Aspects of nitrogen fertilizer rate on tuber dry-matter content of potato cv. Record

Summary Effects of three rates of fertilizer nitrogen, viz. 80, 160 and 240 kg N/ha, on tuber yield and dry-matter percentage in potato cv. Record were compared in two experiments. Crop nitrogen uptake increased with application rate but total uptake differed between experiments. Tuber yield was highest following application of 160 or 240 kg N/ha but differences between these two rates were not significant. Tuber dry-matter percentage was reduced in one experiment with increasing nitrogen rate, but in the second experiment final dry- matter percentage was highest following application of 240 kg N/ha. In all treatments, positive linear relationships were found between dry matter percentage and mean fresh weight of tubers >30 mm, but within experiments, the regression coefficients were generally reduced by increased crop nitrogen uptake.     

Influence of Source and Time of Potassium Application on Potato Growth,Yield, Economics and Crisp Quality

Field studies were conducted at the Central Potato Research Institute Campus, Modipuram (India), during two seasons (2003–2004 and 2004–2005), with two processing cultivars (cvs Kufri Chipsona-1 and Kufri Chipsona-2) and nine combinations of potassium source (K-chloride, K-sulphate and K-nitrate) and time of K application (basal dressing, split application and split application + foliar spray) to investigate their effect on tuber yield and processing attributes for crisp production under subtropical conditions. Yearly variations were observed for most of the variables studied. Between cultivars, the tuber and biomass yield was higher in cv. Kufri Chipsona-1, whereas specific gravity, tuber dry-matter percentage and crisp recovery were higher in cv. Kufri Chipsona-2. Stem number, plant height and compound leaf number were not influenced by sources of K fertilizer or application time. Processing-grade tuber yield, total tuber yield and biomass yield were statistically similar for K-chloride and K-sulphate and lower for K-nitrate. K sources affected both specific gravity and tuber dry-matter percentage significantly; K-sulphate and K-nitrate gave significantly higher values than K-chloride. The application time had no significant effect on processing grade and total tuber yield or on tuber specific gravity and dry-matter percentage. Values for crisp colour and reducing sugars were within the acceptable range for all treatments. Crisp yields were calculated to be highest and oil percentage of the crisps to be lowest when K-sulphate was applied as K fertilizer. Net income and benefit:cost ratio were highest for K-chloride followed by K-sulphate and lowest for K-nitrate. The study suggests that for crisping potatoes, K-sulphate is more suited than K-chloride, as it not only increased tuber dry-matter percentage and crisp yield, but also decreased crisp oil percentage.     

Processing potential of potato cultivars at early harvests

Summary Assessments were made in three seasons of yields and tuber dry-matter percentages at harvests from June to early August in a range of cultivars gorwn at a coastal site in south-west Wales. Lareg differences in tuber dry-matter percentage were found between cultivars within seasons and also at similar dates between seasons.The cultivar Home Guard produced consistently high dry-matter percentages each year in the period from late June to early August but cv. Redord achieved similar or higher dry-matter contents after mid-Julyl. Most other cultivars produced lower dry matter percentages throughout the sampling period. The potential for the use of early maturing cultivars in late June and July for processing into crisps is discussed.     

长沙地区春马铃薯不同栽培方式比较试验

以中熟加工型马铃薯品种大西洋为试验材料,进行了春马铃薯的地膜覆盖栽培、敞土常规栽培、地膜加小拱棚覆盖栽培、稻草覆盖栽培、稻草加地膜覆盖栽培、稻草加小拱棚覆盖栽培和稻草加地膜加小拱棚覆盖栽培,共7种不同栽培方式的比较试验。结果表明:稻草加地膜覆盖栽培无论是在出苗速率,还是在植株生长势、抗病性以及产量和商品薯率等综合方面明显优于其它几种栽培方式,与敞土常规栽培(CK)相比,增产明显,达到了324.2%;其次是稻草加小拱棚覆盖栽培,增产220.3%;而地膜覆盖栽培和稻草覆盖栽培,增产则较小,分别增产42.0%和27.1%。     

