玉米秸秆复合渗灌管研制及渗水性能研究

Development and infiltration performance of corn straw composite infiltration irrigation pipe

秸秆地下灌溉是将作物秸秆与土壤混合挤压形成具有渗水能力的复合渗灌管进行田间灌水的一项技术,开发符合灌水要求的秸秆复合管材关系到秸秆地下灌溉的成败。利用自制的秸秆复合管成型机,以秸秆掺量、含水率、螺旋轴转速为参数,在室内进行了基于玉米秸秆的秸秆复合管性能3因素3水平正交试验,研究了秸秆复合管材的成型和渗水性能,分析了秸秆掺量、初始含水率、螺旋轴转速对秸秆复合管材的容重、渗水速率和渗水均匀系数等的影响。结果表明:1)秸秆复合管材的容重在1.278~1.355g/cm^3之间,影响其容重的主要因素是秸秆掺量,随着秸秆掺量的增加,复合管材的容重减小;秸秆掺量为5%,初始含水率为22%,螺旋轴转速为62r/min时,有利于秸秆复合管成型;2)在0.25m压力水头自由出流条件下,1h的秸秆复合管材渗水速率在0.76~1.40L/(m·h)之间,与常用的微灌灌水器流量相当。秸秆掺量为9%,初始含水率为24%,螺旋轴转速为50r/min时,秸秆复合管材渗水速率最大;3)低压自由出流条件下,秸秆复合管材透水均匀系数在0.13~0.35之间,秸秆掺量为5%,初始含水率为24%,螺旋轴转速为50r/min时,透水均匀系数最大,仍不能满足灌溉要求;4)综合考虑秸秆复合管材容重、渗水速率及渗水均匀度等因素,秸秆掺量为5%,初始含水率为24%,螺旋轴转速为50r/min时,秸秆复合管材综合性能指标最优。上述结论对秸秆复合管材的研究和开发具有一定的参考价值,有利于推动秸秆资源化利用和田间节水技术的发展。

Straw subsurface irrigation(SSI)is an innovative technology based on the combination of straw returning and subsurface drip irrigation.Straw composite infiltration irrigation pipe,which formed from crop straw and soil mixture by extrusion,was used to replace the capillary of subsurface drip irrigation for irrigation.It can help to solve the problems of subsurface drip irrigation to a certain extent,such as the emergence of water shortage,emitter blocking and capillary recycling as well as straw returning.The research and development of straw composite infiltration irrigation pipe that meet the irrigation requirements was related to the success of SSI technology.In the current study,the straw composite pipe(SCP)was produced with corn stalk as the main material by using a self-made straw composite pipe forming machine,orthogonal test of straw composite pipe(SCP)was performed with three-factor and three-levels.The straw content,initial water content and spiral shaft speed were taken as scientific parameters to study the factors affecting the formation and water infiltration properties of SCP.The three levels of straw mass content were 5%,7%,and 9%,respectively.While,the three levels of initial mass water content were 20%,22%,and 24%,and the three levels of the spiral shaft speed were 50,62,and 74 r/min.Effects of straw content,initial water content and spiral shaft speed on the bulk density,permeability rate and water infiltration uniformity coefficient of SCP were analyzed.The results showed that:1)The bulk density of SCP was in between 1.278-1.355 g/cm3,and the main factor affecting the bulk density of SCP was straw content.With the increasing of straw content,the bulk density of SCP was reduced.The best combination to the formation of SCP was 5%straw content,22%initial water content,and 62 r/min spiral shaft rotation speed,the corresponding bulk density of SCP was 1.355 g/cm^3;2)The free water outlet rate of the SCP was between 0.76-1.40 L/(m·h)at 0.25 m working pressure,which meets the requirement of commonly micro-irrigation emitters flow rate.Water infiltration rate was mainly influenced by straw content.When the straw content was 9%,the initial water content was 24%,and the spiral shaft rotation speed was 50 r/min,per unit length of SCP had the largest free water outlet rate;3)Under the condition of free flow,the uniformity coefficient of water permeability for SCP was between 0.13 and 0.35 with low working pressure.The optimal combination was 5%of straw content,24%of water content and 50 r/min of the spiral shaft rotation speed,but it still could not meet the irrigation requirements;4)It took into consideration of the formation,water infiltration and water uniformity of SCP,the best characters of SCP was 5%of straw content,24%of water content and 50 r/min of spiral shaft rotation speed.The conclusions have a certain reference value for the research and development of SCP,which would be beneficial to promote the utilization of straw resources and the development of field water-saving technology.