Low Nitrogen Levels Research Articles

Maize-soybean intercrop silage yield and quality with different nitrogen levels and plant population

This study hypothesizes that maize-soybean intercrop with lower maize plant population and nitrogen levels can allow better soybean development and yield, which may offset lower maize biomass and silage crude protein yield. Experiment was carried out in a randomized complete block design arranged in a 2 x 5 factorial scheme, with three replications. Treatments consisted of two different maize-soybean plant stand (40,000 and 60,000 plants ha-1) and five nitrogen fertilization levels (0, 50, 100, 150, and 200 kg ha-1). As a result, soybean biomass yield increased at the lower maize plant stand, although, maize and total (maize + soybean) biomass yield were higher at the greater maize plant stand. Thus, individual maize plants and total dry matter yield increased as nitrogen levels were increased. However, there was no effect of the studied factors on the silage crude protein yield per area, indicating a great potential of soybean to offset biomass yield reduction trough silage quality improvement. Moreover, since there was no difference on total silage crude protein yield per hectare, it is suggested that the adoption of maize-soybean intercrop with lower maize plant stand (40 thousand maize plants ha-1) and with lower nitrogen values is a more environmentally friendly approach to increase farmland sustainability while decreasing environmental and productivity costs. Intermediate levels may be evaluated in future studies

Exosome-based delivery of super-repressor IκBα ameliorates kidney ischemia-reperfusion injury

Ischemia-reperfusion injury is a major cause of acute kidney injury. Recent studies on the pathophysiology of ischemia-reperfusion-induced acute kidney injury showed that immunologic responses significantly affect kidney ischemia-reperfusion injury and repair. Nuclear factor (NF)-ĸB signaling, which controls cytokine production and cell survival, is significantly involved in ischemia-reperfusion-induced acute kidney injury, and its inhibition can ameliorate ischemic acute kidney injury. Using EXPLOR, a novel, optogenetically engineered exosome technology, we successfully delivered the exosomal super-repressor inhibitor of NF-ĸB (Exo-srIĸB) into B6 wild type mice before/after kidney ischemia-reperfusion surgery, and compared outcomes with those of a control exosome (Exo-Naïve)-injected group. Exo-srIĸB treatment resulted in lower levels of serum blood urea nitrogen, creatinine, and neutrophil gelatinase-associated lipocalin in post-ischemic mice than in the Exo-Naïve treatment group. Systemic delivery of Exo-srIĸB decreased NF-ĸB activity in post-ischemic kidneys and reduced apoptosis. Post-ischemic kidneys showed decreased gene expression of pro-inflammatory cytokines and adhesion molecules with Exo-srIĸB treatment as compared with the control. Intravital imaging confirmed the uptake of exosomes in neutrophils and macrophages. Exo-srIĸB treatment also significantly affected post-ischemic kidney immune cell populations, lowering neutrophil, monocyte/macrophage, and T cell frequencies than those in the control. Thus, modulation of NF-ĸB signaling through exosomal delivery can be used as a novel therapeutic method for ischemia-reperfusion-induced acute kidney injury.

Effects of low temperature and nitrogen addition during cold stratification on seed germination of Korean pine (Pinus koraiensis)

Pinus koraiensis Siebold & Zucc. seeds are primarily dormant following dispersal, restricting the natural regeneration of populations. The aim of this study was to determine the combined effects of increasing low temperature and nitrogen addition during cold stratification on seed germination. We stratified the seeds at 0 °C, 5 °C, and 10 °C for 3.5 months. At each cold stratification temperature, seeds were subjected to 0 (0 nitrogen), 0.08 (low nitrogen), 0.16 (medium nitrogen), and 0.25 mol·L–1 (high nitrogen) nitrate additions. Seed germination response was tested at 25/15 °C and 10/5 °C. Under 0 nitrogen and high nitrogen levels, increasing cold stratification temperature did not markedly affect seed germination at 25/15 °C, but significantly inhibited seed germination at 10/5 °C. At medium nitrogen levels, seed germination at both 25/15 °C and 10/5 °C significantly decreased. At low nitrogen levels, increasing cold stratification temperature significantly decreased germination percentage at 25/15 °C from 86.7% (0 °C) to 50.2% (10 °C) but did not markedly change seed germination percentage at 10/5 °C. We suggest that the effect of increasing cold stratification temperature on seed germination of P. koraiensis depends on both the level of nitrogen addition during cold stratification and subsequent incubation temperature after cold stratification.

