The effect of fertilization and irrigation on potato yield in organic production system

BackgroundLow soil fertility and reduced seasonal rainfall contribute to low potato (Solanum tuberosum L.) yield in Kenya. Nitrogen (N) deficiency is the major problem facing by the smallholder farmers of Kenya due to lack of fallow. Hence an introduction of supplemental irrigation with an adequate application of this nutrient could increase potato yield. The objective of this study was to determine the effects of supplemental irrigation and N-fertilisation on potato tuber yield, water use efficiency (WUE) and nitrogen use efficiency (NUE). The experiment was conducted in Nakuru County, Kenya for two seasons. The experimental soils are classified as mollic Andosols. The treatments comprised two irrigation treatments of full supplemental irrigation (FI) and rainfed production (RF) and four N levels of four N levels of 0 (N0), 60 (N1), 90 (N2) and 130 kg N/ha (N3).ResultsThe results showed that total tuber yield, marketable tuber yield and NUE were significantly (P < 0.001) affected by irrigation × N-fertilisation while WUE was only affected (P < 0.001) by N-fertilisation. The highest total tuber yield, 58.28 tonnes/hectare (t/ha), was recorded under FI combined with N3. Treatment FI significantly increased marketable tuber yield by approximately 125.58% in all N treatments compared to RF. The highest NUE of potato (236.44 kg/kg of N) was obtained under FI combined with N3 but not significantly different from the NUE of potato obtained under FI with N2. N-fertilisation N3 produced the highest WUE of 14.24 kg/m3. Significant correlation was obtained between tuber yield and number of tubers/plant (r = 0.75, P < 0.001), NUE (r = 0.95, P < 0.001) and WUE (r = 0.72, P < 0.001).ConclusionHigh potato yield and marketable tuber yield can be achieved in mollic Andosols when water deficits of the growing season are eliminated with supplemental irrigation and an application of 130 kg N/ha.

The experiment was conducted during main rain fall season from June to October, 2018 in Adet, Ethiopia with the objective of estimating the correlation and identifying the direct and indirect effect of yield contributing traits on potato crop. 36 potato genotypes were evaluated in simple lattice design in two replications. The analysis of variance revealed that highly significant (p&lt;0.001) difference among potato genotypes for all traits except average stem number. Total tuber yield was positively correlated with days to maturity, plant height, average stem number, marketable, unmarketable, total tuber number and marketable yield while it was negatively correlated with late blight severity percentage at both phenotypic and genotypic level. High correlation was observed between total tuber yield and marketable tuber yield (rp=0.982 and rg=0.986) followed by total tuber number (rp=0.735 and rg=0.789), and marketable tuber number (rp=0.700 and rg=0.737). Days to flowering, days to maturity, average stem number, marketable and unmarketable tuber number, starch content percentage, average tuber weight, and unmarketable tuber yield had positive direct effect on the total tuber yield at both genotypic and phenotypic level. Highly direct effect on total tuber yield was observed by marketable and unmarketable tuber number (3.65 and 1.17 respectively) and average tuber weight (0.56). Therefore, traits with significant positive correlated and direct effect on total tuber yield such as days to maturity stem number, marketable tuber number, marketable tuber yield and average tuber weight should be considered in selection criteria for enhancing tuber yield in potato.

