| In the semi-arid area of southern Ningxia,low precipitation in the early stage of crop growth and high temperature in the later stage are the key factors that limit the development of the local potato industry.Regarding the influence of soil water and heat environment and soil respiration under different ratio of furrow and ridge rainwater harvesting planting patterns in combination with mulching.There are few studies on the effects of organic carbon and nitrogen changes and crop yields.In this study,a two-factor randomized block experiment was used to set 3 furrow-ridge ratios(60 cm:60 cm,60 cm:45 cm and 60 cm:30 cm)and 4 furrow and ridge with mulching patterns(the ridges are covered with ordinary plastic film,furrow cover with biodegradable film(DS),hemp mulch film(DM),straw(DJ)and no mulch(DB)respectively,and use traditional flat cropping(CK)as a control to systematically study the soil water and heat conditions of different ratio of furrow and ridge with mulching patterns—mineralization The relationship between speed and carbon and nitrogen components,and explore its effects on soil organic carbon,nitrogen content and mineralization,determine a suitable potato high-yield ridge and ridge dual mulching planting pattern in the semi-arid area of southern Ningxia,with a view to the potato in this area The efficient use of water and fertilizer and the sustainable development and utilization of ridge and furrow mulch planting technology in dry farming areas provide theoretical references.The main research are as follows:(1)Different ratio of furrow and ridge with mulching patterns could increase the soil water storage capacity of 0-40 cm layer during the growth stage,and the soil water storage capacity increases with the increase of ridge width.DJ60,DJ30 and DJ45 treatments performed the best in the water storage capacity of each treatment,which were significantly increased by 26.81%,25.89%and 24.95%respectively compared with CK.Under the same ratio of furrow and ridge,the average water storage capacity of each treatment was DJ>DS>DM>DB>CK.The ratio of furrow and ridge at 60 cm:60 cm have a significant effect on soil moisture preservation than the DJ and DS treatments.(2)Different ratio of furrow and ridge with mulching patterns significantly increased the soil temperature of 0-20 cm soil layer during the growth stage.Under the same ratio of furrow and ridge,the soil temperature between treatments showed DS>DB>DM>DJ,with DS increasing the temperature most significantly.DJ treatment showed a certain cooling effect in the early stage of growth,and the cooling effect in the later stage was transformed into a heat preservation effect.For the three furrow-ridge ratios,60 cm:45 cm had the best warming effect.Among them,the soil heat preservation effect treated with DM and DS was significant.(3)Different ratio of furrow and ridge with mulching patterns significantly increased the soil respiration rate during the potato growth period.The soil respiration rate of DM45,DM30 and DM60 treatments had the highest performance,increasing by 43%,30%and 25%compared with CK,respectively.The 60 cm:45 cm furrow-ridge ratio had the most significant increase effect,and different coverage treatments under the same furrow-ridge ratio showed DM>DS>DJ>DB>CK.Correlation analysis results showed that the soil respiration rate during the potato growth period was significantly positively correlated with the soil temperature of the 0-20 cm soil layer,and the DS and DM treatments had the closest correlation.(4)The soil organic carbon content,total nitrogen content,soil carbon to nitrogen ratio,organic carbon storage,and total nitrogen storage in 0-60 cm layer during the potato harvest period of different ratio of furrow and ridge with mulching patterns gradually decreased with the deepening of the soil layer in the 0-60 cm soil layer.The soil organic carbon content,total nitrogen content,soil carbon to nitrogen ratio and organic carbon storage varied with each other.As the ridge width increases and decreases.The content of soil oxidizable organic carbon during the potato harvest period under different ratio of furrow and ridge with mulching patterns was the highest with a ratio of furrow and ridge at 60 cm:45 cm.Under the same ratio of furrow and ridge,different mulching treatments significantly increased the content of soil oxidizable organic carbon,and DM treatment performed best.Different mulching patterns could increase soil microbial biomass carbon and microbial biomass nitrogen in the 0-40 cm layer.Among them,DJ and DM had the best performance.The ratio of soil microbial biomass carbon and microbial biomass nitrogen in 0-20 cm layer was 60 cm:45 cm>60 cm:30 cm>60 cm:60 cm.