Effects Of Fever Substances On Soil Traits And Nutrients Of Bamboo Shoots During The Mulch Period Of Phyllostachys Violascens

Soil properties,soil CO₂emission rates and plant growth are influenced by a variety of factors including management practices,environmental conditions and human activities.The mulch of bamboo shoots refers to the use of organic materials as heat-generating substances in winter,together with a layer of grain hulls for insulation,in order to raise the soil temperature and promote the early emergence of bamboo shoots,so as to improve bamboo shoot production and economic benefits,and is an important productive management measure for bamboo shoot forests.Bamboo shoot forest mulch can increase soil nutrients,increase the population and number of microorganisms,improve the physical and chemical properties of the soil and enhance the nutrition and taste of bamboo shoots,etc.However,unreasonable mulch materials and mulch measures,or mulch for too long,can also cause soil acidification and nutrient imbalance,leading to bamboo forest degradation and bamboo whip uplift,etc.In particular,mulch can increase soil CO₂emissions.In this study,the shoot-use forest of Phyllostachys violascens was used as a study target,the forest was watered and mulched with additional heat-generating substances,then mulched with grain hulls（insulation material）.27 test plots were set up,using fresh chicken manure(7.50 t hm^-2),dead cakes(3.75 t hm^-2)and wheat ash(45.00t hm^-2).Three heat-generating substances were used in a single-factor,9-replicate experimental design.To investigate the effects of different heat-generating substances on soil properties and nutrient composition and dynamics of bamboo shoots,and to analyse the sensitivity of soil CO₂ emission rate to soil temperature and the correlation between soil nutrients and bamboo shoot nutrition,with the aim of providing reference for selecting suitable heat-generating substances and exploring green and low-carbon forest mulch patterns for bamboo shoots.The study showed that:（1）Soil temperatures were higher during the mulch period than in the unmulched sample sites when dry cake,chicken manure and wheat ash were used as heat-generating materials to mulch the Ph.violascens forest;the dynamics of soil temperature under the three heat-generating substances are similar,all showing a single-peaked curve;however,the magnitude of soil temperature change,the speed of change and the time of peak occurrence differ between different heat-generating substances.The soil temperature of chicken manure as a heat-generating substance is lower and the peak temperature is lower and occurs later;the soil temperature of wilted cake as a heat-generating substance has a higher peak temperature and the high temperature lasts longer,and the soil temperature of wheat ash as a heat-generating substance warms up quickly at the beginning and is higher in the middle.However,the difference in mean soil temperature between the three heat-generating substances only reached a significant level（P<0.05）in the first week after the mulch.（2）Soil p H,total N,organic matter,effective phosphorus,fast-acting potassium,zinc and calcium increased,while soil total phosphorus,total potassium,hydrolytic nitrogen and magnesium decreased during the mulch period of the Ph.violascens forest.The amount of soil chemistry altered by different heat-generating substances varied,but significant differences were only found between the amounts of soil copper,iron and calcium content altered（P<0.05）.All three trace elements of Cu,Fe and Zn in bamboo shoots varied by more than 100%during the mulch period,the dynamics of fat,ash and crude fibre content in bamboo shoots varied considerably between the different heat-generating substances;however,the differences in the content of nutrients in bamboo shoots were small,and only the content of copper differed significantly between the three heat-generating substances（P<0.05）.（3）After the three heat-generating substances were mulched,the soil CO₂ emission rate showed a single-peak curve pattern during the mulch period;however,there are differences in the magnitude of variation in soil CO₂ emission rates,the rate of change and the time of peak occurrence between different heat-generating substances,and the total amount of emissions varies.Rapid increase in soil CO_{2 e}missions from chicken manure as a heating material and high emission rates and total emissions,with the peak occurring earlier;soil CO₂ emission rates from dead cakes as a heat-generating material had a high peak,moderate total emissions;low peak CO₂ emission rates and total emissions from soils with wheat ash as heat-generating material,but soil CO₂ emission rates were higher in the middle and late stages of the mulch.The effect of thermogenic substances on total soil CO₂emissions during the mulch period was small,and the difference in soil CO₂ emission rates between the three thermogenic substances only reached a significant level（P<0.05）at the ninth week after the mulch.（4）Both soil temperature and soil CO₂ emission rates show a single-peaked dynamic during the mulch period,with the peak soil CO₂ emission rate occurring 1 week after the soil temperature.There was a highly significant positive correlation（P<0.01）between soil temperature and soil CO₂ emission rate,with a maximum value of 0.916.Soil CO₂emission rate showed a highly significant linear or exponential response to soil temperature,and the（?）₁₀ value decreased with increasing soil temperature.（5）The correlation between soil temperature and CO₂ emission rate varied according to soil temperature.The correlation coefficient was not significant（P>0.05）when soil temperature was less than 12°C;the correlation coefficient was highest and highly significant（P<0.01）when soil temperature was between 12°C and 18°C;the correlation coefficient decreased with increasing soil temperature when soil temperature was greater than 18°C,but the correlation still reached a highly significant level（P<0.01）.The correlation coefficients between soil temperature and soil CO₂ emission rates also differed under different heat-generating material conditions.The correlation coefficient was higher in the early stage when chicken manure was used as the heat-generating material,higher in the later stage when wilted cake was used as the heat-generating material,and higher in the middle stage when wheat ash was used as the heat-generating material,with less fluctuation throughout the mulch period.（6）The complex correlation between a single soil chemical trait and the nutrient content of bamboo shoots was large,and the complex correlation between the content of soil total nitrogen,total phosphorus,total potassium,organic matter,effective phosphorus,zinc and calcium and the nutrient content of bamboo shoots reached a significant level（P<0.05）.The partial correlation coefficients between a single soil chemical trait and a single bamboo shoot nutrient differed between the different heat-generating substances,but the correlations and the differences between the different heat-generating substances were not significant（P>0.05）.According to comprehensive analysis,it can be concluded that using the widely used dry cake,chicken manure and wheat ash in current production and their application levels as heating substances to mulch the Ph.violascens forest,the differences in mean soil temperature,soil CO₂ emission rate,soil nutrient and bamboo shoot nutrient content between the different heat-generating materials were small,but the dynamic patterns of change over the mulch period varied considerably.There was a highly significant positive correlation between soil temperature and soil CO₂emission rate,and a significant complex correlation between soil chemical properties and bamboo shoot nutrient content.It is better to use fresh dead cakes as heat-generating material when mulch the Ph.violascens forest in winter,and to remove the mulch and reclaim the soil in time after the mulch to reduce the effect of mulch on soil chemical properties and prevent the bamboo whip from floating and the bamboo forest from degrading.