For plant K nutrition, mixed-layer phyllosilicates appeared to be the most important K-bearing mineral phase. Relative contents of mixed-layer phyllosilicates (MLP) significantly correlated with both plant tests and also with chemical extractions. The role of interlayer K in 2:1 soil clay minerals for plant K uptake was emphasized by Barré et al. (2007). Clay content was significantly related to the same extracted K pools as MLP relative content, confirming that MLP minerals constitute the major proportion of soil clay fraction in the studied soils. Soil K non-exch pool is largely determined by soil texture (Škarpa and Hlušek 2005). For other soil parameters (pH, C org , cation exchange capacity), we did not find relation to K pools.
that a wide range of soil fertility conditions existed, from fertiliser responsive soils to soils with excessive K and/or P. At present, the soil K status of a paddock is usually evaluated using a single bulked sample. The wide ranges of values indicated that inadequate sampling to create a bulked sample could result in very wide error margins. Even if the test result of the bulked sample does happen to accurately reflect the arithmetic mean of the soil population, the relevance of a single number remains highly debatable as an adequate representative of such a wide ranging population. A better practise for tests of plant available K may be to analyse a number of separate samples so that the distribution can be characterised, rather than bulking the samples together. If the distributions, once characterised, are stable in time, as indicated in this study, and are also similar between farms, as found in this study and as indicated to be likely by Beckett and Webster ( 1 97 1 ), then an accurate characterisation may only need to be done occasionally to characterise large areas of pasture soils with similar soil parent materials.
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Potassium in the soil solution, which represents a very small fraction of total soil K, is an important indi- cator of K availability (Nye 1972) because the mainly diffusive flux of K to roots takes place in the soil solu- tion (Diest 1978) and the diffusion rate depends on the concentration gradient that develops in the soil adja- cent to an actively absorbing root. We investigated the K concentration in the saturation extract. Even in the treatment K2+ (continuously high K fertiliser applica- tion) the K concentration in the saturation extract was relatively low (Figure 2). This low concentration may be due to the late sampling date (autumn after wheat har- vest) when the soil solution was largely exhausted. Nev- ertheless, a sharp decrease of the K concentration in the saturation extract could be observed in the treatment with the formerly high but discontinued K fertilisation (K2). In this treatment the K concentration decreased to the level of the treatments K1+ and K1, respectively. The K concentration in the saturation extract K1 is almost at the same level as the control (K0) that did not receive any K fertiliser for about 40 years. It should be mentioned that K in the soil solution could become a limiting factor in supplying K to plants.
According to the “build up and maintenance” approach, additional K fertilizer is applied with the intention of building up soil K levels to a specific level and then maintaining them at that level through continuous fertilization (Olson et al. 1982; Voss 1998). But soil K fluctuated similarly for both the control and fertilized plots through the four-year experiment. Plant available soil test K was depleted from crop removal and then increased slowly, peaking between April and June except when corn was grown. This correlates with other studies focusing on the dynamics of K in the soil and emphasizes the importance of sampling times (Liebhardt and Teel 1977). The dynamics of soil K did not change because of fertilization and no significant differences between the soil test K levels of the control and fertilized plots were recorded (Figure 3.1). Therefore, we postulate that any excess soluble K was either taken up by the crop or leached below sampling depth.
