scholarly journals Response of timothy to increasing rates of potassium

1983 ◽  
Vol 55 (2) ◽  
pp. 163-178
Author(s):  
Into Saarela
Keyword(s):  
Relative Yield ◽  
Fine Sand ◽  
Magnesium Content ◽  
Field Trials ◽  
Yield Response ◽  
Silty Clay ◽  
Plant Nitrogen ◽  
Potassium Fertilization ◽  
Inorganic Matter ◽  
Calcium And Magnesium

Five potassium fertilization rates ranging from nil to 80 kg/ha/cut were compared over 2 to 3 years in field trials on timothy leys at nine sites between 61 and 65 °N. The grass was cut twice a year and the contents of nitrogen, potassium, calcium and magnesium in yields were determined. The soils were tested at the beginning and at the end of the trials. On four peat soils the yields over two years without potassium dressings were 34 to 66 % of the respective yields with adequate potassium fertilization. On humus soil the relative yield without potassium was 81 % and on fine sand soil 76 %. On two finesand tills rich inorganic matter the responce of timothy to potassium was 5 %. No significant yield response was obtained on silty clay. In accordance to the depletion of available soil reserves, the differences between the potassium rates increased with time. In average on the six most responsive soils the relative yields without potassium fertilization for the first four successive cuts were 88, 75, 58 and 45 %. For maximum yields, 60 to 80 kg/ ha potassium per cut was required on the organogenic soils and on the finesand, 20 kg/ha was enough on the other three mineral soils. The potassium contents of plants increased greatly, and the contents of nitrogen, calcium and magnesium decreased with increasing potassium fertilization rate. The magnesium content of grass rose to an unusually high level with severe potassium deficiencies. At the end of the trials the soils were quite exhausted of potassium, the subsurface layers being most exhausted. The critical plant potassium content varied from under 2 % to over 3 %. As the large variation was coupled with plant nitrogen, plant K/N ratio was a better indicator for potassium status of ley than plant K. Yield was likely to begin degreasing when the K/N ratio decreased under 1.

Yield response of restricted-tillering wheat to transient waterlogging on duplex soils

2003 ◽  
Vol 54 (10) ◽  
pp. 957 ◽  
Author(s):  
A. G. Condon ◽  
F. Giunta
Keyword(s):  
Grain Size ◽  
Biomass Production ◽  
Wheat Yield ◽  
Relative Yield ◽  
Field Trials ◽  
Growth And Yield ◽  
Yield Response ◽  
South West ◽  
Relative Extent ◽  
Before And After

Transient waterlogging during winter and spring reduces wheat yield in many parts of southern Australia. Yield reductions from waterlogging are associated with reduced production and survival of tillers, fewer and smaller fertile tillers, and smaller grain size. Under favourable conditions, wheats that have the tiller-inhibition ('tin') gene produce a lower total number of tillers but a higher proportion of large, productive tillers and larger grains than wheats without this gene. These characteristics of restricted-tillering wheat may contribute to improved yield under transient waterlogging. We compared the growth and yield of the commercial variety Bodallin and 2 Bodallin backcross derivatives containing the 'tin' gene in 8 field trials grown on shallow, duplex soils in 1995 and 1996 at 3 locations in the south-west of Western Australia. Trials were sown at standard (1995) and standard and high (1996) seeding rates. Trial-mean yield ranged from 0.5 to 4.7 t/ha, depending on the occurrence and severity of waterlogging before anthesis and of soil water deficit before and after anthesis. Grain yield of the restricted-tillering (RT) lines averaged only c. 80% of Bodallin. At all sites and seeding rates the RT lines had fewer spikes per m2 (45% fewer, on average) but averaged 44% more grains per spike. In 1996 only, grain weight of the RT lines was 6% greater than of Bodallin. There was no evidence that the relative yield of the RT lines was greater at waterlogged sites than at other sites. Waterlogging reduced the number of fertile spikes of RT lines and of Bodallin to the same relative extent and differences in grains per spike and grain size had little effect on relative yields. Even though harvest index of the RT lines was slightly elevated in some environments, biomass production of the RT lines was low in all environments. We conclude that wheats with the 'tin' gene are unlikely to have a yield advantage under transient waterlogging unless their biomass production can match that of more freely tillering wheats.

