P l a n t and Soil 44, 231-232 (1975) Ms. 2728

SHORT COMMUNICATION

Iron chloros is in rice (Otyza sativa L.)

Summary Severe chlorosis of rice p lants was observed this year (1974) on field scale

in the s ta te of Pun jab , India, This resul ted in ex tens ive damage to the rice crop due to dry ing ou t of chlorot ic plants. Inves t iga t ions carried out in- d ica ted t h a t the chlorosis of rice p lants was due to iron deficiency. The chlorosis was over come by spraying 1% neutra l ized ferrous sulphate solut ion or by keeping the soil cont inuous ly submerged.

Earl ier , when the cu l t iva t ion of rice was mos t ly l imi ted to the low lauds, iron deficiency did not pose any problem at all. R a t h e r iron tox ic i ty was a p rob lem on some of these soils. Now, wi th the cu l t iva t ion of dwarf rice var ie t ies ex tend ing to the uplands, par t icu lar ly on saline soils in Punjab , India, iron deficiency has appeared this year on field scale. Dur ing the current year, a large scale chlorosis of rice plants was observed in the s ta te of Pun jab (India), and in m a n y cases i t resulted in a to ta l crop failure. The causes of chlorosis were inves t iga ted into and it was found t h a t the large scale chlorosis of rice plants was due to iron deficiency.

The chlorosis first appeared on the emerging leaves af ter about two weeks of t ransplant ing , then passed on to the lower ones and u l t ima te ly the whole p lan t died. The current year witnessed a record water shortage and the iron deficiency concen t ra ted a round such s i tuat ions where the land could not be kep t submerged. W h e n the well grown up rice p lants showing the chlorosis were kep t in submerged condit ion, they recovered considerably. One of the mos t s ignif icant chemical changes which takes place after a soil is subjected to submergence is the reduct ion of iron and the resu l tan t increase in its solubil i ty.

W h e n the rice plants showing severe chlorosis were sprayed wi th 1% neutra l ized ferrous sulphate solution (ferrous sulphate and unslaked l ime in 2 : 1 ratio), t hey exhib i ted remarkable recovery af ter two weeks and bore panicles, where as those kep t w i thou t submergence (only near saturat ion) showed severe chlorosis and died before bear ing any panicle.

In an exper iment , seedlings of rice cu l t ivar I R 8 were t r ansp lan ted on a sandy loam soil (on which the t r ansp lan ted rice was showing severe chlorosis). The seedlings were t ransp lan ted under two sets of wa te r regimes, i.e., near sa tu ra t ion and 5-cm submergence. I t was observed tha t plants raised under

232 SHORT COMMUNICATION

Fig. 1. Showing hea l thy and chlorot ic plants of rice. Sat. = soil kept near sa turat ion, Sub, = soil kep t submerged wi th 5 cm water , 0 = no iron

t r ea tment , FS = ferrous sulphate.

submerged condi t ion did no t show any chlorosis whereas, those raised wi thou t submergence showed severe chlorot ic symptoms. W h e n the chlorot ic plants were sprayed wi th 1% neutra l ized ferrous sulphate solution, t hey s tar ted showing recovery af ter one week of spraying. Several green spots were observed all over the chlorot ic leaves as a result of spray droplets s t icking a t those points. La te r on, when the young leaves emerged f rom the sprayed plants, t h e y were normal green and did no t exhibi t any chlorosis. The plants which were no t subjec ted to iron applicat ion, died af ter about f ive weeks of t ransplant ing .

H. N. SHAHI, C. S. KHIND, and P. S. GILL

Punjab Agricultural University, Rice Research Station, Kapurthala, Punjab, India

Received January 6, 1975