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Soil K gradient response. Yield increases in response to the soil K gradient were observed for all 3 site-years and critical levels were detected at both sites in 2002 (Fig. 6-8). Cox and Barnes (2002) observed a critical soil test K level in 1 of 3 yr at the same Peanut Belt site that indicate actual soil K concentrations achieved as a result of their fertilizer treatments remained deﬁcient. Annual fertilizer ap- plication rates were increased for this study, and by 2002 maximum soil test K levels had approximately doubled those reported by Cox and Barnes (2002). Even with these increased K fertilization and soil test levels, there were few data points in the plateau re- gion of this relationship (Fig. 7). Attainment of even higher levels of soil test K would improve conﬁdence in our estimate of critical levels. Nevertheless, data from other North Carolina ﬁeld sites have failed to detect yield response to soil- or foliar-applied K fertilizer at sites with initial soil test K concentra- tions greater than 130 mg kg -1 (Crozier et al., 2002;
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I n the previous chapter it was shown that the urine K retained as exchangeable soil K+, within the effective plant rooting zone of a ryegrass/white clover pasture, was recycled to the above ground herbage within one growing season. lt was also shown that on the Tokomaru silt loam the effective rooting depth for K uptake was the 0-1 5 cm depth of soil (section 3.3.3). Therefore the amount of urine K that can be adsorbed by the soil within 1 5 cm of the surface is important for conserving and recycling K. Apart from the K+ concentration in soil solution, the extent to which a so il may adsorb K from solution is determined by the quantity of negative charge on the surfaces of the soil. The amount of negative charge carried by a soil is mostly a function of the amounts and types of clay mineral present in the soil, its organic matter content and pH (section 2.2 .3) . There is a considerable amount of literature on K adsorption and K leaching in soils (e.g., Munson and Nelson, 1 963 ; section 2.7.1 . 1 ) with most studies using potassiu m chloride (KCI) as a source of added K. Dairy cow urine not only contains K and Cl but also N in the form of urea, which on contact with soil is hydrolysed to ammonium (NH4 +) and then is subsequently nitrified to nitrate (N03 -) . Hydrolysis of urea initially increases soil pH and then nitrification decreases soil pH (Doak, 1 952; Helyar, 1 976) . Soil pH has been shown to increase by at least 2 units within 48 hours of urine application (Doak, 1 952; Holland · and Du ring, 1 977) . Such an increase in pH could be expected to raise soil cation exchange capacity by 30 me 1 oo g -1 in soils with large amounts of pH dependent charge (Edmeades, 1 982) . This increase in negative surface charge may increase K adsorption and subsequently reduce K leaching. In the sho rt term, after urination the high pH in urine spots may be an important influence on the conservation of K returned to the soil in dairy cow urine (c. 20 g of K per urination) . Moreove r predictions of the amount of K lost fro m field soils using data obtained with KCI solutions rather than urine, do not include the effects of soil pH changes or changes in NH4 + and No 3 - concentrations and could provide misleading results.
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In New Zealand soi ls, the domi nance of either micaceous minerals, or smectite, or 1 : 1 kaolin is influenced by the stage of weathering as well as inheritance from the parent materials. For example, the least weathered zonal soils (brown-grey earths) contain weakly-hydrated mica, illite, clay-vermiculite, and amorphous hydrous oxides of AI and Fe (Fieldes, 1 968) . With increased weathering and leaching, 2: 1 clays are transformed to K-depleted clay vermiculite, and then to 1 : 1 minerals (metahalloysite and kaolinite). Thus in podzols and the podzolized yellow-brown earths, kaolinite and secondary silica I are the main clay-size minerals (Fieldes and Taylor, 1 96 1 ). On the other hand , the mineralogical features of the intrazonal soils (e.g. , yellow-brown pumice soils, yellow brown loams, red loams, brown loams) are largely inherited from the parent materials (rhyolitic or andesitic or mixed tephra, or scoriaceous basalt or flow basalt) , modified by soil development (Fieldes and Taylor, 196 1 ) and hence contain either allophane, mixed amorphous hydrous oxides, hydrous feldspars, metahalloysite, Fe oxides, crystalline oxides, or kaolinite. Layer silicates with 2 : 1 structure are either low or absent in these soils.
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In general, manuka flowers from October to February. This can occur even when plants are only a few centimetres high. The flowers develop in the leaf axils, are normally 6-12 mm in size and are pure white or slightly tinged with pink. Following pollination a hard woody capsule develops which is about 7 mm in diameter and divided into five segments. These capsules often remain closed for a number of years. When they open, usually as a result of fire or during hot dry weather, numerous minute seeds are released from each of the five segments (Wardle, 2011). Manuka establishes readily on exposed soil ground by direct seeding (Bergin et al., 1995; Wardle, 2011). This can be accomplished by scattering ripe manuka seed capsules over the ground, or by laying a mulch of cut manuka containing ripe or near ripe seed capsules. Germination usually occurs within about 10 days. Cuttings taken from March to May can also be used, though it is usually necessary to apply a hormone treatment (Wardle, 2011). The abundant flowering of manuka in young trees, copious production of fine seeds which are easily dispersed by wind aid its rapid establishment on disturbed sites (Whitehead et al., 2004; Ross et al., 2009).
