Chemistry of soil potassium in Atlantic coastal plain soils: A review     

《Communications in Soil Science and Plant Analysis》2012,43(5):435-449

Abstract

Literature dealing with general properties of soil K and with K relationships in Atlantic Coastal Plain Soils was discussed. Potassium, among major and secondary nutrient elements, is the most abundant in soils. It, among mineral cations required by plants, is largest in non‐hydrated size. Potassium has a polarizability equal to .88 ų and a low hydration energy of 34 kcal g^?1 ion^?1. The major K forms in soils are water soluble, exchangeable, nonexchangeable, and mineral. Various dynamic interrelationships exist between these forms with the reaction kinetics between the various phases determining the fate of applied K.

Many Atlantic Coastal Plain soils contain high levels of total K. Most of the total K in these soils is contained in mineral forms such as micas and K‐feldspars. These K forms are slowly released to solution and exchangeable forms that are available to plants. Many researchers have noted a lack of crop response to K fertilization on Atlantic Coastal Plain soils. This lack of response has been ascribed to the high indigenous levels of mineral and non‐exchangeable K in the soils which would become available to crops. Some researchers have also attributed the lack of response to K accumulations in subsoil from leaching of applied K. If the physical and chemical conditions were favorable in the subsoil horizons, e. g., no pan formation and no severe Al toxicity, plant roots could absorb K from the subsoil horizons.  相似文献   

Preliminary studies on triticale,wheat, barley,and rye responses to lime and N.     

《Communications in Soil Science and Plant Analysis》2012,43(6):587-603

Abstract

The lime and N requirements for triticale (X Triticosecale Wittmack) have not been established because of the relatively short history of the crop. This study was designed to evaluate the effects of lime and high N rates on triticale, wheat (Triticum aestivum L.), barley (Hordeum vulgare L.), and rye (Secale cereale L.) on Dickson silt loam (Typic Paleudult) and Decatur silty clay loam (Rhodic Paleudult) in 1974–1976. The soils had pH values of 4.9 and 5.5 with no lime and 5.4 and 5.8, respectively, when limed as recommended. The fertilizer rates were 112, 140, and 170 kg N/ha. Yields and N, P, K, Ca, Mg, Mn, Fe, Al, Zn, Cu, and B were determined in straw and grain. Liming the Dickson soil increased the straw yields of barley at 112 kg N/ha and grain yields of the cultivars generally at the 170 kg N/ha rate. Liming the Decatur soil did not have consistent effects on straw yields but increased the grain yields of the wheat and rye cultivars. Increasing N rate increased the straw yields of wheat on Dickson but decreased the grain yields of barley in the same soil with no lime. Nitrogen fertilization did not have consistent effects on the Decatur soil. The N, P, K, Ca, Mg, and Mn compositions suggested that more differences occured at the species level than at the cultivar level.  相似文献   

Potassium release by some delaware soils     

《Communications in Soil Science and Plant Analysis》2012,43(7):1037-1056

Abstract

The A and B horizons of 29 Delaware soils were extensively cropped to sudan grass (Sorghum vulgare Pers. Piper) and corn (Zea mays L. Pioneer Brand Hybrid No. 3958) to evaluate the K release characteristics of these soils.

Various chemical analyses were made on these soils. The double acid North Carolina extractant (NCE) was good at predicting K uptake during the early stages of the experiment and was most sensitive with A horizon soils. However, this extractant was not suitable for predicting K uptake in the latter part of the experiment when nonexchangeable K was more important. Boiling IN HNO₃ was a good extractant in the latter part of the experiment when nonexchangeable K was being released and it also predicted K uptake from the B horizon well. Soils leached with 0.025M MgCl₂ and incubated 25 days to determine K released were also highly correlated with plant uptake.  相似文献   

Quantity–Intensity Relationships and Potassium Buffering Capacity of Four Ganges River Floodplain Soils     

《Communications in Soil Science and Plant Analysis》2012,43(7-8):1333-1349

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Using Soil Potassium Adsorption and Yield Response Models to Determine Potassium Fertilizer Rates for Potato Crop on a Calcareous Soil in Pakistan     

