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1.
Gram sorghum [ Sorghum bicolor (L.) Moench] is grown on marginal land and johnsongrass [Sorghum haiepense (L.) Pers] is the most common and hard to control weed in this crop. The agronomic performance of gram sorghum at different nitrogen (N) and johnsongrass infestation levels in the field has not been adequately investigated. Therefore, research was conducted on a Decatur silty clay loam soil (Rhodic Paleudult) to determine the influence of N rates (0, 40, 80 and 120 kg ha-1) and johnsongrass infestation levels (0, 2, 4, 6 and 8 plants per 5 m crop row) on the growth and yield of grain sorghum (cv. GK522G) and johnsongrass. Increase in N rates increased seed weight, seed yield and percent protein in grain sorghum as well as dry matter and percent protein of johnsongrass. The increase in johnsongrass infestation (from 0 to 8 plants per 5 m crop row) significantly decreased the performance of grain sorghum and johnsongrass at all the N rates. The results suggest that 40 kg N ha-1 with up to 2 johnsongrass plants per 5 m crop row or 80 kg N ha-1 with up to 4 johnsongrass plants per 5 m crop row produced grain sorghum yields equivalent to absence of johnsongrass in the crop.  相似文献   

2.
Experiments were conducted in two consecutive years to investigate the response of two corn (Zea mays, L.) cultivars, Eperon and Challenger, to timing of N fertilizer in a desert climate. Fertilizer was applied three times (at planting, 6 weeks after sowing (6WAS) and at 9WAS) to give a seasonal total of 180 kg N ha-1 The N treatments were Nooo (control), NLOH (60 kg N ha-1 at planting, none at 6WAS and 120 kg N ha-1 at 9WAS), NLLL (60 kg N ha-1 at sowing, 6WAS and at 9WAS) and NLOH, (60 kgN ha-1 at planting, 120 kg N ha-1 at 6WAS and none at 9WAS). Generally, N ha-1 was associated with the highest grain and dry matter yields. Plants in N treated plots had significantly larger number of leaves and ear leaf N contents than the control at mid-silk. High ear leaf N was associated with high leaf area index and dry matter yield. Based on these results, it would appear that the application of 60 kg N ha-1 at planting, followed by 120 kg N ha at 6WAS (NLHO) is the most suitable for enhancing corn yields in the desert climate.  相似文献   

3.
Response of sunflower ( Helianthus annuus L.) to sulphur applied ca. 0, 30, 90 and 150 mg kg-1 and nitrogen applied ca. 0, 100 and 200 mg kg-1 soil were studied on a Typic Camborthids in greenhouse. Nitrogen and S application had a significant (P < 0.01) main and interactive effect on seed yield and dry weight of leaves and stem. Cumulative N and S contents of sunflower seeds, stem and leaves were significantly (P < 0.01) affected by N and S application. Sulphur transport and accumulation in sunflower seeds was increased with S application. There were significant (P < 0.01) correlations between seed yield and N and S content of sunflower plants. Critical S concentration (%) in 60 days old plants was 0.36 for 95 % relative yield of the maximum. Application of 90 mg S kg-1 with 200 mg N kg-1 resulted in the highest seed yield and maximum total S and N contents in sunflower leaves, stem and seeds. Relative increase in sunflower seeds yield at higher levels of N and S was more than that of dry weight of stem and leaves.  相似文献   

4.
The effects of increased yield and grain number per unit area in barley in response to nitrogen application are well known. However, the influence of applied nitrogen on the rates and durations of developmental phases in barley are less well understood. Our objective was to investigate the effect of applied nitrogen on the duration of pre-anthesis development in barley and the number of spikelets per spike in two barley cultivars, Franklin and Schooner, in two studies. We found no effect of nitrogen on the duration of the pre-anthesis period in Schooner, when applied to pots at a rate of 0 or 55 kg N ha-1, or when applied in the held at 0, 40 or 160 kg N ha-1. However, this duration was extended in Franklin in the first study by an application of 55 kg N ha-1. Both plant biomass and grain yield at maturity were increased between 0 and 55 kg N ha-1, and 0 and 160 kg N ha-1. Meld increase was largely associated with an increase in the number of tillers per plant.  相似文献   