To evaluate the influence of nitrogen rate and split application method on tuber yield and other quantitative characteristics of different potato cultivars, a 2-yr experiment was conducted at Khorasan Razavi Agricultural and Natural Resources Research Center. Experimental treatments consisted of four nitrogen rates (0, 90, 180 and 270 kg N ha-1) with two split applications (emergence and hilling stages) or three split applications (planting, emergence and hilling stages) and six potato cultivars (Fontane, Kuras, Agria, Miriam, Cosmos and Picasso) that were arranged in a randomized complete block split-split plot design. Shoot dry weight, average stem length, tuber number per plant, total tuber yield, marketable tuber yield (<85 g), misshapen tuber yield and jumbo tuber yield (<400 g) increased with the increasing of nitrogen application. However, there was no significant difference between 180 and 270 kg N ha-1 treatments. Split N application method affected potato tuber yields. Maximum total and marketable tuber yields and minimum misshapen and jumbo tuber yields were obtained with two split N applications. There were significant differences between potato cultivars. So that, Cosmos had maximum tuber yields among potato cultivars. Miriam produced minimum total and marketable tuber yields. Cosmos and Picasso had the most and least misshapen tuber yields, respectively. Minimum jumbo tuber yield was belonging to Kuras cultivar. The results showed that application of 180 kg N ha-1, half at emergence and half at hilling, produced the maximum total and marketable tuber yields in different potato cultivars. Key words: Potato, Solanum tuberosum L., Nitrogen, Split application, Tuber yield, Marketable yield, Secondary tuber growth

The present study was carried out at Suleyman Demirel University research farm in Isparta during2008 and 2009 crop seasons to determine the effects of leonardite (54.5% organic matter) on yield and quality of potato. Four leonardite doses (0, 200, 400, 600 kg ha-1) and four potato cultivars (Van Gogh, Milva, Lady Olympia, Agata) were used in the study. A total of seven traits (plant height, tuber number per plant, marketable tuber yield, total tuber yield, protein content, vitamin C content and specific gravity) were measured. Significant differences were detected between control and leonardite applications for all the traits studied. Statisticallysignificant differences were not found between the leonardite doses for plant height and specific gravity. There was no significant difference between 400 and 600 kg ha-1 leornardite application for tuber number per plant, marketable tuber and total tuber yield, protein and vitamin C contents. Leonardite applications increased number of tubers per plant by 22%, marketable tuber yield by 38% and total tuber yield by 15% compared with the control. These results suggest that 400 kg ha-1 leonardite combination to the standard fertilization will be sufficient to obtain adequate yield and quality tubers in potatoes

Sweet potato is one the most important root crops produced in western Ethiopia. However, the yield is far below its genetic potential. Lack of recommendation on appropriate rates of fertilizers is one of the problems limiting yield. A study was conducted to determine the effect of application of farm yard manure and inorganic phosphorus on tuberous root yield and yield related traits of sweet potato at Assosa from July to December 2016. The treatment consisted of four levels of farm yard manure (0, 5, 10 and 15 t ha-1) and four levels of P (0, 23, 46 and 69 kg P2O5 ha-1). The experiment was laid out as a Randomized Complete Block Design in a factorial arrangement and replicated three times. Analysis of the results showed that the main effect of farm yard manure significantly (P<0.05) affected most of the traits studied. The interaction effects of the two also affected most of the growth as well as yield parameters considered. Application of combinations of 15 t ha-1 farm yard manure and the highest rate of P2O5 resulted in 39.3% faster in bud sprouting. The main effects of farm yard manure affects tuber diameter (20.63 cm), unmarketable tuber yield (1.3 t ha-1), weight of tuber/plant (143 g), weight of marketable tuber/plant (140 g), dry matter content (27.04), specific gravity (1.12), length of tubers(15.68 cm). The highest vine length (139.67 cm), total tuber number per plant (8.0), total tuber yield (24.6 t ha-1), marketable tuber yield (23.65 t ha-1) was recorded at 15 t ha-1 farm yard manure+69 kg P2O5 ha-1 whereas the lowest vine length (45.3 cm), tuber number per plant (2.0), total tuber yield (5.52 t ha-1), marketable tuber yield (3.61 t ha-1) was recoreded at un amended control. The main effects of farm yard manure delayed maturity of the crop where the 15 t ha-1 farm yard manure showed delay by about 18 days. Moreover, tuber diameter, length of roots, and weight of tuberous roots exhibited improvement with increment in the amount of applied farm yard manure while none of these parameters were affected by the application of P2O5 fertilizer. From this study, the highest net benefit for tuber yield of sweet potato was recorded from the application of manure and P2O5 at the combination level of 15 t ha-1 farm yard manure+69 kg P2O5 ha-1 which was 57873 Birr ha-1. Therefore, the doses of 15 t farm yard manure ha-1 and 69 kg P2O5 ha-1 could be integrated and applied for sweet potato crops in the study area. However, it warrants further testing to give conclusive recommendation.