《Communications in Soil Science and Plant Analysis》2012,43(6):645-655

Ustochrept soil was collected from a major potato-growing area in Pakistan for a potassium (K) adsorption isotherm experiment. Adsorption data were fitted to Freundlich and Langmuir adsorption models. Results showed that the Freundlich model (R²?=?0.96**) fit the data better than did the Langmuir model. Fertilizer rates were calculated based on the Freundlich model and targeted solution K levels at 0, 3, 6, 9, 12, 15, 18, 21, 24, and 27 mg K L^?1. A field experiment was then conducted on the soil to assess the effect of various soil solution K levels (0–27 mg L^?1, with K fertilizer rates at 0, 24, 49, 75, 101, 128, 155, 182, 210, and 237 kg ha^?1), on tuber yield and quality along with 300 kg N and 250 kg P₂O₅ ha^?1 as basal doses. Yield response models (linear plus plateau, quadratic, square root, quadratic plus plateau, and exponential) were used to calculate the optimal fertilizer rate for potato crop. Linear plus plateau model fit the data with less bias than the other models. There was a significant effect of K use on the yield and quality of potatoes. Potassium fertilizer application at 130 kg K ha^?1, which is equivalent to a soil solution level of 12 mg K L^?1, maximized the tuber yield of potato. However, for the improvement in tuber dry matter, reducing sugars, protein contents, and starch contents, the soil solution K level required was as high as14.62 mg L^?1 (157 kg ha^?1). Even greater rate of K, 17.74 mg L^?1 (190 kg ha^?1), was needed to maximize vitamin C content in potato.  相似文献   

Simple and Inexpensive Water Extraction Method for Assaying Potassium Concentration in Tobacco Plant Tissue     

《Communications in Soil Science and Plant Analysis》2012,43(5):962-970

Potassium (K) in plant tissue is not bound to organic compounds and occurs in soluble forms, thus indicating the ease of its extractability. The conventional methods of plant-sample preparation for K determination are often tedious, time-consuming, and/or require chemicals, making the analysis expensive. In this investigation, we propose a water extraction method for assaying K concentration in tobacco leaf tissue and evaluate it for analytical accuracy and precision in comparison to the established methods, namely, triacid digestion, 1 N ammonium acetate (NH₄OAc) extraction, and 0.5 N hydrochloric acid (HCl) extraction. The proposed method entails extracting K from 0.5 g finely ground plant tissue (<0.5-mm sieve) with distilled water at a 1:100 ratio (sample weight to water volume, w/v) by shaking for 20 mins and filtering before K measurement by flame photometry. Results with 25 tobacco leaf samples having a wide range in K concentrations showed very close agreement between the values of K determined by the proposed water extraction method and the established methods. The mean K concentration obtained with water extraction method was within 3 to 6% of those measured by established methods. The correlations between the K values obtained by the established methods and the water extraction method were highly significant (P?=?0.01), and the relationships are best described by linear regression equations with high values of R² (>0.99). The standard errors (SEs) and coefficient of variation (CV) for K measurements by different methods followed the order water extraction < HCl extraction < triacid digestion < NH₄OAc extraction. The results suggest that the water extraction method is comparable in accuracy and superior in precision to the established methods for K determination. Being simple, rapid, and inexpensive, the water extraction method could be used as an alternative to the most commonly employed standard, triacid digestion, for routine analysis of K in tobacco plant tissue.  相似文献   

Fertilizer Use and Wheat Yield in Central and Eastern European Countries from 1986 to 2005 and Its Implication for Developing Sustainable Fertilizer Management Practices     

