TRADE NEWS •••
••••••• agriculture practices
Root pathogens and soil microbial studies : Being the first season , the observed trends will serve as base line data for the following seasons .
TRIAL : Interactions of plant row width , population density and cultivar as component to the sustainable cultivation of monoculture maize on sandy soils ( Thabo van Zyl , Doornbult , Bothaville ):
Agronomic observations :
• Maize in 1.524 m rows had 2.5 times the number of tillers compared to plants in 1.016 m rows .
• Maize grain yield was affected by both plant population and row width . The mean yield of the 1.016 rows was 1.37 t ha -1 higher than that of the 1.524 m rows . The results on yield per plant as related to plant population and row width indicate that the cultivar displays tolerance to stress caused by increasing plant densities .
• The best margins were realised with narrow ( 1.106 m ) rows at high population densities , compared to wider ( 1.524 m ) rows . For example , R5082 ha -1 and R5153 ha -1 were realised with narrow rows at population densities of 30 000 and 50 000 plants ha -1 , respectively . With wider rows ( 1.524 m ), the highest margin ( R3001 ha -1 ) was obtained at a population of 25 000 plants ha -1 , compared to R1703 and R2356 ha -1 for 20 000 and 50 000 plants ha -1 respectively .
TRIAL : Interaction of population density and cultivar as component to the sustainable cultivation of monoculture maize on sandy soils ( Danie Minnaar , Vlakvlei , Kroonstad ):
Agronomic observations :
• The number of tillers per plant was not affected by seeding density .
• Each cultivar had a unique yield response to seeding density . Optimum population density appeared to be above 23000 ha -1 .
• Cultivar 78-87Bt at plant population of 24 000 plants ha -1 gave a slightly higher ( R12246 ha -1 ) margin than 26 000 plants ha -1 ( R12187 ha -1 ). It appeared as if the economic optimum population for cultivar 78-87Bt is 22000-24000 plants ha -1 .
• For cultivar 78-17Bt a plant population density of 26 000 plants ha -1 yielded a higher ( R11443 ha -1 ) margin than 24 000 plants ha-1 ( R10891 ha -1 ).
• Comparing the margins of the two cultivars , it can be seen that cultivar 78-87Bt with a population of 24 000 plants ha -1 yielded R803 ha -1 more than the 26 000 plants ha -1 of cultivar 78-17Bt .
TRIAL : The optimum depth of ripping for the sustainable cultivation of monoculture maize on sandy soils ( Thabo van Zyl , Doornbult , Kroonstad ):
• Grain yield increased linearly with ripping depths from 45 to 75 cm at a rate of 0.87 t ha -1 per 100 mm increase in ripping depth .
• No significant yield response was found by increasing the ripping depth beyond 75 cm .
• The 90 cm ripping yielded a slightly higher margin than the 75 cm ripping . However , the additional capital cost will eliminate this financial advantage . It can be concluded that 90 cm ripping would not have a financial gain over the current farm practice of ripping to 75 cm depth .
• Ripping shallower than 75 cm will not be economically viable .
IN SUMMARY IT CAN BE CONCLUDED THAT : Although it was the first experimental season , valuable results were obtained that will form the base line for follow-up seasons . All on-farm trials proved to be viable and showed the potential to contribute to practical conservation agriculture practices that will improve soil health as key to sustainable dry land maize production systems on semi-arid sandy soils with water tables in the North- Western Free State .
* E-mail : danie . beukes122 @ gmail . com
SENWES Scenario • DES 2017-MRT 2018 15