Comparison of potato (Solanum tuberosum L.) tuber size distribution fitting methods and evaluation of the relationship between soil properties and estimated distribution parameters

Accurate estimation of tuber size distribution (TSD) parameters in discretely categorized potato (Solanum tuberosum L) yield samples is desirable for estimating modal tuber sizes, which is fundamental to yield prediction. In the current work, systematic yield digs were conducted on five commercial fields (N = 119) to compare the Weibull, Gamma and Gaussian distribution functions for relative-likelihood-based goodness-of-fit to the observed discrete distributions. Parameters were estimated using maximum likelihood estimation (MLE) for the three distributions but were also derived using the percentiles approach for the Weibull distribution to compare accuracy against the MLE approaches. The relationship between TSD and soil nutrient variability was examined using the best-fitting model's parameters. The percentiles approach had lower overall relative likelihood than the MLE approaches across five locations, but had consistently lower Root Mean Square Error in the marketable tuber size range. Negative relationships were observed between the percentile-based shape parameter and the concentrations of Phosphorus and Nitrogen, with significant (non-zero-overlapping 95% confidence interval) regression coefficients for P (−0.74 ± 0.33 for distribution of proportional tuber numbers and −1.3 ± 0.62 for tuber weights). Stem density was negatively associated with the scale and mode of tuber number (regression coefficients −0.98 ± 0.63 and −1.08 ± 0.78 respectively) and tuber weight (regression coefficients −0.99 ± 0.78 and −1.04 ± 0.69 respectively) distributions. Phosphorus is negatively related to the scale of the tuber-number-based distribution while positively associating with the tuber weight distribution. The results suggest that excess P application was associated with the increase in small tubers that did not contribute significant weight to the final yield.

Response of Potato (Solanum tuberosum L.) to NPS Fertilizer Rates and Inter-Row Spacing in Kechi District, South Western Ethiopia

Fertilizer requirement and spacing vary across locations due to differences in soil types, nutrient and moisture availability, economic factors, and other environmental conditions. Therefore, a field experiment was carried out to investigate the effect of different rates of NPS fertilizers and inter-row spacing on growth, yield, yield components, and economic performance of potato in Kechi research farm, Dawro zone of south-western Ethiopia. The experiment was arranged in factorial combination of six NPS (19N–38P2O5–7S) fertilizer rates (0 kg/ha, 50 kg/ha, 100 kg/ha, 150 kg/ha, 200 kg/ha, and 250 kg/ha) and five inter-row spacings (45, 55, 65, 75, and 85 cm) which were laid out in RCBD with three replications using the Gudene variety. Growth, yield component, and yield data were collected and analyzed. In addition, a partial budget analysis was performed. The results showed that the main effect of NPS fertilizer and inter-row spacing had significantly ( P < 0.05 ) affected plant height, tuber number, tuber yield, and tuber size and average tuber weight. Maximum marketable tuber number per plant (11.627), total tuber number per plant (13.020), average tuber weight per plant (83.493 g), the proportion of large-sized tuber number per plant (41.893%), marketable tuber yield (48.056 t/ha), and total tuber yield (51.145 t/ha) were obtained from 200 kg/ha of NPS fertilizer which was statistically at par with 150 kg/ha and 250 kg/ha NPS, while the lowest result for those parameters was recorded from unfertilized plots. Results regarding inter-row spacing revealed that the highest marketable tuber number per plant (11.744), total tuber number per plant (13.144), and average tuber weight per plant (85.559 g) were recorded at 75 cm, while the lowest result for these parameters was recorded at 45 cm. Moreover, the highest marketable tuber yield (45.084 t/ha) and total tuber yield (48.462 t/ha) were obtained from the inter-row spacing of 65 cm which was statistically at par with 55 cm inter-row spacing, while the lowest result for these parameters was recorded at 85 cm. The partial budget analysis further revealed that 200 kg/ha NPS fertilizer gave the maximum net benefit. However, 150 kg/ha NPS resulted in the highest marginal rate of return (4303.91%). Thus, 150 kg/ha NPS fertilizer and inter-row spacing of 55 cm or 65 cm are suggested for attaining higher potato yield.