Phosphate availability and phosphate needs of soils under Siratro pastures as assessed by soil chemical tests

1968 ◽  
Vol 8 (34) ◽  
pp. 561 ◽  
Author(s):  
RE White ◽  
KP Haydock
Keyword(s):  
Phosphate Uptake ◽  
Maximum Yield ◽  
Relative Yield ◽  
Field Trials ◽  
Yield Response ◽  
Phosphate Availability ◽  
Percentage Yield ◽  
Quantity Measurement ◽  
Extraction Period ◽  
The One

In field trials covering a range of soils and environmental conditions, the variation in soil equilibrium phosphate potentialSP accounted for 86 per cent of the variation in the percentage yield response of Siratro (Phaseolus atropurpureus) to phosphorus, compared to 72 per cent accounted for by the Olsen extraction, 51 per cent by Truog's and 38 per cent by Morgan's. The Truog and Morgan extractants gave improved correlations with phosphate uptake, but all four methods were poorly correlated with phosphate concentration in the plant. For the prediction of the soil's phosphate requirement for 90 or 95 per cent of the maximum yield, the Morgan method was superior to the equilibrium potentialSP, Olsen and Truog methods, and comparable to the quantity measurement P sorbed, derived from the soil's quantity-intensity (Q/I) relation at the minimum, non-limiting solution activity of 2.2 �M P : each accounted for 67 per cent of the variation in P required for 90 per cent of the maximum yield. The precision of the extractions in estimating P required decreased as the extractant/soil ratio and the extraction period increased. Of the conventional extractants, a method could be chosen that was well correlated with either P required (Morgan's) or plant relative yield (Olsen's), but none that was well correlated with both criteria. On the other hand, the measurement: of the one Q/I relation provided intensity (equilibrium potentialSP) and quantity (P sorbed) terms for the prediction, respectively, of a soil's phosphate availability and its phosphate needs for optimum plant growth.

Responses of soybean genotypes to intercropping with maize in the Southern Guinea Savanna, Nigeria

2004 ◽  
Vol 52 (2) ◽  
pp. 157-163
Author(s):  
C. U. Egbo ◽  
M. A. Adagba ◽  
D. K. Adedzwa
Keyword(s):  
Seed Yield ◽  
Block Design ◽  
Field Trials ◽  
Yield Response ◽  
Ecological Zone ◽  
Land Equivalent Ratio ◽  
Guinea Savanna ◽  
Days To Maturity ◽  
Soybean Genotypes ◽  
Location Interaction

Field trials were conducted in the wet seasons of 1997 and 1998 at Makurdi, Otukpo and Yandev in the Southern Guinea Savanna ecological zone of Nigeria to study the responses of ten soybean genotypes to intercropping. The experiment was laid out in a randomised complete block design. The genotypes TGX 1807-19F, NCRI-Soy2, Cameroon Late and TGX 1485-1D had the highest grain yield. All the Land Equivalent Ratio (LER) values were higher than unity, indicating that there is great advantage in intercropping maize with soybean. The yield of soybean was positively correlated with the days to 50% flowering, days to maturity, plant height, pods/plant and leaf area, indicating that an improvement in any of these traits will be reflected in an increase in seed yield. There was a significant genotype × yield × location interaction for all traits. This suggests that none of these factors acted independently. Similarly, the genotype × location interaction was more important than the genotype × year interaction for seed yield, indicating that the yield response of the ten soybean genotypes varied across locations rather than across years. Therefore, using more testing sites for evaluation may be more important than the number of years.

scholarly journals THE CALCIUM AND MAGNESIUM CONTENT OF NORMAL URINE

1916 ◽  
Vol 28 (1) ◽  
pp. 237-240
Author(s):  
C.Ferdinand Nelson ◽  
W.E. Burns
Keyword(s):  
Magnesium Content ◽  
Calcium And Magnesium ◽  
Normal Urine

scholarly journals Alkalinity–silicon ratio as an assessment factor for the efficiency of silicate slags in wetland rice

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Thoppil Sreenivasan Sandhya ◽  
Nagabovanalli Basavarajappa Prakash
Keyword(s):  
Silicon Content ◽  
Chemical Properties ◽  
Magnesium Content ◽  
Wetland Rice ◽  
Agronomic Efficiency ◽  
Economic Production ◽  
Incubation Experiments ◽  
Calcium And Magnesium ◽  
Si Content ◽  
Assessment Factor

AbstractSilicate slags are one of the most widely used silicon (Si) source in agriculture. Even though the agronomic significance of slags has been demonstrated in several crops, only a few attempts were made to evaluate these Si sources based on their chemical composition. The main objective of this study was to characterize different silicate slags based on their chemical properties and to explore the effect of these chemical properties on the yield, and Si uptake in wetland rice, and dissolution of Si into the soil. Slags were characterised for pH, calcium and magnesium content (alkalinity, A), silicon content, 5 day Na2CO3 + NH4NO3 extractable Si content, and alkalinity to Si ratio (A/Si). Greenhouse and incubation experiments were also conducted using different silicate slags and wollastonite applied at the rate of 300 kg Si ha−1. Slags with A/Si < 3 were found to be ideal Si sources for the economic production of wetland rice and found consistent in increasing soil Si content and rice Si uptake. We conclude that the A/Si ratio of slags can be used as an important parameter to assess the agronomic efficiency of silicate slags in wetland rice.

