摘要:

AbstractSoybean[Glycine max(L.) Merr.] plant density for maximum yield in Japan is usually from 16 to 25 plants m−2. The objective of this study was to compare yield and yield components, especially node number between square‐ and zigzag‐ (an equilateral triangle‐planting pattern or plants in the row offset from each other) planting patterns within a range of plant populations (16, 20 and 25 plants m−2).Field experiments with cultivar Enrei (Maturity Group VII) were conducted in the field at Niigata University on a loamy sand soil in 1991, 1992 and 1993.Yield increased as density decreased in 1991 and as density increased in 1992 and 1993. This result seemed to be due to adverse weather conditions during seed filling in 1991. Yield tended to be higher in zigzag‐ than in square‐planting patterns except at 20 plants m−2. Seed number m−2due to increased yield was highly correlated with branch node number. The yield increase was caused by an increase in total node number, especially branch node number m−2(about 60 % contribution at 16 plants m−2and about 40 % contribut

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00540.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIncreases in atmospheric carbon dioxide (CO2) concentration have stimulated interest in the response of agricultural crops to elevated levels of CO2. Several studies have addressed the response of C3cereals to CO2, but the interactive effect of nutrient supply and CO2on apical development and spikelet set and survival has not been investigated thoroughly. Hence, an experiment was conducted in the greenhouse to evaluate the effect of high (700 μmol CO2mol−1air) and low (400 μmol mol−1) levels of atmospheric CO2on apical development, spikelet set and abortion, and pre‐ and post‐anthesis growth in spring barley(Hordeum vulgareL.) grown under high N (0.3 g N pot−1before sowing −1–0.11 g N pot−1week−1) and low N (0.3 g N pot−1) regimes. The plants were grown in 5 L pots. Development of spike was hastened due to CO2enrichment, and the C+ plants pollinated few days earlier than the C— plants. Carbon dioxide enrichment had no effect on date of ripening. Development of spike slowed following application of extra N, and plants pollinated 10 days later and matured 2 weeks later when compared with plants under low N. Carbon dioxide enrichment did not affect the number of spikelets at anthesis. Excess N decreased spikelet abortion and the increased maximum number of spikelets under both [CO2]. Barley plants did not tiller when grown in low [CO2] and low N. Increased endogenous IAA concentration in those plants, recorded three days before tillers appeared in other treatments, may have contributed to this. Carbon dioxide enrichment increased the C concentration of plants, but decreased the N concentration under high N regime. Both the C and N concentration of plants were increased under high N regime. Carbon dioxide enrichment increased the total dry matter of mature plants by 9 % under high N regime and by 21 % under low N regime. Under high [CO2] increased kernel number on tiller spikes, and increased kernel weight both on main stem and on tiller spikes resulted in a 23 % increase in kernel yield under low N regime and 76 % increase in kernel yield under high N regime. The rate of N application influenced growth and yield components to a greater extent than CO2enrichment. At maturity, plant dry matter, kernel weight, the number of kernels per spike, and the number of spikes per plant were higher under high N regime than under low N regime.Long days (16 h), low light intensity (280 μmol m−2s−1), and at constant temperature of 20 °C high [CO2] increased kernel weight and the number of kernels on tiller spikes under high and low N application rate, but did not increase the number of kernels on main stem spike, or the number of tille

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00541.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractA nitrification inhibitor which blocks the conversion of ammonium to nitrate may reduce the risk of leaching of nitrate during the growing season. In field experiments in 1988—1990 a nitrogen fertilizer enriched with the nitrification inhibitor dicyandiamid (Alzon) was compared with a standard calcium‐ammonium‐nitrate fertilizer (CAN), using rates of N supply up to 360 kg ha−1. There were no significant differences between CAN and Alzon with respect to: stem length, apical lateral branchmg, fresh and dry weights of haulms and tubers at maturity, and nitrogen uptake. Alzon‐treated plants showed lower concentrations of nitrate in stems and leaves than CAN‐tre

