Studies in soil fertility with special reference to organic manures. I. The field experiments.

1954 ◽  
Vol 5 (2) ◽  
pp. 181
Author(s):  
K Spencer
Keyword(s):  
Rice Straw ◽  
Field Experiments ◽  
Nitrogen Nutrition ◽  
Nitrogen Deficiency ◽  
Dominant Factor ◽  
Available Phosphorus ◽  
Biological Fixation ◽  
Nitrogen And Phosphorus ◽  
Organic Manures ◽  
Rice Hulls

The results for five field experiments with organic manures on three related soil types of the grey and brown soils group are reported. Four experiments were with irrigated summer crops and the fifth was a spring crop with supplemental irrigation. Pea trash and rice hulls were the main organic manures used, but chaffed lucerne and rice straw were also used in one of the experiments. Seedling emergence was delayed and reduced by rice straw when only one month was allowed for decomposition, but these effects were absent following three months of decomposition. Rice straw and rice hulls both induced more or less transitory symptoms of nitrogen deficiency in the absence of added nitrogen. Except in one experiment with pea trash on a near-virgin soil, pea trash, chaffed lucerne, and rice hulls all gave highly significant yield increases. Rice straw also gave yield increases when three months were allowed for decomposition. From an examination of the patterns of response in these experiments, together with data for soil water, nitrate nitrogen, and available phosphorus, it is concluded that phosphorus nutrition may be a dominant factor in yield determination, especially with rice hulls, and that nitrogen nutrition exerts a strong modifying influence in some circumstances. Hypotheses concerning the mineralization and biological fixation of nitrogen and phosphorus are discussed, but seem inapplicable to the specific conditions of these experiments. The origin of the additional phosphorus made available in the soil by organic manures with low content of that element emerges as a significant problem calling for solution. Current hypotheses on this point are considered, but it is contended that far more information than is usually obtainable from field experiments would be required to decide which of a number of possible mechanisms plays a significant role in the release or maintenance of this phosphorus.

Studies in citrus nutrition i. Leaf growth and composition

1956 ◽  
Vol 7 (4) ◽  
pp. 248 ◽  
Author(s):  
RF Williams ◽  
CT Gates
Keyword(s):  
Organic Matter ◽  
Treatment Effects ◽  
Nitrogen Nutrition ◽  
Leaf Growth ◽  
Dry Weight ◽  
Nitrogen Supply ◽  
Dominant Factor ◽  
Nitrogen And Phosphorus ◽  
Citrus Grove ◽  
Four Levels

Vegetative shoots from the spring flush of an experimental citrus grove tagged and sampled on three occasions at intervals of 6 months. The effects of four cultural treatments, four levels of nitrogen supply, four combinations of stock and scion, and of time on leaf area and dry weight, and on relative and absolute contents of water, nitrogen, and phosphorus are presented and discussed. While nitrogen nutrition is still the dominant factor, the evidence strongly suggests that phosphorus nutrition has become important as a determinant of treatment effects within the experimental grove. The possible relevance of soil temperature and soil organic matter for some of the cultural treatment effects is discussed.

The application of production function analysis for the estimation of fertilizer requirements of wheat in northern NSW

1966 ◽  
Vol 6 (23) ◽  
pp. 418 ◽  
Author(s):  
JD Colwell ◽  
RJ Esdaile
Keyword(s):  
Field Experiments ◽  
Function Analysis ◽  
Nitrogen Deficiency ◽  
Nitrogen Fertilizers ◽  
Phosphorus Fertilizer ◽  
Nitrogen And Phosphorus ◽  
Yield Data ◽  
South Wales ◽  
Using Data ◽  
The Mathematical Model

A procedure for the statistical analysis and the interpretation of factorial type field experiments for the assessment of fertilizer requirements is described and demonstrated using data from 49 field experiments in northern New South Wales. Yield data for each site are represented by the mathematical model : Y = b0 + b1N + b2N0.5 + b3P + b4P0.5 + b5NP + b6(NP) 0.5+ b7REPwhere N and P are nitrogen and phosphorus fertilizer rates respectively and REP =replicate. This model is used to solve the simultaneous nitrogen and phosphorus fertilizer requirements, using computer techniques. The data indicate widespread deficiencies of nitrogen and phosphorus, but, in general, only applications of phosphorus fertilizer can be justified at present prices. The development of more efficient procedures for applying nitrogen fertilizers or the reduction in their cost could lead to greater requirements for nitrogen fertilizers. The severity of the widespread nitrogen deficiency is, in general, not sufficient to seriously affect the estimation of phosphorus fertilizer requirements for the majority of sites.

