Genotype, environment and agronomic practices are key determinants of crop   growth and productivity which are important to provide food, feed, raw materials and income to small holder farmers in Africa. The study was conducted at Crop museum, Sokoine University of Agriculture, Morogoro, Tanzania to investigate physiological response of groundnut to calcium and phosphorus nutrition among three improved groundnut genotypes Mangaka (G1), Masasi (G2) and Pendo (G3) with three levels of phosphorus and at calcium control (T0), 125 kg/ha (T1) and 55 kg/ha (T2) supplied from Diammonium Phosphate (DAP) and Minjingu mazao, respectively.  Significant (P< 0.05) influence of calcium was observed on leaf area index (LAI) 4.03; crop biomass 88.79 g/plant; number of nodules 66.22, and crop growth rate (CGR) 15.05 g m2/day. Whereas phosphorus had significant influence on net assimilation rate (NAR) 10.84 g m2/day. Similarly, groundnut genotype (Masasi) had significant influence on LAI (3.95); CGR (13.04 g m2/day); NAR (12.36 g m2/day) and number of nodes (64.93). However, there was no significant effect of genotype on crop biomass recorded from the investigation. Growth  parameters were significant influenced by genotype and fertilizer interactions with Significant (P=0.2) interaction effect for crop biomass observed between G3 x T1, whileG3 x T2 significantly affected number of nodules and G2 x T1 had Significant interaction effects on CGR and NAR. This is an indication that investment in improved genotype and appropriate application rate of fertilizers has the potential to enhance yield and income of smallholder farmers.

Arid and semi-arid lands occupy currently 88% of arable land mass in Kenya, a region with significant diversity of production systems and economic opportunities. However, these areas are characterised by low and erratic rainfall, hence challenges to agriculture and socioeconomic development in the wake of an increasing population and the impacts of climate change. This review seeks to identify key challenges and opportunities associated with the management of agricultural soils in these arid and semi-arid communities. Arid and semi-arid regions in Kenya are dominated by 10 soil types; Solanchaks, Solonetz, Cambisols, Arenosols, Leptosols, Vertisols, Fluvisols, Phoezems, Calcisols, and Gypsisols. Among the main soil fertility challenges in these soils are moisture stress, high erodibility, and low organic matter content, salinity, and sodium toxicity, the deficiencies of mainly N, P, Zn, and Fe, hence the vulnerability of over 14 million inhabitants to the shocks of low crop and pasture production.  Moreover, the adoption of soil conservation practices remains low as existing soil fertility management technologies have been criticized for being too abstract and not providing context and site-specific solutions. Improving soil fertility and moisture levels enhances soil ecosystem functions and food and pasture production in these regions.  Encouraging farmers to join soil and water conservation groups, while providing economic incentives, could potentially accelerate the adoption of soil and water practices at the farm level through pulling resources together. Future research to validate a site and context-specific integrated soil fertility improvement technologies for these soils is evitable to enhance soil functions, agricultural production and livelihood at house hold level.