Wood vinegar and chitosan compound preservative affects on fish balls stability

The application of compound preservative of biological source of the two materials wood vinegar and chitosan increased the stability of food products. The application of chitosan in the food industry is limited by its insolubility. Like chitosan degradation products, the chitosan oligosaccharide (COS) in no high pH has high solubility. The aim of this study was to evaluate the combined effect of wood vinegar (WV) and COS on the quality of rainbow trout fish balls under vacuum storage. The fish balls with different amounts of WV and COS were vacuum packed. In the control group, no preservative was added and distilled water was used instead. The control group had higher aerobic plate count compared to treatment groups during 15 days storage (p < 0.05). All the treatment groups were kept at a lower level of total volatile basic nitrogen compared with the control group (p ≥ 0.05). The lightness of each treatment group was non-significantly lower than that of the control group, but the decreasing range was not obvious (p≥>0.05), and difficult to distinguish visually. The percentage of free water in all treatment groups (0–6 days) was significantly lower than that in the control group (p < 0.05). The pH value of the treatment group was lower than that of the control group (p < 0.05) from 9 to 15 days. The hardness, chewability and resilience of the treatment groups showed a downward trend with increasing storage time. The elasticity was unchanged. After 15 days storage, the gel strengths of all treatment groups were higher than that of the control group (p < 0.05).

Submerged Rootless Macrophytes Sustain a Stable State Against Free-Floating Plants

Both non-rooted submerged vegetation dominated by coontail (Ceratophyllum demersum) and non-rooted floating duckweed vegetation (Lemna gibba) can maintain their stable dominance in small ponds and channels. We examined the competitive interactions between them and how Ceratophyllum can sustain its stable state against floating plants in a range of nutrient concentrations. Coontail and duckweed were co-cultured in static and semi-static microcosm experiments, and their impact on the nutrients (N, P, Fe, Mn) in the water column was analysed. Coontail strongly reduced the growth of duckweed under a low nitrogen level (0.2–2 mg N L−1). This reduction seems to be due to the low availability of nutrients in the water as derived from the lower nutrient concentrations in duckweed tissue or high pH in water. High nitrogen levels in semi-static media (5–10 mg N L−1) resulted in an increasingly higher chance to overgrow C. demersum by L. gibba. Field observations revealed that C. demersum dominated over L. gibba in water bodies with total N below 3 mg L−1, while L. gibba dominance over C. demersum occurred above 5 mg L−1 total N. Ceratophyllum occurrence correlated negatively with total N in the water, while Lemna showed a positive correlation. Furthermore, the occurrence of L. gibba was negatively correlated with the frequency of C. demersum. All findings together support the theory that under a certain nutrient range, rootless submerged macrophytes have a strong potential to inhibit the dominance of floating plants in ponds, ditches and channels, and thus, they stabilize the submerged vegetation state.

Optimization of Texture-Modified Yellowfin Sole (Pleuronectes aspera) by Enzymatic Treatment and Superheated Steam Treating to Improve Quality Characteristics

This study aimed to optimize the texture modification process of yellowfin sole (Pleuronectes aspera) to improve its quality characteristics for easier consumption by the elderly. Yellowfin sole was immersed in enzyme solution (Protamex:Neutrase = 1:2), marinated in herbal extract solution, and roasted by superheated steam. The product was evaluated for microbial, physicochemical, and sensory properties, as well as shelf life. Specifically, the optimal enzymatic treatment comprised a protease concentration of 1.00% (w/v) with an immersion time of 3.16 h. The optimal marination herb was determined to be bay leaves, as indicated by highest overall acceptance. The texture modification process led to lower hardness and higher overall acceptance values (76.23 kN/m2 and 8.38, respectively) compared with nonenzyme processed product (120.43 kN/m2, 7.43), also retaining high nutritional value and low trimethylamine levels. Shelf-life analysis indicated microbial activity was inhibited (not detected), low levels of total volatile basic nitrogen (10.50 mg%), low levels of thiobarbituric acid reactive substances (0.12 mg MDA/kg), and stable pH values (6.5–7.0). Overall, the texture-modified yellowfin sole possessed a soft flesh texture suitable for consumption by the elderly, with acceptable microbial, physicochemical, and sensory qualities.