Soil and tissue tests to predict pasture yield responses to applications of potassium fertiliser in high-rainfall areas of south-western Australia

2002 ◽  
Vol 42 (2) ◽  
pp. 149 ◽  
Author(s):  
M. D. A. Bolland ◽  
W. J. Cox ◽  
B. J. Codling
Keyword(s):  
Western Australia ◽  
Field Experiments ◽  
Relative Yield ◽  
Subterranean Clover ◽  
Test Method ◽  
Yield Response ◽  
Soil Test ◽  
Test Procedures ◽  
Pasture Production ◽  
Yield Responses

Dairy and beef pastures in the high (>800 mm annual average) rainfall areas of south-western Australia, based on subterranean clover (Trifolium subterraneum) and annual ryegrass (Lolium rigidum), grow on acidic to neutral deep (>40 cm) sands, up to 40 cm sand over loam or clay, or where loam or clay occur at the surface. Potassium deficiency is common, particularly for the sandy soils, requiring regular applications of fertiliser potassium for profitable pasture production. A large study was undertaken to assess 6 soil-test procedures, and tissue testing of dried herbage, as predictors of when fertiliser potassium was required for these pastures. The 100 field experiments, each conducted for 1 year, measured dried-herbage production separately for clover and ryegrass in response to applied fertiliser potassium (potassium chloride). Significant (P<0.05) increases in yield to applied potassium (yield response) were obtained in 42 experiments for clover and 6 experiments for ryegrass, indicating that grass roots were more able to access potassium from the soil than clover roots. When percentage of the maximum (relative) yield was related to soil-test potassium values for the top 10 cm of soil, the best relationships were obtained for the exchangeable (1 mol/L NH4Cl) and Colwell (0.5 mol/L NaHCO3-extracted) soil-test procedures for potassium. Both procedures accounted for about 42% of the variation for clover, 15% for ryegrass, and 32% for clover + grass. The Colwell procedure for the top 10 cm of soil is now the standard soil-test method for potassium used in Western Australia. No increases in clover yields to applied potassium were obtained for Colwell potassium at >100 mg/kg soil. There was always a clover-yield increase to applied potassium for Colwell potassium at <30 mg/kg soil. Corresponding potassium concentrations for ryegrass were >50 and <30 mg/kg soil. At potassium concentrations 30–100 mg/kg soil for clover and 30–50 mg/kg soil for ryegrass, the Colwell procedure did not reliably predict yield response, because from nil to large yield responses to applied potassium occurred. The Colwell procedure appears to extract the most labile potassium in the soil, including soluble potassium in soil solution and potassium balancing negative charge sites on soil constituents. In some soils, Colwell potassium was low indicating deficiency, yet plant roots may have accessed potassum deeper in the soil profile. Where the Colwell procedure does not reliably predict soil potassium status, tissue testing may help. The relationship between relative yield and tissue-test potassium varied markedly for different harvests in each year of the experiments, and for different experiments. For clover, the concentration of potassium in dried herbage that was related to 90% of the maximum, potassium non-limiting yield (critical potassium) was at the concentration of about 15 g/kg dried herbage for plants up to 8 weeks old, and at <10 g/kg dried herbage for plants older than 10–12 weeks. For ryegrass, there were insufficient data to provide reliable estimates of critical potassium.

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

Sesame Agronomy in South-east Tanzania. I. Plant Population and Sowing Method

1986 ◽  
Vol 22 (3) ◽  
pp. 243-251 ◽  
Author(s):  
B. R. Taylor ◽  
J. Y. Chambi
Keyword(s):  
Seed Yield ◽  
Field Trials ◽  
Plant Population ◽  
Yield Response ◽  
Seed Rate ◽  
Local Practice ◽  
Optimum Population ◽  
Viable Seeds

SUMMARYField trials are described in which the seed yield response of row-sown sesame to increasing plant population was examined, and in which row-sowing was compared with broadcasting at different seed rates. Maximum yields were obtained at an intended 200 to 250 × 103 plants ha−1 but yields were not greatly affected by a wider range of populations. Broadcasting, the normal local practice, gave yields slightly higher than those from rows 50 cm apart, the un-thinned rate of 800 × 103 viable seeds sown ha−1 yielded as well as treatments thinned to the optimum population, and double this seed rate, unthinned, gave the lowest yields, especially in rows.

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