Maximum Tuber Yield Research Articles

Potato ( Solanum spp.) in the hot tropics. VI. Plant population effects on soil temperature, plant development and tuber yield

Nine experiments were run at three hot tropical sites (5–12°S, 180–800 m) within Peru to quantify the influence of plant population on soil temperature and growth and yield of the potato. Radiation interception was greatest at the highest plant populations and soil cooling was directly proportional to the amount of crop cover over the soil, but no appreciable effect on the timing of tuber initiation was apparent. More stems per unit land area leading to a higher leaf area index ( lai) were primarily responsible for greater interception of radiation at the higher plant populations, although some compensation in stem number per unit land area and in lai at lower populations was evident later in the season. In general, tuber yield increased linearly with increases in planted population over the range studied (2.7–12.5 plants m −2, and in one experiment to 31.7 plants m −2), and was proportional to increases in the amount of intercepted radiation. Tuber yields ranged from 8 to 60 t ha −1 over sites and populations. Vigorous clones with Solanum tuberosum spp. andigena in their genetic background constituted the exceptions to this linear trend, and for these clones yields declined at the highest populations, particularly when the rectangularity of planting vastly deviated from square patterns. Tuber yield of Solanum tuberosum spp. tuberosum and Neotuberosum ( S. tuberosum spp. andigena selected for tuberization under long-day conditions) clones did not respond to variations in rectangularity of planting and, probably due to their small stature and early maturity, did not demonstrate signs of intense between-plant competition for tuber yield as measured with the Kira competition density index. In contrast, for clones with Solanum tuberosum ssp. andigena in their genetic background, maximum tuber yield at populations greater than 5.5 plants m −2 was dependent on the rectangularity of planting, and declined as the latter deviated from squareness. Since the proportion of marketable tubers was scarcely affected by the planting densities, plant population of S. tuberosum ssp. tuberosum clones planted in hot climates should be as close as possible without limiting the amount of soil available for hilling-up.

Planting Dates Related to Tuberous Root Yield, Vine Length, and Quality Attributes of Yam Bean

Abstract Plant growth and tuberous root development in yam beans (Pachyrrhizus erosus L. Urb) were investigated using a series of 2-week plantings from April to December. Decreasing daylength at time of planting initiated tuberous root development, whereas increasing daylength inhibited tuberous root development and promoted vine and leaf growth. Once tuberous root formation and flowering began, stem and leaf growth ceased. At the time of planting, the critical daylength for tuberous root formation and flowering was 11 to 12 hr. The optimum planting date in Hawaii for maximum tuber yield of 24 t·ha–1 for yam beans was found to be September to October. Tuberous root development was sigmoidal, with dry matter percentage declining from 17.5% to 9%. There was little change in tuberous root acidity or total sugars during growth. Titratable acidity was about 20 meq·g–1 fresh weight if not induced to form tuberous roots, and ≈15 meq·g–1 fresh weight in plants forming tuberous roots. Total sugar was in the range of 30 to 50 mg·g–1 fresh weight during tuberous root growth of induced plants. Total phenols in the tuberous root declined during development, whereas roots from plants uninduced to form tuberous roots had an increased level of total phenols.

The effects of nitrogen application on growth and nitrogen distribution within the potato canopy

SUMMARYThe effect of applying nitrogen (N) fertiliser on the growth and distribution of N within the potato canopy was studied in 1983 and 1984. In both years N was applied either in excess of that required to produce maximum tuber yields, or not at all. The large application of N changed the pattern of canopy growth ‐ stimulating growth of leaves at the top of the stem, particularly lateral branches, for longer during the season, and accelerating the death of (shaded) leaves at the base of the canopy. The pattern of canopy senescence was, therefore, changed from a synchronous to a progressive type.Application of nitrogen fertiliser at supra‐optimal rates increased the N contents of leaves, stems and tubers. The extra N in the leaves of these plants was present as reduced N in all leaf positions, and as nitrate (NO‐3) in the lowermost leaves. In addition, substantial quantities of NO‐3 were also stored in the stems. Part of this extra N in the canopy was redistributed during subsequent growth, especially to the lateral branches as crop N uptake slowed towards the end of the season. In addition, substantial quantities of N were also potentially available for redistribution to the growing tubers. There was little redistribution of N from the leaves of N‐deficient plants.It is suggested that redistribution of N in the canopy of N‐replete plants allowed the growth of lateral branches towards the end of the season, thereby maintaining photosynthetically active leaves for longer than N‐deficient plants.