5.
A field experiment was conducted during 1994 and 1995 at Lucknow (26.5°N, 80.5°E, 120 m above mean sea level) to optimize planting density and fertilizer-N application for high essential oil yield of late transplanted mint ( Mentha arvensis ). The treatments studied were 2.5, 2.0 and 1.66 × 105 mint seedlings ha−1 and 0, 80, 160 and 240 kg N ha−1. Under 3 months delayed planting conditions using 2-month-old seedlings, the high planting density of 2.5 × 105 plants ha−1combined with 160 kg N ha−1 gave significantly higher herb and essential oil yields compared with those of lower planting densities (2 and 1.66 × 105 plants ha−1) and all other rates of N application. It is demonstrated that a transplanted mini crop, yielding essential oil at a level of 164 kg ha−1, is feasible after the harvest of rabi cereal, oil seed or legume crops in the north Indian plains.  相似文献   

6.
More detailed information on the causes of yield variability among wheat cultivars is needed to further increase wheat yield. Field studies were conducted in Northern Greece over the two cropping seasons of 1985—1986 and 1986—1987 to assess the effects of nitrogen fertilizer and application timing of the various component traits that determine grain yield, grain nitrogen yield and nitrogen utilization efficiency of two bread ( Triticum aestivum L.) and two durum ( Triticum durum Desf.) wheat cultivars, using yield and yield component analysis. Nitrogen at a rate of 150 kg ha-1 was applied before planting or 100 N kg ha-1 before planting and then 50 N kg ha-1 top dressed at early boot stage. Nitrogen and cultivars affected all traits examined, while split nitrogen application affected only some of the traits. Grain yields in the most cases were correlated with number of grains per unit area and grain weight and grain nitrogen yields in all cases with grain number per unit area. The contribution of the number of grains per spike to total variation in grain yield among cultivars was almost consistent (37 to 55 %), while the contribution of grain weight was more significant (up to 55 %) in high yields (>6.500kg ha-1) and number of spikes per unit area (>500). The number of grains per spike contributed from 60 to 83 % to the total variation in grain nitrogen per spike. Increased grain nitrogen concentration resulted in a reduction of its contribution in grain nitrogen yield variation. Nitrogen utilization efficiency was higher during grain filling than during vegetative biomass accumulation. The contribution of nitrogen harvest index to the variation of utilization efficiency for grain yield was higher in plants receiving nitrogen application.  相似文献   

7.
Three chemicals, viz., thiourea, thiamine and ascorbic acid capable of potentiating-SH turnover, were tested with the objective to improve growth and productivity of maize. Thiourea was tested as seed-soaking and foliar-applied treatments as also in combination. Thiamine and ascorbic acid were tested as foliar sprays alone. Foliar treatments were applied at vegetative stage (30 and 45 days after sowing).
The results of the field experiment showed that seed soaking with thiourea (500 ppm) tended to improve grain yield (13.4 per cent over control), but improvement in biological yield was significant. However, seed soaking plus foliar treatment of thiourea significantly increased both biological and grain yields, besides causing significant improvement in leaf area index and number of green leaves plant-1. The increase in grain yield ha-1 was of the order of 34.6 per cent over control.
It was further noted that foliar sprays of thiourea (1000 ppm), thiamine (100 ppm) and ascorbic acid (100 ppm) significantly increased leaf area index, number of green leaves plant-1 and biological yield ha-1. These treatments also significantly increased grain yield ha-1 by 40.6, 20.2 and 26.3 per cent, respectively over control. Improvement in maize yield with thiourea, thiamine and ascorbic acid treatments appeared to have resulted from increased photosynthetic efficiency and canopy photosynthesis on account of the biological activity of -SH group. It was also apparent that leaf senescence was delayed under the influence of these chemicals. It is therefore suggested that thiourea, thiamine and ascorbic acid are the potential bioregulators for improving photosynthetic efficiency and grain yield of maize and possibly other cereals, and that thiourea, a sulphydryl compound, holds considerable promise in this context.  相似文献   