scholarly journals Effects of Ridge Tillage and Straw Mulching on Cultivation the Fresh Faba Beans

Agronomy ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1054
Author(s):  
Bo Li ◽  
Xinyu Chen ◽  
Xiaoxu Shi ◽  
Jian Liu ◽  
Yafeng Wei ◽  
...  
Keyword(s):  
Rice Straw ◽  
Precision Agriculture ◽  
Field Experiments ◽  
Root Length Density ◽  
Root Surface ◽  
High Yield ◽  
Root Surface Area ◽  
Straw Mulching ◽  
Faba Beans ◽  
Ridge Tillage

Ridge tillage is an effective agronomic practice and a miniature precision agriculture; however, its effects on the growth of faba beans (Vicia faba L.) are poorly understood. This study aimed to determine the effect of ridge tillage and straw mulching on the root growth, nutrient accumulation and yield of faba beans. Field experiments were conducted during 2016 and 2017 cropping seasons and comprised four treatments: ridge tillage without any mulching (RT), flat tillage without any mulch (FT), flat tillage with rice straw mulched on the ridge tillage (FTRSM) and ridge tillage with rice straw mulched on the ridge tillage (RTRSM). The RT and RTRSM increased soil temperature and decreased soil humidity and improved soil total nitrogen, total phosphorus, available potassium and organic matter. RT and RTRSM increased the root length density, root surface area, root diameter and root activity of faba beans at flowering and harvest periods. The RT and RTRSM also increased the nitrogen, phosphorus, potassium absorption and the yield of faba beans. These results indicated that ridge tillage and straw mulching affect faba bean growth by improving soil moisture conditions and providing good air permeability and effective soil nutrition supply. This study provides a theoretical basis for the high yield cultivation improvement of faba beans.

scholarly journals Dissolved and particulate nutrient transport dynamics of a small Irish catchment: the River Owenabue

2014 ◽  
Vol 18 (6) ◽  
pp. 2191-2200 ◽  
Author(s):  
S. T. Harrington ◽  
J. R. Harrington
Keyword(s):  
Suspended Sediment ◽  
Water Discharge ◽  
Nutrient Transport ◽  
Sediment Concentration ◽  
Coefficient Of Determination ◽  
Available Phosphorus ◽  
Nitrogen And Phosphorus ◽  
Particulate Nitrogen ◽  
Monitoring Period ◽  
Nitrogen Concentrations

Abstract. The objective of this research was to investigate the relationship between water and sediment discharge on the transport of nutrients: nitrogen and phosphorus. Water discharge, suspended sediment concentration and dissolved and particulate forms of nitrogen and phosphorus were monitored on the 105 km2 River Owenabue catchment in Ireland. Water discharge was found to have an influence on both particulate and dissolved nutrient transport, but more so for particulate nutrients. The particulate portion of N and P in collected samples was found to be 24 and 39%, respectively. Increased particulate nitrogen concentrations were found at the onset of high discharge events, but did not correlate well to discharge. High concentrations of phosphorus were associated with increased discharge rates and the coefficient of determination (r2) between most forms of phosphorus and both discharge and suspended sediment concentrations were observed to be greater than 0.5. The mean TN yield is 4004 kg km−2 yr−1 for the full 29-month monitoring period with a mean PN yield of 982 kg km−2 yr−1, 25% of the TN yield with the contribution to the yield of PN and PP estimated to be 25 and 53% respectively. These yields represent a PN and PP contribution to the suspended sediment load of 5.6 and 0.28% respectively for the monitoring period. While total nitrogen and total phosphorus levels were similar to other European catchments, levels of bio-available phosphorus were elevated indicating a potential risk of eutrophication within the river.

scholarly journals Flower litters of alpine plants affect soil nitrogen and phosphorus rapidly in the eastern Tibetan Plateau

2016 ◽  
Author(s):  
Jinniu Wang ◽  
Bo Xu ◽  
Yan Wu ◽  
Jing Gao ◽  
Fusun Shi
Keyword(s):  
Tibetan Plateau ◽  
Field Experiments ◽  
Underlying Mechanism ◽  
Pot Experiment ◽  
Eastern Tibetan Plateau ◽  
Nitrogen And Phosphorus ◽  
Nutrient Pool ◽  
Litter Addition ◽  
Litter Bag ◽  
Soil Nutrition

