4.2 Environmental and economic impact of ZT/CA and iCLF-CA
management systems adoption
It is recognized the impacts of ZT/CA in the increase of soil organic
carbon (SOC) sequestration, reduction of the emission of greenhouse
gases (GHGs) and improving economic and agriculture sustainability. The
emissions of GHG are reduced in the ZT/CA by decreasing the use of
fossil fuels in the crop production, the efficient application of
fertilizers and reduction of N2O emissions, as well as
decreasing soil erosion. Pointed as an evolution of ZT/CA, iCLF-CA also
affects positively soil biological, physical and chemical attributes,
for example by increasing C and N stocks in the short- and long-term,
and water retention, and reducing erosion soil losses. The build-up of
SOM improves biological, physical, and chemical soil properties, leading
to an increase in crop yields, with reduction of costs with irrigation,
fertilizers, soil conditioners and other agricultural inputs (Conceição
et al., 2017). The adoption of iCLF-CA also improves environmental,
social and economic services and it is a promising alternative to
recover degraded areas ( Lima et al., 2018; Landers et al.,
2020) .
Other impacts of the adoption of ZT/CA and iCLF-CA includes the off-farm
effects related by Landers et al. (2001a) considering both direct and
environmental benefits, including yield and support capacity decline and
land value depreciation in croplands and rangelands due to water
erosion, especially due to the intensive soil preparation, monoculture
practice and overgrazing. There are also off-farm benefits that implies
in the reduction in public spending such as: the maintenance cost of
rural earth roads – an annual economy of 3.5 US Dollars in a million ha
of crop areas; which implies in a public economy of 280 million US
Dollars; the reduction of turbidity and lower cost for water treatment
for human consumption, estimated to be of US Dollars 5.80 for each 10
thousand m3 (based on Carroll, 1997); and, the
reduction in reservoir volume storage by silting in dams for
hydroelectric power plants and for irrigation projects estimated as
being of more than 700 million US Dollars per year (Carvalho et al.,
2000).
The adoption of ZT/CA principles in irrigated areas with central pivot,
micro-irrigation, drip irrigation or localised irrigation, which
comprises 4.84 million ha in 2017, implies in an economy of 10% in
water volume and in pumping costs. Landers et al (2001a), considering
10% less in consumptive use of water in annual crop irrigated areas, an
annual economy of US$ 20.00 per hectare in need of pumping energy and
800 m3 ha-1 in water volume, valued
to be US$ 8.00 per ha. This means that, if ZT/CA adoption occurs in the
irrigated area, an annual economy of 38.7 million US Dollars,
considering prices of 2001. This implies in less demand of electrical
energy and in water.