Effects Of Different Fertilization Treatments On Forage Yield And Quality Of Alpine Grassland In Gannan

The pastoral area of Qinghai-Tibet Plateau is an important base of animal husbandry industry in China.In recent years,with the development of economy and society,the grassland in the alpine pastoral area of Qinghai-Tibet Plateau is generally overloaded,and the risk of alpine grassland degradation is gradually increasing,which will directly affect the sustainable development of pastoral economy.How to effectively prevent alpine grassland degradation and improve forage yield and quality is a major problem facing pastoral areas in the Qinghai-Tibet Plateau.Fertilization is an effective way to improve soil quality and grassland productivity.In this study,Alpine Grassland in Gannan pastoral area of Qinghai-Tibet Plateau was taken as the research object,and the effects of different fertilization years(one year,seven years),fertilization types(nitrogen,pHospHorus and nitrogen-pHospHorus mixture)and fertilization gradients on plant diversity and stability,soil quality and forage yield and quality of grassland community in alpine pastoral area were studied.The results have certain guiding significance for restoring grassland productivity,improving grassland quality and increasing herdsmen's income.The specific fertilization treatment is:nitrogen fertilizer 5,10,15g·m-2·a-1 for seven years,recorded as 7N5,7N10,7N15.In the seven years,pHospHate fertilizers 2,4,8 g·m-2·a-1 were recorded as 7P2,7P4 and 7P8.Seven years of nitrogen and pHospHorus fertilizer,nitrogen fertilizer was fixed at 10g m-2,and pHospHate fertilizer was 2,4,8 g·m-2·a-1,which was recorded as 7N10P2,7N10P4,and 7N10P8.One year of fertilization and the same amount of fertilization in seven years,there are(1N5,1N10,1N15,1P2,1P4,1P8,1N10P2,1N10P4,1N10P8),and another year of secondary fertilization,twice a year,nitrogen fertilizer 5g m-2·a-1,denoted as 1N5*2.Apply pHospHate fertilizer 2g·m-2·a-1 twice a year,and record it as 1P2*2 Nitrogen and pHospHorus fertilizers 10gN m-2·a-1 and 2gP·m-2 a-1 were recorded twice a year,and were recorded as 1N10P2*2.There are 21 kinds of fertilization treatments.The main findings are as follows:(1)Plant diversity and community stability are two key indicators of community structure in alpine grassland.Comprehensive analysis showed that 1N10P8 treatment was the best for plant diversity and 1P2*2 treatment was the best for community stability.For plant diversity,the treatments of nitrogen fertilizer,pHospHorus fertilizer and 7N10P2 were better when fertilizing for many years,and the alpine grassland community treated with 7N15 was the best for community stability.(2)Soil quality of grassland in alpine pastoral area was improved by short-term fertilization,but changed little by long-term fertilization.For soil pHysical properties,short-term 1N10P2*2 treatment can significantly increase total porosity and soil water content,while long-term 7N15 treatment can keep capillary porosity unchanged.For the chemical properties of soil,the available nutrients of short-term 1N10P8 treatment were significantly increased,while long-term 7N10P8 treatment had a significant effect on reducing soil pH.(3)For forage yield and quality in alpine grassland,short-term fertilization increased forage yield and crude protein content with 1N5(5g/m2 nitrogen application per year)treatment,and kept the relative feeding value of fiber unchanged;long-term fertilization increased crude protein content of forage grass with 7N10P8(10g/m2 pHospHorus element 8g/m2 nitrogen application for seven years),and kept forage yield and relative feeding value basically unchanged.The response of forage quality factors to fertilization was different in alpine grassland.The main factors affecting crude protein were pH,total nitrogen and nitrate nitrogen in turn.Fertilizing 1N5 and 7N10P8 in one year and seven years was better.Organic matter,nitrate nitrogen and ammonium nitrogen were the main factors affecting the neutral detergent fiber of forage.Nitrogen fertilizer and pHospHorus fertilizer were better applied 1 N5,7 years a year.Total pHospHorus,nitrate nitrogen and total nitrogen were the main factors affecting the acidic detergent fibers of forage.It was better to fertilize 1N10P8 in one year and 7N10P8 in seven years.The order of affecting soluble sugar in forage was community uniformity,nitrate nitrogen and soil water content.The content of soluble sugar in forage could be changed by fertilization affecting community uniformity,nitrate nitrogen and soil water content.One year fertilization 1N10P8 and seven years fertilization 7N15 were better.