Abstract. Litters of reproductive organs have been rarely studied, despite their role in allocating nutrients for offspring reproduction. This study determines the mechanism through which flower litters efficiently increase the available soil nutrient pool. Field experiments were conducted to collect plant litters and calculate biomass production in an alpine meadow of the eastern Tibetan Plateau. Carbon, nitrogen, phosphorus, lignin, cellulose, and their relevant ratios of litters were analyzed to identify their decomposition features. A pot experiment was performed to determine the effects of litter addition on soil nutrition pool by comparison between the treated and control samples. Litter-bag method was used to verify decomposition rates. The flower litters of phanerophyte plants were comparable with non-flower litters. Biomass partitioning of other herbaceous species accounted for 10%–40% of the aboveground biomass. Flower litter possessed significantly higher N and P levels but less C/N, N/P, lignin/N, and lignin and cellulose concentrations than leaf litter. Flower litter fed soil nutrition pool more efficiently because of their faster decomposition rate and higher nutrient contents. Litter-bag experiment confirmed that the flower litters of Rhododendron przewalskii and Meconopsis integrifolia decomposes approximately three times faster than mixed litters within 50 days. Moreover, the findings of the pot experiment indicated that flower litter addition significantly increased the available nutrient pool. Flower litter influenced nutrition cycling in alpine ecosystems, as evident by its non-ignorable production and significantly faster decomposition. The underlying mechanism can enrich nutrients, which return to the soil, and non-structural carbohydrates, which feed and enhance the transitions of soil microorganisms.

scholarly journals Does the Mixture of Species change the C:N:P Ecological Stoichiometric Characteristics of fine Roots? A Case Study of Cupressus Funebris Mixed Forest

2021 ◽  
Author(s):  
Wenchun He ◽  
Yang Wang ◽  
Xiaochen Wen ◽  
Yu Wang ◽  
Baoru Xiao ◽  
...  
Keyword(s):  
Fine Roots ◽  
Environmental Changes ◽  
Mixed Forest ◽  
Chemical Properties ◽  
Available Phosphorus ◽  
Biological Factors ◽  
Nitrogen And Phosphorus ◽  
Mixed Stands ◽  
Available Nitrogen ◽  
Low Efficiency

Abstract The growth of fine roots of trees is affected by environmental changes and biological factors. At present, there have been many researches on the physiological plasticity of fine roots caused by environmental changes, but there are still few studies on the influence of biological factors on fine roots. This paper focused on the contents of carbon (C), nitrogen (N), and phosphorus (P), and their ecological stoichiometric ratios in different root orders of Cupressus funebris fine roots in 11 mixed stands with Koelreuteria paniculate or Toona sinensis at different ratios, and the effects of soil physical and chemical properties on the root chemical properties. It aimed to provide new insights into the fine-root nutrient distribution pattern and the transformation or reconstruction of low-efficiency pure forests from the standpoint of forest types. The results showed that: soil pH, and the content of available nitrogen (SAN), available phosphorus (SAP) and available potassium (SAK) differed significantly in the tested mixed forest stands. No significant differences in carbon content of fine roots were observed in different mixed stands. The content of nitrogen and phosphorus in fine roots in mixed forests showed heterogeneity. Species mixing changed the C/N, C/P and N/P of the C. funebris compared the pure stands. The "T. sinensis + C. funebris" forest alleviated the limitation of the lack of phosphorus on fine roots of C. funebris on. The principal component analysis showed that mixed stands of "T. sinensis + C. funebris" had the highest comprehensive score at ratio of "3:1". Thus, our results recommended the adoption of T. sinensis, especially at 75%, to reconstruct the low-efficiency pure C. funebris forest.

scholarly journals Gravity-Based Methods for Heading Computation in Pedestrian Dead Reckoning

Sensors ◽  
2019 ◽  
Vol 19 (5) ◽  
pp. 1170 ◽  
Author(s):  
Adi Manos ◽  
Itzik Klein ◽  
Tamir Hazan
Keyword(s):  
Field Experiments ◽  
Dead Reckoning ◽  
Vertical Direction ◽  
Indoor Navigation ◽  
Magnetic Sensors ◽  
Dominant Factor ◽  
Heading Estimation ◽  
Using Data ◽  
Pedestrian Dead Reckoning ◽  
Gravity Direction

One of the common ways for solving indoor navigation is known as Pedestrian Dead Reckoning (PDR), which employs inertial and magnetic sensors typically embedded in a smartphone carried by a user. Estimation of the pedestrian’s heading is a crucial step in PDR algorithms, since it is a dominant factor in the positioning accuracy. In this paper, rather than assuming the device to be fixed in a certain orientation on the pedestrian, we focus on estimating the vertical direction in the sensor frame of an unconstrained smartphone. To that end, we establish a framework for gravity direction estimation and highlight the important role it has for solving the heading in the horizontal plane. Furthermore, we provide detailed derivation of several approaches for calculating the heading angle, based on either the gyroscope or the magnetic sensor, all of which employ the estimated vertical direction. These various methods—both for gravity direction and for heading estimation—are demonstrated, analyzed and compared using data recorded from field experiments with commercial smartphones.

