Articles
EFFECTS OF IRRIGATION AT DIFFERENT LEVELS OF SOIL WATER TENSION ON GROWTH OF PICEA AND FORSYTHIA AND LEACHING OF NITRATE
Article number
449_94
Pages
683 – 690
Language
Abstract
Knowledge concerning the water requirements of nursery crops is still lacking.
Water is becoming scarce and groundwater pollution is increasing.
To prevent the leaching of nitrate excessive irrigation must to be avoided and an irrigation adapted to soil properties and plant requirements is necessary. Picea abies and Forsythia x intermedia ("young" and "old") were cultivated for three years on a sandy soil with different irrigation regimes resulting in different soil suctions.
The amount of irrigation water was calculated from the soil water characteristics.
The growth of Forsythia increased when the soil suction was reduced by irrigation. Picea did not show any significant reaction to the irrigation treatment.
They do not need any irrigation up to an occasional soil suction higher than 55 kPa after taking root.
For "young" Picea the gratest use of irrigation water was accompanied by considerable leaching of nitrate deeper than 90 cm during the whole vegetation period.
But even without irrigation leaching of nitrate occurred after heavy rain.
Since highly irrigated "young" Forsythia had a high uptake of water and nitrogen, no leaching deeper than 90 cm occurred.
Non-irrigated plants were not able to use all the nitrogen from fertilization and mineralization, so leaching occurred during the growing period of 1995. When cultivating plants like Forsythia, fertilization conformed to nutrient uptake (in quantity and date) and irrigation conformed to the soil water characteristics the risk of leaching nitrate can be reduced even on sandy soils.
On the contrary, when cultivating Forsythia without irrigation, little growth and low nutrient uptake can result in leaching of nitrate.
For Picea, however, no treatment could prevent the leaching of N.
Water is becoming scarce and groundwater pollution is increasing.
To prevent the leaching of nitrate excessive irrigation must to be avoided and an irrigation adapted to soil properties and plant requirements is necessary. Picea abies and Forsythia x intermedia ("young" and "old") were cultivated for three years on a sandy soil with different irrigation regimes resulting in different soil suctions.
The amount of irrigation water was calculated from the soil water characteristics.
The growth of Forsythia increased when the soil suction was reduced by irrigation. Picea did not show any significant reaction to the irrigation treatment.
They do not need any irrigation up to an occasional soil suction higher than 55 kPa after taking root.
For "young" Picea the gratest use of irrigation water was accompanied by considerable leaching of nitrate deeper than 90 cm during the whole vegetation period.
But even without irrigation leaching of nitrate occurred after heavy rain.
Since highly irrigated "young" Forsythia had a high uptake of water and nitrogen, no leaching deeper than 90 cm occurred.
Non-irrigated plants were not able to use all the nitrogen from fertilization and mineralization, so leaching occurred during the growing period of 1995. When cultivating plants like Forsythia, fertilization conformed to nutrient uptake (in quantity and date) and irrigation conformed to the soil water characteristics the risk of leaching nitrate can be reduced even on sandy soils.
On the contrary, when cultivating Forsythia without irrigation, little growth and low nutrient uptake can result in leaching of nitrate.
For Picea, however, no treatment could prevent the leaching of N.
Authors
M. Curtius, H. Bohne
Keywords
Sandy soil, N-uptake, woody crops, nursery production
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