Physiological and Morphological Responses of Cassava Genotypes to Fertilization Regimes in Chromi-Haplic Acrisols Soils

The objective of this study was to evaluate the performances of three cassava genotypes on yield, physiology and morphological traits under different fertilization regimes. A field experiment was conducted in a split-plot design for two consecutive seasons in the Mansa district of the Luapula Province of Northern Zambia in the highly weathered Chromi-haplic Acrisol soils. Four fertilization regimes, control-M3, lime-M1, NPK fertilizer-M4 and NPK fertilizer + lime-M2 were the main plots, while three varieties (Mweru-V1, Bangweulu-V2 and Katobamputa (local)-V3) were subplots. Periodic measurements of leaf area index, light interception, yield and yield components from 75 days after planting (DAP) up to 410 DAP and daily weather measurements of data were recorded. Fertilization significantly increased the radiation use efficiency (RUE) and light extinction coefficient (K) in two seasons compared to the control. Significant fertilization regimes and varietal effects were observed for seasonal LAI, stem yield, root yield, biomass, harvest index (HI), tuber number, root diameter, plant height and SPAD (chlorophyll index). A significant year’s effects on root yield, yield components and physiological performances were observed while significant fertilization × variety interaction was observed on seasonal LAI, tuber number, root diameter, plant height and SPAD. Significant fertilization × year interaction effects were observed on root yield, yield components and physiological performances. Variety × year interaction was significant for seasonal LAI, stem yield, harvest index and plant height and no three-way interactions were observed on all the traits. NPK fertilizer + lime and NPK fertilizer treatments may be adopted to increase the response of cassava varietal yield, physiology and morphological traits in low soil nutrient conditions under high rain-fed conditions.

Effect of time of seed-bed preparation on soil properties and performance of water yam in Owerri southeast, Nigeria

Field experiment was conducted between the months of February and November, 2016 to evaluate the effect of age of seed-bed preparation on soil properties and performance of water yam in Owerri, southeastern Nigeria. Treatments consisted of four time of seed-bed preparations namely 0, 3, 6, and 9 weeks intervals, laid out in a randomized complete block design (RCBD) with three replications. Selected physical and chemical properties of the soil and agronomic parameters of the test crop such as tuber yield (TY) and tuber number (TN) were measured. Data generated were subjected to analysis of variance (ANOVA) and the significant means separated using the Fisher’s Least Significant Difference (FLSD) at P=0.05. The statistical results showed that at harvest, the 0 week and 3 weeks tillage intervals significantly improved the tuber yield and tuber number, respectively. Again, the result of the seed-bed preparation at post-harvest revealed that the 0 week interval proved to cause the highest improvement of the soil physical and chemical properties. Essentially, the effect of age of seed-bed preparation on soil C/N ratio indicate that the 3 weeks interval treatment increased the C/N ratio. It was concluded that the 3 weeks tillage treatment showed the highest level of improvement of both the tuber yield and the soil C/N ratio at post-harvest seedbed preparation, while the 0 week treatment recorded the highest improvement of the tuber number at harvest and of the soil physical and chemical properties at post-harvest, for most of the studied parameters.

The effects of flower removal and earthing up on tuber yield and quality of potato (Solanum tuberosum L.)

A field experiment was conducted in Eastern Tigray, Ethiopia, during the summer season to determine the effects of flower removal and earthing up time on the tuber yield and quality of potato (Solanum tuberosum L.). The experiment comprised three flower removal stages and five earthing up time treatments, which were laid out in a randomized complete block design (RCBD) of a 5x3 factorial arrangement with three replications. Data collected on tuber yield and quality parameters were analyzed using SAS version 9.2. The interaction of flower removal stages and earthing up time treatments affected marketable and unmarketable tuber number and yield, total tuber number and yield, large-sized tuber weight, and number of large-sized tubers. The medium and small-sized tubers were also affected by main treatments but not by their interaction treatments. Similarly, dry matter content was significantly (p<0.05) affected by flower removal alone, but not by earthing up time and its interaction with flower removal. Generally, the highest marketable tuber yield (30.25 t ha-1), large-sized tuber weight (424.9 g), the number of large-sized tubers (5), and total tuber yield (30.96 t ha-1) were recorded in the treatment of potato flower removed at the bud stage and earthed up at 15 days after complete emergence. Therefore, the removal of potato flowers at the bud stage and earthing up at 15 days after complete emergence and common cultivation can be practiced for better tuber yield and quality of potato.