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00542.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractWater conservation often is limited by soil conditions that cause runoff, even from small rainstorms. This study evaluated the influence of tillage‐induced aggregates on infiltration into Pullman soil (Torrertic Paleustoll). Tillage methods were PLOW (plowing and disking), ROTO (rotary), SWEEP (sweep), or NOTILL (no‐tillage). Aggregate sizes were<0.42, 0.42—0.84, 0.84—2.0, 2.0—6.4, and 6.4—18.3mm. Rainwater was applied until runoff and percolation became constant. Final infiltration (If) rates differed due to tillage, aggregate size, and interaction effects, but maximum difference was only 8.1 mm h−1, suggesting that If rate differences have little significance from a water conservation viewpoint during intense, short‐duration rainstorms that occur in semiarid regions. Cumulative infiltration (Ic) apparently is of greater significance; it was greatest for large aggregates. The PLOW treatment resulted in most large aggregates and presumably would result in greatest Ic. However, under field conditions, Icwas similar for PLOW and SWEEP treatments. For the SWEEP treatment, tillage undercut the surface and retained more residues, thus negating the advantage of larger, but apparently less stable, aggregates with the PLOW treatment wit

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00543.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractIn six field experiments conducted over 2 years, the effect of one or two cuttings on grain yield of triticale (×TriticosecaleWittmack) were investigated. In addition, the relationships between triticale grain yield its components were analysed.Grain yield of the uncut plots invariably exceeded the plots with one or two cuttings, regardless of the environment or year. The reductions in grain yield caused by one cutting ranged from 27 % to 60 % under rainfed conditions and 18 % to 20 % under irrigation. With two cuttings the reduction was 45 % to 70 % for rainfed, and 35 % to 48 % for irrigated conditions.The yield components which most influenced grain yield of triticale under cutting treatment were the number of ears m−2in all six experiments and the number of grains per ear under rainfed conditions. At the rainfed sites in 1989 cuttings diminished the number of ears m−2mainly by increasing plant mortality. Nevertheless, at the rainfed sites of 1990 and at the irrigated site of both years, the reduction in the number of ears m−2with cuttings was due principally to a lower survival of tillers per

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00544.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractThree rice varieties, viz. ADT 31 (drought tolerant) CO 41 (upland) and IR 50 (drought susceptible), were employed to study their rooting patterns under different water regimes. ADT 31 had better root penetration and distribution under water stress situation compared to others. The values on root weight also established a similar trend. Isotopic studies with32P also provided evidence in this regard wherein the variety ADT 31 showed its adaptiveness to drought. Marginal reduction in plant height, less tiller production and leaf area reductions were noted in ADT 31 and CO 41 under decreasing soil moisture which showed its ability to cope with the water stress situation. Though IR 50 recorded higher grain yield at normal irrigation, a drastic reduction was noted under extreme water deficit. But ADT 31 recorded consistent values in all situations with slight marginal reduction which evidently proved the interdependent nature of rooting pattern and its influence on productivity.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00545.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractStudies on source‐sink relationship were conducted in two chickpea varietiesCicer arietinumL. namely, Kabuli (L‐550) and Desi (BG‐256). The primary objective of the present study was to assess the influence of source/sink manipulation by defoliation or deflowering or both on dry matter accumulation in different vegetative parts. Seeds were sown in earthen pots containing sandy loam soils. Plants were raised under normal moisture conditions following recommended agronomic practices. In defoliation treatment all the freshly formed leaves were removed from the onset of flowering until harvest. The leaves formed earlier were kept intact. Removal of flower buds from start of flowering until harvest contributed deflowering treatment. Defoliation and deflowering treatment is a combination of both, whereas untreated plants served as control. Significant differences in dry matter distribution and total soluble sugar (TSS) content as a function of source sink manipulation were observed between the varieties. Defoliation treatment preferentially increased more stem dry weight (DW) in L‐550 and more root and nodule dry weight in BG‐256. In both the varieties deflowering treatment resulted in increased leaf and stem DW. This treatment also resulted in increased root and nodule DW in BG‐256, but only nodule DW in L‐550. When defoliation treatment was combined with deflowering, in both the varieties a decrease in DW in leaf and stem and an increase in DW of root and nodule were observed. Total dry matter content increased 2–3‐fold with deflowering in L‐550 but in Bg‐356 there was no significant increase, indicating a possible role of flowers and reproductive organs in dry matter accumulation. Similar results were obtained even with defoliation, which indicates the major role played by leaves formed before flowering in L‐550, and leaves formed after flowering in BG‐256. Thus, this study suggests variation in the functional role of leaves formed b

