Investigation Of Fertilization Status And Potential Of Fertilizer Reduction In Watermelon And Melon In Shaanxi Province

Watermelon and melon are the value-added crops in agricultural economy;In China,the problem of excessive use of chemical fertilizer and pesticide is prominent.It is the basis of fertilizer reduction to define the soil nutrient supply,crop demand parameters and fertilizer reduction potential in watermelon and melon dominant producing area.Therefore,the present situation,yield and soil nutrient status of fertilizer application in the dominant main producing areas of muskmelon and watermelon in Shaanxi Province were investigated to provide a scientific theoretical basis for reducing fertilizer application and increasing efficiency of watermelon and melon production in Shaanxi Province;Provide support to achieve a zero growth in fertilizer by 2020.The main results of the study are as follows:（1）The average yield of early maturing watermelon in Pucheng was 50.9 t/ha,and the average nutrient carrying capacity of N,P₂O₅,K₂O were 118 kg/ha,45 kg/ha,154 kg/ha,respectively.The average nutrient input for N,P₂O₅,K₂O were 579,410,538 kg/ha,and the average nutrient input of organic fertilizer were N 316 kg/ha,P₂O₅ 199 kg/ha,K₂O 237 kg/ha,the amount of nutrient input of organic fertilizer accounted for 54.58%,48.54%,44.05%of the total nutrient input.And the average application of chemical fertilizer for N,P₂O₅,K₂O were264,211,301 kg/ha.The amount of nutrient input were 4.9,9.0 and 3.5 times of the average carrying amount of nutrients,respectively.（2）The analysis of soil nutrient status of protected watermelon shows that the average content of organic matter in cultivated layer was 15.7 g/kg（CV=14%）,with a range of 10.5 g/kg²2.3 g/kg;The average electrical conductivity of soil was 399.1μS/cm（CV=59%）,and the range was 88.7μS/cm to 1736.5μS/cm;the average pH value was 8.32;the average content of mineral nitrogen was 99.3 mg/kg（CV=189%）,the range of mineral nitrogen content was6.70¹755.9 mg/kg;The average content of available phosphorus was 91.2 mg/kg（CV=52%）,and the content range was 30.3²69.5 mg/kg;The average available potassium was 404.4mg/kg（CV=28%）,and the range of variation was 210.2 mg/kg⁷64.7 mg/kg;The content of organic matter in soil was at a low level,and the content of available phosphorus in soil was in the middle and high level,and the content of available potassium in soil was at a high level,with 64.96%proportion exceeded 350 mg/kg.（3）The average yield of early maturing muskmelon in Yanliang and Pucheng was 26.11t/ha（CV=34%）,the average nutrient carrying capacity of N,P₂O₅,K₂O were 91 kg/ha,45kg/ha,180 kg/ha,respectively.the average nutrient input were N 955 kg/ha,P₂O₅ 695 kg/ha,K₂O 769 kg/ha,and the average nutrient input of organic fertilizer were N 671 kg/ha,P₂O₅ 407kg/ha,K₂O 505 kg/ha,the amount of nutrient input of organic fertilizer accounted for70.26,58.56%,65.67%of the total amount of nutrient input;and the average application amount of fertilizer N,P₂O₅,K₂O were 283,288,265 kg/ha,respectively.The nutrient input were 10.5,15.5 and 4.3 times of the average nutrient carrying capacity,respectively.The application rate of nitrogen,phosphorus and potassium in chemical fertilizer were 81%,90.1%and 49.6%in the high level,respectively.（4）The analysis of soil nutrient condition shows that the average content of organic matter in cultivated layer of muskmelon was 19.2 g/kg（CV=19%）,the range of variation was 10³1.2g/kg;the average conductivity of soil was 575.1μS/cm（CV=59%）,the range was 157.7¹947μs/cm;the average pH was 8.26,the average mineral nitrogen was 149.6 mg/kg（CV=70%）,the change range was 12.1 mg/kg⁵83.4 mg/kg;The average available phosphorus was 95.9mg/kg（CV=49%）,with a range of 28.1 mg/kg to 372 mg/kg;The average value of available potassium was 392.8 mg/kg（CV=44%）,the range of available potassium was 137.8 to 1438.8mg/kg;the content of soil organic matter was on the low side.The content of mineral nitrogen in soil was 41.9%higher than that in 150 mg/kg,which was generally in the middle and high level,the content of available phosphorus in soil was in the middle and high level,and the content of available potassium in soil was at a high level,with 52.96%proportion exceeded350 mg/kg.（5）Under the conditions of early maturing watermelon,muskmelon yield and fertilizer input level,the potential range of chemical fertilizer reduction for watermelon are N 44.3%⁶6.6%,P₂O₅ 73.2⁸3.9%,K₂O 36.2%⁶1.7%;the potential range of chemical fertilizer reduction for muskmelon are N 59.7%⁷5.8%,P₂O₅ 80.5%⁸8.3%,K₂O 15.1%⁴9.1%.To sum up,according to the yield and soil nutrient status,the suitable fertilization rate of watermelon in Pucheng County,Shaanxi Province are N 88¹47 kg/ha,P₂O₅ 34⁵7 kg/ha,K₂O 115¹92 kg/ha,and the suitable fertilization rate of muskmelon are N 69¹14 kg/ha,P₂O₅34⁵6 kg/ha,K₂O 135²55 kg/ha.