PR - Optimal Nitrogen Fertilizer Application And Efficient Water Use
The aim with this study in the Thabu Nchu district of South Africa was to determine the optimal nitrogen (N)-fertilizer application rate for dry beans and maize when using the Infield Rain Water Harvesting (IRWH) technique. The Weighted Least Square (WLS) technique was applied to estimate quadratic production functions based on experimental data for 2004 and 2005. The WLS result confirms that dry beans were strongly affected by N-fertilizer application as well as by the interaction between other variables. This implies that small-scale farmers around Thaba Nchu need to adopt not only IRWH, but also apply an appropriate N rate to improve their food security and livelihood status. The determinants of the maize yield analyses show that N-application, N-square, year effect and location were the only statistical significant factors determining higher maize yields at the one percent test level. This indicated that maize yield was predominantly determined by other, unexplained agronomical factors, requiring further study. The study confirms that farmers need information on the fertility of their land, appropriate N-application rate and proper crop selection to reap benefits when adopting the IRWH farming technique.
Keywords: farming technique, fertilizer application and WLS.