Vincenzo Tabaglio1*, Paolo Caprioli1, Roberta Boselli1, Andrea Fiorini1, Cristina Ganimede1, Giovanni Lazzari1, Dora Inés
Melo Ortiz1, Stefano Santelli1, Romano Demaldè2
1 Dipartimento di Scienze delle Produzioni Vegetali Sostenibili, Università Cattolica del Sacro Cuore di Piacenza, Via E. Parmense 84, 29122, Piacenza 2 Istituto di Enologia e ingegneria agro-alimentare, Università Cattolica del Sacro Cuore di Piacenza, Via E. Parmense 84, 29122, Piacenza
*[email protected] Abstract
A field trial was carried out to compare two agricultural management systems in the Po Valley (Northern Italy): Conventional tillage (CT) vs. No-tillage (NT). The different management of the experimental field had been established since 2011. In 2014 the trial was cropped with maize and CT system was compared with NT system concerning crop yields, soil characteristics and operating costs. Experimental trial was set up as randomized complete block design with four replicates. The soil is a fine, mixed, mesic, Udertic Haplustalf. The software C.E.M.A. was used to determine operating costs and fuel consumption of the two agro-ecosystems. In term of net income it was observed a difference of about 100 € per hectare in favor of NT system. Regarding greenhouse gases emissions NT saved about 360 kg per hectare of CO2.
Keywords: no-tillage, conventional tillage, crop yields, operating costs, farmers’ net income, GHG emission, climate
change mitigation.
Parole chiave: non lavorazione, lavorazione convenzionale, rese colturali, costi di esercizio, reddito netto aziendale,
emissioni di gas serra, mitigazione del cambiamento climatico.
Introduction
Conventional tillage practices based on the plowing have several negative aspects: reduction of soil organic carbon (Schlesinger, 1985), enhancing of soil aeration and metabolic respiration of soil biota (Dungait et al., 2012),increasing of soil erosion (Lal, 2003), disruption of soil aggregate stability (Pagliai et al., 2004), and soil compaction (Hamza and
Anderson, 2005). Conservation Agriculture is an approach to managing agro-ecosystems for improved and sustained productivity, increased profits and food security while preserving and enhancing the resource base and the environment (FAO, 2012). Conservation agriculture is a sustainable approach that reduces the number of tillage, saving soil moisture, fuel, labor, and machinery costs, as well as reducing wind and water erosion (Ribera et al., 2004). In particular, no-tillage (NT) rely on direct seeding which is performed by special seed drills, that open a narrow slot with minimal disturbance of the surface crop residue. Moreover, NT does not require additional tillage for seedbed preparation and the agronomic practices in field are limited to fertilizers and pesticides treatments and, if necessary, interventions for weeds control (Hanna, 1995). This approach is based on four basic pillars: (1) crop rotation, (2) minimization of soil tillage, (3)
permanent soil cover by crop residues (4) cover cropping (FAO, 2012; Lal, 2015). This conservation strategy improves
yield stability, enhances inputs use efficiency, increase soil quality and improves agro-ecosystems services.
The aim of this study was to evaluate crop yields, management costs, soil fertility parameters and the impact on the farm’s income in a NT compared to a CT system for maize cropping.
Materials and Methods
The trial was carried out at CERZOO, the experimental farm of the Università Cattolica, near Piacenza (Northern Italy, lat. 45.006108 N; long. 9.707523 E) during 2014. The soil was a fine, mixed, mesic, Udertic Haplustalf (USDA, 2014). Since 2011 the experimental field has been established to compare two different tillage systems: CT and NT. The experiment was designed as a Randomized Complete Block with four replicates. Each plot has a surface of 1430 m2. In 2014 maize was the planned crop in rotation, following wheat and a cover crop. CT plots were ploughed at 30 cm depth and then harrowed twice with a rotating harrow to provide a suitable seedbed. NT plots were direct-planted through the crop residues. Before maize planting all plots were treated with Glyphosate, at the rate of 3 L ha-1 to terminate the cover crop. The maize hybrid
was SNH 9609, FAO 600.
CT plots were sown with a 4-row precision planter (Kuhn mod. Maxima 2) and NT plots with a no-till 4-row precision planter (Semeato mod. SPE 06). Fertilizer was top dressed twice as urea (46% N): 125 kg N ha-1 immediately before
planting, and 85 kg N ha-1 at V6-V8 stage. The software C.E.M.A. (developed by the Department for Sustainable Food Process – DiSTAS of Università Cattolica del Sacro Cuore di Piacenza) was used to calculate the operating costs of agricultural practices on the basis of the used machinery. The main outputs of this software are:operating costs per hectare
and fuel consumption per hour; then, from these parameters it is possible to calculate operating costs of CT and NT systems and to calculate the net income of farmers.
Results and Discussion
OPERATING COSTS
Tab. 1: Operating costs referred to agronomic operations, calculated by adding tractors and tools hourly operating costs (€ per hectare). Tab. 1: Costi di esercizio delle diverse operazioni colturali, calcolati sommando il costo orario di esercizio della specifica trattrice e dell’attrezzo ad essa associato (€ ad ettaro).
Regarding the operating costs, NT system showed an economic advantage of 200 € ha-1 compared with CT system (Table 1), that is 23.5% cost reduction. The main reason was due to the elimination of tillage operations for the seedbed preparation. The total in Table 1 includes all operating costs excluding the agronomic inputs (seeds, fertilizers, agrochemicals), the last one being presented in Table 2. In this case, NT system was more expensive than CT (+30 € ha-1).
The higher costs in NT system were imputable to the treatment against slugs, which can represent one of the major pests in humid years and that could create a failure of maize emergence in NT systems (Hammond et al., 1999).
