WaterSubject

A greenhouse experiment was conducted at Japan International Research Center for Agriculture Science (JIRCAS), Okinawa Subtropical Station, Ishigaki, Japan with three multiple water application and two single water applications to study the effects of them on tomato yield, soil water content and water use efficiency. Multiple water application is a technique use to add the required amount of water during irrigation in multiple equal parts a day instead of one complete set (single water application) during the irrigation event. The multiple water application treatments were the day time (DT), day–night time (DNT) and night time (NT) while the single water application treatments were morning time (MT) and evening time (ET). In multiple water irrigation treatments the water was added to the soil into three equal parts. The supplied irrigation water was the same for all treatments and gradually increased with plant age to cover the crop water requirement during the growing season.

The results revealed that multiple water application increased tomato yield by 5% over the highest yield of single water application. The DT treatment increased tomato yield by 5% and 15% compared to ET and MT treatments, respectively. For multiple water application, the DT was the best irrigation timing because it increases the tomato yield by 8% and 12% compared to DNT and NT, respectively. ET irrigation was better than MT irrigation for single water application. Multiple water application led to an increased in soil water content compared to single water application. By applying the same amount of water for all treatments, the DT treatment increased water use efficiency by 5–15% compared to ET and MT treatments of single water application. In conclusion, multiple water application is better than single water application and by choosing the proper irrigation timing, higher tomato yield resulting from efficient water management can be obtained.

Irrigation timing plays an important role for increasing crop productions per unit of water especially in areas with limited water resources. Proper irrigation timing increases the water use efficiency; consequently the production per unit of water will be increased. Improper irrigation timing can lead to the development of crop water deficit resulting in reduced yield due to water and nutrients deficiencies. Therefore, research needs to be carried out on the effect of single and multiple water application timing on yield and water use efficiency (WUE). Multiple water applications during the day resulted in higher growth and water use efficiency as compared to early morning applications reported that multiple water applications in a day is not practiced widely except on sandy soil during periods of high-crop water use. However, in such situations multiple applications during the day may be required to prevent plant water deficit and significant leaching of water and nutrients. Daily cyclic irrigation applied in a series of cycles comprised of an irrigation and a resting interval improved water use efficiency by 25–38%.

The proper irrigation time could be at the early morning hours before 10:00 h to reduce evaporation of irrigation water and to reduce potential of wind blowing the irrigation water from the target area especially under sprinkler irrigation found that irrigation at early morning (8:00 h) every 3 days increased tomato yield by 11% over irrigation at night time (20:00 h) every day. reported that foliar water spraying at dusk reduced the plant water stress rapidly and accelerated root growth resulting in an increase in soil mass in which plant root were present. This increased water absorption during night and in the morning as well.

The objective of this study was to compare between multiple and single water application timings by evaluate their effects on crop production, soil moisture distribution, soil temperature and water use efficiency in tomato under sub-tropical conditions.Multiple water application increased tomato yield compared to single water application. The DT irrigation of multiple water application increased the tomato yield or water use efficiency by 5–15% compared to ET and MT treatments. ET irrigation was better than MT irrigation for single water application because it increased the yield by 11%. Increasing tomato yield decreased total soluble solids content (Brix). Multiple water application increased soil water content and soil temperature compared to single water application. In conclusion, multiple water application is better than single water application and by choosing the proper irrigation timing efficient water use or higher tomato yield can be obtained.