马铃薯节水栽培模式试验研究

以定薯1号为试验材料,在定西市安定区团结乡和定西市旱作农业科研推广中心两个试验点设置了白地膜全膜双垄沟播种、黑地膜全膜双垄沟播种、白地膜半膜垄上播种、黑地膜半膜垄上播种、白地膜半膜垄侧播种、黑地膜半膜垄侧播种和露地种植（CK）共7个处理的节水模式比较试验。结果表明：黑膜全膜覆盖的出苗率、大薯率、产量和成本均明显优于其他栽培模式,折合产量30 326 kg/hm2,较对照增产8 537 kg/hm2,增幅达39.2%,大薯率达82.3%。     

秸秆粉碎覆盖栽培对马铃薯产量及经济性状的影响

地膜覆盖技术的推广应用造成了土壤与环境的污染,对旱作农业的可持续性发展带来严重挑战。为了降低农业生产对土壤、环境的污染,探索寻求新型的绿色环保覆盖高效模式,通过运用粉碎秸秆来代替地膜,设置秸秆粉碎覆盖垄作侧播处理,与当地常规种植模式对比,研究了秸秆粉碎覆盖栽培对马铃薯产量及经济性状的影响。结果表明,玉米秸秆粉碎覆盖栽培处理的保温保墒效果不及黑色全膜双垄侧播处理,但能明显提高马铃薯单株粒数和单株粒重,单株粒数提高0.4个/株,单株粒重提高0.05 kg/粒,从而明显提高大薯率,大薯率相比黑色全膜双垄侧播栽培模式提高6.0个百分点,进而提高马铃薯产量。秸秆粉碎覆盖栽培处理下产量最高,达到41339 kg/hm^2,较黑色全膜双垄侧播处理增产14.3%,较黑色半膜覆盖侧播处理增产28.1%,较露地穴播增产43.5%。因此,秸秆粉碎覆盖栽培是一项适宜半干旱区马铃薯生产种植的绿色环保覆盖高效栽培模式。     

咸宁市马铃薯双膜小拱棚栽培试验

针对咸宁气候特点和市场需求,进行双膜小拱棚栽培和单膜覆盖栽培比较试验,比较其生育性状、冻害、发病率、块茎数量性状、产量、生产成本及效益。试验结果表明,双膜小拱棚栽培不仅能提早季节,抢占市场,增加效益,而且能有效地防止低温危害,减轻春季雨水多造成烂薯缺苗以及病害流行。     

Effects of temperature and photoperiod on early growth and final number of tubers in potato (Solanum tuberosum L.)

Summary A phytotron experiment with all combinations of two photoperiod (12 or 18 h) and four temperature (18/12, 22/16, 26/20 or 30/24 °C; 12h/12h) treatments was carried out to analyse quantitative effects on early tuber growth, dry-matter partitioning and number of tubers of two cultivars. Higher temperatures and longer photoperiod delayed the onset of expolinear tuber growth and the onset of linear tuber bulking. Higher temperatures also gave lower absolute tuber growth rates. Photoperiod did not affect absolute tuber growth rate at lower temperatures. Higher temperature and longer photoperiod gave lower relative rates of partitioning of dry matter to the tubers. Differences between treatments in numbers of tubers initiated were inconsistent. This quantitative analysis of the effects of temperature and photoperiod on characteristics of tuber growth should prove useful in potato modelling.     

天水市山旱地马铃薯不同栽培方式试验

通过马铃薯不同栽培方式试验研究,选择适宜天水市山旱地马铃薯主栽品种天薯10号获得高产的有效配套栽培技术模式。结果表明:马铃薯不同地膜覆盖相比对照能提早出苗、成熟,表现出较好的抗旱保墒性和增产效应,增产率60.0%～96.7%。黑膜半膜覆盖栽培下的产量最高,为22 969 kg/hm2,比露地栽培增产11 297 kg/hm2,增产率为96.7%;商品薯率、株高、单株薯重、纯收入最高,生育期最长,病害较轻。     

