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Precision Agriculture Technologies Positively Contributing to GHG Emissions Mitigation, Farm Productivity and Economics

“…Variable rate (VR) lime (which is primarily CaCO 3 ) application can increase crop yields and the economic return of the farm [72]. Lime application increases the soil pH to a desired level and an optimal pH level in the soil is important to achieve optimum yields and consistent quality [73].…”

“…Under-application of lime can cause large yield losses. Over-application of lime can be as detrimental as under-liming [72], as it is costly and can create problems with availability of some nutrients (for example inhibiting P and Zn, or leading to toxic levels of Mn), disease pressure, reduced herbicide performance and herbicide degradation [72,73]. Over-and under-liming cannot be avoided if lime is applied uniformly throughout the field.…”

“…The main cost in a VR lime application is the cost of grid sampling. The actual amount of lime used depends on the soil variability, field acidity, environmental factors, the sampling method and the sampling resolution [72]. Weisz et al (2003) [72] concluded that when performing grid sampling and VR lime for 3 consecutive years in Piedmont no-till soybean fields, the net loss is €11.44/ha compared to uniform lime application.…”

“…The actual amount of lime used depends on the soil variability, field acidity, environmental factors, the sampling method and the sampling resolution [72]. Weisz et al (2003) [72] concluded that when performing grid sampling and VR lime for 3 consecutive years in Piedmont no-till soybean fields, the net loss is €11.44/ha compared to uniform lime application. However, when they performed grid sampling only in year 1 and 3, and performed the VR lime in each year (with year 2 based on the PH map of year 1) this turns into a net gain of €4.28/ha over 3 years.…”

“…In 75% of the studies (4 in total) reviewed by Lambert and Lowenberg-DeBoer (2000) [76] investigating VR lime, a positive economic effect was found, while in 25%, the articles indicated mixed results. The lime application can be more effective in legumes than in corn and wheat, as the response of the latter is limited to pH 5-5.5, where in legumes this can go up to pH 6 [72]. Kuang et al (2014) [73] found that VR approach in Danish spring barley can be compared to the traditional approach pointing out that the consumption of lime consumption was increased, but it was followed by an increase in yield resulting in net profit (€3.61/ha) for the VR approach compared to the traditional approach.…”