Potato is one of the most important food security and cash crops in Ethiopia. It is constrained by poor soil fertility. A field experiment was conducted at Assosa Agricultural Research Centre to investigate the effect of phosphorus and potassium fertilizers on the growth performance and yield of potato. The experiment was laid out as a randomized complete block design (RCBD) in 4×6 factorial arrangement of potassium (0, 100, 200 and 300 kg K2O ha-1) and phosphorus (0, 46, 92, 138, 184 and 230 kg P2O5 ha-1) in three replicates. A potato variety, Gudanie (CIP-386423-13) was used. Analysis of the data revealed that the interaction effect of both phosphorus and potassium did not influence the phonotypic, growth parameters and tuber yields of potato, but their main effect they significantly influenced days to 50% flowering, physiological maturity, plant height , marketable and total tuber yields, leaf area, above and underground dry biomasses. Optimum above and underground dry biomass (232.11 and 494.74 Mg* ha-1), marketable (23.94 kg K2O ha-1) and total tuber (29.56 kg K2O ha-1) yields were attained at 200 kg K2O ha-1 ; for phosphorus, optimum marketable tuber (23.30 Mg ha-1), total tuber (28.83 Mg ha-1), and yield of above ground and underground dry matter (218.48 and 479.60 Mg ha-1) were attained at 138 kg P2O5 ha-1. The lowest yield obtained from above ground and underground dry matter, marketable and total tuber in both fertilizers were recorded at zero level. Key words: Fertilizer rate, phenotypic parameter, plant height, biomass, tuber yield, 1 Mg (Megagram) = 1000 kg.

Potato is the dominant tuber and root crop grown in Tigray. However, the productivity is very low due to moisture stress, traditional production techniques, and low-yielding varieties. Hence, this study aimed to optimize potato yield by selecting suitable genotypes under both supplemental and non-supplemental irrigation conditions. The study involved five potato genotypes and two irrigation levels used as treatments arranged in a split plot using a randomized complete block design with three replications. Results revealed a significant difference in days to flowering and maturity, marketable and total tuber yield, and water productivity due to the main and interaction effect of genotype and irrigation. CIP-3960478.90 recorded significantly higher marketable yield (27.13 t ha−1), total tuber yield (28.71 t ha−1), and water productivity (7.59 kg m−3) under supplemental irrigation. Genotype CIP-394611.112 had achieved high marketable yield (24.45 t/ha), total yield (25.60 t/ha) and total water productivity (8.51 kg m−3) under non-irrigated treatment. Additionally, the potato water requirements in September and October exceeded the rainfall amounts, suggesting that supplemental irrigation is necessary during this period for optimal yields. Likewise, genotypes CIP-394611.112 and CIP-3960478.90, are recommended for semi-arid areas to enhance tuber yield with or without irrigation.

