Effect of rainfed green-manure crops on succeeding rice (Oryza sativa)

Abstract

In rice (0r)~za sativa L.) cultivation, low (242 kglha), medium phorsphorus (16.8 kg/ fertilizer-use efficiency warrants the ha) and high potassium (292 kgtha). The application of higher doses of fertilizer for seeds of green-manre crops were treated desirable results. But judicious and balanced with rhizobial culture and sown adopting application of organic manures along with the seed rate of 50 kglha using the initial inorganic fertilizers increases the fertilizer- rains during July 1992. use efficiency. The use of green-manures During the growth period, about 101 mm along withjertilizer nitrogen can aid for N rainfall was received. After 60 days, biomas economy in lowland rice (Khind et al., production, nodule number and nitrogen 7 1982). In a single crop wetlands of the content were recorded. Periyar-Vaigai command area, prior to rice Rice (IR 20) was transplanted in crop, there is possibility of receiving 100 September 1992 after incorporation of the mm rainfall during July-September. Under green-manures. The other cultivation such a situation various green-manure crops practices were followed uniformly to all can be grown for soil enrichment and rice treatment plots. Among the several green- production. manures, S. cannabina, S. speciosa and S. - A tield experiment was conducted during rostrata recorded significantly higher the rainy (klzarifi and winter seasons (rabi) biomass than the other green-manures. of 1992-93 at Agricultural College and Re- (Table 1). The data on growth and yield - search Institute, Madurai, to evaluate the parameters revealed that green-manure- potential of rainfed seen-manure crops dur- incorporated plot6 recorded higher values ing the season preceding rice in the single than the control. The grain yield of single clop wetlands. Seven green-manure crops, crop rice, planted after the green-manure vlz. Sesba~~ia cannabitla (Retz.) Pers.; syn increased substantially compared with rice S. irculeata L., S. speciosa Taub., S. rostra- planted after fallow (Table 1). tl1, G.ota1ar.i~ juncea.L., ,Vigna trilobata L. The yield increase due ta pre-season Verd.; syn Pl~aseolus trilobus sensu Ait. .& rainfed green-manure crops was 4 7 qlha auct. non, Tephrosia purpurea Pers.; Baker with S. rostrata, 3.8 q/ha with S. cartnabina. i n part and Vigna utlguiculata (L.) Walp., 3.6 qlha with S. speciosa and 2 q/ha with -- were compared with pre-season fallow, in Crotalaria juncea. The yield increase m~ght randomized block design wlth 3 replica- be due to addition of organlc matter and tions. he experimental site was sandy loam plant nutrients through green-manures. having pH 7.8 with low available nitrogen Kalidurai and Kannaiyan (1990) also