Productivity of summer forage crops and their effect on succeeding basmati rice (Oryza sativa) in conjunction with phosphogypsum-enriched urea

A field experiment was conducted during summer and rainy seasons of 2007 and 2008 at New Delhi to study the productivity of summer forage crops viz. sole pearlmillet (Pennisetum glaucum L. R. Br. Emend Stuntz), sole cowpea \{Vigna unguiculata (L.)Walp\}, pearlmillet + cowpea mixture and their effect in conjunction with phosphogypsum-enriched urea (PGEU) viz. absolute control, 0, 2.5, 5 and 7.5; PGEU on yield attributes, yields and total N, P, K and S uptake in basmati rice (Otyza sativa L.). Among the three forage crops grown during sum¬mer, pearlmillet + cowpea mixture recorded significantly higher green and dry fodder yields compared to sole pearlmillet and sole cowpea during both the year of experimentation. Percentage increase in fresh yield of pearlmillet + cowpea was 15.3 and 43.4 over sole pearlmillet and sole cowpea respectively during 2007 and simi¬lar trend was also recorded during 2008. Micronutrient uptake viz. zinc, manganese, copper and iron also followed the same pattern to that of dry forage yield of summer fodder crops. In case of basmati rice yield attributes viz. ef¬fective tillers, panicle length, panicle weight and grain weight/panicle were influenced significantly due to preced¬ing forage crops. Application of variable concentrations of PGEU had significant effect on all the yield attributes of basmati rice. Significantly higher grain, biological yield as well as harvest index of basmati rice was recorded when it was grown after the harvest of proceeding summer forage cowpea as compared to other treatments. Similarly, significantly higher grain and biological yields were recorded with 7.5; PGEU. Various preceding summer forage I crops had significant effect on nutrients uptake viz. N, P, K and S total uptake in basmati rice (grain + straw). The significantly higher total (grain + straw) N, P, K and S uptake were recorded with 7.5; PGEU compared to lower levels of PGEU.