High-Pressure Processing for the Production of Added-Value Claw Meat from Edible Crab (Cancer pagurus).

High-pressure processing (HPP) in a large-scale industrial unit was explored as a means for producing added-value claw meat products from edible crab (Cancer pagurus). Quality attributes were comparatively evaluated on the meat extracted from pressurized (300 MPa/2 min, 300 MPa/4 min, 500 MPa/2 min) or cooked (92 °C/15 min) chelipeds (i.e., the limb bearing the claw), before and after a thermal in-pack pasteurization (F9010 = 10). Satisfactory meat detachment from the shell was achieved due to HPP-induced cold protein denaturation. Compared to cooked or cooked–pasteurized counterparts, pressurized claws showed significantly higher yield (p < 0.05), which was possibly related to higher intra-myofibrillar water as evidenced by relaxometry data, together with lower volatile nitrogen levels. The polyunsaturated fatty acids content was unaffected, whereas the inactivation of total viable psychrotrophic and mesophilic bacteria increased with treatment pressure and time (1.1–1.9 log10 CFU g−1). Notably, pressurization at 300 MPa for 4 min resulted in meat with no discolorations and, after pasteurization, with high color similarity (ΔE* = 1.2–1.9) to conventionally thermally processed samples. Following further investigations into eating quality and microbiological stability, these HPP conditions could be exploited for producing uncooked ready-to-heat or pasteurized ready-to-eat claw meat products from edible crab.

Biochemistry and Immune Biomarkers Indicate Interacting Effects of Pre- and Postnatal Stressors in Pigs across Sexes.

Simple SummaryThis study evaluated the effects of MIA elicited by porcine reproductive and respiratory syndrome virus and postnatal metabolic or immune stressors on chemical and inflammatory biomarkers in male and female pigs. Our results provide evidence that MIA interacting with postnatal stressors can have a long-lasting effect on the pig physiology, potentially affecting health, growth, and reproductive performance later in life.The effects of maternal immune activation (MIA) elicited by a prenatal stressor and postnatal metabolic or immune stressors on chemical and inflammatory biomarkers were studied in male and female pigs. Pigs exposed to MIA elicited by porcine reproductive and respiratory syndrome virus and matching controls were assigned at two months of age to fasting stress, immune stress, or a saline group. The serum levels of over 30 chemistry and immune analytes were studied. Significantly low levels of blood urea nitrogen were detected in females exposed to MIA, while the highest creatinine levels were identified in fasting females exposed to MIA. The levels of interferon gamma and interleukin 8 were highest in pigs exposed to postnatal immune challenge. The profiles suggest that MIA may sensitize pigs to postnatal stressors for some indicators while making them more tolerant of other stressors. Effectiveness of practices to ameliorate the impact of postnatal stressors on the physiology of the pig could be enhanced by considering the prenatal stress circumstances.

Application of High-Frequency Defrosting, Superheated Steam, and Quick-Freezing Treatments to Improve the Quality of Seafood Home Meal Replacement Products Consisting of the Adductor Muscle of Pen Shells and Common Squid Meat

