Yield stability and carbon sequestration of agricultural systems are impacted by nutrient management strategies. Major objectives of this study were to understand the effects of long-term (43 years) manure application on a) environmental parameters such as soil organic carbon (SOC) sequestration, enzyme activities in surface and subsurface layers, and b) yield, and yield stability under a soybean-wheat cropping system in a Vertisol. For this, 100% recommended dose of nitrogen (N), N and phosphorus (NP), N, P and potassium (NPK), NPK + farmyard manure (NPKM) was compared with an unfertilized control (UC) and a fallow land. After 43 years, NPKM and NPK plots had ∼63 and 30% higher total SOC stock than UC, and 45 and 17% higher total SOC stock than fallow plots, respectively in the 0-30 cm layer. Acid hydrolysable C was ~ 42 and 57% higher for NPKM plots in those layers respectively than fallow land. The proportion of macroaggregates was less than 30% in both soil layers of cultivated plots. NPKM had 44 and 28% greater humic and fulvic acidassociated C than fallow land in top layer. Enzyme activities improved in NPKM by ~ 60 and 61% as compared with fallow land. A steady decline in soybean productivity over the years might be due to residue effect. However, wheat yield increased steadily with manuring. Higher SOC accumulation (p < .001), greater enzyme activities (p < .05), improved structure (p < .05) could enhance wheat yield under NPKM. Thus, manure application could lead to yield stability and enhance SOC sequestration in subtropical region simultaneously.

No abstract

No abstract

Olive mill wastewater (OMW) is generated seasonally a large amount during the olive oil production in southern Tunisia and it is often discharged in the open environment. OMW has a high amount of phototoxic compounds, high salinity and acidity and therefore is challenging when disposed on soil. However, in southern Tunisia, the condition climatic is arid and semis-arid region. The soil sandy is in degradation and erosion processes. New strategies have been developed to reduce these impacts in soil and to valorize a waste product as olive mill wastewater (OMW) loaded with minerals and organic matters as fertilizer in agronomy. The major aim of this study was to investigate the effects of OMW spraying onto on soil biochemical properties and Faba bean crop productivity was investigated. The result showed that the irrigation of sandy soils by different OMW doses strongly influenced their chemical and microbiological characteristics. Indeed, spreading amounts from 15 m 3 /ha to 45 m 3 /ha for three consecutive years induced a considerable improvement of soil fertility. The pH and soil phosphorus content remain stable during the three years of study, while the soil salinity was increased for the 45 m 3 /ha treatment where it exceeded to 6 dS/m. In conclusions, the dose 15 m 3 /ha is suitable for the vegetative development of the Faba bean tested plant according to the soil characteristics evolution.

No abstract