How does the Adoption of Modern Variety increase Productivity and Income?: A Case of the Rice Sector in Tanzania
Although high yielding modern rice varieties (MVs) have been gradually disseminating over Sub-Saharan Africa, little is known on how the adoption of MVs influences agriculture productivity and household income. To fill this research gap, we analyze two kinds of data sets in Tanzania: a national representative cross section data and a two-year panel data of irrigated farmers in one district. The most important finding is strong complementary relationship between MVs and water control; high yield is achieved when MVs are grown with improved bund in paddy fields in irrigated area. We also find that the use of chemical fertilizer and the practice of transplanting in rows increase yield and income of both the adopters and non-adopters of MVs in the irrigated area. In rain-fed area, we observe limited impact of MVs. These findings suggest that introducing MVs as a package of technologies including other agronomic practices is effective in order to fully achieve their potential. In the long run, development of irrigation would be important to realize a rice Green Revolution in Sub-Saharan Africa.
Can soil bunds increase the production of rain-fed lowland rice in south eastern Tanzania?
Rain-fed lowland rice is by far the most common production system in south eastern Tanzania. Rice is typically cultivated in river valleys and plains on diverse soil types although heavy soil types are preferred as they can retain moisture for a longer period. To assess the effects of soil bunds on the production of rain-fed lowland rice, the crop was cultivated in bunded and non-bunded farmers� plots under the common agronomic practices in the region, in three successive seasons on Grumic Calcic Vertisols (Pellic). For the three seasons and for the two plot types, crop transpiration was simulated with the BUDGET soil water balance model by using the observed weather data, soil and crop parameters. Comparison between the observed yields and the simulated crop transpiration yielded an exponential relationship with a determination factor of 0.87 and an RMSE of 0.15 tonnes ha-1. With the validated soil water balance model crop yields that can be expected in bunded and non-bunded fields were subsequently simulated for wet, normal and dry years and various environmental conditions. Yield comparison shows that soil bunds can appreciably increase the production of rain-fed lowland rice in south eastern Tanzania in three quarters of the years (wet and normal years) when the soil profile is slow draining (KSAT equal to or less than 10 mm day-1). In normal years a minimum yield increase of 30% may be expected on those soil types. In wet years and when the soil hardly drains (drainage class of 0�5 mm day-1), the yield may even double. In dry years the yield increase will be most of the time less than 10% except for plots with a percolation rate of 0�5 mm day-1.
Tillage systems in the tropics: management options and sustainability implications
Tillage systems in the tropics :management options and sustainability implications , Tillage systems in the tropics :management options and sustainability implications , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی