摘要:

AbstractEconomically optimal N‐fertilization as influenced by location, preceding crop, cultivation of soil, phosphatic and potassic fertilization and choice of variety.– The economically optimal quantity of N‐fertilization is mainly influenced by location, preceding crop, cultivation of soil, phosphatic and potassic fertilization and choice of variety. The optimal organization of these factors, however, to the extent that it can be influenced by the farmer, is a precondition of an effective N‐fertilization.– Depending on the above‐mentioned factors the economically optimal quantity of N‐fertilization shows a great variation. In the majority of cases the optimal N‐quantity to winter wheat ranges between 100 and 180 kg/ha and to sugar beets between 12

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00256.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractThe effects of different soil aggregate sizes (10–4, 4–2 and<2 mm) in the seed‐root zone were investigated on the growth of wheat in a sandy loam soil (Typic Ustochrepts, fine loamy) under controlled ecological conditions. Plant growth, as evaluated by the plant height, length of main root, dry matter and root weight, was greater in 10–4 mm soil aggregate treatment than 4–2 mm soil aggregate treatment, which in turn was greater than<2 mm soil aggregate treatment. The coarser tilth of the seed‐root bed maintained higher apparent growth rates, studied upto 84 days after sowing and this declined with decrease in aggr

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00257.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractTwo barley crops, one fertilized with 120 kg N ha−1(B120) and the other without nitrogen fertilization (BO), were cultivated for the second year on the same plot. In 1981 the growth and nitrogen content of the whole plant, above‐ and below‐ground parts were measured by sampling every second week. Production was calculated as the difference between annual maximum and minimum amounts of biomass found above‐ and below‐ground. Nitrogen uptake was estimated as the sum of the peak amounts of nitrogen present in the roots and shoots. The amount and concentration of nitrogen in partly decomposed plant debris in the soil was estimated simultaneously with the biomass.Total net production in B120 was 1004 g m−2of which the roots constituted 16%. The unfertilized barley produced 558 g m−2of which 23% were produced below‐ground. The maximum amount of living roots found in B120 was 160 g ash‐free dry mass m−2and 128 g m−2in BO.In the fertilized treatment 15 g N m−2(21% in roots) was taken up by the plant, compared to 5.8 g N m−2(28% in roots)

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00258.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA field experiment was conducted at Samaru, Nigeria during the 1981–82 dry season to determine the yield and growth responses of wheat (Triticum aestivumL.) to moisture stress imposed at various growth stages and to seeding rate. It was also to identify wheat growth stages that are most sensitive to soil moisture stress. Treatments tested include three seeding rates, namely, 75, 100 and 150 kg per ha, and seven drought treatments, effected by missing one or two consecutive irrigations at different growth stages.Withholding irrigation at any growth stage prior to anthesis had detrimental effects on most of the growth characters and stress during crown root initiation (CRI) and jointing reduced most of the yield characters. Missing two consecutive irrigations at any given growth stage reduced grain yield more than did missing one irrigation; the greatest reductions in grain yield were 13 and 65% when one irrigation was missed at CRI and two consecutive irrigations were missed at jointing (the most sensitive growth stage) respectively. Moisture stress was also detrimental to number of grains, spike number, spike length, leaf area and number of tillers. A seeding rate of 100 kg per ha produced the best wheat performance in the present stud

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00259.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractA field experiment was conducted at Central Research Farm, Indian Grassland and Fodder Research Institute, Jhansi to study the effect of seed pre‐sowing hardening on seed emergence, physiological behaviour — and seed yield of berseem (Trifolium alexandrinumL. Var. S‐99‐1) crop. For this purpose, seed pre‐sowing hardening were made by soaking of seeds in tap water for 24 and 36 hours separately and later dried back to their original weight or left undried. These seeds were sown at two depths (5 and 3 cm) and judged against control (no soaking). Results demonstrated that augmented effect of seed hardening on seed emergence and physiological process responsible for seed yield was recorded in descending order of harden seeds (of 24 hours soaking)>non harden seeds (of 24 hours soaking)>harden seeds (of 36 hours soaking); while non‐harden seeds of 36 hours soaking adversely affect the plant growth because of leaching of sugar during excess soaking — an element for reduced seed vigour potential. Seed hardening system developed the strength of seed emergence on account of efficient catabolic process releasing high water soluble sugars needed for efficient germination process. Further this process augmented the absorption mechanism of mineral nutrients (particularly phosphorus and nitrogen with marginal variation in calcium) was quite evident at bloom stage — indicating a high metabolic activity during this period. Performance of seed hardening was effective at 5

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00260.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractNitrogen utilization and uptake patterns of wheat was studied using15N labelled fertilizer at four rates of application. Plants harvested at maximum tillering and at flowering indicated that plant N levels stabilized with time. Fertilizer N uptake and utilization of added fertilizer increased with time. However, uptake of soil N was not affected by rates of fertilizer at early stages. Increases were observed only at higher rates at the later harvest.

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00261.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractField experiments were conducted for three consecutive years during 1979—80 to 1981—82 to find out the relative efficiency of different forms of urea fertilizer for rice and their residual effect on the succeeding crop of wheat. In rice crop, root zone placement of nitrogen as urea super granule 1.0 g size (USG) under puddled field condition was proved to be superior to other sources. The relative efficiency of USG, urea in splits and sulphur coated urea (SCU) was 116.92%, 107.71% and 101.41% respectively as compared to ordinary urea at planting. Significant residual effect on succeeding crop of wheat was recorded in case of SCU which was followed by USG, urea in splits and urea at plant

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00262.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractIn order to quantify freezing resistance (R50) of winter faba beans from a limited number of plants, leaves were exposed to artificial freezing stresses with different test temperatures (TTi). Injury (Ii) was assessed by rating (score: 0—8) and by conductivity measurements. The basic assumption that Iidepends almost linearly on TTiover a sufficiently broad range with a constant ΔI/ΔTT could be verified and hence a formula is presented to compute freezing resistance R50= (Ii—I50) ×ΔTT/ΔI + TTiwith I50being a medium injury. This formula allows to quantify resistance by assessing Iiafter freezing test(s) with definite TTi. About 25 leaves are required. Rating appeared preferable to conductivity measurements because of easier and quicker performance and a slightly better discrimination between samples of different resistance. Based on a standardized freezing test, ΔI/ΔTT was determined. Application of the formula with ΔI/ΔTT = 2.5 units/°C for unhardened and hardened leaves, restrictions and experiences

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00263.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

AbstractIrrigation practices for rice (Oryza sativa) that are common in South Asia were simulated under greenhouse conditions, and the resulting range of gaseous N losses was determined. The interaction of water and fertilizer management for growing paddy rice was quantitatively evaluated at several rates of N fertilization. Continuous flooding, alternate flooding and drying, and dry periods before, after, and during flowering were combined with 3 rates of N, i.e., 0, 50, and 100 mg kg−1by uniform incorporation and by mud ball placement.Gaseous loss of native soil N was small (10 mg kg−1) when no fertilizer was applied and the crop stand was adequate. Loss increased to 32 mg kg−1when stands were halved. Gaseous loss of 41 to 58% were found when fertilizer was applied. Alternate flooding and drying was the least desirable irrigation practice with losses of 40 to 87 mg N kg−1. Placement of N in mud balls reduced gaseous N loss under all irrigation procedures by 14 to 32% compared to uniform application at the low N application rate. Under continuous flooding only 28% of a second increment of 50 mg kg−1of applied N was lost compared to 82% loss with alternate flooding a

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00264.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Book Reviewed in this article:Klingmüller, W. (Hrsg.): Genforschung im Widerstreit.2., völlig neubearbeitete und ergänzte Auflage. Wissenschaftliche Verlagsgesellschaft mbH Stuttgart.Herzog, H.: Source and Sink during the Reproductive Period of Wheat.Development and its Regulation with Special Reference to Cytokinins.Ross, H.: Potato Breeding — Problems and Perspectives.Fortschritte der Pflanzenzüchtung — Advances in Plant Breeding.Rehm, S. (Hrsg.): Grundlagen des Pflanzenbaues in den Tropen und Subtropen.Hdb. der Landwirtschaft und Ernährung in den Entwicklungsländern, Bd.Schopfer, P., Experimentelle Pflanzenphysiologie, Band 1 — Einführung in die Methoden.Schlichting, E., Einführung in die Bodenkunde.2. Aufl.Laermann, H. T., Verkehrssicherheit und Umweltschutz. Aufwuchsbekämpfung auf Gleisanlagen bei der Deutschen Bundesbahn.Mitteilungen aus der Biologischen Bundesanstalt für Land‐ und Forstwirtsch

ISSN:0931-2250    

DOI:10.1111/j.1439-037X.1987.tb00265.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY