PHOSPHINE RESIDUE AND ITS DESORPTION FROM LEGUMES FUMIGATED WITH PHOSFUME PELLETS

On fumigation with 6 phosfume tablets/ton, legumes (grams) show higher free phosphine (PH3) residue than that found on their splits (dhals), blackgram skewing the higher free PH3 residue of 187 mu g Fieldbean d hal (6 mu g), bengalgram dhal (40 mu g) and blackgram dhal (4 mu g) ho ld about 4, 37 and 3%, respectively of the pre-aired PH3 residue found on corresponding samples of the respective grams Greengram and its dh al are an exception as the latter shows a higher residue (97 mu g) tha n that shown by the former (71 mu g). During 1 d airing, blackgram dha l loses 100% of the pre-aired residua,while the other grants and their dhals lose more than 70% of their corresponding residue. During stora ge, pre-aired samples of bengalgram dhal (11 mu g/(kg.d)), 1 d aired s amples of blackgram (4 mu g/(kg.d)) and blackgram dhal (4 mu g/(kg.d)) show a higher rate of desorption of PH3 residue, while 1 d aired gree ngram samples do nor show desorption. Because of such differences in t heir desorption rate different legumes have taken a different length o f time to attain a nondetectable residue level. Based on extensive dat a collected, it is concluded that phosphine can be a suitable fumigant , based on negligible free phosphine residue during storage.