We developed a new seafood home meal replacement (HMR) product containing the adductor muscle of the pen shell (AMPS) and common squid meat (CSM) via high-frequency defrosting (HFD), superheated steam, and quick freezing. Test HMR products were produced by mixing defrosted and roasted AMPS, CSM, and sauce in ratios of 27.5, 27.5, and 45.0% (w/w), respectively, followed by quick freezing at −35 °C in a polypropylene plastic bowl covered with a plastic film. The chemical characteristics, nutritional quality, microbial and sensory properties, and shelf life of the product were examined. The response surface methodology identified the optimal temperature and heating time of the superheated steam for AMPS (220 °C, 1 min) and CSM (300 °C, 1.5 min). Chemical characteristics showed low levels of volatile basic nitrogen (9.45 mg%) and thiobarbituric acid-reactive substances (1.13 mg Malondialdehyde [MDA]/kg). No significant changes (p &lt; 0.05) were observed in microbial, color, flavor, taste, texture, and overall acceptance at −23 °C for 90 days. After reheating, the sensory scores varied from “like moderately” to “like very much.” The shelf life of the HMR product was estimated to be 24 months. In conclusion, HFD, superheated steam, and quick freezing successfully improved product quality, with little loss of nutrition and texture.

Oxidative Status and Antioxidative Response to Fusarium Attack and Different Nitrogen Levels in Winter Wheat Varieties.

Abiotic and biotic stresses, such as mineral nutrition deficiency (especially nitrogen) and Fusarium attack, pose a global threat with devastating impact on wheat yield and quality losses worldwide. This preliminary study aimed to determine the effect of Fusarium inoculation and two different nitrogen levels on oxidative status and antioxidative response in nine wheat varieties. Level of lipid peroxidation, activities of antioxidant enzymes (catalase, ascorbate peroxidase, glutathione reductase), phenolics, and chloroplast pigments content were measured. In general, wheat variety, nitrogen, and Fusarium treatment had an impact on all tested parameters. The most significant effect had a low nitrogen level itself, which mostly decreased activities of all antioxidant enzymes and reduced the chloroplast pigment content. At low nitrogen level, Fusarium treatment increased activities of some antioxidative enzymes, while in a condition of high nitrogen levels, antioxidative enzyme activities were mostly decreased due to Fusarium treatment. The obtained results provided a better understanding on wheat defense mechanisms against F. culmorum, under different nitrogen treatments and can serve as an additional tool in assessing wheat tolerance to various environmental stress conditions.

Changes in body composition and low blood urea nitrogen level related to an increase in the prevalence of fatty liver over 20years: A cross-sectional study.

Qualitative body composition (BC) change, characterized by the combination of visceral fat gain and muscle loss, is drawing attention as a risk factor for fatty liver (FL). The present study aimed to describe trends in BC change and its association with FL in the Japanese population. Data from medical checkups carried out on 56639 Japanese participants every 5years from 1997 to 2017 were analyzed. Fat mass index (FMI) and fat-free mass index (FFMI) were calculated using body mass index and body fat percentage. Subjects were divided into two groups according to deviations from the correlation line of FMI and FFMI as the reference: FMI-predominant BC and FFM-dominant BC. Fatty liver was determined using abdominal ultrasonography. The prevalence of FL significantly increased from 27.3% to 42.7% in men and from 18.0% to 25.5% in women. The prevalence of FMI predominance significantly increased from 33.6% to 43.9% in men and from 29.1% to 47.0% in women. Fat mass index predominance was independently associated with FL in men and women (odds ratio: 1.96 and 1.94, respectively). Serum blood urea nitrogen level was inversely associated with FL in men and women (0.958 and 0.961, respectively) and significantly decreased from 15.8 to 14.9mg/dl in men and from 15.1 to 14.0mg/dl in women. Increasing FMI-predominant BC and decreasing serum blood urea nitrogen level could account for the increase in the prevalence of FL over 20years. We believe that these factors stem from current lifestyle habits in Japan.