Nitrogen management of potatoes in the presence of farmyard manure and PK fertilizer on acid hill soil of Shimla

SUMMARYA field experiment was conducted on acid soil of Kufri (Shimla) from 1980 to 1982 to study the effect of 30 t farmyard manure/ha (FYM) and 88 kg P + 160 kg K/ha (PK) on the response of potatoes to N fertilizer and on soil properties. There was a highly significant response of potato to N and the response was greater in the presence of PK than in the presence of FYM. The dose of N for maximum tuber yield with PK (39·9 t/ha) was 194 kg/ha, whereas for maximum yield with FYM (33·2 t/ha) it was 128 kg/ha. FYM met the P and K needs of potato when 100 kg N/ha was applied but not when 180 kg N/ha was applied. N fertilizer increased N concentration but decreased P and K concentration in leaves and tubers. The concentration of P and K was higher but that of N was lower with PK than with FYM. N fertilizer enhanced the uptake of P and K but its effect was not significant with FYM.After 3 years of treatment FYM improved organic carbon, total N and NO3 status of the soil. N as calcium ammonium nitrate increased organic carbon in the presence of PK but decreased it in the presence of FYM. N fertilizer had little effect on total N, NO3 and available P content. N application depleted available K and the depletion was proportionate to the rate of N applied. The application of FYM and PK increased available P and K content of the soil and the increase was more with PK than with FYM.

The successful use of intercropping for weed management in medicinal yam (Dioscorea floribundamart and gal)

Abstract Herbicides (fluchloralin, methabenzthiazuron, diuron oxyfluorfen, simazine, thiobencarb and alachlor), organic mulch and intercropping with cowpea (Vigna unguiculata L. Walp) and blackgram (Vigna mungo L.), In comparison with unweeded and weed free check, were studied during the rainy seasons (July‐Sept) of 1982 and 1983 in a 2 year crop of medicinai yam. Simazine 2 kg/ha was most effective in arresting weed dry matter but like other herbicides was phytotoxic to medicinal yam. The weed free check gave maximum tuber yield. Organic mulch, yam plus cowpea and yam plus blackgram were similar in effect and superior to any of the herbicides. The yam plus blackgram association proved most economical due to the additional grain yield of 10–5 and 8 q/ha obtained in the first and second years of study, respectively.

STUDIES IN POTATO AGRONOMY 1 EFFECT OF LANT DENSITY AND TIME OF FERTILIZER APPLICATION ON GROWTH AND DEVELOPMENT OF POTATO VARIETIES

Experiments conducted with different plant densities, time of fertilizer application and varieties revealed that a plant density of 100,000 plants/hectare (50 cm x 20 cm spacing) recorded quite high LAI, RGR, NAR and CGR of potato crop in most of the growth stages and this ultimately helped in producing high TGR and finally recorded high tuber yield per plant under this mild and short winter conditions of West Bengal. All growth parameters after their initial rise declined gradually as the crop progressed towards its maturity. Application of fertilizers (150, 100 and 100 kg/ha of N. p., and K,0 respectively) in two splits-half at planting and half at 25 days after planting was found most conducive for high rates of growth and development of this crop particularly at the early growth stages which ultimately produced maxium tuber yield per plant. Both Kufri Chandramukhi and Kufri Jyoti performed well under this conditions, however, Kufri Chandramukhi gave early harvest while Kufri Jyoti produced maximum tuber yield per piant.

Optimum phosphate and potassium levels in potato tops

The feasibility of using chemical plant analysis for early diagnosis of phosphate and potassium deficiencies in potatoes was studied. Plant tops (leaves including stems) were sampled from fertilizer field experiments and analyzed for total N, P and K. The inverse relationship between plant N concentration and plant age was used for correcting plant P and K concentration to a standard N content, thus partly eliminating growth stage differences. Maximum tuber yields were associated with leaf P above 0.5% and leaf K above 5%, both at 5% N in DM. With each percent decrease in N concentration the critical value for P decreases by about 0.1% and that for K by about 0.5%. Serious yield reductions may be found below 0.3% P and below 3% K, again at an N-level of 5%.