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00546.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractEffects of rotational fallows (‘set‐aside land’) on subsequent winter wheat. The aim of the present study was to investigate the effects of different fallow treatment on subsequent winter wheat. The field trials included rotational fallows planted withTrifolium repens, Festuca rubraandLolium perennesown under winter barley compared to complete fallow and natural fallow without seed application and fallows planted withTrifolium pratense, Festuca rubraandDactylis glomeratasown under winter wheat. After ploughing up the fallow vegetation, winter wheat was planted for 2 succeeding years at two levels of N‐fertilization. Herbicides and fungicides were not applied. The following criteria were investigated: biomass‐production, N‐uptake, yield, weed infestation, nitrate and water content of the soil. In autumn, after ploughing up the fallow vegetation, the nitrate content of the soil (0—150 cm) increased by up to 210 kg NO3‐N/ha after complete fallow, by up to 60 kg NO3‐N/ha after natural fallow and by up to 75 and 130 kg NO3‐N/ha after fallows cropped withTrifolium repensandTrifolium pratense, respectively. Low nitrate levels of 20—27 kg NO3‐N/ha were observed after fallows planted with grass. N‐immobilization caused by ploughing up grass fallows continued until the first harvest of the subsequent winter wheat. In the second year of winter‐wheat, no differences of N‐mineralization dependent on the previous fallow crop occurred, except in the case complete fallow which showed lower N‐mineralization. It can be concluded that fallows cropped with grass lead to a higher nitrogen fertilizer requirement m the succeeding crops.Festuca rubrawas able to form dense swards in strong competition with weeds and to decrease the abundance ofAlopecurus myosuroidesandApera spíca‐ventiin subsequent winter wheat, while natural fallow and fallow planted withTrifolium repensandLolium perennecaused epidemical increases in grass‐weed density. Preceding crop effects on grain yield of the winter wheat showed a close relation to N‐supply and were compensated by mineral N‐fertilization. After natural fallow and fallow covered withTrifolinm repens, yield reductions due to grass‐weed competition occurred. UndersownFestuca rubraseems to possess a special suitabihty for cultivation in routional fallows. It establishes itself strongly under different cover crops and is able to form dense swards in strong competition with weeds. Grass‐weed density in the succeeding crops will be reduced and nitrate leaching will still be prevented after ploughing up the fallow vegetation. N‐fertilization of the subsequent crops must be carried out under considerations of higher N‐requirements which is probably

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00547.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

AbstractShoot‐ and full‐competition between first‐year seedlings of meadow fescue(Festuca pratensisHuds.) and timothy(Phleum pratenseL.) was studied m two separate experiments in a greenhouse. Timothy had a higher competitive ability than meadow fescue and produced more tillers, had a higher shoot weight and a larger leaf area in all strata of the canopy.Competition for light was important up to the first harvest. The upright growth form of timothy plants during the reproductive phase enabled them to shade the unvernalized and prostrately‐growing meadow fescue. Root competition may have been important afterwards. After the first harvest, tiller formation in timothy plants was high, and significantly enhanced when grown with meadow fescue. Meadow fescue produced few new tillers, and its tiller formation was depressed when competing with

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00548.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY

摘要:

Book reviewed in this article:Pospelowa, G. und M. Zoschke unter Mitarheit von H. Fließ, Stand der Triticale‐Forschung in der Sowjetunion (GUS). In: Osteuropastudien der Hochschulen des Landes Hessen. Reihe 1: Gießener Abhandlungen zur Agrar‐ und Wirtschaftsforschung des Europäischen Ostens. Band 194.Klapp, E., Zur Prohlematik des Acker‐ und Pflan

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1994.tb00549.x

出版商:Blackwell Publishing Ltd    

年代:1994

数据来源: WILEY