The Effects of Irrigation Regime on Silage Maize Chlorophyll Content (SPAD) in Sewage Sludge Applied Soil

Domestic stabilized sewage sludge is a potential source of organic matter and nutrients

(especially nitrogen and phosphorus). The application of sludge can be practical in order to obtain high yields in

silage maize cultivation, which uses nitrogen actively. The chlorophyll content has a positive relationship with

the rate of photosynthesis. It is known that the accuracy of chlorophyll meter (SPAD) measurement values,

which are widely used in determining the amount of chlorophyll in leaves, is high and there is a positive

relationship between nitrogen sufficiency and SPAD readings. Considering the effect of soil moisture on organic

matter mineralization and therefore on nitrogen release, in this study, three different irrigation regimes

(irrigations when real-time water consumption values and effective precipitation difference is 25, 50 and 75 mm)

in the soil mixed of four different doses of sewage sludge effects on SPAD were evaluated by seasonal

measurements. As a result, it was determined that the SPAD values of silage maize decreased with the increase

in the longer the surface soil remains dry, and the increase in the treatment sludge dose increased the SPAD

values. It has been determined that the increase in SPAD values has a positive effect on silage yield.