EFFECT OF PLANT DENSITY AND TIME OF FERTILIZER APPLICATION ON TUBER RUI KING RATE, SIZE DISTRIBUTION AND TUBER YIELD OF POTATO

The results of the field experiments conducted in lateritic acid soils at the College of Agriculture Farm, Sriniketran, Visva Bharti, West Bengal during the rabi seasons of 1979-80 and 1980-81, revealed that a plant density of 100,000 plants per hectare resulted in high level of tuber bulking rate, produced large quantity of medium and big sized tubers which ultimately recorded maximum tuber yield of potato under this short and mild winter condition of West Bengal. Split application of fertilizers (150 kg N, 100 kg P. O, and 100 kg K, O/hat-hait at planting and the other half at 25 days after planting was found beneficial for achieving high rate of tuber bulking, more of larage sized tubers and finally high tuber yield. Kufri Jyoti produced maximum yield (198 g/ha) through large quantity of medium and big sized tubers whlie Kufri Chandramukhi gave an early harvest producing 170 q/ha of potato tubers

The Effect of Lime on the Availability of Residual Phosphorus and its Extractability by Dilute Acid

Liming recommendations for acid soils are often intended to give a soil pH of 6.5. However, liming highly weathered soils to pH levels near neutrality often results in low soil P availability. The objective of this study was to determine the long-term effects of liming an acid, P-deficient Placid sand (sandy, siliceous, hyperthermic Typic Humaquept) on the availability of residual fertilizer P to potatoes (Solanum tuberosum L.). Dolomitic limestone was applied in November 1977, at rates of 0, 2,240, 4,480, and 8,960 kg/ha in a split-plot design with lime as main plots and P treatments as subplots. Phosphorus was applied at rates of 0, 56, 112, and 168 kg/ha in 1978. In 1979 and 1980, P plots were split with one-half fertilized with 56 kg P/ha and the other one-half not fertilized with P (residual). In 1978, maximum tuber yields and top dry weights occurred at the 2,240 kg/ha lime rate which resulted in a soil pH of 5.8. Plant P concentrations were unaffected by lime at any sampling date. In 1979, availability of residual soil P decreased with lime rates > 2,240 kg/ha but not enough to significantly affect yields. However, in 1980, overliming injury was observed for tuber yields at the higher lime rates which was the result of P deficiency. Application of P at planting eliminated the overliming injury with maximum yields occurring in the pH range of 6.0 to 6.5. The decrease in available P at soil pH levels above 5.5 was not accompanied by similar changes in Mehlich I-extractable P. It appears that liming to pH 6.5 in this study resulted in fertilizer reaction products that were more soluble in dilute acid but less plant available than those formed under more acid conditions. However, the Mehlich I extractant appeared to be a suitable extractant for P on this soil if pH was taken into account when interpreting soil-test P.

Growth and plant-water relations of sweet potato (Ipomea batata) as affected by soil moisture regimes

Effects of four water table (WT) depths (15, 30, 50, and 70 cm below the soil surface) were compared with a free draining control and with transient and continuous flooding for growth and plant-water relations of two sweet potato cultivars, TIS 2148 (C-1) and TIS 2295 (C-2). Cultivar C-1 accumulated significantly more dry matter at 101 days after planting for transient flooding (TF) in comparison with WT15, WT50, WT70, and freely drained control treatments. Cultivar C-2 produced less dry matter than C-1 and its dry matter production was also more for TF compared with WT15 and free draining control. At 137 days after planting, however, the maximum above ground dry matter production was observed in WT70 for C-1 and in TF treatment for C-2 cultivars. The maximum tuber yield was obtained in WT15 and WT50 treatments, whereas tubers in the TF treatment were partly decomposed and rotten. No tuber yield was obtained in continuous flooding treatment for 14 consecutive days. Leaf water potential and leaf diffusive resistance were also affected by soil moisture regimes.

