| Plastic film mulching cultivation of fruit trees is a kind of soil management method laid on orchard ground with plastic film,which has the functions of drought prevention,moisture preservation,humidity preservation,light improvement and weed control,etc.,thus having an important impact on the growth and development of fruit trees,flowering and fruit setting,and has been widely used in fruit tree cultivation.Rosa roxburghii Tratt.is a characteristic fruit tree that has been developed in Guizhou Province in recent years.At present,the cultivation area of Rosa roxburghii tratt.has exceeded 130,000 hm in the whole province.However,due to its short economic cultivation time,the soil management and cultivation techniques are still not perfect.In addition,the difficulty of water and fertilizer conservation in Guizhou mountainous areas and the high weeding cost in orchards make the per unit area yield of Rosa roxburghii lower,and the production benefit needs to be improved urgently.In this paper,’ Guinong No.5’ thorn pear orchard with the largest cultivation area was taken as the experimental object,and ten different types of plastic films including colorless,blue,silvery black,red,green,green permeable(referred to as green permeable),black and black permeable degradable(referred to as black permeable),black grass-proof cloth,white grass-proof cloth,etc.were covered(compared with uncovered natural grass)The results are as follows:1.Plastic film mulching has a significant impact on the soil environment of Cili Garden.Plastic film mulching can increase the soil temperature in different degrees,especially in winter and spring,and the heat preservation effect of colorless,blue,red and green plastic film mulching is obviously higher than that of other treatments.Soil physical parameters such as salinity,volume water content,total dissolved solids,electrical conductivity and dielectric constant under black and silver-black plastic films are higher than those under the control,while other plastic films have no such effect,but the soil physical properties under plastic films tend to be more stable.Mulching can all lead to the increase of soil microbial content in the plant development stage,while the effect of blue and white grass-proof cloth mulching on microbial content in the whole experimental stage shows a steady and continuous increase,and the fruit harvest is22.65% and 16.65% higher than that of the control respectively.The content of soil organic matter showed a downward trend as a whole.When fruits were harvested,the content of soil organic matter covered with black grass-proof cloth and black plastic film increased by 4.94% and 3.71% respectively compared with the control.Different types of plastic film mulching can inhibit the growth of weeds in prickly pear orchard,among which dark plastic films such as black mulch,black mulch cloth and silver-black mulch film have the most significant effect,and the biomass of weeds in the covered area is reduced by 99.82%,97.81%and 96.26% respectively compared with the control,which is beneficial to reducing the weeding cost of orchard.2.Effects of different types of plastic film mulching on shoot growth,flowering and fruiting of Rosa roxburghii.Plastic film mulching can increase the diameter of new shoots and chlorophyll content of leaves in different degrees,and silver-black and green plastic films can also increase the number and length of new shoots.Plastic film mulching can all lead to the advance of phenology,and the flowering period of the treatments covered with silver-black,black,blue and red plastic films is 4-5 days earlier than that of the control.Covering silver-black,colorless,black and blue plastic films can significantly promote the flowering of Rosa roxburghii,and the early fruit setting of these four plastic films increased by about65.8%,43.8%,37% and 28.57%,respectively,compared with the control,indicating a better yield-increasing potential.3.Effects of different types of plastic film mulching on the fruit yield and quality of Rosa roxburghii.Plastic film mulching can increase the final yield of Rosa roxburghii in different degrees,with the yield increasing rate ranging from 14.39% to 72.26%.The increasing effect from big to small is: silver black > colorless > blue > white grass-proof cloth > black grass-proof cloth > black penetration > green >red > green penetration > black > contrast.It can be seen that the increasing effect of silver black plastic film is the most prominent.The fruit quality analysis showed that all mulching treatments could increase the average single fruit weight of Rosa roxburghii,which increased by 11.98%-40.01% compared with the control.Among them,the most obvious effect was black grass-proof cloth,followed by green plastic film.Moreover,green,black grass-proof cloth,black mulch and silver-black mulch can obviously improve the sugar-acid ratio of Rosa roxburghii fruit.Covering with black grass-proof cloth,blue and green plastic film can increase the vitamin C content of fruit in different degrees;Except black and blue films,other types of plastic film mulching can promote the accumulation of total phenols in fruits.In addition,covering different plastic films will also affect the contents of flavonoids,SOD and total triterpenes in fruits.The above results show that different types of plastic films have different effects on the fruit quality of Rosa roxburghii,and can be selected according to the processing and development needs in production.4.Comprehensive evaluation of the effect of different types of plastic films.From the above results,it can be seen that different types of plastic films have their own characteristics or advantages.For example,colorless,blue,red and green plastic films are beneficial to soil heat preservation in winter.Dark mulch films such as black mulch,black grass cloth and silver mulch film can inhibit the growth of weeds in summer,thus greatly reducing the weeding cost in production.Silver,black,blue and red mulch films are beneficial to advance the flowering period;Silver and colorless mulch film has outstanding yield increasing effect;Black grass-proof cloth and green plastic film are beneficial to increase the single fruit weight,sugar-acid ratio and vitamin C content of fruit.From the effect of increasing yield,mulching cultivation can increase the income in different degrees(increasing by 13.04-74.04%)compared with the control;Considering the main benefit factors of Rosa roxburghii industry at present,such as the cost of plastic film itself,the yield increase range and the reduction of weeding cost,it can be calculated that the output value of silver-black and colorless plastic film mulching is 74.04% and 54.54% higher than that of the control,respectively,and the yield increase effect is the best.Among them,silver-black mulch film has the advantages of lower damage rate and higher recovery rate than colorless mulch film,so it can be the preferred mulch film type for Rosa roxburghii at present.However,although the current price and cost of black grass-proof cloth and black transparent plastic film are high,its long service life and environment-friendly characteristics make it have more popularization potential in the future. |
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