Study On Suitable Dosage Of Slow Controlled Release Compound Fertilizer For Winter Potato In Guangdong Province

In terms of over-using the universal compound fertilizers with“Black plastic film+one base fertilization zero topdressing”technique in the main winter potato producing region of Guangdong Province,seven treatments were designed:T1(N:195.0kg·hm^-2,N:P₂O₅:K₂O=1:0.5:2);T2(N:240.0 kg·hm^-2,N:P₂O₅:K₂O=1:0.5:2);T3(N:285.0 kg·hm^-2,N:P₂O₅:K₂O=1:0.5:2);T4(Conventional fertilization by potato growers,N:329.4 kg·hm^-2,N:P₂O₅:K₂O=1:0.88:1.42);T5(N:240.0 kg·hm^-2,N:P₂O₅:K₂O=1:0.5:2);T6 referred to treatment with only organic manure,and T7 referred to zero fertilizer treatment,among which the N and K fertilizers consisted of 40%-controlled-release fertilizer N and K₂O and 60%-conventional fertilizer N and K₂O in T1^T3 treatments,respectively.The effects of different fertilizer treatment combinations on the growth and development of potato,nitrogen,phosphorus and potassium nutritional characteristics,yield,economic benefit,fertilizer efficiency parameters and tuber quality were studied in this paper.The study objectives were to clarify the rational application rates of the controlled-release compound fertilizer,which was suitable for high yield,quality and efficiency production of potato under the test conditions,so as to provide theoretical basis and technical support for the winter potato planting region in Guangdong Province.The main results were as follows:（1）Slow controlled-release compound fertilizer and conventional fertilizer treatment combinations（T1^T5）increased the mass and tuber mass of single plant and tuber mass at all times,compared with T6（organic fertilizer treatment）and T7（no fertilizer treatment）;Compared with conventional fertilizer treatments T4 and T5,the slow controlled-release compound fertilizer treatment（T1^T3）showed that the potato tuber mass was higher and the growth rates of tuber was faster in the late stage of potato growth.（2）The total yield and the marketable yield of winter potato with T1 were 48420kg·hm^-2 and 45329 kg·hm^-2,respectively,both being higher than those with treatments from T2 to T5,showing that T1 treatment could reduce the fertilizer application rates and increase the total yield and the marketable yield of winter potato as well.（3）The total income and output ratio of T1 reached 97167 Yuan RMB·hm^-2 and 2.32respectively among T1^T5,which were significantly higher than those with treatments from T2 to T5（p<0.05）.（4）In the treatments of T1^T5,the apparent agronomic efficiency of N,P and K in T1reached 162.35 kg·kg^-1,858.17 kg·kg^-1 and 88.13 kg·kg^-1 respectively,and the total agricultural efficiency and fertilizer partial productivity with NPK were 17.33 kg·kg^-1 and70.94 kg·kg^-1,respectively,which were significantly higher than those with treatments from T2 to T5（p<0.05）.（5）N requirement per ton of tubers was between 2.79³.47 kg,P₂O₅ requirement was0.92¹.06 kg,K₂O requirement was between 7.23⁸.92 kg,respectively.And with the highest total yield and commercial potato yield,the fertilizer requirement per each ton tubers in T1 treatment were 2.79 kg N,0.99 kg P₂O₅ and 7.23 kg K₂O,respectively.（6）The integrated results of this study showed that T1(N:195 kg·hm^-2,N:P₂O₅:K₂O=1:0.5:2,which consisted of 40%-controlled-release fertilizer N and K₂O and60%-conventional fertilizer N and K₂O)was the suitable fertilization treatment combination under this test conditions.