reached 110 mm at the end of July and coincided with anthesis. Consequently the yield response was due to an increase in number of seeds per unit area and no other seed yield component was affected. In 1974 peak deficit also reached about 100 mm but started to build up rapidly very early in the season and had reached 80 mm by the time that the first ears emerged. Consequently the yield response was due to increases in number of fertile tillers, number of seeds per unit area and 1000-seed weight.Irrigation had no significant effect on number of florets or seeds, except in 1974 when percentage of florets which produced seed was increased by 2%.Irrigation had some effect on threshed straw yields, total dry matter, harvest index and total number of tillers but where this occurred the response was much smaller than that of seed yield which indicates that irrigation had greater effects on the reproductive development of the crop than on yield of dry matter and tillering patterns. Increasing the quantity of nitrogen from 0 to 80 kg/ha increased seed yields, all seed yield components except 1000-seed weight, threshed straw yields and total dry matter and number of tillers at most sampling dates. Increasing the quantity of nitrogen from 80 to 160 kg/ha had little further effect on the above components except in 1972 where seed yields were significantly decreased.In 1972 number of florets was increased and percentage of florets which produced seed decreased with increasing quantities of nitrogen.

scholarly journals Effects of nitrogen on accumulation and partitioning of dry matter and nitrogen of vegetables. 3. Spinach

1996 ◽  
Vol 44 (3) ◽  
pp. 227-239
Author(s):  
H. Biemond ◽  
J. Vos ◽  
P.C. Struik
Keyword(s):  
Dry Matter ◽  
Field Experiments ◽  
Leaf Age ◽  
High Yield ◽  
Organic N ◽  
N Accumulation ◽  
N Application ◽  
N Concentration ◽  
Application Techniques ◽  
High Yields

Four greenhouse and 2 field experiments (the latter on a sandy soil) were carried out with different amounts and dates of N application to analyse the dynamics of dry matter and N accumulation in spinach (cv. Trias). Frequent measurements were carried out on dry matter and N accumulation in leaf blades, petioles and stems. The total accumulation of dry matter and N differed largely among and within experiments. Increasing N application increased yield of dry matter and N accumulation, whereas splitting N applications had much smaller effects. However, the partitioning of dry matter and N proved insensitive to N treatments. Harvest indices for dry matter (about 0.67) or N (about 0.74) of crops at a marketable stage were fairly constant over treatments and experiments. Increasing or splitting the N application affected N accumulation more than dry matter production, resulting in large effects on N concentrations. The lack of variation in response to N for different N regimes facilitates the development of N application techniques aimed at high yield, high quality and reduced emissions. The organic N concentration of leaf blades and petioles decreased with leaf age, although in most experiments this decrease was smaller at higher leaf numbers. The nitrate-N concentration decreased with increasing leaf number at any sampling date; it was higher when N was abundant. High yields in autumn crops were associated with high nitrate concentrations but also with potentially high losses of N.

Effect of duration and pattern of underfeeding in early lactation on milk production and reproduction of dairy cows

1979 ◽  
Vol 19 (99) ◽  
pp. 395 ◽  
Author(s):  
C Grainger ◽  
G Wilhelms
Keyword(s):  
Milk Fat ◽  
Dry Matter ◽  
Post Partum ◽  
Residual Effects ◽  
Early Lactation ◽  
Lactation Performance ◽  
Factors Affecting ◽  
Poor Understanding ◽  
Moderate Condition ◽  
Ad Libitum

Eighty cows of mixed breeds were fed so that they calved in moderate condition, and were then strip-grazed at different rates over the first ten weeks of lactation. Two levels of feeding were used factorially ; either ad libitum pasture intake (H) or an allowance of pasture which resulted in an intake of 7 kg of pasture dry matter cow-1 day-1 (L), for the first or second five-week period. After ten weeks, all cows were grazed as one group as well as seasonal conditions permitted. The effects of five-week periods of underfeeding on milk, milk fat and protein yield were equal and additive over the first ten weeks of lactation, HL and LH groups producing 11 kg and LL group 22 kg less milk fat than the HH group. Residual effects, however, from week 11 to the end of lactation differed markedly between treatments, the LH group producing the same as, but HL and LL groups producing 9 and 21 kg less than, the HH group. Residual effects of only 0.7 and 1.0 times the immediate effect were recorded for underfeeding in the first five and ten weeks of lactation, respectively. Cows underfed in early lactation gained more liveweight in later lactation at the expense of milk yield. An extra 10 kg pasture dry matter was required in early lactation to give an extra kilogram of milk fat over the lactation. The calving to conception interval in the LL group was 18 days longer than in the HH group (P < 0.05). The delay was associated with both a longer post-partum anoestrus and a higher number of services per conception. There was no effect of stage of underfeeding (HL vs LH) on reproductive performance. The poor understanding of factors affecting residual effects from underfeeding in early lactation is highlighted. As pattern of underfeeding has little effect on lactation performance, this gives the farmer considerable flexibility in allocating feed supplies in early lactation.

