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The effect of soil pH on nutrient availability. 

The effect of soil pH on nutrient availability. 

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Technical Report
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This review investigates the importance of non-NPKS nutrients within cereal and oilseed rape production systems. The review considers crop requirements, sources of nutrients, occurrence and diagnosis of deficiencies, strategies for avoiding/rectifying deficiencies, and knowledge gaps. Crop requirements: The function of each nutrient for the plant...

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Context 1
... detail is therefore largely excluded from the current review, with only the key factors and their impacts considered in relation to soil supply, crop requirements and potential nutrient deficiency. In general, the availability of most micronutrients decreases at higher soil pH levels ( Figure 2). Low temperatures and other factors that affect root growth and activity, such as waterlogging or soil compaction, will also reduce micronutrient and other nutrient uptake. ...
Context 2
... most of the other micronutrients, Mo occurs in soils mainly as an oxycomplex, molybdate (MoO 4 2 ˉ) and, as a result, its behaviour in soil is similar to that of phosphate, being adsorbed by sesquioxides and clay minerals. The molybdate anion is strongly bound by ligand exchange, most strongly at pH 4.0 and decreasing with increasing soil pH ( Figure 2). Liming is well known to increase Mo availability and is the most effective treatment to correct/prevent the deficiency. ...
Context 3
... thorough description of micronutrient visual symptoms in wheat is discussed by Snowball and Robson (1991) and is summarised below and in Figure 20. Orlovius (2003) describes the main visual symptoms for micronutrient deficiencies in oilseed rape and this is summarised below ...
Context 4
... (Feng et al, 2005). * and ** indicate stati stical significance at the probability level of P<0.05, and P<0.01 re spectively. ...
Context 5
... close to the thresholds there are inconsistencies such that 1.8 mg/l zinc would be interpreted 'very low, deficiency very likely in susceptible crops' by ADAS (Anon, 1980a), 'risk' by NRM and 'moderate, no deficiency expected' by SAC ( Edwards et al., 2012) ( Figure 23); and a soil with 1.2 mg/l Cu would be above the RB209 threshold for 'possible deficiency' but would be interpreted by NRM as 'very low' and by SAC as 'low, deficiency possible' (Figure 22). ...
Context 6
... close to the thresholds there are inconsistencies such that 1.8 mg/l zinc would be interpreted 'very low, deficiency very likely in susceptible crops' by ADAS (Anon, 1980a), 'risk' by NRM and 'moderate, no deficiency expected' by SAC ( Edwards et al., 2012) ( Figure 23); and a soil with 1.2 mg/l Cu would be above the RB209 threshold for 'possible deficiency' but would be interpreted by NRM as 'very low' and by SAC as 'low, deficiency possible' (Figure 22). ...
Context 7
... include the NRM oilseed rape and the Teagasc scales for B (Figure 24), and the NRM wheat and oilseed rape scales for Zn (Figure 26), all of which are more sensitive than the values in Reuter (1986), i.e. tending to diagnose deficiency more readily than may be justified. ...
Context 8
... include the NRM oilseed rape and the Teagasc scales for B (Figure 24), and the NRM wheat and oilseed rape scales for Zn (Figure 26), all of which are more sensitive than the values in Reuter (1986), i.e. tending to diagnose deficiency more readily than may be justified. ...
Context 9
... interpretative scales for soil Cu (Figure 20) can also be compared to the analysis of yield responses shown in Figure 5. The RB209 and SAC scales most closely describes the relationship shown in Figure 5, which suggested a threshold of about 1.0 mg/kg soil Cu. ...
Context 10
... a typical randomised block experiment with four treatments and five replicates had a yield LSD of 0.5 t/ha, then increasing the replicate number to approximately 17 would reduce the LSD to 0.25 t/ha. Figure 25 gives an illustration of how changing replicate number may affect the LSD for a specific experiment with four treatments. This analysis shows that increases in replicate number have a diminishing effect on reducing the LSD and it indicates that it will be very difficult to reduce the LSD of a modest sized conventional randomised block experiment to <0.1 t/ha through simply increasing the number of replicates. ...

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... The next largest element that can be recovered is Zn, with an average of 4451 kg available. In cereal crops, Zn is required for protein synthesis, sugar formation and optimal photosynthesis levels [28,29]. Rehman, Farooq [29] reported that that wheat yields in Turkey increased by 32% when Zn-deficient soils were amended with adequate Zn fertilisation. ...
... Rehman, Farooq [29] reported that that wheat yields in Turkey increased by 32% when Zn-deficient soils were amended with adequate Zn fertilisation. Roques, Kendall [28] report that barley crops (grain only) remove 0.03 kg t −1 . This suggests that, using the mean values for wool yield ( Table 2) and Zn content of wool (Table 3), hydrolysing wool and utilising the product as a soil amendment would provide enough Zn to meet the offtake needs of 5.3 million ha of barley with an average yield of 10 t ha −1 . ...
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... Mn 2+ plays an important role in plant metabolic functions acting as an essential cofactor in the reduction of oxygen and stimulating the photosynthetic machinery by catalyzing the water division in photosynthesis [66]. In addition, Cu 2+ is an essential component of various proteins that act in photosynthesis, respiration, and phytohormones linked to pollen production [64]. Therefore, the metallic micronutrients are essential to plant hormonal metabolism related to crop performance, as observed in the PCA analysis in our study (Figure 2). ...
... Therefore, the metallic micronutrients are essential to plant hormonal metabolism related to crop performance, as observed in the PCA analysis in our study (Figure 2). Their deficiency generally is associated with high pH (Figure 4), low SOM content, and dry soil [64], as verified in the Northeast field in our study (Table 2). ...
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... These are, albeit, very small changes. The pH values in the gypsum amended soils may not have any adverse impact on the crop nutrition as these values fall in the adequate pH range for optimal bioavailability (Roques et al. 2013). ...
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