摘要:

A field experiment was conducted to evaluate the effects ofBradyrhizobium japonicuminoculation and N fertilization on nodulation, total nitrogen in plant shoots, and yields ofGlycine maxcv. FN3. Inoculation enhanced the nodule number per plant by up to 355–380% and nodule mass per plant by up to 336–182% for TAL 377 and TAL 379 respectively. Total N in plant shoots, plant mass and yields of inoculated and N-fertilized plants were similar and greater than those of uninoculated and unfertilized plants. Inoculation increased the N yield in soyabean by up to 35–55%, compared to 70–102% with N fertilization. Inoculation was equivalent to an application of 75 kg N/ha and 65 kg N/ha for TAL 377 and TAL 379 respectively. Our findings demonstrate the symbiotic effectiveness of the strainsB. japonicumTAL 377 and TAL 379 under field conditions.

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754781

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Snails are well known as carriers of diseases and vectors of pests. Being largely herbivorous, land snails cause immense damage to both cultivated and useful non-cultivated plants. A large population of snails, however, inhabits freshwaters, where the larvae of parasitic trematodes also pass part of their life. Many aquatic snails act as vectors for the larvae of trematodes and thereby cause a number of diseases. Two diseases carried by aquatic snails, fascioliasis and schistosomiasis cause immense harm to man and his domestic animals. Snails are next only to insects in the harm they cause to mankind. The World Health Organization has tested thousands of synthetic compounds for the eradication of snails. Though effective, these pesticides have so far not proved themselves to be entirely satisfactory. With a growing awareness of environmental pollution which such compounds can cause, efforts are being made to find molluscicidal products of plant origin. Being the products of biosynthesis, these are potentially biodegradable. Several groups of compounds present in various plants have been found to be toxic to snails. Thus, saponins, tannins, miscellaneous alkaloids, alkenyl phenols, glycoalkaloids, flavonoids, sesquiterpenes lactones, terpenoid and phorbol esters have been found to be poisonous to snails at acceptable doses ranging from <1–100 ppm. These molluscicidal compounds come from 56 families of angiosperms. Although the active moiety in many cases has been identified, systematic studies on their long term effects on non-target organisms as well as their structure-activity relationship remains largely unknown. In this review we have tried to assemble all the known information on products of plant origin, which might possibly be used for snail control.

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754782

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

In order to determine how dependent a woody legume can be upon potential N sources, the time course of N2fixation and N absorption was studied onGliricidia sepiumcv. ILG50,Leucaena leucocephalacv. K28, andAlbizia lebbeckin a screenhouse for 16 months usingSenna siameaas a reference tree. Dry matter and N yield in all four species increased steadily with time. The numbers and dry weight of nodules also increased with tree age. N-difference and15N dilution methods correlated well (r = 0.87–0.93) in defining an increasing pattern of N2fixation with time in all species, with the highest increment rate between sowing and 8 months. The percent N2fixed ranged from 17.9 to 74%, 27.7 to 71.9% and 43.6 to 83.6%, equivalent to 191 to 3385 mg, 321 to 2863 mg and 533 to 6419 mg N inLeucaena, GliricidiaandAlbizia, respectively, for the period between 4 and 16 months. In contrast to others,G. sepiumhad its peak of amount of N2fixed at 12 months after planting. In both the proportion and amount of N2fixed over time,A. lebbeckwas superior toL. leucocephalaandG. sepiumwhich were similar. The proportion of plant N derived from absorption (soil+fertilizer) over time decreased inversely to the increase in symbiotic N2fixation, with soil being the predominant source. This study evidenced the benefit of relying on N2-fixing woody legumes as sustainable N-supplying sources to soil-crop systems.

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754783

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

A detailed ecological analysis of the energetics and biomass utilization patterns of the existing traditional hill agroecosystems in three different localities/villages situated along an alititudinal transect in the outer Garhwal Himalaya was performed in order to understand the functions of the hill agroecosystem in relation to current environmental perspectives.

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754784

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

摘要:

Four organic manures and NPK fertilizer, each at four rates, were assessed under field conditions for their comparative effects on the growth and yield of castor oil plant. Castor seed yields (5.11 and 5.01 t ha−1) were greatest with poultry or swine manure applied at the rate of 10 t ha−1. Yields of 4.01 or 4.00 t ha−1were obtained with fresh rice husk dust or burnt rice husk dust applied at 20 t ha−1, while with NPK the highest yield (3.84 t ha−1) was obtained with the formulation of N50 P40 K40 kg ha−1. Very high manure application of 30 t ha−1depressed growth and yield, irrespective of the manure sources. The potential fertilizer values of the organic manures were not fully reflected by early growth parameters as they were with NPK treatment, apparently due to slow release of the elements bound in organic forms in the manures. The ultimate yield advantages associated with the organic manures compared with NPK were, in part, ascribed to their probable effects on the soil physical characteristics, and their supply of macro- and micro-nutrient elements not contained in NPK fertilizers.

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754785

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754786

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754787

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754788

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor

ISSN:0144-8765    

DOI:10.1080/01448765.1996.9754780

出版商:Taylor & Francis Group    

年代:1996

数据来源: Taylor