Growth, yield and soil water extraction of irrigated and dryland peanuts in South Sulawesi, Indonesia

Abstract

Irrigation at 35 and 70 mm of pan evaporation applied during the pre and/or post early podfilling stages increased pod yield of spanish peanuts (100 day maturity) three fold compared to a dryland crop. There was no difference in pod yield in crops receiving 12 compared to 6 irrigations. Soil water sampling immediately after irrigations on selected treatments revealed that infiltration of irrigation water was probably restricted to less than ca. 20 cm, a response which resulted in poor soil water replenishment and low irrigation efficiency (Fig. 3). Even though roots extracted soil water below the compaction layer which was at 20 cm severe crop water deficits had developed by the end of irrigation cycles during later but not early stages of growth. The dryland crop, which received no rainfall during the season, presumably extracted significant amounts of soil water at depths to and below 1.2 m (Fig. 3). Despite producing ca. 2.9 t ha-1 of total dry matter yield, pod yield was extremely low (0.5 t ha -1) arising from low pod numbers and high percentage of empty pods.Throughout much of South Sulawesi the present cropping system consists of wet season (paddy) rice, with very little dry season production of non-rice field crops (palawija) such as peanuts, soybeans, maize and mungbeans. The lack of field crops is largely due to water limitations, both of rainfall and of irrigation, during the growing season (Willatt and Samosir 1984). Recent investigations have revealed large areas of good quality and easily accessible groundwater available for pumping throughout many of the lowland areas of South Sulawesi. A potential therefore exists for more widespread field crop production using sup-*

Opportunities for improving crop water productivity through genetic enhancement of dryland crops.

“…The extent of the root depth and RLD becomes important for soil water extraction during prolonged water deficit. Deep rooting and faster extraction may be very appropriate in tropical environments, where groundnut is grown solely on stored moisture in the dry season on high water-holding capacity soils (Prabowo et al, 1990). Genotypic variability for root characteristics (root volume, root dry weight, root length and number) has been reported in groundnut (Ketring, 1984).…”