| Agriculture is one of the pillar industries of Yunxiao County,with a total agricultural output value of 5.218 billion yuan in 2017.Rice,early maturing loquat,sweet potato are the leading industries of agriculture in Yunxiao County.It is of great significance to understand the nutrient status of cultivated soil and orchard soil in the county,which can provide basis for guiding agricultural production.In this paper,264 paddy soils,60 dry land soils and 80 loquat garden soils in Yunxiao County were analyzed and tested.Through five routine and medium trace element tests,the physical and chemical properties of soils were analyzed,the influencing factors were discussed,the status quo of soil nutrition barrier was revealed,the causes of nutrition barrier were diagnosed,and rice"3414"field test was carried out on representative soil types and"3414"sweet potato field experiment,to establish fertilization model,to explore the best Fertilization Formula.1.The soil acidification was serious and the content of organic matter was in the middle level,The content of alkaline hydrolysis nitrogen was medium and low.The average p H value of paddy soil in Yunxiao County was 5.53,and 95.45%of the total samples were in acid level（p H<6.5）,which was serious in paddy soil acidification;the average p H value of dry land soil was 5.62;the average content of organic matter in paddy soil was 21.68 g/kg,in which the proportion in medium level（20-30 g/kg）was 52.65%;the average content of organic matter in dry land soil was 22.97 g/kg,the coefficient of variation was27.14%,and the samples in the middle level accounted for 53.33%of the total samples,indicated that the content of soil organic matter in cultivated land was in the middle level.The proportion in rice soil with a medium level of alkaline hydrolysis nitrogen content was 64.78%and in dry soil at deficiency level was 66.67%,indicated that the alkaline hydrolysis nitrogen content was medium and low.2.The soil of cultivated land was rich in phosphorus,but lack of potassium and boron and magnesium was at a medium level.The average value of available phosphorus content in paddy soil was 29.83 mg/kg,and the samples at the rich level accounted for 51.52%of the total samples,28.03%of the samples were soil samples whose available P content was higher than the ecological risk critical value（>40 mg/kg）.The average value of available phosphorus content in dry land soil was 36.72 mg/kg,rich（>25 mg/kg）soil samples accounted for 96.67%of the total samples,and 31.67%of the samples whose available phosphorus content in dryland exceeded the ecological risk critical value（>60 mg/kg）of high available phosphorus,indicated that the available phosphorus content in cultivated land in Yunxiao County was high and there was a risk of enrichment.In Yunxiao County,the average content of available potassium in paddy soil was 87.31 mg/kg,59.5%of the samples were in the lack level,58.22 mg/kg in dry land,31.95%of the samples were in the low level,indicated that the content of available potassium in cultivated land was in the low level.The average content of available boron in paddy soil was 0.41 mg/kg,and 77.65%of paddy soil lacks boron.The available boron content of dry land soil was 0.32 mg/kg,and the available boron content of all soil samples was in the deficient level（<0.5 mg/kg）.The average content of exchangeable magnesium was86.99 mg/kg,the number of samples in the middle level accounts for48.86%of the total number of samples,the average content of exchangeable magnesium in dry land soil was 85.87 mg/kg,and 85%of the soil samples were at a medium level（40-120 mg/kg）,indicated that the exchangeable magnesium content of cultivated soil was at a moderate level.3.Based on the agronomic effect of rice fertilization optimization.Based on the experiment of rice"3414"in the typical soil type-grey yellow mud field,the mathematical model of rice was established,and the regression equation was y=375.248-2.113X1-2.341X2+28.814X3+0.218X12-2.302X22-0.556X32+2.903X1X2-1.251X1X3-0.957X2X3.The best fertilizationN10.58 kg,P2O53.64 kg,K2O 8.63 kg.The results showed that the application of NPK could improve the economic characters of rice and increase the yield of rice.Within the range of fertilizer applied in this experiment,the yield of rice increased with the increase of N,P and K application,and the effect of N application was the best.The effect of N,P and K on rice yield was N>P>K.4.Based on the agronomic effect of sweet potato fertilization optimization.The regression equation of Experiment was as follows y=982.668+77.631X1+110.298X2+44.553X3-5.673X12-12.881X22-2.417X32+0.931X1X2+3.052 X1X3+0.019 X2X3.The best economic benefit fertilization amountwas N 11.46 kg,P2O54.62 kg,K2O 16.07kg.It could be seen from the experiment that the application of NPK could increase the yield and benefit of sweet potato.Within the range of fertilizer applied in this experiment,the yield of sweet potato increased with the increase of N,P and K application.The effect of N,P and K on the yield of sweet potato was N>K>P,and the benefit was N>K>P.5.Loquat garden soil organic matter content was high,but potassium was deficient,phosphorus was enriched,and the soil was acidic.The average content of organic matter in the soil was 26.42 g/kg,and the proportion of rich（>20 g/kg）samples was 80%,indicated that the content of organic matter in the loquat garden was relatively high.The p H of loquat garden soil was in the range of 4.1-6.9,the average value was 5.45;the average content of available potassium was 155.21 mg/kg,CV was 77.9%.the number of samples at the deficiency level（<100mg/kg）accounted for 46.25%of the total samples,which indicated that the content of available potassium in loquat garden soil was in the lack level;the average value of effective phosphorus content was 47.63 mg/kg,which showed that available phosphorus in loquat garden was enriched,and the content of available phosphorus varies greatly in different soil blocks.According to the production practice survey,it was recommended that for adult loquat trees more than 5 years old,the annual fertilizer application of 667 m2should be N 42 kg,P2O522.4 kg,and K2O 38kg（purification）,and be applied in four times. |
