blueberry irrigation andsoil moisture management

Blueberry Irrigation andSoil Moisture ManagementRong Zhou

President of Mini Rain CompanyDeputy Director of China Irrigation Association

Importance of irrigation for blueberry

-Keeping proper soil moisture is very important for blueberry growth, yields and quality. The soil water is from natural rain, irrigation and capillary rising from deeper soil. Irrigation is necessary when the soil water from rain and deeper soil is not enough .-The fruits could be smaller ,yield would be reduced and quality could get lower when the blue berry lacks water frequently.-Water stressing at critical time of blueberry growth will cause yield reduction dramatically.

The following factors causes difficulty for water taking by blueberry -Root： shallow root system(20-30cm) limits plant to absorb water from deeper soil. -Mounding: Growing blueberries on mounds makes them susceptible to water stress as the mounds are free draining. -Poor water penetration: Plastic covered mounds allow little natural rainfall penetration. -Use of mulches: woodchip mulches are difficult to re-wet if allowed to dry out. -Dripper clogging ： bad filtration makes dripper clogged.

Hazards of over watering

-Over application of water can make mounds saturated, reduce soil aeration, increase incidence

of root diseases and root death from drowning, and will also reduce fruit quality. Plant death may also occur.

-Over watering also leaches fertilizer out of the root zone. This not only wastes fertiliser but also poses a serious environmental hazard, polluting groundwater with excessive amounts of nutrients, which contributes to soil acidification

-Over watering increases cost of water and electricity for pump operation.

-Poor irrigation schedule makes too much water applied and makes mounds saturated.-No soil moisture monitoring or wrong monitoring makes wrong amount of water application .-Wrong irrigation system design makes wrong flow rate from pump and dripper. The operator of the system losses control of irrigation volume.

What makes over watering?

Irrigation methods for blueberry-The traditional surface irrigation should be stopped since its low efficiency of water and fertilizer application (lower than 50%)-Sprinkler irrigation： It is generally not recommended for blueberry due to the increased humidity created in the crop resulting in a higher incidence of leaf diseases. The efficiency of water and fertilizer application are also lower than drip method significantly.-Drip irrigation: It has been worldwide recommended method for blueberry due to its high water and fertilizer application efficiency.

Drip line laid along with blueberry row

The high standard and high quality Filter and fertilizer Injection system needed

Blueberry drip irrigation

A good drip system means:-Uniform water application-Meet demand of blueberry growth and yield-Flexibility for controlling-System runs safely-Advanced features, robust , clogging resistance-Economic -Good for fertigation

One drip line or two drip line per row are all acceptable depending on crop water requirement and soil.

Single line could be hanged on the tree

Double lines laid on the top

Sandy soil needs frequent irrigationDouble lines is good option

Clogging is the weak point of drip irrigation, good Filtration is always needed. Filtration design:

Surface water: Primary filter +sand media filter+screen filter or disc filter

Under ground water: Hydrocyclone +screen or disc filter

System automation is good for Blueberry growth, yield and qualitySince higher efficiency of water and fertilizer application. Labor saving is also a good consideration.

Fertilizer should be applied through drip system

Fertilizer tank and Venturi pipe are common used, but not the best choice. The liquid fertilizer for Blueberry growth should be used for higher application efficiency.

Venturi pipe

Fertilizer tank

Liquid fertilizer

The dose metering pump should be used for fertilizer Injection for bigger blueberry farm

Soil moisture monitoring for Irrigation Schedule making-Know soil structure and key points of soil water content:Soil water capacity, wilting point, allowable lowest soil Water content.-Monitoring soil moisture continuously along in whole grow season.-Making irrigation schedule according to soil moisture Variation.

The instruments for soil moisture monitoring

Tensiometer Gypsum block meter TDR meter

Water resource for drip irrigationWater from reservoir , river, lake ,pond, borehole, drinking water all can be used for drip irrigation. But water from yellow river and reservoir far away must be treated carefully since their rich sand and silt content. If the water must be from pond, EPDM geomembrane is recommended since its:-outstanding resistance to UV exposure - Easy installation- 10 years Warranty

Thanks！