Soil Nutrient Balance and Stock on Smallholder Farms at Agew Mariam Watershed in Northern Ethiopia

IntroductionSoil nutrient balance is used to evaluate the state of soil fertility, rate of nutrient depletion, sustainability of land productivity, the environmental wellbeing of an area, and to take appropriate management decisions. This study was conducted to quantify soil nutrient balance and stocks on smallholder farms at the Agew Mariam watershed in northern Ethiopia in the 2020/21 main season.MethodsInflows and outflows of nitrogen (N), phosphorus (P), and potassium (K) into, and out of barley, tef, and wheat farms were determined through, field measurement, laboratory analysis, and interviews. The balance quantification was done by subtracting nutrient outputs from the inputs. ResultsThe N partial balance of barley, tef and wheat was -66, -9.8, and -50.7 kg ha-1 yr-1 respectively. The P balance was also -5.9, 0.9, and -2.6 kg ha-1 yr-1 for barley, tef, and wheat respectively. Whereas, K balance was -12.3, -3.2, and -5.4 kg ha-1 yr-1 from barley, tef, and wheat respectively. The balance results revealed that N, P, and K had negative values except for P in tef. Grain yield and crop residue removal were the major paths of nutrient loss. The stock of N was 1295, 1510, and 1240 from barley, tef, and wheat kg ha-1respectively. While, the P stock was 63, 18.7, and 27.5, kg ha-1 from barley, tef, and wheat farms respectively. Similarly, K stock was 1092.7, 1059.4, and 1090.6 kg ha-1 from barley, tef, and wheat cropping systems respectively. ConclusionsReversing the imbalance between inflows and outflows via adding organic and inorganic fertilizers is critically essential for the study area.

Gastrointestinal Residue Removal Using a Balloon Overtube under Ultrathin Endoscopic Navigation: Ex Vivo and In Vivo Experimental Studies

Pooled gastric residues involving blood clots and food interrupt appropriate endoscopic intervention, leading to poor outcomes in endoscopic hemostasis and lifesaving. However, procedures and devices that enable the effective removal of gastrointestinal residues remain unsatisfactory. This study aimed to evaluate the efficacy and safety of our developed suction method in ex vivo and in vivo studies. We created a hand-made device with a large suction diameter, consisting of a balloon overtube and an ultrathin endoscope for navigation. In the ex vivo study, we compared the success rate and the suctioning time for four types of simulated residue between a standard endoscope and our device. Our device had s significantly higher suction ability and a shorter procedure time than the standard endoscope. The subsequent in vivo animal study involved five beagle dogs that were administered with food jelly to mimic gastric residue. Suction was performed twice for five dogs (ten attempts). The outcome measure was the successful procedure rate; secondary outcomes were procedure-associated complications and procedure time. The procedure was successful in all attempts, without any complications. The mean procedure time was 5 min. This novel method enabled the efficient and safe removal of gastric residue, and our findings will likely lead to the development of the instrument.

Eucalyptus globulus Coppices in Portugal: Influence of Site and Percentage of Residues Collected for Energy

Studies that quantify forest bioenergy potentials hardly address the questions of site quality, proportion and type of residues removed from the stands, and environmental impacts of those removals. However, those factors are important for energy-potential results and forest sustainability. This study compares, in terms of residual biomass availability for energy production and of sustainability, different locations, site indices, and forest management strategies in Eucalyptus globulus stands for pulp and paper in northern and central Portugal. A growth and production simulator was used to calculate the availability of residues and the area needed to supply a biomass-fired power plant under a variety of scenarios. Regions with more rainfall generate more residues, but site index and quantity and type of residues harvested are the most important factors. Under the different scenarios analyzed, the amount of residues potentially harvested range from 0.7 to 4.3 Mg ha−1 a−1, the upper bound corresponding to a scenario where stumps are valorized. The maximization of residue removal maximizes the bioenergy produced but has to be considered prudently. Studies indicate that stump removal has limited effect on Eucalyptus globulus stand productivity, diversity, and system sustainability, but impacts of residue removals increase with a decrease in site index.

