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【Objective】The present paper aimed to clarify the comprehensive soil fertility status of pitaya orchards in Hainan province, and the spatial distribution and changing trend of soil nutrients in pitaya orchards in Hainan province were analyzed and predicted by means of survey sampling and statistical methods, so as to provide the basis for scientific fertilization and soil management of pitaya orchards.【Method】60 soil samples were collected from pitaya orchards in the main producing areas of Hainan province.Soil pH, organic matter, available nitrogen, available phosphorus, available potassium, exchangeable calcium, exchangeable magnesium, available copper and available zinc were used as evaluation indicators.Inverse distance weight interpolation method（IDW） was used to analyze the spatial distribution of each index, and used the factor analysis method combined with IDW to evaluate and predict the comprehensive soil fertility of the pitaya orchards in the survey area.【Result】The orchard soil in the survey area was neutral and slightly acidic, and 50% of the soil samples, pH were lower than 6.5; The organic matter content was moderately low, and some areas of Ledong and Sanya were insufficient; The average value of alkaline hydrolysis nitrogen was only 79.17 mg/kg, and the soil in the survey area was relatively lack of alkali-hydrolyzable nitrogen; The content of available phosphorus and available potassium were both high, and the average available phosphorus was 119.06 mg/kg, far exceeding its environmental risk threshold（60 mg/kg）; Orchards in the survey area the content of trace elements in the soil was relatively abundant. The IDW prediction map showed that the content of trace elements in Dongfang and Lingshui was high, and the content of Ledong and Sanya was low; Based on the analysis of the comprehensive score IFI, the results of the comprehensive fertility prediction of pitaya orchards in the entire study area using IDW showed that the eastern part of the study area, the comprehensive soil fertility of the orchards in the eastern and western regions of the study area was relatively high, while the soil comprehensive fertility of the orchards in the central part of Ledong and Sanya was relatively low.【Conclusion】The pitaya orchards in Ledong and Sanya still need to increase the input of organic fertilizers or increase the application of lime to improve the soil pH and supplement the medium and trace elements; The orchards in the survey area need to increase the input of nitrogen fertilizer and control the application of phosphate fertilizer. [ABSTRACT FROM AUTHOR]

【Objective】 Base ion in soil is an important index to evaluate soil fertility. The problems of different depth of soil nutrient ion concentration, hardening in drought, sticking and decaying in waterlogging, low water storage and soil moisture conservation capacity seriously affect crop constants. 【Method】In the present paper, the calcareous chernozem in a certain area of Heilongjiang province is taken as the research object to study the effect of soil replacement and fertilization on base ion in calcareous chernozem soil; Under the condition of soil replacement and directional fertilization, the distribution and change of soil salt were studied. 0-20 cm soil and 20-40 cm soil were treated with directional fertilization for three consecutive years after one-year soil replacement. Under the premise of normal application of base fertilizer, the soil replacement(T1), soil replacement + straw(T2), soil replacement + 500 kg/667 m~2 were taken as the control without soil replacement.In the experiment group, the treatment methods of M2 dried chicken manure(T3) and soil replacement + 40 % theoretical phosphate fertilizer application(T4) were used to study the effect of different fertilization conditions on directional fertilization after soil replacement. 【Result】Soil replacement + basal fertilizer and application of organic fertilizer(T3) had the best effect, which could increase the content of water-soluble potassium ions, balance the content of sodium ions, bicarbonate ions and pH acidity and alkalinity, and reduce the content of calcium ions, magnesium ions, sulfate ions and chloride ions. 【Conclusion】The results show that the effect of soil layer replacement technology is obvious in the process of improving soil cation and anion. It can balance the pH value of soil, among which the effect of drying chicken manure with soil layer replacement + 500 kg/667 m~2 is the best. It can balance the content of anion and cation in soil, improve the pH value of soil, and create a good soil environment for corn, which is suitable for popularization and application. [ABSTRACT FROM AUTHOR]

[Objective] This paper aims to provide optimal fertilization guidance for high-yield cultivation of P. frutescens and promotion of new P. frutescens varieties. [ Method] The effects of nitrogen, phosphorus and potassium fertilizers on the yield of two new P. frutescens varieties ( Qisu 2 and Qisu 3) were studied by ternary quadratic orthogonal rotation design. The regression equation and model analysis were constructed to optimize the high-yield fertilization mode. [ Result] N was the most important factor influencing the yield of P. frutescens. However, the two varieties varied in response to P and K fertilization. The regression models of nitrogen (x1) , phosphorus (x2) and potassium (x3) of the yield (Y) are Y = 2219.384 + 405.410x1, +304.926x2 - 156.723x12 -78.676x22 - 214. 479x1x2, and Y =2048.806 + 319.535x1, +54.722x3 -63. 102x12 - 113. 664x22 +76.017x32 -69.069x1x2, respectively. The best fertilization ratio of N, P and K fertilizer was (286.022 ±25.288),(139.059 ±20. 819),(180. 000 ± 35. 860) kg/hm2 , and (338. 180 ± 16.617) , (80. 923 ±21.314) , (203.529 ± 24. 278 ) kg/hm2, respectively. The yield of P. frutescens could reach 2250 kg/hm2. [ Conclusion ] Compound application of NPK fertilizers functioned significantly in enhancing P. frutescens yield. [ABSTRACT FROM AUTHOR]