8.
Brasisca Juncea , cv. Pusa Bold, and B. campestris , cv. Pusa Kalyani, were raised under field conditions with varying levels of N supply from 0–120 kg ha-1. The production profile of branches and pods thereon was measured, per unit area basis, throughout the crop ontogeny. At maturity, data on the yield contributing characters, viz. pod dry weight, pod number, seed number per pod, 1000 seed weight, seed wall ratio and seed yield in different order branches, was recorded.
The branching pattern and the number of pods produced on different order branches, in the two species, was favourably modified by the increasing levels of N supply. Primary and secondary branches contributed to the seed yield to an extent of 80 % of the total yield. Nitrogen treatment had no significant effect on 1000 seed weight. B. juncea exhibited significantly higher yield over B. campestris. N supply up to 120 kg ha -1 linearly increased seed yield in both the species. However, it exerted a negative effect too partitioning of assimilates from pod wall to seed. The study indicated that rapeseed-mustard, grown under short winter-season environment with adequate soil moisture, has the potential for higher N-fertilizer optima exceeding 120 kg ha -1.  相似文献   

9.
A simple randomized field experiment was conducted to assess the growth and yield of rape-seed-mustard in relation to sulphur and nitrogen interaction. Three levels of sulphur (0, 40 and 60 kg ha−1) in combination with three levels of nitrogen (60, 100 and 150 kg ha−1) were tested as treatments, T1, T2, T3, T4, and T5. Results indicated significant favourable effects of sulphur and nitrogen, when applied together, on yield components, seed and oil yield. Maximum response was observed with treatment T3 (having S and N of 40 and 100 kg ha1, respectively). Percentage oil content of seed was maximal at T4 (having S and N of 60 and 100 kg ha1) in both cultivars. The increase in N dose from 100 to 150 kg ha−1 without any change in applied S, i.e. 60 kg ha1 (T5), decreased the percentage oil content. The seed and oil yield, however, were similar to T3. Favourable responses of S and N interaction on leaf area index, rate of photosynthesis and biomass production were also observed.  相似文献   

10.
The effect of varying seed rates (100–1000 seeds m−2) and nitrogen fertilizer (0–60 kg N ha-1) applied either in a single basal dose or in splits was investigated on a tall elongating, photosensitive rice variety, Nalini, under semi-deepwater conditions (0–100cm) during 1993 and 1994 at Cuttack, India. Seedling emergence was higher in 1993 (53.9 %) than in 1994 (44.1 %) and it increased proportionately with increasing seed rate, Increase in the number of tillers and panicles m−2 at higher seed rates was associated with a corresponding decrease in panicle weight. Regression analysis indicated a decrease of 0.91–1.28g in panicle weight for an increase of 100 panicles m−2. The grain yield of rice was significantly higher at 400 seeds m−2 in 1993 and at 600 seeds m−2 in 1994 than at low seed rates but further increase in seed rate did not increase the yield. Application of N fertilizer increased the panicle number and thereby grain yield significantly. The effect of basal and split applied N at active or maximum tillering stages as well as between 30 and 60 kg N ha−1 was not significant on the grain yield. The results suggest that a basal dose of 30kg N ha−1 and seeding density of 400–600 seeds m−2, resulting in 40–50 % seedling emergence and 150–200 panicles m−2, each with 2.0–2.5 g weight, may be adequate for optimum productivity of rice under semideepwater conditions.  相似文献   