Effect of phosphate fertilization and inoculation with VA-mycorrhizal fungi on performance of cassava ( Manihot esculenta crantz) grown on an alfisol

Field and greenhouse investigations were carried out in southern Nigeria to study the effects of phosphate fertilization and inoculation with vesicular—arbuscular mycorrhiza on performance of the local cassava ( Manihot esculenta Crantz) cultivar Ishinukakijan grown on Egbeda soil series (Oxic Paleustalf). Field-grown cassava appears to have a low P requirement. At 3.4 ppm Bray P-1 or about 0.01 ppm P soil solution tuber yield was still reasonably high at 35 t/ha. Eight ppm Bray P-1 or 0.04 ppm P in the soil solution were required for maximum tuber yield, about 49 t/ha. Sampled at 3 months after planting, a P concentration of above 0.5% and 0.38% in leaf blades and leaf petioles, respectively, were considered adequate. Percentage mycorrhizal fungal infection of cassava fibrous roots depended on extractable soil P levels, being low at high soil P levels and high at low soil P levels. Inoculation with mixed native VA-mycorrhizal fungi or with Glomus mosseae significantly improved growth, lowered P response and increased P uptake in plant tops of pot-grown cassava in sterilized soil. Mycorrhized cassava to utilize phosphorus better from the more available Morocco rock phosphate than one from Togo. Inoculation with Glomus mosseae reduced plant growth and P uptake in unsterilized soil. The results of the pot trials lend support tha the observation that the low P requirement of field-grown cassava may be related to its association with VA-mycorrhizal fungi.

Nitrogen and potassium fertilization of potato

Fourteen one-year N- and K-fertilization experiments for potato were carried out on coarse mineral soils on different sites in Finland. The nitrogen fertilization (from 50 to 156 kg/ha N) was given in the form of ammonium nitrate limestone, and the potassium (42—179 kg/ha K) in potassium sulphate. The nitrogen fertilization affected significantly both the yield and the quality of the tubers. The maximum tuber yield was achieved at the nitrogen application rate of 110 kg/ha. The economically most advantageous fertilization rate was 80 kg of nitrogen per hectare, if only the amount of the yield was taken into account. The nitrogen fertilization weakened the quality of the tubers. The weight and the size of the tubers increased, but the starch content of the tubers decreased as a result of the nitrogen fertilization. The starch yield also turned out to be the smallest at the heaviest nitrogen fertilization. Further, the biggest rate of nitrogen weakened the flavor of the tubers, depressed their mealiness, and increased slightly their discoloration when raw. The fertilization had no effect on the darkening of cooked potatoes. In these one-year experiments, the increase of the potassium fertilization from 42 kg/ha K did not have a significant effect on the yield and the quality of the tubers.

Effects of magnesium on the performance of potato in the Tista Meander Floodplain soil

The experiment was conducted in the farmers' field of the Farming Systems Research and Development (FSRD) site, Rangpur under Tista Meander Floodplain highland soils (AEZ # 3b) for three consecutive Rabi seasons (2002-03 to 2004-05). The potato variety Cardinal was tested with 5 levels of magnesium viz., 0, 5, 10, 15, and 20 kg/ha to observe its effects on potato and to find out the optimum and economic dose of Mg for potato. The three years’ results revealed that magnesium had significant effects on tuber yield of potato. Significantly higher tuber yield (32.33, 31.63, and 28.03 t/ha in three successive years) was obtained from 10 kg/ha of Mg. Tuber yield tended to decrease with increasing rate of Mg beyond 10 kg/ha. Tuber yields increased over control by 18 and 31 % when magnesium was applied @ 5 and 10 kg/ha, respectively. Yield response to added Mg was quadratic in nature. The regression with Mg levels indicate that maximum tuber yield (30.32 t/ha) could be obtained at 13 kg/ha of Mg and the economic dose was also 13 kg/ha of Mg. Use efficiency of Mg was 512.25 kg tuber of potato per kg Mg per ha. After optimum level of Mg (13 kg/ha) tuber yield reduced by 3.83 kg for additional use of one kg Mg/ha. Key Words: Potato; tuber yield; magnesium; use efficiency. DOI: 10.3329/bjar.v34i2.5797Bangladesh J. Agril. Res. 34(2): 255-261, June 2009