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Integrated soil nutrient management is required to increase and sustain agricultural productivity. Assessment of soil, organic matter and nutrient losses was carried out in a 3-year integrated maize cropping system in Ghana. The treatments: no-till (NT), minimum tillage (MT), conventional tillage (CT) and soil amendments (Control, NPK, poultry manure and their combination), were arranged in a factorial design. The results showed soil loss to range from 0.140- 4.907 Mg·haˉ¹ in the order of NT < MT < CT < Bare. Soil loss reduction over the Bare was 88% by ½ Rates of NPK+PM, 87% by PM and 85% by NPK. Soil depth reductions in NT and MT were 92% lower than in CT. The loss of organic matter ranged from 47.6 kg·haˉ¹ to 120.70 kg/ha and was in the order of Bare > CT > MT > NT. Nutrient losses followed the same trend. Losses in soil organic matter, N, P, K, Ca, Mg and Na under tillage x soil amendments interactions were higher in the CT and bare plots. NT and MT, which were recognised as conservation tillage systems, amended with combination of organic and mineral fertilisers were found as better options in minimising soil quality degradation.
The field experiment was conducted with four tillage and three nutrient management practices at Agronomy field unit, University of Agricultural Sciences, GKVK, Bangalore, Karnataka, India. The results of the study indicated that, higher groundnut pod yield (1307 and 1282 kg ha-1) and haulm yield (2733 and 2889 kg ha-1) was recorded with mechanical tillage + two intercultivations and integrated application of 50% organics and 50% inorganics, respectively as compared to rest of the treatments. Further, the same treatments noticed higher availability of N, P2O5 and K2O in soil after harvest of groundnut, but greater improvement in soil organic carbon content was observed with conventional tillage + one intercultivation (0.62%) as compared to rest of the tillage practices. The maximum net returns and benefit-cost ratio was recorded with mechanical tillage + two intercultivations (Rs. 11,287 ha-1 and 1.75, respectively) and integrated application of 50% organics + 50% inorganics (Rs. 10,462 ha-1 and 1.69, respectively). However, interaction effect of tillage and nutrient management practices were not influenced significantly on soil fertility and productivity of groundnut under rainfed farming system.
Soil nutrient pattern can be a functional tool for grassland restoration. In order to promote the growth of a specific or group of expected plant species, it is necessary to measure the responses of different species to nutrient – rich patches and detect the differences among them. In this article, we measured aboveground biomass and morphological traits of six species as dry weight, length, surface area, specific root length and diameter of fine roots in response to nitrogen addition patches using ingrowth core method. The six species are Artemisia scoparia, Stipa bungeana, Artemisia sacrorum, Artemisia giraldii, Lespedeza dahurica and Astragalus melilotoides. All are the dominant species in different stages of secondary succession of loess hilly region, China. Twelve individuals of each species were selected to install ingrowth cores. Six of the individuals were used as treatment group, they were treated to install with four cores of no (addition’s control), low, medium and high levels of nitrogen additions. Another six of them were used as species’ control group, the four installed cores around them had no nitrogen addition. The results showed that: 1) After 105 days in situ, for all the six species, summed dry weight, length and surface area measured in the four cores of the treatment group were significantly greater than the corresponding values in species’ control group. In aboveground biomass, however, only A. scoparia in the treatment group had significantly outweighed that in the species’ control group. 2) Irrespective of nitrogen additions levels, significant differences of length, diameter and surface area existed among the six species, which implied that species had their intrinsic species specific morphological traits. 3) In dry weight, length and surface area, the responses of all the six species to nitrogen addition levels were positive, significantly more roots were grew into the cores with higher nitrogen additions; while in specific root length, the responses were negative. 4) Perhaps the six species had a special nitrogen requirement, as interaction effects of species and addition levels in surface area were found significant. 5) The foraging precision of the six species to nutrient-rich patches had positive but insignificant correlation with root system size; there existed a significant positive correlation between the precision and the sensitivity to the designed patchy habiats. 6) Among the six species, A. scoparia, A. sacrorum and S. bungeana have higher sensitivity and precision than L. dahurica and A. melilotoides in terms of foraging the nitrogen addition cores or patches. It seems that fast growing species that dominate in early successional stage, like A. scoparia and S. bungeana in our case, obtained more benefits from nutrient patchy habitat. We advised that, in infertile lands, fertiliser be applied in a patchy way to accelerate the restoration of old fields as early as possible once they were abandoned.
Demographic processes due to fast growth of the global population and urbanization are the main reason for increasing demands for food and feed. Due to urbanization processes about 50% of food is exported into towns. In consequence on a world scale about 83 million t NPK are also transferred into towns and hardly recycle to the land where they came from. In the last decade the global production of cereals, oilseed crops, sugar crops showed some specific trends, i.e. the sown area declined (cereals, sugar beets), but the production level has been almost constant due to higher yields per ha. It means higher nutrients removal from the field with the harvest. The increasing intensity of oilseed crops, root crops and sugar crops production requires, in turn, higher level of soil fertility due to relatively poor root systems when compared to cereals. However, the current fertilizer use patterns are much worse that at the end of the 80-ies. The consumption of fertilizers, generally decreased, but also the structure of NPK use underwent some negative changes. The special attention should be focused on the potassium consumption. The resulting NK ratio in global fertilizer use depreciated rapidly from a fairly balanced ratio of 1:0,4 to currently 1:0,27. This ratio dramatically worsened in the Central Europe countries, including Poland. It has been documented, through long-term experiments, that negative K balance results in a huge reduction in the content of soil K, causing its mining. On the other hand, numerous field trials give evidence that adequate use of potassium fertilizers, i.e. in balance with the other essential nutrients increases yield and improves its quality. It is important to many countries, like Poland, that adequate K fertilization also increases crops response to water deficits, increases resistance to diseases. There are some other benefits of balanced potassium use (i) environmental — higher efficiency of nitrogen (ii) economic — increasing farmer’s profits generates income, which is partly used for purchase of non-agricultural products; business attraction to the rural areas (iii) social — rural areas development, social security, etc.
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