Potato (Solonaum tuberosum L.) which belongs to the Solanaceae, family, genus Solanum which also includes tomato eggplant and pepper etc., is one of the most important tuber crops in the world. It is a cool-season crop, most dependable and early maturing root and tuber crop Potato tuber consists of main carbohydrates, proteins, and lipids. The tuber is used locally alone or with meat, and vegetables as substituent with pulse in stew preparation in Sheka Zone, southwestern Ethiopia, the potato is one of the widely grown and major cultivated tuber crops. It is a preferable crop in the study area due to that it can be produced more than twice per year [1].

inadequate agronomic management practices specifically, inadequate and inappropriate application of fertilizers, low nutrient reserves in arable soils, a negative nutrient balance on crop and by potato growers are factors Contributing to the low yield of potato in study areas. Potato is one of the heavy feeders requiring relatively large quantities of fertilizers. However, scarcity use of only chemical fertilizers without supplementing with organic sources due to the high cost of chemical fertilizers and limited availability for the smallholder farmers accompanied with a high amount of rainfall that might have caused leaching of macro- and micro-nutrients significantly reduced soil fertility and crop productivity in the study area.

In addition to the high cost, use of mineral fertilizers constantly lead to decline soil chemical and physical properties, biological activities and thus, overall, the total soil health [2-4]. Due to this, nutrients supplied exclusively through chemical sources, though enhance yield initially, and lead to unsustainable productivity over the years [2,5]. Thus, the undesirable impacts of chemical fertilizers, coupled with their high prices, have prompted the interest in the use of organic fertilizers as a source of nutrients. The combined use of Organic together with mineral fertilizer application has been reported to improve crop growth by supplying plant nutrients including micronutrients as well as improving soil physical, chemical, and biological properties there by provide a better environment for root growth by improving the soil structure [6].

Many research findings have shown that neither mineral fertilizers nor organic sources alone can result in sustainable productivity [5,7]. Furthermore, the price of mineral fertilizers is increasing and becoming unaffordable for resource-poor smallholder farmers. The best remedy for soil fertility management is, therefore, a combination of both mineral and organic fertilizers, where the mineral fertilizer provides readily available nutrients and the organic fertilizer mainly increases soil organic matter and improves soil structure and buffering capacity of the soil [7,8]. The combined application of mineral and organic fertilizers, usually termed as integrated nutrient management, is widely recognized as a way of increasing yield and or improving the productivity of the soil sustainably [2,9]. Several researchers have verified the beneficial effect of integrated nutrient management in moderating the deficiency of several macros- and micro-nutrients. In view of this fact, identifying the optimum dose of integrated nutrients application is crucial and is required for maintaining sufficient amount of nutrients for increased yield of the crop [2,10-12].

Cattle manure is a decayed mixture of the dung and urine of cattle or other livestock with the straw and litter used as bedding and residues from the fodder fed to them. Whatever is collected for manuring is usually heaped on the ground surface with residues from fodder and other house sweepings. The nitrogen in the manure is subject to volatilization and leaching losses and the material that finally will be spread on the field may have low nitrogen content. The application of well-decomposed manure is more desirable than using fresh materials [13,14].

Daniel and Niguse reported high tuber yield of potato was obtained when CM (cattle manure) at the rate of 10 qha^-1 was combined with mineral nitrogen at 111 kg N ha^-1 and phosphorous at 90 kg P₂O₅ ha^-1 on Nitosol, of Bako Ethiopia. Shiferaw, 2014 reported that the highest potato tuber yield was attained by combined Application of 15 t ha^-1 CM with the application of 100% recommended rate NPK (100-100-100 kg ha^-1) and NP (100/100 kg ha^-1) increased tuber yield over control by 567.9 and 393.9%, respectively as compared to the application of organic or mineral fertilizers in isolation.

Biruk stated that application of 30 t ha^-1 cattle manure along with nitrogen at 120 kg N ha^-1 and phosphorous at 92 kg P₂O₅ ha^-1 gave yield advantage of 8.4 t ha^-1 in North-Eastern Ethiopia. However, research on integrated nutrient management for potato production has not been yet conducted at Masha district Sheka Zone, southwestern Ethiopia. Thus, this study was conducted to determine the effect of combined application of CM with mineral NP fertilizers on the growth, yield components, yield of potato and physico-chemical characteristics of the soil, and to determine appropriate rates of combined CM with mineral NP fertilizers for better productivity of the potato [15-18].