Chronic, low-level nitrogen deposition enhances abundances of ant-protected herbivores inhabiting an imperiled foundation species

Atmospheric nitrogen (N) deposition is driving changes in plant assemblages worldwide, but animal responses are not well understood, especially in relation to current widespread rates of low-level N deposition. Big sagebrush (Artemisia tridentata) is a foundation species in steppe ecosystems of western North America, where elevated, but low-level N deposition is prevalent. Sagebrush hosts numerous herbivorous and predatory arthropods, some of which form mutualistic (i.e. mutually beneficial) herbivore-predator associations that may be harmful for sagebrush. Here, I evaluated the response of a sagebrush arthropod assemblage to four and nine years of low-level N enrichment in Colorado, USA. Though sagebrush cover and arthropod abundances were not different in the fourth year, by the ninth year, N additions increased arthropod abundances due to greater numbers of sap-feeding insects that are mutualist partners of predaceous ants. Ant and non-mutualist herbivore abundances did not significantly respond to N treatments in the ninth year, but non-mutualist predators were only found in ambient N plots, suggesting ants provided greater anti-predator protection for mutualist herbivores under N enrichment. These responses occurred during drought conditions, which may have increased sagebrush nutritional quality for sap-feeding insects. Sagebrush is experiencing multiple stressors that are transforming steppe ecosystems; these results suggest chronic exposure to common rates of low-level N deposition may create further stress as herbivorous insects proliferate. Additional work is needed to understand and manage the repercussions of N deposition for plant-animal assemblages, particularly in contexts including species of conservation concern and both mutualistic and antagonistic species interactions.

Risk factors for peritoneal dialysis withdrawal due to peritoneal dialysis-related peritonitis

BackgroundPeritoneal dialysis has become commonly used for renal replacement therapy; however, some patients withdraw from peritoneal dialysis due to complications, including peritoneal dialysis-related peritonitis, resulting in the low number of patients on peritoneal dialysis. Risk factors for peritoneal dialysis withdrawal due to peritoneal dialysis-related peritonitis are less certain. This retrospective study aimed to investigate these risk factors. MethodsWe retrospectively analyzed clinical characteristics, laboratory data, and causative microorganisms of 204 episodes of peritoneal dialysis-related peritonitis between 2007 and 2018 at our institution. ResultsOf the 204 episodes, 38 resulted in withdrawal from peritoneal dialysis due to peritoneal dialysis-related peritonitis. The number of peritonitis episodes per patient-year and the incidence of cardiovascular disease were significantly higher in the withdrawal group. Similarly, this group had low levels of serum creatinine, urea nitrogen, serum albumin, alanine aminotransferase, cholinesterase and high C-reactive protein, and second dialysate cell counts after antibiotic administration. Multivariate logistic regression analysis revealed that serum albumin (odds ratio: 0.465; 95% confidence interval: 0.249–0.868; P=0.016) and cardiovascular disease (odds ratio: 2.508; 95% confidence interval: 1.184–5.315; P=0.016) exhibited significant differences. ConclusionsThe results of this study suggest that hypoalbuminemia and the presence of cardiovascular disease were independent risk factors for withdrawal from peritoneal dialysis due to peritoneal dialysis-related peritonitis.

Intercropping desmodium and maize improves nitrogen and phosphorus availability and performance of maize in Kenya

Abstract Low levels of nitrogen (N) and phosphorus (P) in soils in sub-Saharan Africa (SSA) limit maize (Zea mays) production in smallholder farms. We tested the hypothesis that desmodium (Desmodium intortum (Mill.) Urb.), a fodder legume, and food legumes commonly grown with maize in Western Kenya avail N and P and improve the performance of maize in intercrops. We measured available N and P in 15 cm topsoil at 4, 8 and 12 weeks after planting (WAP), and corresponding maize shoot weight in three seasons: 2017 long rains (LR), 2017 short rains (SR), and 2018 LR at Thomas Odhiambo Campus of icipe at Mbita Point in western Kenya. Treatments were additive 1:1 maize-legume intercrops; maize-bean (Phaseolus vulgaris L.), maize-cowpea (Vigna unguiculata (L.) Walp.), maize-crotalaria (Crotalaria ochroleuca G. Don), maize-desmodium, maize-green gram [Vigna radiata (L.) Wilczek] and maize-groundnut (Arachis hypogaea L.), and maize monocrop as a control, replicated four times in a complete randomized design. This experiment was established in 2003 and treatments were repeated every season on the same plot (for 31 seasons up to 2018 LR). At the beginning (year 2003), experimental plots were infested with 100 g of striga seeds per 250 g soil. Across the three last seasons corresponding to this study, we observed an increase in available N in maize-desmodium plots compared to maize monocrop plots. Available P measured at 4, 8 and 12 WAP in 2017 SR and at 4 WAP in 2018 LR was higher in maize-desmodium than in maize monocrop at the same sampling times (P

Genomic basis of geographical adaptation to soil nitrogen in rice.

