Application of the principles of Regenerative Agriculture to increase levels of nutrients in the soil and face an emergency of local food and nutritional security in Guanacaste, Costa Rica

Abstract

It is known that the implementation of regenerative agriculture improves soil health, increases biodiversity and returns carbon to it, while recycling nutrients, increasing yields, and improving the health and vitality of rural communities under the vision soil and healthy food, however there are few results in the application of these principles to strengthen food security in emergency situations. We report the results of an exploratory research focused on the establishment of an emerging food production system that integrated the application of regenerative agriculture principles and nature-based solutions, including the application of high doses of compost (100 t / ha) and a layer of dry grass (¨mulch¨ or vegetable cover) at a rate of 2-3 kg/m2, in combination with polyculture in a high bed of soil of different species and varieties of vegetables, the application of Integrated Pest Management and drip irrigation. The tests were carried out in Tempate, Santa Cruz, Guanacaste, Costa Rica, in a clay loam soil. It was shown that the carbon content in the soil increased from 1,65% (m/m) at the beginning of the experiments to 4,05%(m/m)  and 3.70%(m/m)  at 6 months and 12 months later, with an average of 2,26%(m/m); values ​​higher than those found in the nearby gallery forest; this indicates the feasibility of increasing the sequestration capacity of C in regenerative orchards to levels equivalent to 58,9 t/ of C/ha/year, which was accompanied by an increase in the content of nitrogen in the soil from 0,14%(m/m) to 0,32% (m/m) and 0.37%(m/m) in those times, with  values ​​of the C/N ratio, similar to those of the nearby gallery forest, without significant changes in pH. The increases in the levels of assimilable phosphorus were particularly important, which rose from 1,67 mg/L of soil at the beginning of the experiments to values ​​that fluctuated from 64,67 mg/L of soil (6 months) to 73,33 mg/L of soil (12 months), while potassium concentrations increased from 0,14 cmol(+)/L of soil to 1,21 cmol/L of soil (6 months) and 0,61 cmol(+)/L of soil (12 months), in correspondence with the lower values ​​of the calcium/potassium, magnesium/potassium and (calcium + magnesium)/potassium ratios, which demonstrates the beginning of an important soil regeneration process associated with the cultivation of more than thirty species. In these trials, potential yields were estimated at 94 t/ha, with the consequent improvement in food and nutritional security, as well as the livelihoods of the beneficiaries.