Description of the study site

The experiment was conducted at the abelo area in Masha district of Sheka Zone, southwestern Ethiopia, in 2016 main cropping season from July to November. The study site of Masha district located at UTM WGCs 1984 Zone 36 N between 861,000 MN-873,000 MN latitude. Longitude Attitudinally 1642 to 2025 [19].

The rainfall pattern of these areas is characterized by monomodal distribution with small rainy season in Belg (February -May) and main rainy season’s Meher (June October) [19,20].

Experimental materials

A potato variety called ‘Belete’ was used as a test crop. The variety was released in 2009 by Holeta Agricultural Research Center, Ethiopia, for its high yield and promising agronomic performances. The variety matures in 90-120 days. The yield ranges from 29.13 t ha^-1 under farmers 44.8 t ha^-1 under research Source [21].

Potato variety Belete, obtained from Holleta Agricultural Research Center, was used for the experiment. Belete is one of the potential potato cultivars for south-west highlands such as Masha woreda and it has the following characteristics (Table 1).

Table 1: Some characteristics of potato variety Belte. Source: EARO (Ethiopian Agricultural Research Organization), 2009.

Urea (46% N) and TSP (46% P₂O₅) were used as mineral N and P sources whereas Cattle manure was used as an organic fertilizer. Cattle manure was collected from those farmers trained and supervised by the teppi soil testing research Centre under the financial aid of sustainable land management (SLM) project in Masha distinct Sheka Zone; Urea and TSP were collected from Teppi Soil Testing Research Center.

Treatments and experimental design

The treatments consisted of combinations of three rates of CM (2.5, 5, 7 t ha^-1) and with three rates (25%, 50%, and 75%) of recommended mineral NP fertilizers. In addition, 100% recommended rate of mineral NP fertilizer (165 kg N ha^-1 and 60 kg P₂O₅ ha^-1) and zero rates were used for comparison. Thus, there were 11 treatments. The experiment was laid out in a randomized complete block design with three replications.

Each block and plots within a block were spaced 1 m and 0.5 m apart, respectively. Each plot had 12 rows of 75 cm apart each with 3.6 m length. The gross plot size was, therefore, 3.6 m × 4.5 m (16.2 m²). The first rows from each side of the plots were considered as a border. The second rows from each side of the plot were designated as sampling rows. In each plot, 1.5 and 0.6 m row length at the end of each row and column were left as a border to avoid the border effect. Therefore, the net plot size was 3 m × 3 m (9 m²).

Soil sampling and analysis

Before planting, surface (0-20 cm) soil samples, from five spots across the experimental fields, were collected in a zigzag pattern, composited and analyzed for soil physico-chemical properties and the results are depicted in Table 2. The soil sample was air dried and crushed to pass through a 2-mm mesh size and soil physico-chemical properties were analyzed in Teppi soil testing laboratory, following the procedures depicted below.

Table 2: Selected physico-chemical characteristics of soil of the experimental sites.

Soil texture was determined using Bouyoucos hydrometer method; soil pH and electrical conductivity of the soils were measured in water (1: 2.5 soil: water ratio). by digital pH and Ec meter; soil organic carbon by wet digestion method and total N by Kjeldhal method. Available phosphorous was determined. The cation exchange capacity (CEC) was determined using 1 M-neutral ammonium acetate [22-26].

Exchangeable acidity (Al and H) was determined by saturating the soil samples with 1 M KCl solution and titrated with 0.02 M NaOH as described by Rowell [27]. From the same extract, exchangeable Al was titrated with standard solution of 0.02 M HCl. Finally, exchangeable H was obtained by subtracting exchangeable Al from exchangeable acidity (Al+H).

Experimental procedures

To have fine seedbed for good root development, the experimental field was plowed three times using a pair of oxen and the plots were leveled manually. Cattle manure (CM) was applied on dry weight basis three weeks before to planting and totally mixed with the soil in the field. The potato tuber was planted in rows spaced 30 cm apart by hand drilling at the seed rate of 20 Q ha^-1 in the first week of February 2016.

Crop data collection

Yield components and yield: Total tuber numbers/hill: was obtained by adding up the number of marketable and unmarketable tubers. This parameter constituted all tubers: small, medium, large, diseased, deformed etc., that were produced by the plants. Marketable tuber number/hill: the number of tubers was counted as marketable which is greater or equal to 25 g, free from disease and insect attack in each plot and divided by the respective number of plants harvested.