The Crop Residue Removal Threshold Ensures Sustainable Agriculture in the Purple Soil Region of Sichuan, China

Sichuan, a hilly area in southwestern China, is recommended as a bioethanol production base because of its abundant crop residue resources. However, removing the crop straw for bioethanol may negatively affect soil fertility and productivity due to the local purple soil vulnerability. To explore the impact of crop residue removal on soil fertility and productivity and meet the needs of sustainable agriculture, we conducted a crop residue removal experiment by measuring the soil organic carbon (SOC), total nitrogen (TN), and total phosphorus (TP) contents, and crop yield in the purple soil region in southwest China. Soil erosion was also simulated by Revised Universal Soil Loss Equation version 2 (RUSLE 2). The results showed that soil erosion increased with the increase of the straw removal rate. Compared with 0% removal treatment, the SOC content reduced at other removal rate treatments, especially for long-term residue removal. The effect of residue removal on soil TN and TP was not consistent within one year. After two years, residue removal greater than 25% caused a decrease in TN by 1.6–3.7%, and straw removal greater than 50% caused a TP decrease by 8.5–9.3%. More than 25% of the residue removed reduced maize and canola yields, and TN and TP content. However, all crop residue removal treatments resulted in SOC content reduction and soil erosion deterioration. In conclusion, crop residue removal was not recommended due to agricultural sustainability in Sichuan, China.

Impact of Tillage and Crop Residue Management on the Weed Community and Wheat Yield in a Wheat–Maize Double Cropping System

Weeds are often harmful to crop growth due to the competition for space and resources. A field experiment containing four treatments with three replications in a complete randomized design was conducted at Yucheng Comprehensive Experiment Station, Chinese Academy of Sciences since 2008 to assess the impact of shifting from conventional tillage to no-till with crop residue management on weeds and wheat production at the North China Plain. We found that both aboveground weed density and species richness were higher under continuous no-till (NT) than conventional tillage (CT) in the regrowth and stem elongation stage of wheat growth. On the other hand, aboveground weed density in the stage of flowering and filling decreased with crop residue mulching. The density of the soil seed bank in crop residue removal treatments was significantly higher than that of crop residue retention. Besides, either crop residue mulching or incorporating into the soil significantly increased the wheat yield compared with crop residue removal regardless of tillage management. In conclusion, crop residue retention could decrease the weed density and species richness both aboveground and in the soil seed bank and inhibit the growth of broadleaf weeds by the residue layer. Moreover, crop residue retention could improve the wheat yield.

Economics of forest biomass for bioenergy: potential site preparation savings from coarse woody harvesting residue removal in a short-rotation Eucalyptus globulus (Labill.) plantation

The study used time studies and cost analysis to assess potential economic benefits from site preparation cost reductions resulting from producing coarse woody harvesting residue (CWHR) for bioenergy. In contrast, previous studies have predominantly used anecdotal estimates of site preparation costs.The study was performed in a recently clearfelled 15-year-old plantation of Eucalyptus globulus (Labill) in Tasmania, Australia. The study area consisted of the control area (0.51 ha), containing ~35 m3 ha-1 of CWHR and the CWHR harvest area (2.47 ha), containing &le;12 m3 ha-1 of CWHR. The control area had been harvested with a harvester &ndash; forwarder system, which left all harvesting residue (HR) onsite, where-as the CWHR harvest area had been harvested with a feller-buncher &ndash; skidder &ndash; processor system which removed most of the HR. The latter site was used to simulate an area where CWHR had been harvested. The study examined productivities and costs of machines performing site preparation in each area. The preparation of the control area site was performed with an excavator that windrowed CWHR, fol-lowed by a skidder-mounted plough constructing planting furrows. Residual CWHR post-windrowing was <1 m3 ha-1. Productivities and costs were 0.53 ha PMH0-1 and AUD$319 ha-1 for the excavator and 1.1 ha PMH0-1 and AUD$139 PMH0-1 for the skidder-mounted plough. The excavator was not required in the CWHR harvest area. In this area, skidder-mounted plough productivity and cost were 1.16 ha PMH0-1 and AUD$109 ha-1 suggesting CWHR reduction to &le;12 m3 ha-1 could reduce site preparation costs by AUD$319 ha-1. Further studies on costs and revenues associated with CWHR removal and sale are required to determine net economic benefits and determine excavator cost and productivity for a range of CWHR quantities.