摘要:

AbstractHigher growth and grain yield in rice was obtained in February planting as compared to July and October plantings. This was achieved through favourable leaf characteristics. In all the three plantings, leaf number monitored the leaf area rather than ILS which showed minimal alterations by the seasonality. There was a considerable variation in the attainment of critical leaf area index (LAI) among cultivars in different seasons. Thus, attainment of critical LAI would be necessary to influence the sink strength positively.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00866.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractA number of field experiments were conducted at the Viswavidyalaya Research Farm during 1984–85 to 1986–87 to study the effects of five growth regulatorsviz.Miraculan (a triacontanol based growth stimulant), Nutron (1‐triacontanol growth stimulant), Planofix (α‐napthylacetic acid), Paras or Mixtalol (Higher alcoholic carbon compounds) and N‐triacontanol on productivity of five different major oilseed cropsviz.rapeseed (Brassica campestrisL. var. yellow sarson), mustard (Brassica junceaL. Czern and Coss), sesame (Sesamum indicumL.), linseed (Linum usitatissimumL.) and safflower (Carthemus tinctoriusL.). Results showed the positive influence of growth regulators on the productivity of crops (10–40 % increase in yield); however the influence was not consistent over the years. N‐triacontanol when tried on mustard only improved the grain yield significantly, more so when applied with paras or planofix, sesame was most influenced by spraying planofix and paras. Nutron favourably influenced safflower and linseed. The test weight of grains followed by the number of pods/plant were influenced most by the application of growth regulators. Inconsistency in results over the years, however, need further investigations on the timi

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00867.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractNitrogen transportation from different organs was investigated by labelling pods, leaves and internodes of upper stem with15N‐urea during flowering. Labelled plants were harvested one month after flowering and determined the amount of15N in relative parts. The results of the experiment show the directions of15N applied in different organs during flowering. Transportation of15N applied in pods of lower terminal of the main stem and first branch was mainly directed to seeds inside the labelled pods, about 17 % of15N entered into seeds 7 days after last labelling, a little transportation each other between the branch and terminal was found, more than 80 % of15N applied on leaves during flowering was transported out of the leaves after flowering, 35 % and 67.93 % on average was translocated in pods for early and late flowering, respectively, while 55.97 % of15N applied on surface of internodes of upper stem below terminal was found in pods. It was corroborated that nitrogen transportation also occurs within pods by labelling different parts of pods, much greater amount of nitrogen was transported from lower part to upper part of pods than those in opposite directio

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00868.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractField experiments were conducted at Coimbatore, India with four dates of sowings in each of three seasons to determine the duration of phenological phases, heat unit requirements and evaluation of heat units to predict the developmental phases of Soybean (Glycine max[L.] Merr.). The variations in development of different phenological phases and maturity of Soybean due to season and sowing dates was manifested by varied accumulation of heat units calculated. There was a linear relationship between the number of days to flower initiation and cumulative day length. Growing degree days (GDD) were better predictors for development of phenological phases whereas maturity was controlled by Calender days and was closely followed by GDD. Photothermal units were the next best predictors for soybean developmental phases.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00869.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe effects of stand establishment and nitrogen fertilizer on yield and yield stability of winter oil‐seed rape (Brassica napusL.) were investigated in two field experiments in north eastern Germany (Mecklenburg‐Vorpommern). During six years of testing from 1984/85 to 1989/90 three sowing dates (10 Aug, 20 Aug, 5 Sept) as combined with three plant densities (60, 100, 140 plants/m2in autumn) were compared. Although seed yield did not respond to the main effects of these treatments, the two‐way classification resulted in significant differences from the average yield. August sowing combined with lower plant densities caused comparably high yields, while delayed sowing was somewhat effective only with higher plant density. Highest yield stability was achieved at early sowing when combined with lower plant densities. From 1986/87 to 1988/89 nitrogen top‐dressings were applied during early March, at start of stem extension and shortly before start of flowering at five locations. 200 kg N/ha in one dose resulted in lowest yield performance and enhanced instability. Contrastingly, the 240 kg N/ha treatment advanced yield stability regardless of split regimes. Nevertheless, split application to 100 kg N/ha + 50 kg N/ha + 50 kg N/ha also guaranteed that high yield performance and optimum yield stability were reached simultaneously and, that the total nitrogen input could be limited to 200