Irish potato (Solanum tuberosum L.) is cultivated for food and cash in Ethiopia. However, its productivity is limited by various constraints among which are particularly high demands of potassium (K) fertilizer for growth and development coupled with low soil fertility. Further studies need to be done to prove the emerging research evidences that Potassium (K) is becoming a limiting nutrient in some Ethiopian soils. A field experiment was conducted to determine effects of K-fertilizer (KF) on yield components (YC) and yield of potato in Abota-Ulto (Loc-1) and Gututo-Ampokosha (Loc-2) locations, Southern Ethiopia. Treatments included different rates of potassium fertilizer: 0, 30, 60, 90, 120, 150 and 180 kgha-1. The experiment was laid out in RCBD (randomized complete block design) with three replications. Results revealed that YC and yield of potato were significantly affected by both main and interaction effects of KF rates and locations. Marketable tuber yield (MTY) was significantly increased from 15.6mtha-1 in the control to 33.6mtha-1 with KF (potassium fertilizer) rate 150 kgha-1. Significantly higher MTY was obtained in Loc-1 than Loc-2. K-fertilizer rates by location interaction effects were significant on YC and yield of potato. In Loc-1 the highest MTY was obtained with KF applied at150 kgha-1 whereas in Loc-2 the highest MTY was obtained with KF applied at120 kgha-1. Results of partial budget analyses showed that in Loc-1, the highest net benefit (Ethiopian Birr 96060ha-1) with marginal rate of return was 1102% with KF applied at 150 kgha-1. In Loc-2, the highest net benefit (Ethiopian Birr 73312.8 ha-1) with marginal rate of return was 910% with KF applied at120 kgha-1. It was concluded that potato significantly responded to KF indicating insufficient amount of K content in the soils of both locations for optimum potato production. Application of potassium fertilizer is economically feasible in both locations. Key words: K- Fertilizer application, Potato production, Marketable yield, Economic feasibility, Locations

The growing period for early potatoes is extremely short, only 50-80 days from planting to harvest. To obtain a high marketable tuber yield in such a short period good conditions for plant growth must be ensured. In modern agriculture, plant growth stimulants have been gaining increasing importance. Although titanium (Ti) is neither a major nor minor nutrient for plants, it is classified as a beneficial element for plant growth. This paper analyses the effect of dose (0.2 dm3*ha-1 or 0.4 dm3*ha-1) and date (leaf development stage – BBCH 14-16, tuber formation stage – BBCH 41-43, leaf development stage and tuber formation stage) of the application of Tytanit® (8.5 g Ti in 1 dm3) on the yield and yield components of very early-maturing potato cultivars (‘Lord’ and ‘Miłek’). Potatoes were harvested 75 days after planting (the end of June). Tytanit® caused an increase in the tuber number and tuber weight per plant, particularly under stress conditions, although the effect of cultivars was not consistent. The growth stimulant did not have any effect on the average tuber weight. Following the application of Tytanit®, the total tuber yield was higher, on average, by 2.26 t*ha-1 (7.5%), and the marketable tuber yield (diameter above 30 mm) by 1.88 t*ha-1 (6.4%). The tuber number per plant was higher when Tytanit® was applied at the dose of 0.2 dm3*ha-1. Potato plants produced greatest tubers when Tytanit® was only applied in the leaf development stage (BBCH 1416). With double Tytanit® applications, i.e. in the leaf development stage and with repeated treatment in the tuber formation stage, both the tuber number and tuber weight per plant were lower. The Tytanit® application contributed to improved marketable value of the early potato yield due to a decreased share of small tubers (diameter below 40 mm) and an increased share of large tubers (diameter above 51 mm) especially in a year with a periodical water shortage in the tuber growth period. The examined very earlymaturing potato cultivars showed a differential response to Tytanit®. The growth stimulant had a greater effect on the tuber number and tuber weight per plant for the ‘Lord’ cultivar. Following the Tytanit® application, the total tuber yield of ‘Lord’ cultivar was higher , on average by 3.71 t*ha-1 (12.7%) and marketable tuber yield by 3.22 t*ha-1 (11.4%). Tytanit® caused an increase in tuber yield of ‘Miłek’ cultivar only in year with the highest air temperature and water shortage in June – the total tuber yield was higher, on average by 2.16 t*ha-1 (8.5%) and marketable tuber yield by 2.02 t*ha-1 (8.2%).