The intensive application of inorganic nitrogen underlies marked increases in crop production, but imposes detrimental effects on ecosystems1,2: it is therefore crucial for future sustainable agriculture to improve the nitrogen-use efficiency of crop plants. Here we report the genetic basis of nitrogen-use efficiency associated with adaptation to local soils in rice (Oryza sativa L.). Using a panel of diverse rice germplasm collected from different ecogeographical regions, we performed a genome-wide association study on the tillering response to nitrogen-the trait that is most closely correlated with nitrogen-use efficiency in rice-and identified OsTCP19 as a modulator of this tillering response through its transcriptional response to nitrogen and its targeting to the tiller-promoting gene DWARF AND LOW-TILLERING (DLT)3,4. A 29-bp insertion and/or deletion in the OsTCP19 promoter confers a differential transcriptional response and variation in the tillering response to nitrogen among rice varieties. The allele of OsTCP19 associated with a high tillering response to nitrogen is prevalent in wild rice populations, but has largely been lost in modern cultivars: this loss correlates with increased local soil nitrogen content, which suggests that it might have contributed to geographical adaptation in rice. Introgression of the allele associated with a high tillering response into modern rice cultivars boosts grain yield and nitrogen-use efficiency under low or moderate levels of nitrogen, which demonstrates substantial potential for rice breeding and the amelioration of negative environment effects by reducing the application of nitrogen to crops.

Potential of Bioenergy in Rural Ghana

Crop residues are common in rural Ghana due to the predominant role agriculture plays in livelihood activities in these communities. In this paper we investigate the prospects of exploiting agricultural crop residues for rural development in Ghana through bioenergy schemes. A theoretical energy potential of 623.84 PJ per year, which is equivalent to 19,781 MW was estimated using crop production data from the Food and Agricultural Organization of the United Nations and residue-to-product ratios. Ghana has a total installed generation capacity of 4577 MW which is four times less the energy potential of crop residues in the country. Cocoa pod husks were identified as important biomass resources for energy generation as they are currently wasted. To further assess the energy potential of cocoa pod husks, different cocoa pod husks samples were collected across the six cocoa growing regions in Ghana and thermo-chemically characterised using proximate and ultimate analysis. The low levels of nitrogen and sulphur observed, together with the high heating value, suggest that cocoa pod husks and for that matter crop residues are eco-friendly feedstock that can be used to power rural communities in Ghana.

The mechanisms underlying melatonin improved soybean seedling growth at different nitrogen levels

To investigate the function of melatonin (MT) on nitrogen uptake and metabolism in soybean, six groups of treatments, with and without 100μM melatonin were conducted at low, normal, and high nitrogen levels (1.5, 7.5, and 15mM, respectively). The related indexes of nitrogen metabolism and the antioxidant system of seedlings were measured and analysed. Results indicated that MT could enhance the level of nitrogen metabolism by upregulating the coding genes of enzymes related to nitrogen metabolism and increasing total nitrogen content, especially under low nitrogen levels. Under high nitrogen conditions, the addition of MT not only accelerated ammonium assimilation and utilisation by enhancing the activity of glutamine synthetase involved in ammonium assimilation, but also reduced the extent of membrane lipid peroxidation to alleviate the degree of damage by improving the activity of antioxidant enzymes. In addition, MT enhanced soybean growth with positive effects in morphological changes at different nitrogen levels, including significantly increased stem diameter, total leaf area, and root nodule number, and biomass accumulation. Finally, biomass accumulation increased under low, normal, and high nitrogen levels by 9.80%, 14.06%, and 11.44%, respectively. The results suggested that MT could enhance the soybean tolerance to low and excessive N treatments.