Unmarketable tuber number/hill: the number of tubers counted as unmarketable which were diseased, insect attacked, deformed and weight less than 25 g. Marketable tubers yield (t ha^-1): these were recorded as the weight of marketable tubers that remain from diseases, insect pests, and above or equal to 25 g in weight [28]. These were taken from hills in the net plot area at harvest and changed to t ha^-1. Unmarketable tubers yield (t ha^-1): tubers yield recorded as unmarketable which were diseased, insect attacked, deformed and weight less than 25 g. Total tubers yield (t ha^-1): it was recorded as the sum of marketable and unmarketable tuber yield from net plot area harvested and changed into t ha^-1.

Statistical data analysis

The agronomic and post-harvest soil data were subjected to analysis of variance (GLM procedure) using SAS software program version 9.2 [29]. Homogeneity of variances was calculated using the F-test as described by Gomez and Gomez [30] and since the F-test has shown heterogeneity of the variances of the two seasons for most of the agronomic parameters, a separate analysis was used for the two seasons. The Fisher’s protected least significant difference (LSD) test at 0.05 probability level was employed to separate treatment means where significant treatment differences occurred.

Partial budget analysis

The partial budget analysis as justified by CIMMYT (1988) was done to determine the economic feasibility of the fertilizer application. It was computed by considering the additional input costs (variable costs) involved and the gross benefit gained from different treatments. The variable costs also included in the cost (Urea, TSP) and its application, cattle manure preparation, and application and cost of fungicide in the Meher season as this varied according to the treatment. A wage rate of 25.0 Birr per man-day was assumed where ten and two-man days were considered for preparation and application of one ton of Cattle manure the average marketable yield adjusted downward by 10% was used to reflect the difference between the experimental field and the expected yield at farmers’ fields and with farmers’ practices from the same treatments. This is because of experimental yields, even from on-farm experiments under representative conditions, are often higher than the yields farmers could obtain using the same treatments. For determining the gross benefit, the prevailing local market price at the harvest of potato (4 and 5.00 Birr kg^-1 in Belg and Meher, season respectively) was used for computation. (1 ETB=0.043 USD Gross field benefit(GFB), total variable cost (TVC) and net benefit (NB) were some of the concepts used in the partial budget analysis. The dominance analysis was also carried out to select potentially profitable treatments and a percentage marginal rate of return (% MRR) was calculated for the nondominated treatments.

Initial soil properties and cattle manure compositions

These results of the initial soil test analysis showed that the soils at the sites were low in fertility, acidic, with low amounts of total N, organic carbon, total and extractable phosphorous and exchangeable bases (Table 2). This could be attributed to the poor management of crop residue, thus resulting in nutrient reduction and the decline in soil fertility. The crop response to added organic and mineral fertilizer at different season is expected to show responses on crops and soils.

Prior to planting, surface (0-20 cm) soil samples, from five spots across the experimental fields, were collected in a zigzag pattern, in 2016 Belg and Meher cropping seasons composite, and analyzed in teppi soil testing, research Centre for soil physico-chemical properties as per the procedures given in experiment I (Table 2).

Analysis of composition of soil and cattle manure reveled better nutrient composition in Belg than in Meher season (Tables 2 and 3).

Table 3: Organic matter, N, P, K, pH, Total N, Ca, Mg, K, Na, CEC, EC and moisture content of of the substrates used in the experiment in Belg and Meher season at Abelo area masha district south west Ethiopia.

Farmers in masha mostly use cattle manure as the organic source. The de- composition rate of these materials in soil depends on the chemical composition of the material (C:N ratio), soil temperature, soil moisture, method of application (surface applied, soil incorporated, etc.), and rate of application.

The soil physico chemical analysis of the study sites revealed that the soils of the experimental field were loam in texture in both Belg and Meher cropping season. The results also indicated that the soil of Belg and Meher cropping season are strongly and very strongly acidic with pH of 5.2 and 4.8, respectively. The soils have low organic carbon, total N (g kg^-1) and available P (ppm) and medium in exchangeable base except trace in sodium, CEC and high in micronutrient cation Fe, Mn, Cu, Zn both in Belg and Meher season.

The soil physico-chemical analysis of the study areas revealed that the soils of the experimental field were loam in texture in both Belg and Meher season in abelo area with pH of 5.01(Strongly acidic) in Belg season and 4.8 (Very Strongly acidic) in Meher season.

The soil had also relatively high content of exchangeable acidity and aluminum (3.83 and 3.82 cmolc kg^-1) in belg and Al (2.01 and 2.46) cmolc kg^-1). In meher season.