Tab. 2: Costs of agronomic inputs (fertilizers, herbicides, insecticides, seeds).
Tab. 2: Costo degli input agronomici (concimi, diserbanti, insetticidi, sementi).
The reduction of operating costs in NT systems can reach up to 70% after stabilization of the biotic no-till regimen and the requirement for chemical inputs, especially herbicides, can decrease due to crop rotations and to allelopathic cover crops (Tabaglio et al., 2013).
CROP YIELDS
Maize yields are shown in Table 3 both for grain and total biomass, on dry matter basis (Mg ha-1). CT grain yield was only
3% higher than NT, without statistical differences. These yields are comparable with the maize average performances observed in the Po Valley environment, this is a positive aspect considering that the field in 2014 was at the third year of transition to NT system (Soane et al., 2012).
Tab.3: Maize yields (on dry matter basis).
Tab.3: Rese colturali del mais sulla sostanza secca.
Operating costs (€ ha-1) Operation CT NT Residue chopping 39 - Plowing (30 cm depth) 123 - Harrowing (No. 2) 83 - Pre-sowing weeding 36 36 Pre-sowing fertilization 25 25 Sowing 46 108 Post-emergence weeding 36 36 Irrigation (No. 2) 240 240 Fertilization + Cultivation (only CT) 42 25 Pest treatment (insecticide) 42 42
Harvesting 138 138 Total 850 650 Balance -200 Agronomic inputs (€ ha-1) CT NT Fertilizers (urea) 85 85 Pre-sowing herbicides 12 12 Seed 210 210
Bait against slugs - 30 Post-emergence herbicides 78 78 Insecticides 70 70 Total 455 485 Balance +30 Crop yields (Mg ha-1) CT NT
Grain dry yield 13.1 12.7 Total dry yield 25.2 25.0
3
NET INCOME
Gross saleable production, obtained multiplying yield by average market price (2014), was used to calculate net income by deducing costs. Net income generated by NT system was 100 € higher than CT one (Table 4).
Tab. 4: Determination of gross saleable product and net income. Tab. 4: Calcolo della produzione lorda vendibile e del reddito netto.
FUEL CONSUMPTION
Considering other environmental benefits, fuel consumption was calculated for each agricultural operation and, as shown in
Table 5, NT system saved 136 liters of diesel fuel per hectare, which corresponds about to 360 kg ha-1 of CO
2 emissions
(EIA, 2016).
Tab. 5: Fuel consumption for agronomic intervention.
Tab. 5: Consumo di carburante per ogni operazione colturale.
SOIL FERTILITY
Some soil fertility indicators that were monitored for both tillage systems during the period 2011-2014 are shown in Table 6). A comparison between values observed at the beginning of the conversion to NT system (2011) and at the end of 2014 is presented for soil organic matter (SOM), total nitrogen (Nk), C/N ratio, and water aggregate stability (WAS).
Tab. 6: Soil fertility parameters at the beginning of the NT conversion and at the end of the third year.
Tab. 6: Parametri di fertilità del suolo all’inizio della conversione a no-till e alla fine del terzo anno.
After three years of the comparison trial it was observed a little, statistically not significant, decrease in SOM content in CT plots, while no change was observed in NT plots. Soil N was declined in CT plots, and raised in NT ones, again without statistical significance. Furthermore, an opposite dynamic was observed for C/N ratio, but with no statistical relevance. As regarding water aggregate stability, obtained according to the Malquori-Cecconi method, in CT plots was noticed a slight
Cropping system Yield (Mg ha-1) Market price (€ Mg-1) Gross saleable product (€ ha-1) Costs (€ ha-1) Net income (€ ha-1) CT 13.1 175 2,292.50 1,305.00 987.50 NT 12.7 175 2,222.50 1,135.00 1,087.50 D NT – CT -0.4 - -70,00 - 170.00 +100.00 Fuel consumption (L ha-1) Operation CT NT Residue chopping 23 - Plowing 55 - Harrowing (n° 2) 60 - Pre sowing weeding 13 13 Pre sowing fertilization 15 15
Sowing 13 30
Post emergence weeding 13 13 Irrigation (n° 2) 80 80 Fertilization + Cultivation (only CT) 30 15 Pest treatment (insecticide) 13 13
Harvesting 38 38 Total 353 217 Balance -136 Soil parameters (0-30 cm) CT 2011 2014 Significance SOM (g kg-1) 23 21 n. s. Total N (g kg-1) 1.3 1.0 n. s. C/N 10 11 n. s.
Water aggregate stability (%) 27 36 n. s.
NT 2011 2014 Significance
SOM (g kg-1) 23 23 n. s. Total N (g kg-1) 1.1 1.3 n. s.
C/N 11 10 n. s.
increase, statistically not significant. On the contrary, in NT plots, WAS was significantly doubled, from 24 to 50%, (Tukey test, α = 0.05).
Conclusions
The objective of this study was to evaluate positive effect of adopting conservation agriculture principles in conventional agroecosystems, comparing costs and revenues of CT and NT systems on maize, and considering CO2 emissions and soil
fertility effects.
Regarding operating costs, NT system allowed a reduction of 200 € per hectare compared with CT system; while the expense for the purchase of agronomic inputs was 30 € per hectare higher in NT than CT.
Considering maize yield, net income was obtained by deducing costs from gross saleable production; in NT net income was 100 € higher than in CT, without considering the premium payment by the EU Rural Development Policy for NT adoption. In addition, NT management has spared 360 kg ha-1 of CO2 emissions and has favored the stabilization of organic matter
and the improvement of nitrogen and aggregate stability in soil.
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