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through two ways. one is the physical way, the establishment of C. microphylla trapped wind- blown fine materials and dust which were rich in nutrients and deposited in the surface soils under their canopies (Su et al. 2004). the other is chemical way. For example, the n released by litter decomposition resulted in an increase in soil n. the development of herbs formed an important component of net primary productivity, and their rapid growth and death provided an important input of C, n and other nutrients (Cao et al. 2008). root architecture of shrubs plays a key role through both physical and chemical ways in improving soil nutrient. larger of roots of C. microphylla appeared at 20 cm soil layer in US and beneath 50 cm soil layer in BS. More roots had larger contact area with soil and possessed stronger sand fixa- tion ability. root system of C. microphylla with a lot of nodules could fix the free nitrogen and increased the contents of soil nitrogen (Cao et al. 2004). the number and biomass of roots affected the distribution range of soil nutrient (Hansson et al. 1994, 1995). these were the reasons why soil nutrients were significant among different soil depths and between US and BS in our study.
Nitrogen (N) is generally considered to be the most limiting element in temperate and boreal forests of North America (Kimmins and Feller, 1976; Krause, 1982; Vitousek and Matson, 1985; Binkley, 1986; Munson et al., 1993). The incorporation of nutrient-rich post-harvest forest residues can increase soil N and carbon (C) pools (Burger and Pritchett, 1984; Sanchez et al., 2000; Sanchez et al., 2003; Smethurst and Nambiar, 1990). Intensively managed pine plantation (Pinus taeda L.) sites in the southeastern U.S. are limited by low N or phosphorus (P) availability (Ducey and Allen 2001; Valentine and Allen 1990; Allen 1987), and low biomass productivity and therefore synthetic fertilizer applications have become common, and the fertilizer applications have increased forest floor accumulations (Gurlevick et al. 2003). Past research shows that typical shearing and piling of woody debris along with the movement of these materials off site may result in a site productivity decline due to a loss of site organic matter (Burger and Kluender, 1982; Burger and Pritchett, 1984). Hence, these on-site accumulated pools of post-harvest forest floor and slash have the potential to be large nutrient reservoirs for the subsequent pine plantation rotation.
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For those 1990’s enthusiasm toward soil personal satisfaction and seeing its vitality need come to the bleeding edge for ecological maintainability. The terms soil quality, soil degradation, soil health, soil flexibility are constantly utilized additional every now and again with more excellent desperation to association with methodologies on secure our worldwide earth. Those will enhance our personal satisfaction for an aggregation and ensure numerous rare regular assets are forcing the public eye to perceive the vitality about their soil asset. However, soil personal satisfaction and territory administration both have immediate impact around water Furthermore climatic nature also toward development with mankind's creature wellbeing. Same time apparently a straight-ahead concept, soil personal satisfaction had been troublesome with define and additional challenging to quantify.
Abstract: The objective of this study was to evaluate the effect of tillage system and previously cultivated crop on the chemical properties and enzyme activity of soil. The first-order experimental factor was the tillage system, i.e., (1) conventional tillage (CT) and (2) reduced tillage (RT), whereas the second-order experimental factor was the previously cultivated crop, i.e., (a) pea and (b) durum wheat. Samples of soil were analyzed for the contents of organic C, total N, available forms of P, K, and Mg, as well as soil pH, total sorption capacity, and activity of soil enzymes (dehydrogenases, phosphatases, ureases, and proteases). The study demonstrated that the contents of organic C, total N, and available forms of K and Mg as well as soil pH were higher in soil subjected to RT than in that subjected to CT. In plots after pea cultivation, higher values were determined for the contents of total N and Mg, whereas in plots after durum wheat cultivation, the contents of organic C, P, and K and the soil pH were higher. Higher activities of dehydrogenases and phosphatases in soil were noted in soils subjected to the CT system than in those subjected to the RT system, whereas the activities of ureases and proteases were higher in soils subjected to RT. In addition, higher activities of dehydrogenases, phosphatases, and proteases were determined in the soil after pea cultivation than after durum wheat cultivation, whereas a higher activity of ureases was found in the soil after durum wheat cultivation. The C/N ratio was more beneficial after CT than after RT, as well as in the soil from plots after pea cultivation than after durum wheat cultivation.
Při porovnání hodnot faktoru K stanoveného na základě zrnitostních rozborů vzorků půd a fakto- ru K, který byl vyhledán v tabulkách podle pětimíst- ného kódu BPEJ, byly zjištěny rozdíly v zrnitosti půd u HPJ. Proto by hodnoty faktoru K odvozené z kódů BPEJ měly být považovány jen za orientační hodnoty. Nejpřesnější stanovení faktoru K lze získat pouze z laboratorních analýz a následných výpočtů.