Agronomic factors affecting the yield and quality of forage maize in Ireland: effect of sowing date and plastic film treatment

The objectives of these studies were to examine the effects of sowing date and plastic film on the yield and quality of forage maize ( Zea mays L.) in Ireland, a marginal maize-growing area. In 1989–95, comparisons were made of maize sown through clear plastic film (PP treatment), and maize sown in the conventional manner without plastic (NP treatment), in terms of dry-matter (DM) yield and quality (cob, grain and starch contents). The PP treatment significantly increased DM yields in five years, with a mean yield increase of 3·10 t ha⁻¹. Whole-plant DM content increased (significant in four years) by a mean of 0·15; cob content increased (significant in five years) by a mean of 0·32; grain content increased (significant in all of the three years examined) by 0·75; and starch content increased from 236 to 318 g kg⁻¹ DM ( P  < 0·01) in 1995 where the plastic film treatment was used. Organic matter digestibility values were similar for both treatments in 1995. Sowing date in the April-May period had no consistent effect on DM yields, but early sowings did increase cob (significant, except in 1994), grain (significant in one (1995) of the two years tested) and starch ( P  < 0·05) contents (only tested in 1995). Sowing on 11 April 1995 through perforated plastic gave lower yields than the NP treatment sown on the same date, due to severe frost damage in early May.     

Factors affecting the relationship between tuber size and dry-matter content

Two experiments are reported which examined the effect of various treatments on the relationship between tuber dry-matter content and tuber size using 0.25 inch size grade increments. The data were analyzed by an orthogonal polynomial technique and it was found that the relationship was of a quadratic nature in all cases. Significant treatment differences were found between planting densities, row widths and varieties. At small tuber sizes treatments with high stem densities produced tubers with a higher dry-matter content than tubers from low stem densities. At larger tuber sizes the dry-matter content of tubers from high densities declined most rapidly. The treatment differences at small tuber sizes were generally explained by the rates of water use by the crop and it is suggested that the decline in tuber dry-matter content at large tuber sizes may be a result of a moisture sress induced change from starch to sugar in parts of the tuber. The implications of these findings are discussed. The type of relationship found would indicate that the production of large tubers does not necessarily result in high dry-matter content. It is clearly essential to use very closely graded sizes of tuber when examining treatment effects on factors such as dry-matter content.     

马铃薯地膜覆盖栽培的地积温效应及其生物学意义

两年的田间试验表明，地膜覆盖栽培马铃薯具有显著的早熟增产效应．对不同处理的土壤温度、地下积温和地上积温比较后发现，地下积温是限制马铃薯生长发育的重要生态因素。覆膜栽培可以提早满足马铃薯生育早、中期对地积温的要求，从而达到早熟高产的目的。多熟制条件下，这种效应尤为重要．     

LEAFINESS, CHEMICAL COMPOSITION AND YIELD OF SOME LUCERNE VARIETIES

The leaf: stem ratio on green and dry weights, chemical composition and yield of dry-matter and protein per acre were determined for ten varieties of lucerne at the National Institute of Agricultural Botany during 1955–8. The first cut was taken when about 20% of the flowers were open and the subsequent cuts when 10–15% were open.
The mean leaf: stem ratio, based on green weights, showed no significant difference between varieties. The early varieties, however, contained a higher proportion of dry-matter in the leaf and a lower proportion in the stem than did the mid-season and late types. As a result, the early types tended to show a higher leaf: stem ratio based on dry-matter than the mid-season and late types.
The early types also contained a significantly higher percentage of protein than the mid-season and late types, and had a lower crude fibre content for the whole plant.
Highly significant differences were established between varieties and types in the total yields of dry-matter and protein from three cuts in each of three seasons, when all were cut at similar stages of maturity. The heaviest yields of dry-matter and protein were secured from Eynsford, Chartrain-villiers and Du Puits, the lowest from certified Provence and Grimm, both of which came from an environment vastly different from that of Cambridge. Gamma, an early variety, had the highest percentage of crude protein at each cut during the three year period, but it was similar to FD 100 and Marais in total dry matter yield.     