Low-Level Nitrogen and Short-Term Addition Increase Soil Carbon Sequestration in Chinese Forest Ecosystems

Low-Level Nitrogen and Short-Term Addition Increase Soil Carbon Sequestration in Chinese Forest Ecosystems

Effect of Integrated Use of Coffee Husk Compost and NPS Fertilizer on Soil Physicochemical Properties and Yield of Coffee (&amp;lt;i&amp;gt;Coffea arabica L&amp;lt;/i&amp;gt;.) at Haru, Ethiopia

Integrated application of inorganic and organic fertilizers is the main sources for replenishing plant nutrients in agricultural soils. However, selecting the optimum combination of these resources based on soil type and crop species is necessary. In this context, field experiment was conducted at Haru research center to assess the effect of coffee husk Compost and NPS Fertilizer on soil physicochemical properties and Yield of coffee in 2018/2019. The treatments were the different rates of both compost and NPS fertilizers laid out in randomized complete block design. The results of the study showed that combined application of coffee husk compost and NPS fertilizers were improved soil moisture and total porosity over control, while, bulk density was decreased below the control. Combined application of coffee husk compost at (7.5 t ha^-1) and mineral NPS fertilizer at (50 kg ha^-1) has better improved yield of coffee crop. The experimental yield of Manasibu variety for present study from the station was 1.59 t ha^-1. Therefore, based on the result of the study it can be concluded that under condition of low soil pH of study area the availability of essential nutrients (e.g. P, N, K, Ca, Mg, and Mo) are critically affected. This indicates that the strong acid pH values at Haru Research sub-center require more attention. Moreover, the low levels of CEC, organic carbon, total nitrogen, and available P contents at study area soils confirm that soil fertility is among the constraints for sustainable coffee production in the Haru district. In response to this application of integrated NPS fertilizer and coffee husk compost with different rates improved soil physicochemical properties and coffee yield. The study recommended that the use of 7.5 t ha^-1 coffee husk compost and 50 kg ha^-1 of NPS fertilizer can be the best alternative integrated soil fertility management option in place of the sole application of inorganic fertilizers at study area tentatively. Nevertheless, in order to give conclusive recommendation further research studies are needed for more soil types and coffee crop varieties.

Status of Selected Physicochemical Properties of Soils Under Long Term Sugarcane Cultivation Fields at Wonji-Shoa Sugar Estate

A declining trend in per hectare yield of sugarcane in Wonji-Shoa Sugar Estate is being observed due to altering of soil physicochemical properties resulted from long term sugarcane cultivation. Cognizant of this fact, a study was conducted in 2017at Wonji-Shoa Sugar Estate with the objective of determining the effects of more than 62 years of sugarcane cultivation on the physicochemical properties of soil. In order to achieve this objective disturbed and undisturbed soil samples were collected from 0-30 and 30-60 cm layers of selected cultivated and uncultivated light and heavy soils for laboratory analysis. Results of the study indicated that long term cultivation of sugarcane at the same depth and low soil organic matter content of cultivated fields induced soil compaction and consequently highest bulk density was recorded in subsoil layer of cultivated than uncultivated land. The bulk density and total porosity values were out of ranges recommended for optimum sugarcane cultivation and suggest the existence of some degree of compaction. The finding further showed that the pH of study area soils is out of the normal pH range for sugarcane plant growth. The soil organic carbon, total nitrogen content and available phosphorus concentration of soils under both land uses of all soils was found within low range. Therefore, based on the result of the study it can be concluded that under condition of strong base soil pH of study area the availability of essential nutrients are critically affected. This indicates that the strong pH values at Wonji-Shoa Estate require more attention. Moreover, the low levels of organic carbon, total nitrogen, and available P contents under both cultivated and uncultivated soils indicated that soil fertility is among the constraints for sustainable sugarcane production in the estate. Based on the findings and conclusions of this study one can recommend that to maintain sustainability of sugarcane production in the estate soil management practices that can protect as well as ameliorate soil compaction, increase soil organic carbon, total nitrogen, soil available P and that can decrease soil pH are important. Nevertheless, in order to give conclusive recommendation further research studies are needed for more soil management units in the estate.