11.
Effect of Simulated Lodging on Soybean Yield   总被引:1,自引:0,他引:1  
Soybean ( Glycine max [L.] Merr.) grain yields may be reduced when the plants lodge. The magnitude of yield reduction is dependent on the growth stage at which lodging occurs. The stage of plant development most vulnerable to yield reduction from lodging has not been conclusively determined. The objective of this two-year study was to determine soybean yield reduction caused by simulated lodging at three stages of reproductive development: the onset of flowering (R1), beginning pod (R3) and beginning seed (R5). At each developmental stage the plants were lodged at either 45° or 90°. A natural lodging control and an artificially maintained erect treatment were included.
The 1976 results indicated no yield differences due to any of the lodging treatments. In 1977, yields were significantly reduced for the R3 lodging treatments. Soybeans lodged 90° at the R1, R3, and R5 growth stages yielded 2.63, 1.88 and 2.26 Mg ha−1, respectively. The natural lodging and erect treatments yielded 2.73 and 2.43 Mg ha−1, respectively.
Lodging treatments applied at the R1 stage produced plants with a two-year average of 30% of their seeds on the main stems, compared to 62% of the seeds on the main stems for the R5 stage treatments. The percentage of seeds on the main stem was 69% on the erect plants, as compared with 45% on the 90° lodged plants. In 1977, lodging treatments also reduced pods per plant, seeds per plant, 100 seed weight and seed weight per plant.  相似文献   

12.
The optimal N-supply in spring for different plant densities of winter wheat
The influence of plant density (plt./m2) on the optimal N-supply in spring (Nmin-content + N-fertilization) has been tested at three sites. The different plant density was produced by different seed rates in autumn of about 150, 250, 350, 450 and 550 grains/m2. The N-supply in spring was - apart from a non-fertilized field (Nmin-content) 80, 100, 120, 140 and 160 kg N/ha. Additionally, 80 kg N/ha were applicated as N-topdressing. Moreover the optimal N-supply in spring has been tested on a winter wheat field thinned out due to winterkilling. In detail we got the following results:
1. The reduction of the Nmin-content due to the N-uptake by the plants slowed down in accordance with minor plant density.
2. The same N-supply in the soil produced a higher N-supply per individual plant in accordance with decreasing plant density and lead to a considerable increase of N-nutrition.
3. Thin crops showed a higher tillering. The differences in plant density between 150 and 550 plt./m2 in spring diminished to about 90 ears/m2 at harvest.
4. Independently of plant density the maximum yield was obtained by a N-supply (Nmin+ N-fertilization) in spring of about 120 kg/ha N. Due to the abundant N-nutrition of the individual plants and the minor increase of yield a higher N-supply is not necessary with a minor plant density.
5. Essentially the yield level was only diminished with the lowest plant density (100-140 plt./m2).  相似文献   

13.
Two field experiments were conducted during] 994-95 to study the effect of spray of 10−5 M GA3 at 40 days after sowing on mustard ( Brassica juncea (L.) Czern & Coss.) cv. Varuna grown with basally applied 0, 40, 80 and 120 kg N ha−1 (Expt. 1) and 0,15, 30 and 45 kg P ha−1 (Expt. 2) on pod number per plant, seeds per pod, 1000 seed weight, seed yield, biological yield, harvest index and fatty acid composition of oil. No significant difference between water and GA3 spray was found when basally applied nitrogen was 0 or 40 kg N ha−1. N80 proved to be the best for yield characteristics. In another experiment on phosphorus, GA3 and 30 kg P ha−1 individually enhanced the yield, but interaction of GA3 and P remained non-significant. The fatty acid composition of oil in both experiments was significantly affected only by nitrogen and phosphorus treatments for oleic acid and erucic acid. It was found that return in the form of yield was more for every kg applied fertilizer under GA, spray treatment. The response was more for N fertilizer in comparison to P. GA3 at a low level of fertilization significantly increased the return from fertilization.  相似文献   