Aims: The current study was carried out to examine the impact of humic-acid-based bio-stimulant (liquid formulation) ‘Humetsu’ on growth and yield attributes of potato variety Kufri Chipsona-4. Study Design: The study used a Randomized Block Design with 3 replications and 8 treatments. Place and Duration of Study: The existing experiment was worked out at Teaching Farm, College of Agriculture under BCKV, Burdwan Sadar during Rabi, 2019-20 and Rabi, 2020-21. Methodology: The test product humic-acid based bio-stimulant (liquid formulation) ‘Humetsu’ was used for seed treatment at the rate of 5 ml/kg tuber before sowing of potato and 2.5 ml /L water was sprayed treatment-wise as per protocol using a water volume of 500 liters per ha with knapsack sprayer fitted with flat fan deflector nozzle in potato. Results: The results elucidated that significantly maximum plant emergence, number of branches per plant and increased available N, P, K and Organic carbon (OC) in both years were recorded in treatment T4 (100% NPK + 3 application of ‘Humetsu’ (Seed treatment at the rate of 5 ml/kg of tuber and 2 foliar sprays at the rate 2.5ml L-1 water at 30 DAS &amp; 55 DAS). The highest plant height, TSS (%), and fewer days to harvest were found in treatment T7 (80% NPK + 3 application of ‘Humetsu’ (Seed treatment at the rate 5ml/kg of tuber and 2 foliar sprays at the rate 2.5ml L-1 water at 30 DAS &amp; 55 DAS) followed by treatment T4, T5, and T6. The maximum number of tubers per plant, total tuber yield, and marketable tuber yield were noticed in the treatment T7 during both years. The highest microbial population in the soil was noticed in the T7 during both the years. On the other hand, the least plant height, TSS (%), plant emergence, number of tubers per plant, total tuber yield, marketable yield per ha, more days to harvest, and the least microbial population in soil were observed in (control) treatment (T8) during both the years. Conclusion: Application of 80% NPK + 3 application of ‘Humetsu’ (Seed treatment at the rate 5ml/kg of tuber and 2 foliar sprays at the rate 2.5ml l-1 water at 30 DAS&amp; 55 DAS) has a significant impact in yield of potato with 20% reduction of the recommended dose of NPK fertilizers.

In this study, adaptation trial of improved potato varieties was conducted in Buno Bedele Zone with the objective of recommending best-performing variety. Four potato varieties (Belete, Gudenie Jalanie and Horo) were evaluated for their vegetative growth performance and tuber yield under rain fed conditions. Combined analysis of data revealed that, varieties showed highly significant at (P &lt;0.01) variations for days to maturity, number of tubers per plant, Marketable and tuber yield. The longest days to maturity (95.25 days) was recorded from Gudanie while the shortest days to maturity (87.25 days) was recorded from Horo. Besides, the tested potato varieties showed highly significant (P &lt; 0.01) variations for the number of total tubers per hill. The highest tuber number per hill (22.37) was recorded from Belete variety where as the lowest tuber number per hill (13) was recorded from Jalanie. Variety Belete had also highest (24.24 t/ha) marketable tuber yield followed by Gudanie variety (19.14t/ha) as compared with other Varieties where as, Jalanie variety had the lowest (9.83 t/ha) marketable tuber yield. There was highly significant (p&lt;0.01) difference in total tuber yield among the potato varieties evaluated. The highest total tuber yield (26.24 t/ha) was recorded from Belete variety followed by Gudanie variety (22.06 t/ha). On the other hand, the lowest total tuber yield (11.14 t/ha was recorded from Jalane variety which was found to be at par with Horo variety Belete and Gudenie varities were also relatively resistant to late blight diseaseas compared to other varieties. On the other hand Jalanie and Horo varieties were moderately susceptible and moderately resistant, respectively. The result of the correlation analysis also revealed that tuber number and number of tubers per plant were significantly and positively correlated with marketable and total tuber yield. Likewise marketable tuber yield was also significantly and positively correlated with total tuber yield. Belete and Gudanie were varieties that showed better performance in terms of yield and yield component as well as disease resistance. Therefore, the two varieties are recommended to be demonstrated on farmer’s field for further scaling up.