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Incubation experiment and K release analysis. The experiment was a completely randomized 5 × 4 × 3 factorial arrangement. It was done in polyethylene pots, with 200 g soil. Treatments consisted of five soils and four soil amendments with three replicates. The soil amendment treatments included 20 g/kg zeolite (Z), 20 g/kg vermicompost (V), 20 g/kg vermicompost + zeolite (1:1) (ZV), and control (C). The samples were incubated at 22 ± 3°C for 90 days. Enough distilled water was added to bring the soil moisture level to field capacity. At the end of incubation time, samples were air-dried and analyzed to determine different forms of K and K release to 0.01M CaCl 2 .
Figure: 7. Paddy leaf showing zinc deficiency Zinc sulphate heptahydrate (Zn – 21%) is recommended for soil application at the rate prescribed by the State Agricultural Universities/ Soil Testing Laboratories. The doses varies from 25 to 60 kg/ha depending on soil type, cropping intensity and crop productivity levels. In the absence of basal application, foliar spray of 0.5% solution of zinc sulphate heptahydrate for 15 days after transplanting of rice should be practiced. Care needs to be taken that zinc sulphate should not be mixed with phosphate fertilizers, as water soluble zinc is transformed to relatively insoluble zinc phosphate.
The values of exchangeable K are depicted in Fig. 2. It was found that soils amended with either humate or sulphate under 50% of IR recorded the highest increases in the fraction of exchangeable K. Such increases were 21 and 10%, respectively, compared to the control. This might take place because K-humate is a soluble K source that is readily available to be absorbed by the cultivated plants (Sparks, 2000), while on the other hand, this treatment decreased K fixation by clay minerals (Bansal, 2000). Increasing the irrigation water level from 75 to 100% of IR led to significant reduction in the exchangeable K fraction, while on the other hand, decreasing soil moisture from 75 to 50% of IR recorded no significant effect on this fraction. Potassium fixed by clay minerals or difficult to exchange
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We have conclude that, the concentration of sodium present in the soil sample is more than potassium and The RFSS has greater K content than BFSS, and the Na content of RFSS is slightly greater than BFSS. This may be due to use of chemical fertilizers and Alkali water. This method is easy for handling and accurate.
ficients as additional measure of the strength of the linear relationships are presented. The coef- ficients proved that sill-nugget is a more stable (r = 0.74 for P and 0.83 for K) parameter than nugget (r = 0.30 for P and 0.53 for K). It can be expected that prediction of sill-nugget is more reliable than prediction of nugget. The reason is that the nugget represents uncorrelated spatial variation related to measurement error and spatial variation at distances smaller than shortest sam- pling interval. Slopes of the linear relationship for prediction of sill-nugget were found similar to those in Figure 3 of the between-field proportionality. This infers the comparability of the parameters. Range parameter was not functionally described, as there is no reason to see proportionality with the statistics used here. McBratney and Pringle (1999) note that the range is less likely related to the distribution and more likely is a function of the sampling scheme applied.
For many decades soil scientists have sought ways of indicating the availability to plants of nutrients, like phosphorus, potassium and nitrogen. The total quantities of these which occur in soil can be large although invariably not all is plant available. For consultative purposes analytical procedures for 'plant-available' nutrients have to be quick and reproducible; over time appropriate chemical extract ants have been found and are now widely used. Once a reliable analytical method for assessing the readily plant available status of a nutrient in soil became established, fertiliser recommendations were based on this method of characterising soils.
In the early spring (April to May), with the increase of air temperature, snowmelt occurs from the lower regions to the mountain areas. However, during this period (April to May), the air temperature exceeds 0 ◦ C only at noon, but drops to below 0 ◦ C at night. Consequently, much of the snowmelt water freezes again at night before its departure from snow- pack. Therefore, the snowmelt runoff in the early spring is small (around 15% of annual runoff; Zhang and Yang, 1991). From May to June (late spring), the air temperature increases to above 0 ◦ C stably, and the snowmelt runoff becomes very large (greater than 25% of annual runoff; Zhang and Yang, 1991). This is also attributed to the little permeability of the underlying seasonal frozen soil layers which have thawed only in upper soil layers (Kane and Stein, 1983). In summer, snow and seasonal frozen soil layers disappear, and thus rain- fall becomes the major source for river discharges. But the permanent frozen soil layers still exist, which prohibit the water infiltration to deeper layers. Heavy rainfall events in summer will usually result in severe flash floods in this wa- tershed, along with landslides and debris flows (Yang et al., 1993).
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