The soils of both study sites have medium CEC of 20 Cmol (+) kg^-1) in Belg season and 19.3 Cmol (+) kg^-1), in Meher season low organic carbon content of 1.2 and 1.15 (g kg^-1 and Following the rating of total N of <0.05% as very low, 0.05-0.12 low, 0.12-0.25 Medium, >0.25 high N status as indicated that the surface Soils of both the Belg and Meher season qualify low status of N. low total N of 0.1 and 0.08 (g kg^-1 content in Belg and Meher season, respectively The analysis also revealed that the available P of the soils was 5.5 and 5 ppm in Belge and Meher, season respectively. Thus, the soils of the experimental sites are low in available P content both in Belge and Meher season (Table 3) according to the rating of [31].

Just after harvesting the crop, composite surface (0-20 cm) soil samples were collected from three spots for each plot from every replication. These samples were composited to yield one representative sample per replication from each plot for determination of CEC, pH, total N, available P, available K and organic carbon contents using procedures indicated for pre-sowing soil analysis. The extract of K was analyzed using flame photometer. The bulk density (Db) of the soil was measured from the undisturbed soil samples collected from each plot using core sampler, which was weighed at field moisture, and after drying the pre-weighed core soil sample to a steady weight in an oven at 105°C [32,33]. while particle density (ƥs) was measured using psychnometer [34].

where, BD=bulk density; PD=particle density [35].

Cattle manure Because of its alkalinity and elevated contents of alkali and alkaline earth elements, cattle manure can be utilized to raise the pH of acid soils. Therefore, cattle manure can be used as an alternative to lime either by itself or as a mixture of mineral NP. The cattle manure in Belg season has also relatively higher content of total P compared to cattle manure in Meher season [36].

The organic carbon, N, P, K pH, Electrical conductivity, Total Ca, Total Mg, Total K, Total Na, CEC and moisture contents of the CM at different season used in the experiments were determined and depicted in Table 3.

Yield components and yield

Effect of combined use of cattle manure with mineral NP dosages on yield component and yield parameter parameters at masha in Belg and Meher season: The effect of increased combined rate was found highly significant (p<0.001) on yield parameters such as Marketable tuber number and total number and average tuber weight (Table 4).

Table 4: Marketable tuber number (MTN), Unmarketable tuber number (UTN) and total tuber number (TTN) of potato as influenced by the integrated nutrient management in Belgand Meher, season at abelo area Masha district sheka zone southwestern Ethiopia.

Total tuber number (count/hill): Increasing the application of dosage of cattle manure and mineral NP increased total tuber number per hill from 10.4880 -13.2975 counthill^-1 and 9.504- 11.076 counthill^-1 in Belg and Meher season respectively (Table 4). This can be attributed to the increased vegetative growth of the potato plant and then potato tubers set per unit. The current result is inconsistent with the work of many researchers in addition to others who reported that combined had use of 5.0 t/ha CM+50% RDF increases tuber number as compared to 100% Mineral NP and zero application of fertilizers. In the present study, raising the rate of applied Cattle manure from 0-7.5 t CM+75% RDF ha^-1 increased total tuber number by 26.7 and 18.1% in Belg and Meher season respectively. It was observed at both seasons, Total tuber number increased when highest rate of cattle manure (7.5 tha^-1) was combined with the highest rate (75%) of the recommended mineral NP. whereas the lowest total tuber number (10.4880 counthill^-1) in Belg season and (9.504 counthill^-1) in Meher season was recorded at zero application of mineral NP and 7.5 tha^-1 cattle manure in lined with this. It is reported the lowest marketable tuber number was obtained in the zero application of fertilizers.

Marketable tuber number (counthill^-1): Marketable tuber number increased with the increased rate of cattle manure and mineral NP. Hence, increasing rate of Cattle manure and mineral NP application from 0-7.5 t CM+75% RDF ha^-1 increased marketable tuber number from 6.2046-9.72 and 9.50-11.08/hill without affecting the unmarketable tuber number (Table 4). This could be probably since marketable tuber number increases at the highest integration rate because the combined use of warm-compost and mineral NP can trigger the vegetative growth and development. Application of 7.5 t CM+75% RDF ha^-1 increased marketable tuber number by 56.7% and 50.2% in both Belg and Meher season as compared to control or no cattle manure and mineral NP application [42,43].

