Considerations for Selecting Potassium Placement Methods in Soil

AbstractPlacement strategies can be a key determinant of efficient use of applied fertilizer potassium (K), given the relative immobility of K in all except the lightest textured soils or high rainfall environments. Limitations to K accessibility by plants caused by immobility in the soil are further compounded by the general lack of K-stimulated root proliferation in localized soil zones enriched with K alone, compared with root proliferation due to concentrated N and P. Further, effects of K fixation reactions in soils with certain clay mineralogies and the declining concentration and activity of soil solution K with increasing clay content can also limit plant K acquisition. Variation in root system characteristics among crops in a rotation sequence and fluctuating soil moisture conditions in fertilized soil horizons in rain-fed systems increase the complexity of fertilizer placement decisions to ensure efficient K recovery and use. This complexity has resulted in extensive exploration of fertilizer K application strategies, with this chapter focusing on K applications to the soil. Issues discussed include comparisons of broadcast versus banded applications, depth of fertilizer placement, and the impacts of co-location of K with other nutrients. While research findings are often specific to the crop, soil, and seasonal conditions under which they are conducted, we attempt to identify strategies that most consistently deliver improved crop recovery and utilization of fertilizer K.

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Adsorption Characteristics of Atrazine and Alachlor in Kansas Soils

Weed Science ◽

10.1017/s0043174500081479 ◽

1995 ◽

Vol 43 (3) ◽

pp. 461-466 ◽

Cited By ~ 28

Author(s):

Leticia S. Sonon ◽

A. Paul Schwab

Keyword(s):

Organic Carbon ◽

Distribution Coefficient ◽

Linear Function ◽

Soil Depth ◽

Equilibrium Concentration ◽

Clay Content ◽

Adsorption Coefficient ◽

Soil Horizons ◽

Adsorption Affinity ◽

Different Soils

The adsorption of atrazine and alachlor was studied on samples of three horizons from soils with different textures and organic carbon contents. Soils were equilibrated with five concentrations of atrazine and alachlor using batch techniques. Adsorption affinity for atrazine and alachlor was approximated by the Freundlich constant (Kf), distribution coefficient (Kd), and the normalizedKdbased on organic carbon (Koc). Adsorption was not significantly correlated with soil depth, clay content, or organic carbon. Atrazine adsorption was a linear function of equilibrium concentration for nearly all soil horizons but was nonlinear in most horizons for alachlor. The extent of atrazine adsorption was greater in all horizons of the fine-textured soils (Kd= 1.5 to 5.5) compared to coarse-textured soils (Kd= 0.40 to 0.87). The same general trends with texture were not apparent for alachlor. Conversion ofKdtoKocfailed to reduce the variability in the linear adsorption coefficient for atrazine and alachlor in the different soils of this study.

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Effect of rhizospheric nutrient management on root growth, yield, and nutrient use efficiency of wheat (Triticum aestivum L.) under Tarai region of Uttarakhand, India

Journal of Applied and Natural Science ◽

10.31018/jans.v12i4.2362 ◽

2020 ◽

Vol 12 (4) ◽

pp. 511-518

Author(s):

Arvind Kumar ◽

Vijay Pal Singh ◽

Rajeew Kumar ◽

D. S. Pandey ◽

V.K. Singh

Keyword(s):

Triticum Aestivum ◽

Grain Yield ◽

Nutrient Management ◽

Block Design ◽

Nutrient Use Efficiency ◽

Triticum Aestivum L ◽

Root Proliferation ◽

Flowering Stage ◽

Fertilizer Placement ◽

Absolute Control

Rhizospheric nutrient management and fertilizer placement can be a useful measure to improve wheat crops productivity in Tarai regions of India. An experiment was conducted to evaluate the effects of rhizospheric nutrient management on wheat (Triticum aestivum L.) to explore the relationship between root proliferation, grain yield and NUE in Tarai region of Uttarakhand, India. It comprised 3 fertilizer application (P1 to P3) and 6 nutrient management treatments (T1 to T6) with absolute control in a randomized complete block design and replicated thrice. Experimental results indicated that P1 (1.29 and 1.47; 1.84 and 2.29 mg/cc) produced greater root density, and compared to P3 (1.39 and 1.49; 1.74 and 2.17 mg/cc), P2 (1.24 and 1.36; 1.68 and 1.97 mg/cc) and absolute control (0.85 and 1.19; 1.42 and 1.69 mg/cc) at maximum tillering and flowering stage in year 2017-18 and 2018-19, respectively .The root proliferation also influenced the grain yield (5.4 and 5.5; 5.3 and 5.3; 5.1 and 5.2; 3.5 and 3.3 t/ha ) in P1, P3, P2 and absolute control in the year 2017-18 and 2018-19, respectively. However, the grain yield and root distributions (at the flowering stage) recorded significantly (p=0.05) maximum in T4 (5.8 and 5.7 t/ha; 1.84 and 2.32 mg/cc) followed by T3, T6, T1, T5, T2 treatments and minimum in absolute control (3.5 and3.3 t/ha; 1.42 and 1.69 mg /cc) in the year of 2017-18 and 2018-19, respectively. Thus, the rhizospheric nutrient management (75% RDF+ vermicompost + PSB) with fertilizer placement can be a feasible approach for increasing grain yield and NUE in Tarai regions of Uttarakhand, by promoting deep root development and reducing fertilizer inputs in wheat.