14.
Field studies were conducted during the winter seasons of 1995–96 and 1996–97 at the Agricultural Farm of Aligarh Muslim University, Aligarh, India on mustard ( Brassica juncea L. Czern & Coss., var. Alankar) under non-irrigated conditions, to evaluate the effect of foliar spray of 200 p.p.m. ethrel (2-chloroethyl phosphonic acid) at flowering growth stage along with basal 0, 40, 80 or 120 kg N ha−1 on net photosynthetic rate (PN), stomatal conductance (CS), stomatal resistance (RS), leaf K content, relative water content (RWC), leaf area index (LAI) and total dry matter (TDM) production monitored at 20 days after spray application, and plant N content, seed N content, nitrogen harvest index (NHI), nitrogen yield merit (NYM), pods plant−1, 1000 seed weight, seed yield, biological yield, harvest index (HI), seed yield merit (SYM) and merit of genotype (MOG) at harvest. Results indicated that, at 0 or 40 kg N ha−1, ethrel did not produce any significance effect, but at basal 80 kg N ha−1, ethrel affected the parameters favourably with the exception of 1000 seed weight, HI, seed N and NHI. Ethrel-sprayed plants utilized N from the soil more effectively and showed increased NYM. Yield attributes, seed yield and merit of genotype (in terms of NYM and SYM) were also enhanced. Ethrel spray enhanced seed yield under water stress conditions mainly by increasing K uptake and retaining higher RWC, thereby decreasing RS and increasing LAI, PN and TDM production.  相似文献   

15.
Knowledge of optimum fertilization for com production is required to increase crop yields while minimizing fertilizer costs. Field experiments were carried out from 1988 to 1993 to study the effects of fertilizer N rates on yield and N concentration of corn ( Zea mays L.) grain on a clay soil in Quebec. Grain yields and grain N concentrations generally followed a exponential relationship with increasing N fertilizer rates. The critical grain N concentration, defined as that associated with the highest grain yield, occurred at 285 kg N ha-1 for all years except 1969 when it occurred at 170 kg N ha-1. The critical grain N concentrations and grain yields over the years were found to be linearly related. The relationship between the critical grain N concentration and grain yield could serve as a diagnostic tool for N applications.  相似文献   

16.
Field beans of indeterminate (cv. Nadwiślański) and determinate (cv. Tibo) growth habits were grown on field plots with a density of 20, 40 and 80 plants m−2 at two levels of nitrogen fertilization: low (20 kg N ha−1) and very high (150 kg N ha−1). At the phase of intense pod growth the number and the dry matter weight of root nodules as well as their nitrogenase activity and some features of the plants growth were determined, and in the period of ripeness the components of seed yield were established.
It was found that increased density of sowing as well as the high level of nitrogen fertilization inhibited the growth and development of root nodules and limited their nitrogenase activity in both cultivars. Plants of both varieties were characterized by a similar potential of forming the root nodules, however, in plants of the cv. Tibo the nitrogenase activity of nodules was much lower than in the cv. Nadwiślański.
Increased population density of the plants has in both varieties given increased seed yield when calculated per m2 of the soil, compensating in excess the depression of the seed yield from one plant. Such compensation did not occur in the case of the depression of nitrogen fixation under intense nitrogen fertilization.  相似文献   

17.
The influence of undersown green manure crops for fallows – set-aside land – in view of vegetation-development and the dynamic of nitrate
In view of the establishment of rotational fallows - set-aside land - as well as the bridging of the vegetation-free winter period the suitability of different undersown grasses and legumes m winter cereals was investigated in field trials. Festuca rubra developed well in winter barley and winter wheat. The success of the cultivation of Lolium perenne, Trifolium pratense and Trifolium repens in winter cereals is uncertain because of the risk of light and water deficiences. Dactylis glomerata caused an negative influence on the yield of the cover crop. During the fallow period only low levels of nitrate could be found in the soil. Under fallow tilled repeatedly complete fallow- a nitrate accumulation could be observed during the fallow period. After ploughing up the fallow vegetation, nitrate concentrations - depth 0–150 cm – increased to 60 kg NO3-N · ha-1 after the natural fallow without seeding, between 60 and 130 kg NO3-N · ha-1 after Trifolium and between 160 and 210 kg NO3-N · ha-1 after complete fallow. Lowest nitrate levels were observed from the grass-sites. Undersown Festuca rubra seems to be the best choice in order to compete with weeds, to form a dense sod and to prevent nitrate leaching. In general a seed rate of 8 kg · ha-1 can be recommended.  相似文献   

