Effects Of Biochar-based Fertilizer And Water Stress On Peanut Yield And Soil Nutrient Utilization

Peanut is an important oil and econonmic crop.The main planting area of peanut in Liaoning Province locates in the semi-arid area of Northwest Liaoning Province,where more than 93%of the planting area is distributed.The availability of water is one of the most important limiting factors for peanut yield increasement and stability.Biochar-based fertilizer is a way of biochar utilization in agriculture,which is a type of compound fertilizer by the combination of biochar and chemical fertilizers,has the charactristics of the amendment of soil,the improvement of soil water content,the delay of the nutrients releasement and the improvement of crop nutrient absorption etc.It has been widely applied in different regions and got good results.At present,the application of biochar-based fertilizer on peanut production has been studied,but the interaction effect of biochar-based fertilizer and water stress on peanut growth and yield has not been reported.Therefore,this study was conducted with a two-factor split plot design,the two factors are biochaer-based fertilizer and water stress.The effects of biochar-based fertilizer and water stress on peanut growth,physiological characteristics,dry matter accumulation,nitrogen and potassium uptake,soil nutrients,yield,water consumption and water use efficiency were investigated through a pot experimentwithin two years.The optimal management mode of water and fertilizer was recommended in order to provide a theoretical basis for the management of peanut in arid and semi-arid areas.The main results are listed as followed:?1?The total flowering and main stem height was significantly increased when the biochar-based fertilizer application was 750 kg·hm^-2?BF₁?and 1 500 kg·hm^-2?BF₂?.The growth of the main stem of peanut would not be significantly inhibited in the moderate water stress?60%-65%of field capacity,W₁?when biochar-based fertilizer was applied,and the largest peanut main stem height was 16.3 cm,which was achieved at the biochar-based fertilizer application rate of 1 500 kg·hm^-2 in moderate water stress.?2?Compared with the treatments without biochar-based fertilizer application?BF₀?,those with biochar-based fertilizer application of 750 and 1 500 kg·hm^-2 promoted the growth of peanut leaves,maintained higher chlorophyll content and net photosynthetic rate,and improved the dry matter accumulation of plant.In addition to the heavy water stress level?50%-55%of field capacity,W₂?,normal irrigation?70%-75%of field capacity,W₀?and moderate water stress levels were beneficial to maintain the net photosynthetic rate of peanut leaves and improved the dry matter accumulation of the plant.The application of biochar-based fertilizer increased the leaf area of peanut under different water stress.Under moderate water stress level,the dry matter accumulation of treatments with biochar-based fertilizer application of 750 and 1 500 kg·hm^-2 were increased by 46.2%and 39.7%?2016?,43.1%and 43.2%?2017?compared with those without biochar-based fertilizer,respectively.?3?The biochar-based fertilizer application of 750,1 500 kg hm^-2 could obtain higher soil total nitrogen content of the 0-15 cm soil layer,as well as available potassium,ammonium nitrogen and nitrate-nitrogen.Also promote the absorption of nitrogen and potassium in the plant;In addition to heavy water stress level,the other two water stress levels could increase 11.1%and 3.7%?2016?,13.1%and 10.8%?2017?soil the available potassium content,20.6%and 17.6%,17.1%and 20.3%soil nitrate-nitrogen content,which promote the nutrients uptake of plants.Under moderate water stress level,the nitrogen and potassium uptake of the plant could be significantly improved by applied 750,1 500 kg·hm^-2biochar-based fertilizer compared with those without biochar-based fertilizer.?4?The treatment with the highest peanut yield was BF₁W₀ in the two years,there was no significant difference between BF₁W₀ and BF₁W₁ treatment,the yield were increased by43.1%and 28.3%?2016?,32.7%and 22.8%?2017?compared with BF₀W₀ treatment,respectively.which was identical with full pods,seed weight and kernel rate.The water consumption of peanut was decreased with the increase of water stress level under the same biochar-based fertilizer application rate.The water use efficiency was improved with the increase of water stress level in the same biochar-based fertilizer application rate,however the increase of water use efficiency under heavy water stress level were at the expenses of the decrease of the peanut yield.Therefore,from the multi-objective development trend of water saving,high efficiency and stable yield,the BF₁W₁ treatment can reduce the water consumption while applying 750 kg·hm^-22 biochar-based fertilizer and improve the water use efficiency under the precondition of not significantly affecting the yield.So,the optimal treatment considering water saving,high efficiency and stable yield recommended by this study was treatment with the biochar-based fertilizer application 750kg·hm^-2,and the lower limit of soil water content 60%-65%in whole growth period.