scholarly journals Tillering does not interfere on white oat grain yield response to plant density

2003 ◽  
Vol 60 (2) ◽  
pp. 253-258 ◽  
Author(s):  
Milton Luiz de Almeida ◽  
Luís Sangoi ◽  
Márcio Ender ◽  
Anderson Fernando Wamser
Keyword(s):  
Grain Yield ◽  
Dry Matter ◽  
Field Experiments ◽  
Plant Density ◽  
Dry Mass ◽  
Main Stem ◽  
Yield Response ◽  
Individual Plant ◽  
Growing Seasons ◽  
Plant Densities

Plant density is one of the cropping practices that has the largest impact on individual plant growth. This work was conducted to evaluate the response of white oat (Avena sativa) cultivars with contrasting tillering patterns to variations in plant density. Two field experiments were carried out in Lages, SC, Brazil, during the 1998 and 1999 growing seasons. A split plot experimental design was used. Four oat cultivars were tested in the main plots: UFRGS 14, UFRGS 18, UPF 16 and UPF 17 using five plant densities split plots: 50, 185, 320, 455 and 550 plants m-2. Five plant samples were taken 25, 34, 48, 58 and 70 days after plant emergence to assess the treatment effects on dry matter partition between main stem and tillers. UFRGS 18 promoted dry matter allocation to tillers whereas UPF 17 directed dry mass mostly to the main stem. Differences in dry mass allocation between the main stem and tillers had no impact on grain yield, UPF 16 presenting the highest values for both growing seasons. The lack of interaction between population density and cultivar and the small effect of plant population on grain yield indicates that the oat tillering ability is not fundamental to define its grain yield.

scholarly journals Plant density and peanut crop yield (Arachis hypogaea) in the peanut growing region of Córdoba (Argentina)

2018 ◽  
Vol 45 (2) ◽  
pp. 82-86 ◽  
Author(s):  
F.D. Morla ◽  
O. Giayetto ◽  
E. M. Fernandez ◽  
G. A. Cerioni ◽  
C. Cerliani
Keyword(s):  
Field Experiments ◽  
Plant Density ◽  
Yield Response ◽  
Factors Affecting ◽  
Growing Seasons ◽  
Peanut Crop ◽  
Wide Range ◽  
Plant Densities ◽  
Growing Conditions ◽  
Growing Region

ABSTRACT Plant density is one of the most important management factors affecting the peanut growth, modifying the capacity to capture radiation, water and nutrients. Peanut yield response to increased plant density changes according to environmental conditions, the genotype used, and planting date. Therefore, the optimum plant density (OPD) may vary with location. The aim of this project was (i) to fit the Mitscherlich's equation of diminishing productivities to the yield response of runner-type peanuts to increasing plant density under different growing conditions in the peanut growing region of Cordoba Argentina; and (ii) validate this model with independent experimental data. The first stage was based on the analysis of data from different projects of plant densities carried out in the peanut growing area of Córdoba. This information was adjusted to the decreasing yield equation and the OPD was calculated. For validation, a field experiment was conducted during the 2013/14 and 2014/15 growing seasons under irrigated and rain-fed conditions where pod yield was evaluated for 5, 12, 18, 25 and 36 plants/m2. No interaction was detected between soil moisture conditions and plant density. Yield response to plant density had a high degree of fitness for a wide range of environmental and crop conditions. In field experiments, the peanut yield decreased only at the lowest plant density (5 plants/m2). Yield response to density adjusted to the Mitscherlich equation indicated that OPD ranged from 10.5 to 24.8 plants/m2. Using a single adjustment equation y = 1(1 – e−0.1784x), OPD was estimated to be 16.8 plants/m2 at harvest (11.7 plants per linear meter in 0.7 m between rows) for the peanut growing region of Cordoba. This approach can be a valuable input, along with other variables to analyze, when choosing peanut sowing density.

