Ratooning ability increases sugarcane production economics by reducing frequency of planting. During sugarcane breeding, indirect selection for pest resistance and direct selection for high ratoon yields increases ratooning ability. The objective of this study was to describe the simultaneous screening of genotypes for yield and ratooning ability in sugarcane breeding trials using analysis of covariance. Data for cane yield (tons ha -1 ) and stalk population (×10 3 ha -1 ) collected from five trials harvested from plant to fourth ratoon crops were analysed using the Statistical Analysis System (SAS). There were significant differences in parameters for yield (intercept) and ratooning ability (slope) among test genotypes indicating potential for simultaneous screening. Comparison of genotypes to a control with known ratooning ability identified higher yield and good ratooning genotypes. Graphical trends identified genotype differences in yield and ratooning ability. The economics of yield and ratooning ability of two varieties was compared providing a mechanism for variety choice at planting. The method described provided statistical tests that would increase genotype selection efficiency for ratooning ability. The decline in yield among genotypes is slowed by the increase in stalk population.

Soil fertility depletion is a major limitation to crop production in sub-Saharan Africa and Zimbabwe is no exception to this phenomenon. This research was conducted to assess the soil chemical characteristics in three contrasting cropping systems of Zimbabwe. The contrasting production systems under study were communal area, A2 (large scale resettlement) and A1 (small scale resettlement).All these systems are in Manicaland province, Zimbabwe. The A1 and A2 production systems were brought about during the 2000 land reform programme. The soil samples were collected during the off season of 2006, 2007 and 2008. The following soil chemical characteristics were determined: Ca, Mg, K, Zn, pH and organic matter. There were significant differences (P=0.001) between the production systems and soil chemical properties. Calcium, magnesium and potassium levels were generally low in all the three production systems. This was due to low soil pH. However, A2 farms had significantly the highest (P<0.05) Ca, Mg and K while communal area had significantly the lowest (P<0.05) soil organic matter content. The soil organic matter content in A2 farms can sustain plant growth. This could also be compounded by good land management practices such as fertilisation and liming. However, there may be need for the communal and A1 farmers to apply organic matter so as to boost SOM in their fields. The optimum soil organic matter in Zimbabwe is from 1.5% to 5%. Results showed that soil pH was between 5.0 and 6.8 (slightly acidic), in all the three production systems. However, it was strongly acidic in communal areas at 0-30cm depth. Soil acidity in communal areas impacted negatively on the yield of maize and groundnut. In the A1 and A2 farms acidity levels may sustain the production of crops like tobacco and sunflower. Generally, there is need for the farmers in the three production systems to lime the soils and improve their organic matter through addition of crop residues and cattle manure.