| Potato has a large planting area in calcareous soil,but potatoes prefer an acidic environment(the most suitable pH is 5.0～5.5),which is contradictory to the calcareous soil which is slightly alkaline(pH 7.5～8.5).High pH value is unfavorable to the formation of potato yield and the improvement of potato quality.Therefore,acidification of calcareous soil is particularly important,which can reduce soil pH value and activate soil nutrients,thus promoting the growth of acid-loving plants such as potatoes.The study adopted a combination of simulation experiment and field experiment.The effects of different materials on the acidification of calcareous soil were studied through simulation tests,and the best acidifier was selected;Field experiments were conducted to explore the acidification effect on potato root zone in calcareous soil after centralized application of acidifiers,and to reveal the growth promoting effect of acidification on potato from both soil and crop aspects.The purpose is to create a"low pH and high nutrient"environment for potato root zone,which has important theoretical significance and practical guiding value for high-yield and high-efficiency cultivation of potato and development of high-efficiency special acidifier for potato.The main results of the study are as follows:1.Strip application of acidifying material significantly reduced the pH of calcareous soil.The range of acidifying materials was 6 cm,the effect of acid regulating increased with the increase of the dosage.After applying furfural residue,weathered coal,peat,sulfur,particulate sulfur fertilizer and mono-ammonium phosphate with 450㎏/hm~2,the soil pH decreased by 0.25,0.31,0.29,0.15 and 0.52 units,respectively,compared with the control without acidifying materials.The acidification effect of mono-ammonium phosphate,sulfur and peat decreased with the increase of the range of acid regulating.After 450 kg/hm~2acidifier MS(monoammonium phosphate and sulfur are prepared in a mass ratio of 1:1)and acidifier MSP(monoammonium phosphate,sulfur and peat are prepared in a mass ratio of 1:1:1.5)were applied to tight sandy soil,light loam and heavy loam,soil pH within 6 cm were reduced;MS decreased soil pH by 0.16～0.37,0.15～0.34,0.08～0.19 units and MSP by 0.03～0.37,0.14～0.34,0.02～0.17 units in 45～100days compared with the control.The acidification effect of acidifier MS was stronger than that of acidifier MSP.The acidification effect of acidifier MS increased with the increase of application amount.After the application of low level(225 kg/hm~2),medium level(450 kg/hm~2)and high level(675 kg/hm~2),the pH of tight sandy soil decreased by0.10～0.44 compared with the control,light loam decreased by 0.02～0.45,and heavy loam decreased by 0.06～0.22.The application of acidifiers in the field significantly reduced the soil pH values in root zone and non-root zone of potato.The pH of soil in root zone decreased by 0.41～0.74 units and that in non-root zone decreased by 0.03～0.23 units after the application of acidifiers at low,medium and high levels.2.Strip application of acidifiers increased the organic matter and nutrient content of calcareous soil.The strip application of acidifier increased the content of soil organic matter,nitrate nitrogen,available phosphorus,available potassium,available zinc,available iron,available manganese,available boron,and available molybdenum in tight sandy soil,light loam,and heavy loam.Acidifier MS had better synergistic effects on nitrate nitrogen and available phosphorus;Acidifier MSP had better synergism on available potassium;The synergistic effect of acidifiers on available nutrients in the three kinds of soils was as follows:tight sandy soil>light loam soil>heavy loam soil.Field application of acidifiers increased the content of organic matter,alkali hydrolyzable nitrogen,available phosphorus,available potassium,available zinc and available boron in root zone soil and non-root zone soil of potato.The content of soil available nutrients increased with the increase of the dosage of acidifier;The content of available nutrients in root zone was higher than that in non-root zone.3.The application of acidifiers changed soil enzyme activity and microbial diversity.The application of acidifiers in the field decreased the activities of catalase,urease and invertase in the soil of potato root zone,and increased the activity of alkaline phosphatase in the soil.The application of acidifiers at a medium level increased the taxon of soil bacteria and fungi,and changed the number of microbial populations;The bacteria with relatively high abundance are Proteus,Actinomyces,Campylobacter and Acidobacter;The higher relative abundance of fungi is Ascomycetes.Organic matter,pH value,available potassium,available molybdenum and alkaline phosphatase in soil are the main factors affecting the relative abundance of soil bacteria and fungi.4.The application of acidifiers in the field promoted the growth and nutrient absorption of potatoes.The plant height,stem diameter,branch number and SPAD value of potato increased significantly after the acidifier MS strip was applied to the soil with different dosage;The dry matter accumulation of leaves,stems and tubers increased;The N,P,K uptake of potato leaves and stems showed a slow-fast-slow change trend with potato growth,and the maximum N,P,K uptake mostly occurred in the tuber expansion stage.5.The application of acidifiers in the field increased potato yield and improved potato tuber quality.The yield of acidifier applied at medium level was the highest and increased by 14.56%compared with the control;The content of zinc in tuber decreased by 14.81%,and the content of boron increased by 63.10%;The content of crude protein and reducing sugar was increased,and the content of starch and nitrate was decreased.6.Under the condition of equal nutrients,the application of acidifiers in the field can improve the acidification effect and nutrient content of calcareous soil,promote potato growth and nutrient absorption,improve quality,and have a trend to increase yield.The optimized fertilization and acidified fertilization decreased 0.03～0.72 units of root zone soil and 0.02～0.41 units of non root zone soil pH respectively;The contents of organic matter,alkali hydrolyzable nitrogen,available phosphorus and available potassium in potato soil were increased;The plant height,stem diameter,branch number and SPAD value were increased;At starch accumulation stage,the dry matter accumulation of potato leaves,stems and tubers and the dry matter accumulation of tubers at harvest stage were increased,and the nitrogen,phosphorus and potassium absorption of tubers were increased;Compared with optimized fertilization,acid fertilization increased yield by 10.26%,reduced crude protein,reducing sugar,vitamin C content,and increased starch and nitrate content.To sum up,acidifiers applied to calcareous soil strips can significantly reduce the pH value of root zone soil,have a positive effect on soil nutrient level,enzyme activity,microbial community structure,and have a positive effect on potato growth,nutrient absorption,yield and quality improvement.From the perspective of acidification and growth promotion effect,when monoammonium phosphate and sulfur are mixed in 1:1to form an acidifiers,the effect is the best when applied with 450 kg/hm~2strips.Acidification is an important factor affecting the growth and development of potato in calc... |
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