18.
In a soil lacking indigenous Bradyrhizobium japonicum , soybean ( Glycine max [L.] Merr.) nodulation depends upon the number of rhizobia applied with the inoculum. This field study reports the effect of different rates of applied rhizobia on nodulation, dry matter and nitrogen content in soybean in a Mediterranean soil lacking B. japonicum.
Treatments included six rates of B. japonicum , ranging from 2.5 × 104 to 6.075 × 106 rhizobia cells per seed applied to the seed as peat inoculant at planting, 100 kg N ha−1 and an uninoculated control. The experiment was conducted in an Entisol soil. Regression analysis showed linear relationship between the rate of applied rhizobia and the number of the nodules per plant or the dry weight per nodule. In early stages of development (32 and 68 days after planting) plant dry weight was not affected by inoculation rate. At harvest a rate of 7.5 × 104 rhizobia cells per seed was necessary for maximum total and stover dry weight. A higher rate, 6.75 × 105 rhizobia cells per seed, was required to obtain maximum grain yield, total N content in plant tops and grain N content. Grain percentage N was increased up to 2.025 × 106 rhizobia cells per seed. Nitrogen application increased grain yield, total N content and grain N content at the same level as the lower inoculation rate.  相似文献   

19.
Linseed ( Linum usitatissimum L.) stems, which contain bast fibres, make up a considerable part of the linseed biomass, but are considered a by-product of no value. The feasibility of cultivating existing linseed cultivars and breeding lines for dual-purpose use of stem and seed was studied in 1995–97 in Jokioinen, Finland. Finnish linseed cv. Helmi was compared with 10 linseed genotypes and one flax cultivar for stem yield, ratio of stem yield to seed yield, and plant stand height and density. The stem yield of cv. Helmi averaged 1317 kg dry matter ha-1. Significantly higher stem yields were produced by breeding lines Bor 15 and Bor 18 and cvs Gold Merchant, Norlin and Martta. The cv. Helmi produced lower stem yield than seed yield while breeding lines Bor 15 and Bor 18 and cvs Gold Merchant and Martta yielded more stem than seeds. The difference in the ratio of stem yield to seed yield between them and cv. Helmi was statistically significant. The mean plant stand height was 60.3 cm and the final plant density 594 plants m-2. No relationship was found between stem yield and height or density. Within 2 days of seed threshing, stems of early maturing Finnish genotypes dried up in the field to nearly 15 % moisture content, even in the middle of September (1996). The early maturing breeding lines Bor 15 and Bor 18, with their significantly higher stem yields relative to cv. Helmi, are recommended for dual-purpose use.  相似文献   

20.
In a field trial conducted during 1992–93 and 1993–94, the effect of basal (B) nitrogen (N) (45 and 60 kg N ha−1) and foliar application (F) of water (W) or 10 kg N ha−1 and 400 or 600 ppm ethrel (E) (2-Chloro ethyl phosphonic acid) at 70 days after sowing was studied on leaf area index and dry mass at 90 days and pod number per plant, seeds per pod, 1000 seed weight, seed yield, oil content and oil vield at harvest of mustard ( Brassica juncea L. Czern & Coss.) cv. T-59. Recommended basal (B) application of 90 kg N ha (BN90) was used as control. On the basis of 2 year data it was found that basal application of 60 kg N and foliar spray of 10 kg N ha −1 and 600 ppm ethrel gave higher values for growth and yield characteristics and enhanced seed yield and oil yield by 12.5 and 14.8%, respectively over control BN90.  相似文献   

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