Agronomic factors affecting the yield and quality of forage maize in Ireland: effect of plastic film system and seeding rate

The objectives were to compare the effects of two plastic film systems [perforated (PP) and complete‐cover (CC) systems] on the yield and quality of forage maize, and to study the effects of seeding rate on maize grown with, and without, plastic film. Between 1995 and 1998 (Experiments 1 and 2), comparisons were made of maize without plastic film systems (NP), sown through clear plastic film (PP) and covered with clear plastic film (CC). In the CC system, the plastic was removed manually from the crop. Two dates of removal (CC1 and CC2) were compared in 1995, while four removal dates (CC1, CC2, CC3 and CC4) were examined in 1996–98. In 1996–98, three sowing dates (early, mid‐April; mid, early‐May; late, mid‐May) were also examined. Four seeding rates (78 200, 93 900, 107 000 and 126 000 seeds ha^?1) were examined in two experiments (Experiment 3 in 1996 and Experiment 4 in 1996–98). No plastic was used in Experiment 3, while three plastic treatments (NP, PP and CC) were examined in Experiment 4. In the CC treatment, the plastic film was removed at the six‐ to eight‐leaf stage. In Experiment 1, the PP treatment gave lower DM yields than the NP treatment due to frost damage which killed 0·30 of the plants in the PP treatment. Plants were undamaged by frost in both CC treatments, and the CC2 treatment (plastic removal at the six‐leaf stage) gave significant increases in DM and grain yields. In Experiment 2, averaged over years and sowing dates, DM yields were significantly increased by all plastic film treatments except CC4. All plastic film treatments gave significantly earlier tassel emergence than the NP treatment, and significantly increased grain yields and contents of DM and grain. The highest yields of DM and grain were obtained from the PP system. Within the CC treatments, leaving the plastic film intact until the ten‐leaf stage (CC4) gave lower yields of DM and grain than removing the plastic film at an earlier stage. Averaged over years, the largest DM yields were obtained from the CC system with early‐sown material, while the yield differences between treatments with late‐sown crops under this system were not significant. Highest DM and grain yields were obtained with early sowing, while late sowing gave lower contents of DM and grain, and later tassel emergence. In Experiments 3 and 4, DM and grain yields increased as seeding rate increased up to 126 000 seeds ha^?1 with NP and CC plastic treatments. With the PP treatment, DM yield reached a plateau at 107 000 seeds ha^?1. Seeding rate did not significantly affect DM content in either experiments but grain content declined in both experiments as seeding rate increased.     

种薯重量对旱地马铃薯生长发育及产量的影响

在内蒙古阴山北部丘陵区半干旱条件下,通过田间试验研究了不同重量种薯对马铃薯生长发育及产量的影响。结果表明：在干旱条件下,马铃薯植株生长发育、主茎数及块茎产量与种薯重量有着十分密切的关系。在一定范围内,随种薯重量的增加,每穴茎数相应增加,植株表现生长旺盛,单位面积产量呈上升趋势,净产量则随种薯重量的增加呈下降趋势。以５０～７５ｇ种薯净产量最高,达９２８０．５～８０３１．０ｋｇ／ｈｍ２,商品薯率较高,经济效益最佳,种薯重量≥３００ｇ,净产量最低,仅３２２５．０ｋｇ／ｈｍ２,经济效益最差。     

Potato growth with and without plastic mulch in two typical regions of Northern China

Plastic film mulching is an important agricultural practice to save water and improve crop productivity in Northern China. Three field experiments were conducted to examine the effect of plastic mulch on soil temperature, potato (Solanum tuberosum L.) growth and evapotranspiration under drip irrigation in two typical regions of Northern China in 2001 and 2006. Results suggest that daily mean soil temperature under mulch was 2–9 °C higher than without mulch, especially during the early growth. Potato growth was restrained under mulching conditions in the North China Plain mainly due to the higher air temperature in this region and thus the higher soil temperature. The negative effects of mulching included a lower emergence and fewer marketable tubers per plant. Evapotranspiration and potato tuber yield were both reduced by mulch, especially in the North China Plain. In northwest China, mulch favorably increased the weight of jumbo tubers (W ≥ 300 g) per plant. Mulching duration had little effect on potato evapotranspiration in northwest China. However, both tuber yield and water use efficiency (WUE) decreased with increases in mulch duration, which suggests the plastic mulch should be removed early.     

