Premium
Effect of Gypsum and Drought Stress on Maize ( Zea mays L). II. Consumptive Use of Water 1
Author(s) -
Downey Lloyd A.
Publication year - 1971
Publication title -
agronomy journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.752
H-Index - 131
eISSN - 1435-0645
pISSN - 0002-1962
DOI - 10.2134/agronj1971.00021962006300040025x
Subject(s) - soil water , evapotranspiration , water balance , irrigation , agronomy , gypsum , environmental science , water content , zoology , hydrology (agriculture) , soil science , geology , biology , ecology , paleontology , geotechnical engineering
The effect of three defined periods of drought stress on the consumptive use of water by field grown maize ( Zea mays L.) was measured using a complete water balance approach. Water status within the crop was defined by noon measurements of relative turgidity (RT). The treatments were set out in a randomised block design with a further comparison between the untreated (sodic) soil and the same soil treated with gypsum at 22.4 m tons ha −1 . The components of the water balance — soil stored moisture, rain, and applied irrigation — were measured directly, and deep drainage was calculated from chloride redistribution. The no‐stress treatment (RT at noon maintained > 90%) used 59 cm in evapotranspiration during the growing period. Drought stress (RT at noon < 90%) for a period of 20 days during male meiosis (early stress) reduced this total evapotranspiration to 44 cm, while drought stress during grain filling (late stress) reduced it to 51 cm. The application of gypsum had no significant effect on water use nor on water entry at irrigation. Application efficiency (total evapotranspiration/total applied water) was 86%, 79%, and 85% on the no‐stress, early‐stress, and late‐stress treatments respectively. The balance (15 to 20%) of applied water was lost as deep drainage, indicating that results on more permeable soils would be inaccurate if this component were ignored. Maximum water use of 0.9 cm day −1 (or 0.8 of class “A” pan) occurred during anthesis. This period was delayed 10 days by early stress. Water use efficiency was highest for the early stress‐87 kg dry grain/cm water/ha and lowest for the late stress‐26kg.