Nutrient variations from swine manure to agricultural land

Abstract

ObjectiveSwine manure in Korea is separated into solid and liquid phases which are composted separately and then applied on land. The nutrient accumulation in soil has been a big issue in Korea but the basic investigation about nutrient input on arable land has not been achieved in detail. Within the nutrient production from livestock at the national level, most values are calculated by multiplication of the number of animals with the excreta unit per animal. However, the actual amount of nutrients from swine manure may be totally different with the nutrients applied to soil since livestock breeding systems are not the same with each country.MethodsThis study investigated 15 farms producing solid compost and 14 farms producing liquid compost. Composting for solid phase used the Turning+Aeration (TA) or Turning (T) only methods, while liquid phase aeration composting was achieved by continuous (CA), intermittent (IA), or no aeration (NA). Three scenarios were constructed for investigating solid compost: i) farm investigation, ii) reference study, and iii) theoretical P changes (ΔP = 0), whereas an experiment for water evaporation was conducted for analyzing liquid compost.ResultsIn farm investigation, weight loss rates of 62% and 63% were obtained for TA and T, respectively, while evaporation rates for liquid compost were 8.75, 7.27, and 5.14 L/m2·d for CA, IA, and NA, respectively. Farm investigation provided with the combined nutrient load (solid+liquid) of VS, N, and P of 117.6, 7.2, and 2.7 kg/head·yr. Nutrient load calculated from farm investigation is about two times higher than the calculated with reference documents.ConclusionThe nutrient loading coefficients from one swine (solid+liquid) were (volatile solids, 0.79; nitrogen, 0.53; phosphorus, 0.71) with nutrient loss of 21%, 47%, and 29%, respectively. The nutrient count from livestock manure using the excretion unit has probably been overestimated without consideration of the nutrient loss.

Rational budgeting approach as a nutrient management tool for mixed crop-swine farms in Korea

“…Data obtained from farm census and lab estimation together with data collected from the published literature were used to construct the farm nutrient budgets [6,7,[9][10][11][12][13][14][15][16][17][18][19][20][21]. Nutrient fluxes were used to convert the different components of the nutrient budgets from their original reported unit to common units (Table 2).…”

“…Nutrient fluxes were used to convert the different components of the nutrient budgets from their original reported unit to common units (Table 2). Most of the fluxes used in this study were derived from the studies focused on Korea [6,7,[9][10][11][12][13][14]. Seed nutrient inputs fluxes were obtained from Kremer [15].…”

“…The Korean government has regulations such as the prohibition of direct use of livestock manure on agricultural land and stringent nutrient concentration limits in compost and effluents of livestock wastewater treatment process to reduce nutrient loading from livestock manures and protect the environment. The swine production and manure management system in Korea is quite different compared to other countries due to climatic conditions and the limited available arable land [6]. Swine manure in Korea is usually segregated into solid and liquid phases and composted prior to land application.…”

“…Composting process (both solid and liquid) is generally carried out within the farms to reduce the environmental impact of land spreading of swine manure. Solid composting is done by aeration and turning+aeration (TA) method, while the liquid composting process is operated under continuous, intermittent, and no-aeration [6]. However, there is widespread speculation about the livestock sector in Korea that, nutrient loading from livestock manure is the main reason for water quality deterioration and soil nutrient surpluses.…”

“…The nutrient inputs from livestock manure were calculated using the following equations: N man = AH×D×C N man +"BA×C N bed (5) P man = AH×D×C P man +BA×C P bed (6) where N man and P man are the nutrient inputs from livestock manure (kg/yr); AH is the number of animals (head); D is unit discharge coefficient (kg/head/yr); C N man and C P man are the nutrient content in swine manure (g/kg); BA is the bulking agent (kg) and C N bed and C P bed are the nutrient content in BA (g/kg). iv) Nutrient inputs from compost Swine farms in Korea segregate the swine manure into solid and liquid phases and following segregation, manure is composted [6]. Unit discharge fluxes for both solid (feces) and liquid (urine + wastewater) published by the MoE, Korea [10] were used to calculate individual farm manure production.…”