Effect of Preceding Winter Crops and Herbicidal Combinations on Weeds, Yield and Econemic Feasability of Broadcast-Seeded Rice Productivity.

Abstract

Nowadays, in Egypt there is a big shift towards increasing the cultivated area with broadcast-seeded rice which needs to overcome the heavy out weeds infestation in this case. Thus, four field experiments were conducted at the Experimental Farm of El-Serw Agri. Res. Station, Damietta Governorate in 2014 and 2015 summer seasons, to investigate effect of clover and wheat as two preceding winter crops before sowing the rice as broadcast-seeded rice and six weed control treatments [Saturn at 2.0 L/ faddan + Basagran at 1.5 L/ faddan, Ronstar at 0.75 L/ faddan + Enpul at 20 g/faddan, Rainbow at 0.4 L/ faddan + Enpul at 20 g/ faddan, Rainbow at 0.4 L/ faddan + Basagran at 1.5 L/ faddan combinations, hand weeding twice and untreated check] in each experiment on weeds, rice grain yield and its components with economic evaluation. The main findings indicated that sowing the rice as broadcasted after clover; and weed control treatments irrespective of the preceding winter crops decreased significantly the dry weight of both dicot and monocot weeds and markedly increased rice grain yield (ton/faddan) and its components i.e., plant height, number of tillers/m2, number of panicles/m2, number of filled grain/panicle and weight of grain/panicle, that is true in both seasons. In first season the interaction between clover as a preceding winter crop and herbicides combinations i.e. Rainbow 2.5% OD (penoxsulam) at 0.4 L/ faddan followed by Enpul 75% WG (halosulfuron-methyl) at 20 g/faddan; Rainbow 2.5% OD at 0.4 L/faddan followed by Basagran 48% AS (bentazon) at 1.5 L/ faddan; Ronstar 25% EC (oxadiazon) followed by Enpul 75% WG at 20 g/faddan and Saturn 50% EC (thiobencarb) at 2.0 L/faddan followed by Basagran 48% AS at 1.5 L/faddan reduced the total weeds by 91.7, 91.3, 88.5 and 86.3%, respectively, at 70 DAS, and accompanied with significant increases on rice grain yield by 145.3, 154.0, 122.0 and 148.0% than untreated check, respectively. Whilst, hand weeding twice was less effective on reducing the total weeds by 56.5 and 53.4% at the respective assessments and reflect that to increase rice grain yield in both seasons. The highest net income/faddan were obtained by the previous herbicidal combinations in trials preceded with clover than wheat during the two seasons. This study throw lights about suitable and satisfactory herbicidal combinations to overcome the heavy weeds infestation problem in broadcast-seeded rice. These results indicated that under heavy infestation with weeds in broadcast- seeded rice, it is possible to grow broadcast-seeded rice after clover with using one herbicides combinations,( Rainbow at 0.4L/fed + Enpul at 20 g/fed, Rainbow at 0.4L/fed + Basagran at 1.5 L/fed, Ronstar at 0.75 L/fed + Enpul at 20g/fed; and Saturn at 2.0 L/fed + Basagran at 1.5 L/fed) which, gave the highest redution weeds, increase broadcast- seeded rice yield and the highest economic values in both seasons.