Response of potato clones to planting dates in Pokhara, Kaski, Nepal

A field trial was conducted to optimize the planting date and appropriate clone for ware potato production at Horticulture Research Station, Malepatan, Pokhara from October 2015 to March 2016. The trial was laid out in two factors Factorial Randomized Complete Block Design. There were nine treatments with three replications. The treatments comprised of three dates of planting (30th October, 14th and 29th November) and three potato clones (Janakdev, Lbr 40 and PRP 266264.1). The results showed that the main effects of planting dates and potato clones significantly (P<0.05) affected most growth, yield and yield attributing parameters of the crop. Interaction effect of planting dates and potato clones also significantly influenced the number of above-ground stems per plant, ground cover percentage, number of tubers per plant, number and weight of small size tuber (<25 g), weight of medium or seed size (25-50 g) tuber and large size (>50 g) tuber, number and yield of tubers per plot, and yield t/ha. The highest yield (37.05 t/ha) was obtained from 14th November planting. The clone Lbr 40 produced a higher yield (36.05t/ha). The clone PRP 266264.1 planting on 30th October planting produced significantly a higher yield (41.34t/ha). The clone Lbr 40 produced significantly highest number and weight of large size (>50 g) tuber. Number of small size (<25 g) tuber per plot or unmarketable tuber significantly increased on delayed planting.

Plant Growth and Tuber Yield of Several Exotic Potato Genotypes

Potato stolon and tuber number are the most important determinants of yield and these traits are associated with planting time and genotype. This study was conducted to evaluate plant growth, tuber yield contributing traits and tuber yield of potato genotypes in two planting dates. The experiment was done in randomized complete block design with three replications. Results showed that plant growth and traits that contribute to tuber yield of potato were significantly influenced by planting dates and genotypes. Stolon and tuber number as well as tuber weight were periodically investigated. It was observed that the performance of those traits were always higher in 23rd November planting. Different genotypes performed differently on all the studied parameters. Among the genotypes tested, G1 (AC 10069) produced the highest number of stolons, tubers, tuber weight, length and yield of tuber as compared to the check variety. It was observed that 23rd November planted G1 (AC 10069) gave the highest tuber yield (17.79 t.ha-1) which was statistically similar with G3 (AC 10110) (17.00 t.ha-1) when compared to the check variety. It can be concluded that planting time as well as genotype are the critical factors that determine potato yield.

APLIKASI PUPUK KOMPOS DAN FREKUENSI PEMUPUKAN NPK DALAM MENINGKATKAN PRODUKSI BAWANG MERAH (Allium ascalonicum L) PADA TANAH GAMBUT

ABSTRACT Peatlands is a very specific ecosystem with conditions that are always flooded, fragile, relatively infertile, able to absorb more water, and bad aeration. Riau has the largest peat land, which is 64% of the total peatlands area in Sumatra, but the development of shallot has not been intensively cultivated. So it must be dealt with seriously. The use of compost fertilizer and the frequency of NPK apply can improve the nature of these peatlands and increase crop production. The aim of study was to determine the interaction effect and the main application of compost and the frequency of NPK apply to increasing shallot production on peat soil. Research conducted at the Faculty of Agriculture Experimental Farm, Riau Islamic University during 6 month, i.e. form March - August 2018. Factorial Completely Randomized Research design, the first factor was 10, 20 and 30 tons/ha of corn compost, the second factor was NPK 16:16:16 fertilization frequency 1 and 2 fertilizing doses of 150, 300 and 450 kg/ha. Parameters observed were peat analysis, tuber number, tuber diameter, wet tuber weight per clump, dry tuber weight per clump and percentage of tuber shrinkage. The results showed that the interaction and main effects were significant for all observed parameters with the best treatment of compost is 30 tons/ha and 2 times the fertilizer dose of 150 kg/ha per application (300 kg/ha). Keywords: Shallot, Frequency, Compost, Fertilization, NPK, Production

Pengaruh Konsentrasi Pupuk Organik Cair Nasa dan Jarak Tanam Terhadap Pertumbuhan dan Hasil Tanaman Bawang Merah (Allium ascalonicum L). Asal Biji.