《Communications in Soil Science and Plant Analysis》2012,43(18):2358-2375

Economic and political challenges impact agricultural practices, production efficiency, and crop yields. We hypothesize that increased conversion efficiency of fertilizer to crop yield resulted from changes in fertilizer management in Central and Eastern European countries. Efficient nutrient management depends on fertilizer applied, management practices, and weather, which impact uptake, utilization efficiency, and crop yield. Trends in fertilizer consumption and wheat yields from 1986 to 2005 were studied for five countries. There were significant differences in yield gap, defined as the difference between potential and actual yields. Partial factor productivity of applied nitrogen fertilizer (N) is calculated from real and modified indices. A predictive metric is introduced based on the quantity of unworked, or nonproductive, N (N_uw). Sustainable cropping practices reduce N_uw and yield gap. Improved knowledge of crop responses to balanced plant nutrition at the country level contribute to improved agricultural and environmental policies and enhance production sustainability.  相似文献   

Foliar diagnostic norms for sorghum     

《Communications in Soil Science and Plant Analysis》2012,43(9):817-825

Abstract

The Diagnosis and Recommendation Integrated System, previously applied successfully to many other crops, is shown to be an appropriate foliar diagnostic tool for sorghum (Sorghum bicolor L.) with respect to N, P, K, Ca and Mg. The norms were developed from a data bank comprising 907 observations of tissue composition and yield gathered from the literature and investigators’ files. The total population of observations is divided into a high and low subpopulation on the basis of yield. Those forms of expressing tissue composition which discriminate best between the two subpopulations are used to compute DRIS indices which measure the extent of the deviation from the established norm. An independent set of data from two field experiments is used to show that the norms can validly diagnose nutrient insufficiences which when, corrected result, in yield increases.  相似文献   

Soil testing of horticultural substrates (v) Evaluation of 1: 1.5 water extract and ammonium acetate extract for potassium and desirable potassium values     

《Communications in Soil Science and Plant Analysis》2012,43(9):867-879

Abstract

The 1: 1.5 water extraction of horticultural substrate for K was evaluated using K uptake as the criterion. Two crops, chrysanthemum (2 trials) and verbena (2 trials) were grown in peat, peat + pumice (PP), pine bark and peat + sawdust + sand (PSS). The ammonium acetate (NH₄OAc) extraction for K was evaluated in one trial. The number of K application rates varied from 9 to 23.

The relationship between both soil tests and plant uptake was very good for all substrates, although it was generally poorer in bark, particularly in the verbena trials. This was probably due to the relatively high level of native K in bark and the lower K requirement of verbena. The relationship between water extractable K and NH₄OAc extractable K was linear and very good.

Percentage maximum dry weight and net growth rate were regressed against soil test values using a quadratic function and desirable values (DV) were estimated from the response curve. The initial DV for water extractable K For maximum dry weight in the chrysanthemum trials varied from about 45 ‐ 139 ppm and for NH₄OAc extractable K in one chrysanthemum trial varied from 284 ‐ 469 ppm. The DV obtained from growth rate measurements were similar to those obtained using percent maximum dry weight. It was not possible to determine DV for plants growing in bark and in PSS in one trial.

The DV for verbena, which could be determined in peat in only one trial due to lack of response in the others was 10–11 ppm in the water extract.  相似文献   

Denitrification rate relationships with soil parameters in the field     

《Communications in Soil Science and Plant Analysis》2012,43(5):539-549

Abstract

It has been recently shown that there is a large spatial variability in denltrification rates measured in the field. The objective of this study was to assign this variability to twelve measurable or determined soil parameters known or suspected to be Important to denitrification during the early part of the growing season. Relationships were sought with 16 cores at a grid spacing of 25 cm on three sites (dates) within a 0.07 ha area of a cultivated silt loam soil. The denitrification rate was estimated from the N₂O production rate with the acetylene blockage technique.

Only few statistical significant relationships were found with simple and multiple regression analyses and there was a lack of consistency from site to site. Plotting the data revealed a tentative negative relationship between the N₂O production rate and percent air‐filled porosity. A few cores at each site showed a much greater N₂O production rate for no discernable reason, but these rates were also negatively related to percent air‐filled porosity. Tentative positive relationships between N₂O production rate and total organic carbon or water‐soluble carbon were similarly found.  相似文献