(5)The ratio of easily oxidizable organic carbon to total organic carbon during potato harvest under different furrow and ridge with mulching patterns ranged from 31.6%to 57.7%,and the ratio of soil microbial biomass to organic carbon ranged from 0.6%to 4.9%.In the 0-40 cm soil layer,the furrow-ridge ratio of 60 cm:45 cm was the best.Under the same ratio of furrow and ridge,the ratio of easily oxidizable organic carbon to total organic carbon and the ratio of soil microbial biomass carbon to organic carbon in different furrow and ridge with mulching treatments were significantly higher than that of CK treatment,and DM and DS treatments were higher for different mulching materials.The ratio of soil microbial biomass nitrogen to total nitrogen ranged from 2.4%to 22.3%.Different mulching treatments of 0-20 cm soil layer significantly increased the ratio of soil microbial biomass nitrogen to total nitrogen,and the ratio of 60 cm:45 cm furrow to ridge performed best.Among them,DM and DJ processing performed best.Soil carbon pool management index(CMI),soil carbon pool activity(L),and soil carbon pool activity index(LI)under different ratio of furrow and ridge with mulching patterns were basically the same in 0-40 cm layer,with 60 cm:45 cm furrow-ridge ratio had the highest performance.Under the same furow-ridge ratio,different coverage treatments could increase CMI,L and LI,and DS and DM treatments were higher.The soil carbon stock index(CPI)decreased with the increase of ridge width.Different mulching treatments under the same ratio of furrow to ridge reduced CPI,and each treatment was less than CK.The change trend of CMI,L and LI was opposite to that of CPI.The increase and decrease of active organic carbon content in soil was different from the increase and decrease of soil organic carbon.(6)The soil organic carbon mineralization rate of 0-60 cm in the potato harvest period under different ratio of furrow and ridge with mulching patterns varied with the cultivation time into a rapid release stage and a slow release stage.Soil organic carbon mineralization rate,average organic carbon mineralization rate,soil organic carbon cumulative mineralization amount and cumulative mineralization rate increased with the increase of ridge width.Under the same ratio of furrow and ridge,different furrow and ridge with mulching treatments could increase the amount of accumulated organic carbon mineralization,and increased the average soil organic carbon mineralization rate,organic carbon mineralization rate and accumulated mineralization rate.The DM treatment in all furrow and ridge with mulching patterns had the highest performance,and the DS treatment second.(7)Potato yield increased first and then decreased with the increase of ridge width.The 60cm:45cm furrow-ridge ratio performed best,and DJ and DM treatments were the best.Potato yield was extremely significantly positively correlated with soil moisture and organic carbon accumulation and mineralization rate,and significantly positively correlated with soil temperature.In summary,different ratio of furrow and ridge with mulching patterns could improve the soil hydrothermal environment,increase the soil respiration rate,and increase the ratio of easily oxidizable organic carbon,soil microbial biomass carbon,and soil microbial biomass nitrogen to organic carbon and total nitrogen;increase soil carbon pool management index(CMI),soil carbon pool activity(L)and soil carbon pool activity index(LI)increase the accumulation and mineralization rate of soil organic carbon,thereby affecting soil physical and chemical properties,changing soil quality and improving soil productivity for potato growth and yield formation.Considering environmental factors such as soil water and heat and a series of "consumption-replenishment" interaction process changes in the organic carbon pool,the dual coverage of different furrows and ridges had the best ratio of furrow and ridge at 60 cm:45 cm.The ridge mulching plastic film and furrow covering fiber fully degradable mulching pattern had significant performance in improving the soil water and heat environment,maintaining the balance of carbon pool,improving soil organic carbon and total nitrogen content and promoting potato yield.It was the best furrow and ridge suitable for high yield of potatoes in the semi-arid area of southern Ningxia.The meta-cover planting pattern could be developed and utilized sustainably in this area. |
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