Effect Of Organic Fertilizers And Soil Conditioners On The Growth Of Continuous Garlic Crop And Soil Fertility By Replacing Chemical Fertilizers

Daming County,Hebei Province,is one of the major garlic growing areas in China.Due to long-term monoculture,excessive application of chemical fertilizers and unbalanced nutrients,soil degradation and frequent diseases have affected the stability of garlic yield and quality,and restricted the sustainable development of local garlic industry.This paper explores the feasibility of organic fertilizers and their combination with soil conditioners and reduced chemical fertilizers to alleviate the continuous crop problem of Daming garlic.The experiment was conducted by using Daming purple-skinned garlic as the test plant material and collecting soil from long-term continuous garlic crops for potting trials,with no fertilizer(CK),100% chemical fertilizer and 80% chemical fertilizer as controls,respectively.Set up different types of organic fertilizers(straw,green manure,commercial organic fertilizers),common soil conditioners(biochar,microbial bacteria,calcium carbonate)applied singly or in combination.The growth and development,SPAD value,yield,nutrient concentration,quality and soil fertility changes of garlic in different fertility periods were studied under the condition of 20% reduction of chemical fertilizer,aiming to clarify the best technical combination of organic fertilizer and soil conditioner suitable for efficient production of garlic in Daming County,Hebei Province,and help to improve garlic yield and quality.The main research results are as follows:(1)Corn straw or green manure combined with microbial bacteria or biochar can replace 20% chemical fertilizer to ensure the supply of nutrients and stabilize or promote the growth of garlic.80% chemical fertilizer + corn straw + biochar or microbial bacteria has the best effect of replacing 20% chemical fertilizer to improve plant height,with an increase of 3.2% to 23.0% compared with 100% chemical fertilizer;corn straw or green manure combined with microbial bacteria or biochar replaces 20% chemical fertilizer The effect of replacing 20% of chemical fertilizer with corn straw or green manure with microbial bacteria or biochar increased the thickness of pseudostem by 0.4% to 3.4%,7.8% to 16.2% and 5.3% to 24.4% at seedling stage,flower bud and bulb differentiation stage and maturity stage,respectively,and the thickness of bulb at maturity stage increased by 2.8% to 9.1%.(2)The 100% chemical fertilizer treatment promoted the growth and development of garlic only in the early stages of growth,and organic fertilizer substitution for 20%chemical fertilizer generally resulted in increased yields in all three reproductive stages.80% fertilizer + corn stover treatment yield at the seedling stage was increased by 52.6%compared to the 100% fertilizer treatment,and the bulb yield at the maturity stage was increased the most by 48.5%,followed by the 80% fertilizer + corn straw + microbial bacteria and 80% + green manure + biochar treatments.80% corn straw + microbial bacteria treatment increased the yield at the flower bud and bulb differentiation stage by74.7% compared to the 100% fertilizer treatment.The yield of 80% fertilizer + corn straw+ microbial bacteria treatment at flower bud and scale bud differentiation stage was74.7% higher than that of 100% fertilizer treatment.(3)Application of organic fertilizer and soil conditioner significantly increased Vc content of garlic under 20% chemical fertilizer reduction,with increases of 17.2% to90.6%,15.1% to 27.2% and 13.9% to 50.3% in the three periods,respectively.Compared with the 100% chemical fertilizer treatment,the nitrate content of 80% chemical fertilizer+ green manure biochar treatment decreased by 30.7% at the seedling stage of garlic,and the soluble sugar and soluble protein contents of seedling leaves under 80% chemical fertilizer + green manure + microbial bacteria treatment increased by 18.7% and 43.9%,respectively.The soluble sugar content of bulbs at the maturity stage increased by 4.6%.(4)Organic fertilizer(straw,green manure,commercial organic fertilizer)combined with soil conditioner(biochar,calcium carbonate,microbial bacteria)replacing 20%chemical fertilizer can improve soil fertility.Each technical measure can reduce soil p H by 2.4% to 3.3% and increase soil organic matter by 14.6% to 42.6%.Among them,80%chemical fertilizer + green manure + biochar had the greatest increase in soil total nitrogen,effective phosphorus and fast-acting potassium content,which increased by5.9%,9.4% and 12.5%,respectively,compared with 100% chemical fertilizer treatment.In conclusion,80% fertilizer + corn straw + biochar,80% fertilizer + corn straw +microbial bacteria,80% fertilizer + green manure + biochar and 80% fertilizer + green manure + microbial bacteria are the recommended fertilization measures,which can improve soil fertility,coordinate nutrient supply and demand between soil and garlic,promote garlic growth and development,and have the effect of improving quality while ensuring stable garlic yield.