Total tuber yield: Increasing the application rates of combined use of cattle manure and mineral NP resulted in increasing the total tuber yield from 25.780 to 40.202 t ha^-1 and22.634-34.221 (Table 5). While the highest yield was obtained at 7.5 t CM+75% RDF ha^-1 but the lowest yield was obtained at zero dosage of cattle manure and mineral NP application. Increasing the application rates of cattle manure and mineral NP from zero to 7.5 t YM+75% RDF ha^-1 increased total tuber yield by 55.9%, 42.90% and 51.19%, 36.64% in both Belg and Meher season as compared to zero and 100% Mineral NP application of fertilizers respectively. This show there is an opportunity for additional gain in tuber yield through the further application of more rates of combined cattle manure with mineral NP fertilizers above 7.5 t CM +75% RDF ha^-1, respectively. This result is in line with the finding of researchers who reported that Combined administration of cattle manure and mineral fertilizers increased the total tuber yield [44-46].

Table 5: Cattle manure and mineral NP in Belg and Meher season at abelo area mash district, southwestern Ethiopia.

Results have shown that all the treatments increased Total tuber yield in both Belg and Meher season as compared to control in both Belg and Meher season but the increment in total tuber yield is higher in Belg season than Meher season.

According to the current investigation the results obtained in terms of the following yield parameters such as marketable tuber yield (MTY), unmarketable tuber yield (UMTY), and total tuber yield (TTY), average tuber weight (ATW) of potato as influenced by combined use

Marketable tuber yield: The highest marketable tuber yield (27.491 and 28.700 t ha^-1) were recorded at 7.5 t CM in combination with 75% RDF ha^-1 but the lowest marketable tuber yield (14.045 and 21.280 tha^-1 was obtained from the combination of zero levels of cattle manure and mineral NP. The combined application of cattle manure and mineral NP showed significant differences in marketable tuber yield (Table 6), indicating that the effect of different levels of cattle manure and mineral NP on marketable tuber yield is dependent on the levels of cattle manure and mineral NP. This may be due to the positive interaction and Complementary effect between cattle manure and mineral NP in affecting and increasing the marketable tuber yield.

Table 6: Results of partial budget analysis to estimate the net benefit of combined use of cattle manure and mineral NP of potato in 2016 Belg season, at abelo area Masha district sheka zone southwestern Ethiopia.

Average tuber weight: The highest average weight of tubers (68.08 g and 69.53 g) were found in the treatment that received 7.5 t CM with 75% RDF ha^-1 in Belg and Meher season respectively and this value was Statistical similar with the application of and the lowest average weight of tubers (55.31 g and 53.61 g) were obtained in the treatments that received no cattle manure and mineral NP. The increased application rate of combined use of Cattle manure and mineral NP from 0-7.5 t CM with 75% RDF ha^-1 increased average tuber weight by 23.08 and 29.68% as compared to the control in both Belg and Meher season respectively.

Economic evaluation

In this study, fixed costs were not considered and the highest net return of 91704.6, Birr ha^-1 in Belg and (119887 ETBha^-1) in a Meher season was recorded at the same rate (Tables 7 and 8). Further, the Net benefit increased with increasing dosage of farmyard manure and mineral NP application that was most probably due to better improvement of soil condition that consequently resulted in increased tuber yield. Again, there was variation between two seasons in net benefit because of higher market price in Meher season thought the yield is generally less from Belg season though there were additional input costs fungicide application whereas the highest total variable cost of (7263, ETBha^-1) in Belg and (9263, ETBha^-1) in Meher was recorded from the combined use of 7.5 t CM+75% RDF further except for the four treatments (T2, T5, T7, T8) in Belg and five treatments (T3, T2, T5, T7, T8) in Mhere all other treatments (T1, T3, T4, T6, T9, T10, T11) in Belg and (T1, T4, T6, T9, T10, T11) in Meher were found to be non-dominated and thus, selected for the analysis of the marginal rate of return (MRR).

Table 7: The marginal rate of return for NP fertilizers and Cattle manure for potato production in Belg season.

Table 8: Results of partial budget analysis to estimate net benefit of combined use of cattle manure and mineral NP of potato in 2016 Meher season, at abelo area Masha district sheka zone southwestern Ethiopia.

Moreover, the highest marginal rate of return (Tables 3 and 4) was recorded for the latter treatment T7. 5 t CM+50% RDF, (1974.02%) followed by T6. 5 t CM+25% RDF (1043.88%), T3. 2.5 t CM+25%RDF (929.59%) in Belg season and the highest marginal rate of return of T9. 7.5 t CM+25% RDF (1552.33%) followed by T6. 5 t CM+25% RDF (1463.257), T11. 7.5 t CM+75% RDF (908.17%) in Meher season

This indicates that, for every 1 Birr ha^-1 invested in the respective treatments, there was a rate of return of 197.40 Birr ha^-1, 104.388 Birr ha^-1, and 92.96 Birr ha^-1. In Belg and 15.52 Birr ha^-1, 146.32 Birr ha^-1, 90.81 Birr ha^-1.