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Pedological Investigations of Pleistocene Glacial Drift Surfaces in the Central Yukon

Géographie physique et Quaternaire ◽

10.7202/032620ar ◽

2007 ◽

Vol 40 (1) ◽

pp. 29-37 ◽

Cited By ~ 23

Author(s):

C. A. S. Smith ◽

C. Tarnocai ◽

O. L. Hughes

Keyword(s):

Boreal Forest ◽

Small Proportion ◽

Clay Content ◽

Strong Relationship ◽

Soil Horizons ◽

Glacial Deposits ◽

Skin Development ◽

Local Areas ◽

Forest Regions ◽

Regional Landscape

ABSTRACT Distinct soil morphologies associated with three different ages of Quaternary glacial deposits are characterized and subsequently named. Properties which provide a basis for distinguishing these in the field include solum depth, B horizon colour, clay skin development, coarse fragment weathering and periglacial features. A strong relationship is evident between the clay content at depth and the age of soil. Low values of Na pyrophosphate-extractable Fe and Al confirm the absence of any active podzol-forming processes even within the reddest (5YR, 2.5YR) soil horizons. Wounded Moose paleosols are the preserved soils observed on pre-Reid Glaciation (.2-1.2 Ma) deposits which show strong paleoargillic horizon development with red colours, high clay content, and common periglacial modification. Diversion Creek paleosols are the preserved soils found on Reid (80-120 ka) glacial deposits which show moderate paleoargillic horizon development and resemble the contemporary Gray Luvisols of the mid and southern boreal forest regions of Canada. Stewart soils are the weakly developed Brunisols formed on stable landform surfaces of McConnell (14-30 ka) glacial deposits. The Wounded Moose and Diversion Creek paleosols, while found commonly in local areas, occupy only a small proportion of the regional landscape.

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Application of the “4R” Nutrient Stewardship Concept to Horticultural Crops: Getting Nutrients in the “Right” Place

HortTechnology ◽

10.21273/horttech.21.6.674 ◽

2011 ◽

Vol 21 (6) ◽

pp. 674-682 ◽

Cited By ~ 5

Author(s):

David R. Bryla

Keyword(s):

Cultural Practices ◽

Foliar Application ◽

Weather Conditions ◽

Fertilizer Placement ◽

Horticultural Crops ◽

Placement Decisions ◽

Crop Development ◽

Use Efficiency ◽

Source Rate ◽

The Right

Right fertilizer placement is one of the 4Rs of an effective nutrient stewardship system and should be combined with considerations for the right fertilizer source, rate, and timing. Fertilizer placement decisions depend on mobility of applied nutrients in the soil and the depth and distribution of the crop's root system. Various methods are used to apply fertilizers to horticultural crops, including broadcasting, banding, fertigation, foliar application, and microinjection. Generally, the most appropriate method for any crop increases productivity and profitability and improves fertilizer use efficiency but varies depending on the nutrient element, fertilizer source, soil characteristics, cultural practices, stage of crop development, weather conditions, and farming enterprise constraints. Comparisons among application methods are available for many crops and provide useful information for improving fertilizer placement practices, but many practical questions such as how fertilizer source and availability are affected by irrigation interactions or whether there are ways to manage crop roots for more effective nutrient uptake still remain.

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What Does Evidence-Based Practice Mean to You? A Follow-Up Study Examining School-Based Speech-Language Pathologists' Perspectives on Evidence-Based Practice

American Journal of Speech-Language Pathology ◽

10.1044/2019_ajslp-19-00171 ◽

2020 ◽

Vol 29 (2) ◽

pp. 688-704

Author(s):

Katrina Fulcher-Rood ◽

Anny Castilla-Earls ◽

Jeff Higginbotham

Keyword(s):

Clinical Practice ◽

Research Evidence ◽

Evidence Based Practice ◽

Evidence Based ◽

Clinical Expertise ◽

Speech Language Pathologists ◽

School Based ◽

Research Findings ◽

Ebp Implementation

Purpose The current investigation is a follow-up from a previous study examining child language diagnostic decision making in school-based speech-language pathologists (SLPs). The purpose of this study was to examine the SLPs' perspectives regarding the use of evidence-based practice (EBP) in their clinical work. Method Semistructured phone interviews were conducted with 25 school-based SLPs who previously participated in an earlier study by Fulcher-Rood et al. 2018). SLPs were asked questions regarding their definition of EBP, the value of research evidence, contexts in which they implement scientific literature in clinical practice, and the barriers to implementing EBP. Results SLPs' definitions of EBP differed from current definitions, in that SLPs only included the use of research findings. SLPs seem to discuss EBP as it relates to treatment and not assessment. Reported barriers to EBP implementation were insufficient time, limited funding, and restrictions from their employment setting. SLPs found it difficult to translate research findings to clinical practice. SLPs implemented external research evidence when they did not have enough clinical expertise regarding a specific client or when they needed scientific evidence to support a strategy they used. Conclusions SLPs appear to use EBP for specific reasons and not for every clinical decision they make. In addition, SLPs rely on EBP for treatment decisions and not for assessment decisions. Educational systems potentially present other challenges that need to be considered for EBP implementation. Considerations for implementation science and the research-to-practice gap are discussed.

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