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00870.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractNitrogenase activity during the reproductive phase of theHodgson 78soybean variety was tested in a growth chamber experiment to evaluate its relationships with number, weight and specific nitrogenase activity of the nodules. A multiple regression model is proposed.The number of nodules did not change, while the total nodule dry weight increased with the increase of the average dry weight.The regression model adopted showed that the main factors affecting the total nitrogenase activity were the specific activity and the nodule mass, but the former induces the wider variations.Unlike other crops the counting of the nodules cannot be considered as an indirect predictor for nitrogen fixation.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00871.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractTwo varieties of soybean were grown in large pots out of doors. At the R2 stage, a state of temporary root anoxia appeared caused by a heavy rainfall and in R3, nitrogen was applied. The nitrogenase activity of the nodules was measured at weekly intervals (ARA test).During the vegetative stage, the number of nodules and their weight increased rapidly, although the anoxia caused a slowing down followed by a recovery in the successive stages (R3–5). The same effect was apparent in consequence of a late nitrogen fertilization; both varieties attaining values close to those of the control 15 days after the treatment. Nitrogenase activity also showed an inhibition caused by the anoxia but it appeared earlier. During the latest stages of the cycle (R6–7), the nitrogen treatment increased the rate of nitrogen fixation in Hodgson 78 only. The use of a multiple regression model allowed a verification that the parameters controlling nitrogen fixation acted in a similar way in both varieties. In the field, the weight of the nodules, both single and total, appeared to be particularly important in determining the total nitrogen fixation r

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00872.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractField studies on nitrogen dynamics after cultivation of grain legumes Field trials were conducted in order to study the nitrogen dynamics in soil after cultivation of grain legumes and to investigate the possibility of reduction of nitrate leaching due to catch crops or suitable following crops. Accordingly, in 1989/90 soil samples were taken on 12 farms at depths of 0–80 cm in 4 week intervals and analysed for NO3‐N. Furthermore,Brassica napusandSinapis albawere sown after grain legumes on two farms, and at the experimental station Roggenstein field trials were carried out with different catch crops (Sinapis alba, Raphanus sativus, Lolium multiflorumandPisum sativum) after grain peas.Considerable amounts of nitrogen (100–150 kg N/ha) in the form of crop residues (straw and grains) were left on the fields cultivated with grain legumes. After harvesting, nitrate content in the soil layer 0–80 cm was on grain legume fields almost twice as high as on fields cultivated with winter wheat. During autumn, the soil nitrate contents increased remarkably. In the soil layer 0–80 cm the maximum values rose to 140 kg N/ha after peas, to 120 kg N/ha after faba beans and only to 65 kg N/ha after winter wheat. The more intensive N‐mineralization after peas compared to faba beans is due to a lower C/N‐ratio of crop residues and an earlier harvest time of 2‐3 weeks of peas.In winter extremely high N‐leaching was measured on fallow land after cultivation of grain legumes. Cultivation of catch crops makes it possible to retain up to 110 kg N/ha in plant material.Raphanus sativusandSinapis albaare most suitable for this purpose due to their high N‐uptake even when they are sown late. Ploughing up catch crops in autumn results in a fast mineralization of their immobilized nitrogen. This implies the risk of N‐leaching into deeper soil layers during winter, depending on the amount of rainfall and water capacity of the soil. Particularly on soils with low water capacity, early N‐mineralization needs to be prevented by cultivating catch crops which freeze off or survive in winter. Cultivation ofBrassica napus(winter form) after grain legumes leads to an extensive uptake of soil nitrate before the beginning of the seepage period, and therefore almost exclu

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00873.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractThe significance of N, K and P fertilizers on corn yield and smut incidence was evaluated in the field during the seasons 1988 and 1989. Rates of fertilizers were 30, 60 and 90 kg N/acre; 0, 50 and 100 kg K2O/acre and 0 and 30 kg P2O5/acre. The corn plants were artificially inoculated withU. maydisspore suspension at 6‐leaf growth stage. The results showed that N fertilization acted to enhance N content of ear‐leaf and smut index and imposed depressing effects on leaf K. Unlike N, enhanced K‐fertility performed opposite results on leaf N and smut index. A significant N x K interaction was detected on ear‐leaf K and smut index, due to the antagonistic effects between ions. Grain yield data showed positive response to each N, K and P application, but the effect was much greater at the highest application rates. Yield losses were clearly pronounced, along all of the applied nutrient fertilizers, on plants where galls are located above ear than those with galls below ear. On average, the relative losses were 12.8 and 5.9 %, respectively, compared with 3.7 % for the main plot treatment. The 2‐way interaction (except N × P) showed variable effects on yield p

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00874.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY

摘要:

AbstractNegative correlation between Al concentrations and root and shoot growth was detected in two populations ofAvena sterilisL. investigated [one from a bauxite area (1) and the other (2) from a pasture area]. Al solubility and Al content of plant tissue depend on pH levels of nutrient solution. Population‐1 although in all treatments contained greater amounts of Al in its roots, was grown better than population‐2, suggesting that population‐1 is more tolerant than population‐2. Al content of shoot and root of both populations was greater at pH 10.0 than at pH 4.5, a fact that may indicate that Al ions in alkaline medium are preferentially absorbed than Al ions in acid medium. The better growth of both populations observed in all Al concentrations at pH 10.0, where Al content of plant tissues was greater, may indicate that Al forms predominant in acid nutrient medium are more harmful than Al forms in alkaline nutrient

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1991.tb00875.x

出版商:Blackwell Publishing Ltd    

年代:1991

数据来源: WILEY