In this study, fixed costs were not considered and the highest net return of 91704.6, Birr ha^-1 in Belg and (119887 ETBha^-1) in a Meher season was recorded at the same rate. Further, the Net benefit increased with increasing dosage of farmyard manure and mineral NP application that was most probably due to better improvement of soil condition that consequently resulted in increased tuber yield. Again, there was variation between two seasons in net benefit because of higher market price in Meher season thought the yield is generally less from Belg season though there were additional input costs fungicide application whereas the highest total variable cost of (7263, ETBha^-1) in Belg and (9263, ETBha^-1) in Meher was recorded from the combined use of 7.5 t CM+75% RDF further except for the four treatments (T2, T5, T7, T8) in Belg and five treatments (T3. T2 T5. T7 T8) in Mhere all other treatments (T1, T3, T4, T6, T9, T10, T11) in Belg and (T1, T4, T6, T9, T10, T11) in Meher were found to be nondominated and thus, selected for the analysis of the marginal rate of return (MRR).

Moreover, the highest marginal rate of return (Tables 3 and 4) was recorded for the latter treatment T7. 5 t CM+50% RDF, (1974.02%) followed by T6. 5 t CM+25% RDF (1043.88%), T3. 2.5 t CM+25%RDF (929.59%) in Belg season and the highest marginal rate of return T9. 7.5 t CM+25% RDF (1552.33%) followed by T6. 5 t CM+25% RDF (1463.257), T11. 7.5 t CM+75% RDF (908.17%) in Meher season.

This indicates that, for every 1 Birr ha^-1 invested in the respective treatments, there was a rate of return of 197.40 Birr ha^-1, 104.388 Birr ha^-1, and 92.96 Birr ha^-1. In Belg and 15.52 Birr ha^-1, 146.32 Birr ha^-1, 90.81 Birr ha^-1.

In line with this result, it is also reported that the application of 120 kg N+92 kg P+30 t CM ha^-1 on potato Variety belte 2012 and 2013 cropping season Clay loam soils at Kobo District North-Eastern Ethiopia. Gave the highest net return of 218% as compared to the control in addition, reported that smallholder farmers should apply higher rates of CM together with inorganic fertilizers to improve cost of potato production [47-51] (Tables 7-9).

Table 9: The marginal rate of return for NP fertilizers and Cattle manure for potato production in Belg season at abelo area Masha district sheka zone southwestern Ethiopia.

Potato growth, development and high yield depend on soil properties, climatic conditions, The result of most of growth, yield component yield, quality economic evaluation and soil analysis indicated the fertility of the soil at Masha is very low and that is why all treatments with the combined use of cattle manure and mineral NP gave a higher tuber yield than the treatment with either no fertilizer or sole application of mineral NP, which gave a very low yield. Application of CM has a residual effect for the next cropping seasons. The combined application of mineral NP and cattle manure (CM) gave a better result than the application of sole, which indicates integrated nutrient management is the best method for soil fertility management. This is due to cattle manure contains more calcium and magnesium and raises the pH electrical conductivity, exchangeable bases present pore space and reduces bulk density and particle density per ton on a dry weight basis. Therefore, applying manure to acid soils not only supply much needed nutrients and organic matter for plant growth but also reduce soil acidity, thus improve phosphorus availability and reduce aluminum toxicity. In Masha south west Ethiopia, many fields are acidic, and cattle manure would be a good amendment. Hence, the usage of 165 kg N 60 kg P+7.5 t CMha^-1 can be recommended for better potato production, productivity, economic feasibility at abelo area Masha District. Yields varied slightly due to seasonal effects Yields were slightly higher in the short rainy (Belg) season than the long rainy (Meher) season.

We thank Ministry of Education (MoE), Ethiopia for Financial support and Haramaya University and Teppi and Hawsa soil Testing Research Center also deserve special thanks for facilitating the finance and for providing the required research supply, respectively. We also acknowledge the staff members, especially laboratory technicians at Teppi Soil Testing research Centre the sustainable land management (SLM) project in Masha District Sheka zone is highly acknowledged for providing Cattle manure and sponsoring the laboratory cost incurred for this work.