Plant uptake of nitrogen and phosphorus among grassland species affected by drought along a soil available phosphorus gradient

2020 ◽  
Vol 448 (1-2) ◽  
pp. 121-132 ◽  
Author(s):  
Pierre Mariotte ◽  
Tom Cresswell ◽  
Mathew P. Johansen ◽  
Jennifer J. Harrison ◽  
Claudia Keitel ◽  
...  
Keyword(s):  
Plant Uptake ◽  
Available Phosphorus ◽  
Nitrogen And Phosphorus ◽  
Grassland Species ◽  
Soil Available Phosphorus

scholarly journals Three Invasive Tree Species Change Soil Chemistry in Guam Forests

Forests ◽  
2020 ◽  
Vol 11 (3) ◽  
pp. 279 ◽  
Author(s):  
Thomas E. Marler
Keyword(s):  
Tree Species ◽  
Soil Chemistry ◽  
Chemical Properties ◽  
Total Carbon ◽  
Tree Cover ◽  
Available Phosphorus ◽  
Nitrogen And Phosphorus ◽  
Invasive Tree ◽  
Invasive Tree Species ◽  
Forms Of Carbon

Research Highlights: Established stands of Leucaena leucocephala (Lam.) de Wit, Spathodea campanulata P. Beauv., and Vitex parviflora Juss. modified soils in Guam’s limestone forests, reducing storage pools of carbon, nitrogen, and phosphorus. Background and Objectives: Invasive plants may engineer negative changes in ecosystem properties. This study was conducted to determine changes in soil chemistry following infestations of three problematic tree species on Guam. Materials and Methods: Minerals, metals, and mineralization dynamics were measured in invaded sites and paired sites with biodiverse native tree cover. Results: Most soil properties were significantly changed by long-term infestations of the invasive tree species. The soils within invaded sites exhibited total carbon, total nitrogen, and available phosphorus that were less than native sites. In contrast, the carbon/nitrogen ratio increased for every species-site combination. The other chemical properties were idiosyncratic among the sites and species. Conclusions: Mitigation and restoration activities that include the removal of these trees from project sites may require many years for the below-ground ecosystems to return to their native state. These three invasive trees decrease the ability of Guam soils to sequester recalcitrant forms of carbon, nitrogen, and phosphorus.

Methods and time of application of labelled nitrogen and phosphorus fertilizers in maize (Zea mays L.) cultivation

1985 ◽  
Vol 104 (3) ◽  
pp. 529-534
Author(s):  
E. P. Papanicolaou ◽  
V. D. Skarlou ◽  
C. Nobeli ◽  
N. S. Katranis
Keyword(s):  
Field Experiments ◽  
Zea Mays L ◽  
Foliar Application ◽  
Alluvial Soil ◽  
Nitrogen Sources ◽  
Maize Yield ◽  
Nitrogen And Phosphorus ◽  
Maize Crop ◽  
Time Of Application ◽  
Maize Grain

SummaryIn this study two field experiments were conducted on a heavy to medium heavy, calcareous, recent alluvial soil of Central Greece. The main aim of these experiments was to study the effect of the most common nitrogen sources, applied in one or two doses, on maize growth and fertilizer utilization. Foliar application of urea was also a treatment included in these experiments.Phosphorus alone had no significant effect on maize yield. Nitrogen (various forms), alone or in combination with phosphorus, increased the yield and nitrogen content of maize. Maize yield was not significantly affected by the form of nitrogen or by dividing the application of nitrogen. Foliar applications of urea were as effective as soil applications in increasing maize grain yields.The percentage of fertilizer nitrogen taken up (utilization coefficient) ranged between ca. 58% for sodium nitrate and ammonium nitrate, and ca. 39% for ammonium sulphate and urea, when the fertilizers were applied about 10 weeks after sowing. Foliar urea was nearly as efficiently utilized as urea applied as a sidedressing. Application of the tested fertilizers before sowing was nearly as efficient as or more efficient than application of the fertilizers as a sidedressing at 70 cm plant height (38 days after sowing). Finally, addition of 120 kg N/ha enhanced the amount of soil nitrogen taken up in the maize crop by 33%.

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