Organic fertilizers with low C:N ratios can be applied to supply both macro and micronutrients to the soil. Aside nutrient supply, they can improve soil structure, texture, water holding capacity and nutrient holding capacity. The mechanisms that may interplay to allow organic fertilizers to affect the soil and crop yields may include improved nutrient synchrony, general improvement in fertility and/or priming effects. The rate, timing and method of organic fertilizer application must be considered to reduce N and P losses during organic fertilizer application. To meet the nutrient requirement of crops, organic fertilizers must be applied in large quantities, so it is more prudent to apply locally available resources. In a case study where sole organic fertilizer, sole inorganic fertilizer and their combinations were applied under rain-fed conditions, it was observed that manure had the potential to hold nutrients longer. This is a positive finding for drought prone areas.

Purpose: An 8-week incubation study was conducted to monitor soil inorganic nitrogen (N), dissolved organic carbon (DOC), greenhouse gases (GHG) [CO₂, N₂O and CH₄] and cumulative global warming potential (GWP) in dryland soil.Methods: Soil was amended with variable rates of compost (zero, 15, 30 and 45 dry Mg ha⁻¹) and soil moistures [5% (dry), 7% (normal) and 14% (wet) water filled pore space (WFPS)] and experienced biweekly temperature transitions from 5 °C (late winter) to 10 °C (early spring) to 15 °C (late spring) to 25 °C (early summer).Results: The addition of 30 and 45 Mg ha⁻¹compost enhanced N mineralization with 13% more soil inorganic N (7.49 and 7.72 µg Ng⁻¹ day⁻¹, respectively) during early summer compared with lower compost rates. Normal and wet soils had 35% more DOC in the late spring (an average of 34 µg g⁻¹ day⁻¹) compared to the dry WFPS, but transitioning from late spring to early summer, DOC at all soil WFPS levels increased. Highest rates of compost were not significant sources of GHG with normal soil WFPS, compared with lower compost rates. Carbon dioxide emissions increased by 59 and 15%, respectively, as soil WFPS increased from dry to normal and normal to wet. Soils with normal WFPS were the most effective CH₄sink.Conclusion: One-time application of high compost rates to dryland soils leads to enhanced N and C mineralization under normal soil moisture and warmer temperature of the summer but will not pose significant global warming dangers to the environment through GHG emissions since soils are rarely wet.

Soil loss due to water erosion is a common phenomenon, which affects Kimchi cabbage (KC) productivity in the highland regions of Gangwon State Government. It is important to estimate soil losses in these cropping systems to provide basis for proper soil conservation measures. This research was conducted at the Highland Agriculture Research Institute to evaluate soil losses during KC cultivation and post-harvest in 2, 7 and 15% slope lysimeters in the 2021/2022 and 2022/2023 growing seasons. Cabbage residue was spread on the land post-harvest, after which it decomposed and was succeeded by volunteer grass. Rainfall amounts and intensities, percent soil coverage, soil losses and cover management factors (C factor) were investigated. Soil losses ranged from 0-2.689 tons ha-1 in 2% slope, 0-13.818 tons ha-1 in 7% slope and 0-85.596 tons ha-1 in 15% slope lysimeters in both KC cultivated land and bare land. However, soil losses under KC cultivation were always in minimal sections of the range. The order of importance for the soil loss contributors was as follows: rainfall intensity > rainfall amount > percent soil cover. Reduction in C factors as slope gradients increased (in both years) showed that KC was more efficient at reducing soil losses at steeper slopes. Post-harvest soil loss depended largely on rainfall amounts received, which directly affected the rate of cabbage residue decomposition and the length of time land may be uncovered. It was concluded that growing KC in the highland region conserves soil, however, it is equally important to grow cover crops after KC harvest to keep the soil covered for longer. Cover crops may also replenish soil fertility if tilled back into the soil before the next KC growing season.

A considerable proportion of applied nutrients are adsorbed by the calcite surface of calcareous soils, making them unavailable to plants. A combination of organic amendments and fertilizers can improve nutrient retention and mineralization, and also reduce greenhouse gas (GHG) emissions. A two-years field experiment was undertaken to investigate the impacts of inorganic fertilizer, biochar and silicon on nutrient uptake, growth, yield and post-harvest soil chemistry in calcareous soil using rice (Oryza sativa L.) as a test crop. The implication of each treatment on methane emissions was also investigated. The combination of NPK, biochar and silicon significantly improved rice growth, yield, P and Si uptake; and post-harvest soil nutrition. Biochar increased soil organic carbon content between 4.2 and 108.5% across the years. An increase from 2.4 to 6.1% was observed in the inorganic fertilizer treatments, 11.4–12.0% for the biochar treatments and 2.5–19.0% for ½NPK + biochar from 2020 to 2021. Maximum grain yield was achieved with the treatment ½NPK + biochar + 100 kg Si ha^− 1 which was comparable to NPK + 100 kg Si ha^− 1. Also, the combination of ½NPK + biochar + 50 kg Si reduced CH₄ emissions and produced a comparable yield to NPK + 50 kg Si in both years. While further research is required to explore the effects of the length of time biochar is applied on reducing CH₄ emissions, this study suggests a basis for predicting the impact of biochar on the management of CH₄ emissions in calcareous soils.