The effect of nitrogen, phosphate and potash fertilizers on three grass species

1968 ◽  
Vol 70 (2) ◽  
pp. 195-202 ◽  
Author(s):  
K. Margaret Wolton ◽  
J. S. Brockman ◽  
D. W. T. Brough ◽  
P. G. Shaw
Keyword(s):  
Dry Matter ◽  
The Other ◽  
Grass Species ◽  
Yield Response ◽  
Meadow Fescue ◽  
Nutrient Yield ◽  
Second Year ◽  
Large Response

SUMMARYThe effects of annual applications of up to 300 lb/acre of N, 100 lb/acre of P2O5 and 200 lb/acre of K2O on cut swards of S. 24 ryegrass, S. 37 cocksfoot and S. 215 meadow fescue were measured in an experiment lasting 3 years.There were some differences between species in their dry-matter and nutrient yield response to nitrogen and potash applications, but not to phosphate. These differences were inconsistent and over the 3-year period were negligible.A large response to nitrogen was only fully maintained when phosphate and potash were also applied. There was no response above 50 lb/acre of P2O5 in any year. In the second year, 100 lb/acre of K2O was sufficient, but more than this was necessary in the other years. Symptoms of phosphate and potash deficiency were seen where high rates of nitrogen were applied without phosphate and potash respectively.

scholarly journals Steps in Predicting the Relationship of Yield on Fungicide Dose

2001 ◽  
Vol 91 (7) ◽  
pp. 708-716 ◽  
Author(s):  
N. D. Paveley ◽  
R. Sylvester-Bradley ◽  
R. K. Scott ◽  
J. Craigon ◽  
W. Day
Keyword(s):  
Dry Matter ◽  
Field Experiments ◽  
Sensitivity Analyses ◽  
Septoria Tritici ◽  
Yield Response ◽  
Optimum Dose ◽  
Dry Matter Accumulation ◽  
Response Curves ◽  
Marketable Yield ◽  
Area Index

A set of hypothetical steps has been defined, which links fungicide dose to marketable yield, whereby (i) increasing dose decreases symptom area, according to a dose-response curve, (ii) decreased symptom area increases crop green area index (GAI), (iii) increasing GAI increases fractional interception of photosynthetically active radiation, (iv) increased fractional interception increases crop dry matter accumulation, and (v) yield increases, depending on the partitioning of dry matter to the marketable fraction. One equation represented all five steps. By integrating this equation for light interception during the yield forming period and differentiating with respect to the ratio of fungicide cost over yield value, an analytical solution was obtained for the economic optimum dose. Taking published ranges of parameter values for the Septoria tritici wheat pathosystem as an example, yield-response curves and optimum doses were biologically plausible when compared with data from four field experiments. The analytical and empirical results imply that the dose required to optimize economic return will vary substantially between sites, seasons, and cultivars. Sensitivity analyses identified parameters describing specific facets of disease severity, fungicide efficacy, and assimilate partitioning as most influential in determining the dose optimum.

scholarly journals The Morphological Features and Canopy Parameters as Factors Affecting the Competition Between Winter Wheat Varieties and Weeds

2013 ◽  
Vol 53 (3) ◽  
pp. 203-209
Author(s):  
Beata Feledyn-Szewczyk ◽  
Krzysztof Jończyk ◽  
Adam Berbeć
Keyword(s):  
Winter Wheat ◽  
Dry Matter ◽  
Field Experiments ◽  
Plant Density ◽  
Morphological Features ◽  
Wheat Varieties ◽  
Factors Affecting ◽  
Weed Infestation ◽  
Different Response ◽  
Winter Wheat Varieties

Abstract The aim of the study was to determine the relationship between morphological features and canopy parameters of winter wheat varieties and weed infestation. The 2-year-long field experiments were conducted at 3 locations, on 13 varieties of winter wheat cultivated on organic farms. The response of the tested cultivars to weed infestation was similar regardless of the location. The number of weeds did not differ significantly between the wheat varieties and was similar in all locations and years of the study (109-122 plants/m2). The weed dry matter was significantly lower in Chomentowo (38 g/m2) compared to Osiny and Chwałowice (66 and 85 g/ m2). Nateja and Legenda wheat varieties showed the biggest competitiveness against weeds in both years and locations, whereas Alcazar, Boomer and Jenga were characterized as having the least competitive ability. Natula, Kohelia, Batuta and Ostroga wheat varieties showed a different response to weed infestation over the years. The analysis of correlation and cluster analysis showed that wheat dry matter, plant density, and wheat height had the greatest impact on the number and dry matter of weeds. There was no significant correlation between number of tillers per plant and weed infestation parameters measured in the dough stage

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