Comparison of growth and yield parameters of Russet Burbank for a two-year period

The effect of three planting dates on stem, stolon, tuber number and size were compared throughout the 1979 and 1980 growing seasons. A relatively warm April and early May and a relatively cool late May and June in 1980 resulted in significantly higher stem and stolon numbers and a tuber population over double that of 1979. The highest average commercial yields ever recorded in the Columbia Basin were obtained with yields in some fields of 100 tons per ha on 48 hectare irrigation circles. On experimental plots tuber numbers increased from the latter part of May with successive sampling dates until late June and early July when a peak in number was reached after which a significant decline in number occurred. The decrease in tuber number was attributed to the phenomenon of reabsorption which was much greater with later planted potatoes. It occurred only in tubers of approximately 10 g size or smaller. Average tuber size in 1980 was one-half that of 1979 although total yield was 25 tons per ha higher because of significantly larger tuber numbers.     

不同揭膜期对南宁春植蔗生长及蔗茎产量的影响

为了探明覆膜甘蔗生长、产量及经济效益同步提高的最佳揭膜时期的栽培措施,本试验以桂糖03-2287甘蔗品种为材料,采用地膜覆盖栽培,设置齐苗期、分蘖末期和拔节伸长前期等3个不同生长时期揭膜处理,以不盖膜作对照,探讨不同时期揭膜对甘蔗生长及产量的影响。结果表明,比较不盖膜对照,地膜覆盖分蘖末期揭膜处理增产13.1%,差异极显著,齐苗期揭膜和拔节伸长前期揭膜分别增产6.4%和6.9%,差异显著;地膜覆盖处理间,分蘖末期揭膜比齐苗期揭膜和拔节伸长前期揭膜处理增产也达到极显著,而齐苗期揭膜与拔节伸长前期揭膜间的产量差异不显著。各处理的经济效益与蔗茎产量的高低成正相关,即分蘖末期揭膜拔节伸长前期揭膜齐苗期揭膜对照。由此表明,南宁春植蔗覆膜栽培以分蘖末期揭膜增产效果较好,过早或过迟揭膜都不利于产量的进一步提高。     

Effects of shoot,root and stolon temperature on the development of the potato (Solanum tuberosum L.) plant. III. Development of tubers

Summary The cultivars Bintje and Désirée were growth with their shoots, roots and stolons at different temperatures, to study the effects on tuber development. More tuber sites were initiated in ‘Bintje’ when the air, root or stolon temperature was increased but a combined increase of air and root temperature greatly reduced the number of sites. In contrast, each temperature increase reduced the number of tuber sites in ‘Désirée’ but an increase in temperature in one compartment usually increased the number of tubers set. The relative tuber set was enhanced by a combination of high stolon temperature and low root temperature. Especially an increase in air temperature reduced tuber yield and tuber dry-matter content, but increasing stolon temperature had the largest effects on the induction of second growth. Stolon and tuber development, dry-matter partitioning and initiation of second growth responded differently to variation in temperature around different plant parts suggesting that these processes are affected by different regulation mechanisms.     

播种方式对小麦生长发育及产量的影响

选用大穗型陕253和多穗型长武112两个品种，进行地膜穴播、露地穴播和露地条播，结果表明，地膜穴播对照露地条播的小麦生长发育显著加快，成穗率提高12－22个百分点,在穗数增加103－258万／hm^2，增产1350．0－1600．5mg/hm^2，增产幅度达27．5％－35．2％，增收906－1293元／hm^2；露地穴播的小麦前期比对照生长慢，拔节后生长速度猛增，干物质积累增加1．3－1．4倍，成穗率提高7－9个百分点，增产5．5％－15．1％，增收346－842元／hm^2。