| Shaanxi Province is the largest apple production region in China. High-yield andhigh-quality of apple affect farmers’ income a lot. However, there are some problems in appleproduction such as excessive application of nitrogen fertilizer and unreasonable use ofmicroelements fertilizer. In order to promote rational fertilization of apple production inWeibei Dry Highland, the mineral nutrient concentration in red Fuji apple leaves duringdifferent growth stages were determined. Apple tree leaves were sampled at June, July andAugust respectively in Heyang County, Shaanxi Province, and concentrations of mineralnutrients were determined. We analyzed the change law of main nutrients elements in leavesand nutrients concentration differences between high-yield tree and low-yield tree leaves fromJune to August. Sufficiency range method and three different DRIS methods raised byBeaufils, Jones, Elwali&Gascho respectively were used to diagnosis the nutritional status ofFuji apple. By doing this, we founded the leaf diagnosis indexes for Fuji apple in our studyarea and raised out the fertilizer demand for both high-yielding and low-yielding trees duringdifferent growth stage.The main results were showed as follows:1. Nutrients concentrations in apple leaves varied from June to August. During thisperiod, high yield trees (yield>25kg per tree), N concentration decreased in July and thenincreased slightly in August, while P concentration decreased all the time. For low yield trees(yield≤25kg per tree), N concentration decreased all the time, the change of P just followedthe tendency of N in high yield trees. Other nutrients showed the same trend in both kinds oftrees: K and Zn decreased; Mg increased; Cu, Fe and Mn increased in July and then decreasedin August. All mineral nutrients concentration in high-yield trees were higher than inlow-yield trees in June except Cu. N, P, Zn and Mg were significant higher in high-yield treesthan in low-yield trees(for N, P, Zn, P<0.01, for Mg, P<0.05). In July, P, K, Fe and Znconcentration in high-yield trees were higher than those in low-yield trees and with lowervariability. When it comes to August, only N, P and Zn concentration in high-yield trees were still higher than those in low-trees.2. The sufficiency ranges of leaf mineral nutrients in Fuji apple from high-yieldingorchards were established at three growth stages. The ranges for the nutrients underconsideration in June were as follows:N22.85~29.29g/kg, P1.42~1.93g/kg, K10.44~16.67g/kg, Ca11.53~17.30g/kg, Mg2.49~3.92g/kg, Cu9.81~15.53mg/kg, Fe193.84~329.54mg/kg, Mn65.29~133.30mg/kg, Zn14.70~31.73mg/kg; the ranges for the nutrients underconsideration in July were as follows: N20.06~26.17g/kg, P1.27~1.70g/kg, K9.79~13.46g/kg, Ca13.80~23.60g/kg, Mg2.32~4.19g/kg, Cu8.68~20.38mg/kg, Fe214.30~345.12mg/kg, Mn81.55~197.86mg/kg, Zn11.80~21.16mg/kg; the ranges for the nutrients underconsideration in August were as follows: N21.41~25.09g/kg, P1.23~1.68g/kg, K8.88~12.66g/kg, Ca16.53~22.40g/kg, Mg2.84~3.99g/kg, Cu5.93~15.89mg/kg, Fe149.67~225.90mg/kg, Mn89.03~170.09mg/kg, Zn10.00~19.76mg/kg.3. The nutrient reference values, nutrient-ratio reference values for red Fuji apple leavesfrom high-yielding orchards were put forward, and the diagnosis parameters determined byDRIS standard program were different during different periods.4. The DRISes proposed by Beaufils, Jones and Elwali&Gascho was used to diagnosenutrient status and requirements of red Fuji apple tree. Compared with the diagnosis indexcalculated with method of Elwali&Gascho, that with methods of Beaufils and Jones weresignificantly correlated with nutrient concentration, and the corresponding order of nutrientrequirement was similar. From June to August, the elements needed mostly were K, Fe,Ca+Mg by Beaufils and K, Ca, Ca+Mg by Jones for high yield trees, and K, Fe, N for lowyield trees. The results suggested that that leaf nutrient diagnose should be conducted duringdifferent growth periods of red Fuji apple. |
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