[Objective] The composition and intensity of soil phosphorus forms played an important role in improving the phosphorus bio-avail-ahilitv of crop and the utilization efficiency of phosphorus fertilizer. This paper aimed to investigate the possibility and potential of application rate of P fertilizer, which provide a technical support for cotton production system. [ Method]The experiments applied 4 rates of P fertilizer [0 kg/hm2 ( P0) , 75 kg/hm2 ( P75 ) , 150 kg/hm2 ( PI50) , 400 kg/hm2 ( P400) ] were conducted to investigate the content of soil inorganic P in different soil layers during the critical periods of cotton phosphorus nutrition of three cotton cultivars ( XLZ57 , XLZ50, XLZ13). [ Result ] Compared with the control treatment(P0) , the Ca2-P, Ca8-P, Ca10-P, Fe-P, Al-P in seedling stage root layer (0 -20 cm soil layer) under the low P level ( P75) averagely increased by 68.5 % , 42. 0 % , -17.6%, 38. 8 % , 60. 5 % , and in blooming-boiling stage root layer (0 - 20 cm soil layer) averagely increased by 52.8%, 18.8%, -17.7%, 38.3%, 44. 7 % , respectively; Under the proper P level (P150) , in seedling stage averagely increased by 148. 9 % , 88. 1 % , -31.5%, 65. 5 % , 46. 7 % , in blooming-boiling stage averagely increased by 113.7 % , 54.5 % , 29.4 % , 77.6 % , 27. 7 % , respectively; Under the surplus P level (P400), in seedling stage averagely increased by 58. 6 % , 53.4 % , 44.4 % , 105. 8 % , 32. 8 % , in blooming-boiling stage averagely increased by 52. 3 % , 19.3 % , 40. 8 % , 143.8 %, 13.7 %, respectively. Under the different phosphorus conditions, the soil Ca8-P, Ca10-P, Fe-P contents of XLZ50 were higher than that of XLZ57 and XLZ13, the soil Ca2-P and Al-P contents of XLZ57 were higher than that of XLZ50 and XLZ13 in seedling stage, and the soil Ca8-P, Ca10-P contents of XLZ50 were higher than that of other two cotton varieties, the Ca2-P, Fe-P and Al-P contents of XLZ57 were higher than that of other two cotton varieties in blooming-boiling stage. [ Conclusion] Different phosphorus application levels and different genotypes of cotton have different effects on soil inorganic phosphorus accumulation, soil Ca2-P content in the 150 kg P2O5/hm2 treatment was highest, and the soil Ca2-P content of XLZ57 was higher than that of XLZ50 and XLZ13 during the critical periods in the 75-150 kg P2O5/hm2 treatment. Therefore, rational application of phosphorus fertilized (150 kg P2O5/hm2 ) and selecting of cotton varieties( XLZ57) can improve the available phosphorus source in soil, and improve the phosphorus fertilizer use efficiency. [ABSTRACT FROM AUTHOR]

[Objective] The aim of this paper was to provide a theoretical relerence for the application of loss-control urea in rice production in yellow soil. [Method] Based on the same application rates of phosphorus and potassium fertilizer, the rice cultivar Leyou 58 was employed to explore the ellects of loss-control urea, with various adding amount of loss-control agent (1 %,2%,3%,4%,5%,6%), on rice yield, nutrients uptake and utilization. Meanwhile, no nitrogen and common urea fertilizer were taken as the controls. [Result] No regular changes of rice yield observed with increasing the dosage of loss-control agent, while the accumulation of nitrogen in rice grain, nitrogen, phosphorus and potassium in rice straw, and potassium in aboveground parts showed regular variation. At the same time, regular changes were also observed on rice nitrogen, phosphorus, potassium harvest index and potassium absorption efficiency. Compared with common urea treatment, six kinds of loss-control urea with the loss-control agent of 1 % -6 % could increase the rice yield in some degree, among which 1 % adding amount performed the best. The yield increasing rate was up to 12.22 %. The adding amounts of 1 % , 2 % and 6 % enables absorption of nitrogen, phosphorus, potassium by rice and accumulation in the rice seeds sufficiently to promote the yield and quality of rice. The adding amount of 3 % enhanced the accumulation of nitrogen, phosphorus and potassium in rice straw, increased the resistance and promoted the growth. [Conclusion] To sum up, the effect of urea with 1 % loss-control agent performed the best in rice production. [ABSTRACT FROM AUTHOR]