Abstrak. Penelitian tentang Pengaruh Konsentrasi Pupuk Organik Cair Nasa dan Jarak Tanam Terhadap Pertumbuhan dan Hasil Tanaman Bawang Merah (Allium ascalonicum L). Asal Biji, telah dilakukan di Kebun Percobaan dan Laboratorium Hortikultura Fakultas Pertanian Universitas Syiah Kuala Darussalam Banda Aceh. Penelitian dimulai dari bulan Januari sampai Juni 2016. Penelitian ini bertujuan untuk mengetahui pengaruh konsentrasi pupuk organik cair Nasa dan jarak tanam terhadap pertumbuhan dan hasil tanaman bawang merah, serta interaksi antara kedua factor tersebut. Rancangan yang digunakan pada penelitian ini adalah Rancangan Acak Kelompok faktorial yang terdiri atas 2 faktor dengan pola 3 x 3. Faktor pertama adalah konsentrasi pupuk organik cair Nasa dan faktor kedua adalah jarak tanam. Parameter yang diamati meliputi tinggi tanaman umur 20, 40, 60 HSPT, jumlah daun umur 20, 40, 60 HSPT, bobot berangkasan basah, bobot berangkasan kering, berat umbi kering, jumlah umbi, diameter umbi dan potensi hasil. Hasil penelitian menunjukkan konsentrasi pupuk organik cair Nasa berpengaruh sangat nyata terhadap tinggi tanaman umur 20 HSPT, bobot berangkasan basah, bobot berangkasan kering, berat umbi kering, jumlah umbi, potensi hasil, serta berpengaruh nyata terhadap tinggi tanaman umur 40 HSPT. Pertumbuhan dan hasil terbaik dijumpai pada konsentrasi 5 ml/L air. Jarak tanam berpengaruh sangat nyata terhadap tinggi tanaman umur 40 HSPT, jumlah daun umur 40 HSPT, berat umbi kering, potensi hasil, serta berpengaruh nyata terhadap bobot berangkasan kering. Pertumbuhan dan hasil terbaik dijumpai pada jarak tanam 15 cm x 15 cm. Terdapat interaksi yang sangat nyata antara konsentrasi pupuk organik cair Nasa dengan jarak tanam terhadap tinggi tanaman 20 HSPT, serta interaksi yang nyata terhadap bobot berangkasan basah, bobot berangkasan kering dan potensi hasil. Interaksi terbaik diperoleh pada kombinasi perlakuan antara konsentrasi pupuk organik cair Nasa 5 ml/L air dengan jarak tanam 15 cm x 15 cm.Effect of Nasa Liquid Organic Fertilizer Concentration and Planting Distance to Growth and Red Onion Plant Results (Allium ascalonicum L). Origin of SeedsAbstract. Research on the Effect of Nasa Liquid Organic Fertilizer Concentration and Planting Distance to Growth and the Result of Red Onion (Allium ascalonicum L). The Origin of Seeds, has been done in the Experimental Garden and Horticultural Laboratory of the Faculty of Agriculture, Syiah Kuala University of Darussalam Banda Aceh. This study starts from January to June 2016. This study aims to determine the effect of Nasa liquid organic fertilizer concentration and plant spacing on the growth and yield of shallot crops, and the presence or absence of interaction between the two factors. The design used in this research is Randomized Block Design The factorial pattern consists of 2 factors with 3 x 3 pattern. The first factor is the concentration of liquid organic fertilizer Nasa and the second factor is plant spacing. The parameters observed were plant height of 20, 40, 60 HSPT, number of leaves aged 20, 40, 60 HSPT, wet weighted weights, dry weighted weights, tuber weight, tuber number, tuber diameter and yield potential. The results showed that the concentration of Nasa liquid organic fertilizer had very significant effect on plant height of 20 HSPT, wet trimmed weight, dry weighted weight, dry bulb weight, tuber number, yield potential, and significant effect on plant height of 40 HSPT. The best growth and yield is found at a concentration of 5 ml / L of water. Plant spacing has a very significant effect on plant height of 40 HSPT, number of leaves aged 40 HSPT, weight of dry bulb, yield potential, and significant effect on dry-weighted weights. Growth and yield of best plants are found at plant spacing of 15 cm x 15 cm. There is a very real interaction between the concentration of Nasa organic liquid fertilizer with plant spacing to plant height of 20 HSPT, as well as the apparent interaction of wet weighted weights, dry weighted weights and yield potential. The best interaction was obtained by a combination of the treatment of concentration of liquid organic fertilizer Nasa 5 ml / L of water with spacing of 15 cm x 15 cm.

Evaluation of Yield and Yield Components of Two Potato Cultivars in Khorasan Razavi Province of Iran

In order to study the yield and yield components of two potato cultivars, an experiment was conducted as a split plot based on a randomized complete block design with three replicates. The experiment was performed in two locations, Jolgeh-Rokh district, and Fariman city, in professional farmers’ fields in Khoarasan Razavi province. The main plots consisted of two potato cultivars, Agria and Fontane cultivars (medium maturing), which were identified as the main cultivars used in chips production factories in the Province. Our results showed higher potential of Agria cultivar for production of stems per plant compared to Fontana cultivar. Both stem number and tuber number per plant along with tuber weight and tuber yield were higher in Fariman location than in Jolgeh-Rokh.