Two field experiments were conducted to investigate the effects of two gel‐polymer formulations (pure and fertiliser‐fused) and moisture stress on yield and quality of potato (Solanum tuberosum). The experiments were carried out at the Hatfield Experimental Farm of the University of Pretoria, South Africa. Six gel‐polymer rates, consisting of pure gel polymer at 1.5kg/m3 of soil, with 85% and 70% fertiliser rate of the control, and fertiliser‐fused gel polymer at 1.5, 2, and 3kg/m3 soil, and control (without gel polymer) were assigned to the subplots. Four maximum allowable moisture depletion (MAD) levels, 25%, 40%, 55%, and 70% of the plant available soil moisture, were allocated to the main plots. Rate of phosphorus (P) was the same for all treatments (168kg/ha). Total nitrogen (N) and potassium (K) budget for the treatments (except one pure gel‐polymer treatment received 85%) were balanced to 70% of the control. The fertiliser‐fused gel polymer showed no substantial improvement in tuber yield parameters for all rates. The pure gel polymer, especially at higher fertiliser rate, improved total and marketable tuber yield. Marketable tuber number and yield, and total tuber mass showed declining trend with an increase in MAD. Significant reduction in tuber fresh and dry mass was observed at the 55% and 70% MAD irrigation levels. Both high and low soil moisture levels reduced tuber specific gravity. Incidence of common scab was inversely related to the irrigation frequency.

Tuber yield and quality are the two main factors that can increase or decrease the market value of potatoes. Soil moisture availability and nutrient concentration within the potato root zone play a pivotal role in controlling tuber yield and quality. This study was conducted in Southern Manitoba to compare the effects of overhead irrigation (IR) and no-irrigation (NI) on marketable tuber yield and quality during the 2013- and 2014-growing seasons. The total yield of potato was not significantly different between the two treatments in both years. In 2013, the marketable yield of the irrigated (IR) treatment (36.89 MT/ha) was 20% higher (p = 0.017) compared to the non-irrigated (NI) treatment (30.74 MT/ha). However, no significant difference in marketable yield was found between the irrigated (39.0 MT/ha) and non-irrigated (43.7 MT/ha) treatments in 2014. Excess nitrate accumulation within the root zone tends to promote the formation of over-sized tubers. Although the incidence of hollow hearts and sugar ends showed a higher trend in the non-irrigated treatment it was statistically not significantly different from the irrigated treatment. Overhead irrigation was found to be economically advantageous to produce better quality potatoes with higher marketable yields.

This research was conducted in 2020 to determine the effects of leonardite-derived humic acids (Humas-15, Liquid Humus and Humico Maximix-K) with different properties, along with reduced nitrogen fertilization, on tuber yield and quality in potatoes (cv. Van Gogh). In the study, chemical fertilizer applications were made as basic fertilization (20 N 10 P 10 K), reduced fertilization I (15 N 10 P 10 K) and reduced fertilization II (10 N 10 P 10 K). Humic acids were applied twice with irrigation water, at the beginning of the flowering period and 15 days later. Humas-15 and Liquid Humus were applied at 1.0 and 2.0 lt/da doses, and Humico Maximix-K was applied at 400 and 800 g/da doses. A total of seven traits (tuber number per plant, tuber yield per plant, marketable tuber yield, total tuber yield, dry matter content, reducing sugar content and total sugar content) were measured. Reducing nitrogen applications with humic acid applications significantly affected all the traits studied. Humic acid applications combined with reduced nitrogen fertilization increased the number of tubers per plant by up to 13%, marketable tuber yield by up to 18% and total tuber yield by up to 16% compared with the control. Total and reducing sugar contents varied between 1.27-1.58% and 159-389 mg/100g fw, respectively depending on the applications. In the study, the highest tuber yield was obtained from 1.0 and 2.0 L/da Humas-15 and 2.0 L/da Liquid Humus applications applied together with reducing nitrogen applications which have close values to the recommended fertilization applications.

Effects of irrigation and fertilization on different potato varieties growth, yield and resources use efficiency in the Northwest China