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91.
A study on seasonal soil nutrient dynamics was made in large cardamom (Amonum subulatum) and mandarin (Citrus reticulata) agroforestry systems in the Sikkim Himalaya, India. Alnus nepalensis was the N2-fixing associate in the large cardamom system, and Albizia stipulata in the mandarin agroforestry system. Sites without N2-fixing species in both agroforestry types comprised native non-symbiotic mixed tree species. Soil was acidic in the cardamom agroforestry and slightly acidic to neutral in the mandarin agroforestry system. Total-N in soils was the highest in the forest-cardamom stand and the lowest in the mandarin-based agroforestry systems. Soil ammonium-N and nitrate-N concentrations were highly seasonal, and the ratio of seasonal maximum and minimum varied up to six times. The C/N ratio was higher in cardamom agroforestry indicating lower N availability than in the mandarin agroforestry. Cardamom stand with Alnus showed a relatively narrower C/N ratio. N2-fixing species help in maintenance of soil organic matter levels with higher N-mineralization rate as land use change from natural-forest system to agroforestry systems with sparse tree populations. Ratios of inorganic-P/total-P were lower in cardamom agroforestry than the mandarin agroforestry. Seasonal fluctuation in Ca-PO4, Al-PO4 and Fe-PO4 contents regulated the availability of phosphates to some extent for plant uptake. 相似文献
92.
93.
We studied two clones of Eucalypt urograndis hybrid (Eucalyptus grandis 9 E. urophylla), GR283 and GR330, grown in Tumkur district of Karnataka (India), and felled 5–6 years old three trees of each clo... 相似文献
94.
A long-term field study was initiated during 1995 at Central Soil Salinity Research Institute, Regional Research Station, Lucknow(26°47′58′′ N and 80°46′24′′ E) to analyze the effect of agroforestry systems on amelioration of alkali soils. Three agroforestry systems(pastoral, silvipastoral and silvicultural) were compared with the control where no agroforestry system was introduced. Tree-based silvicultural and silvipastoral systems were characterized by tree species Prosopis juliflora and Acacia nilotica along with grass species Leptochloa fusca, Panicum maximum, Trifolium alexandrium and Chloris gayana. Growth of ten-year-old Prosopis juliflora and Acacia nilotica planted in combination with grasses was significantly higher over the silviculture system with the same species. Tree biomass yields of P. juliflora(77.20 t?ha-1) and A. nilotica(63.20 t?ha-1) planted under silvipastoral system were significantly higher than the sole plantation of(64.50 t?ha-1 and 52.75 t?ha-1). Fodder yield under the pastoral system was significantly higher than the silvipastoral system during initial years but it was at par with that of silvipastoral systems after eight years of plantation. The microbial biomass carbon in the soils of silvipastoral systems was significantly higher than in soils under sole plantation of trees and control systems. The Prosopis-based silvipastoral system proved more effective in reducing soil pH, displacing Na+ from the exchange complex, increasing organic carbon and available N, P and K. Improvement in soil physical properties such as bulk density, porosity, soil moisture and infiltration rate was higher in the Prosopis-based silvipastoral system than in the silviculture system or control. On the basis of biomass production and improvement in soil health due to tree + grass systems, silvipastoral agroforestry system could be adopted for sustainable reclamation of highly alkali soils. 相似文献
95.
Background: Progress of forest production in response to the environment requires a quantitative understanding of leaf area development. Therefore, it is necessary to investigate the dynamics of seasonal crown foliage in order to understand the productivity of mangroves, which play an important role in the subtropical and tropical coastlines of the world. Method: Crown foliage dynamics of the mangrove Rhizophora styloso were studies to reveal patterns of leaf recruitment, survival and seasonal leaf area growth. Results: Flushing of leaves occurred throughout the year, but both flushing and leaf area growth pattern of leaves varied with season. Maximum flushing occurred in summer, but leaf areas did not differ significantly with season. The half-expansion period is longer, and the intrinsic rate of increase was lower in winter. Summer flushed leaves grew faster at their initial stage and reached their maximum area over a shorter period of time. The difference in temperature and air vapor pressure deficit (VPD) between summer and winter contributed to the present dynamics of foliage patterns. The mean leaf longevity was estimated to be 13.1 month. The crown foliage area was almost stable throughout the year. Conclusions: Homeostatic control of the crown foliage area may be accompanied by the existence of ecophysiological mechanisms in R. stylosa. Integrating crown foliage dynamics into forest models represents an important step towards incorporating physiological mechanisms into the models for predicting growth responses to environmental changes and for understanding the complex responses of tree growth and litter production. 相似文献
96.
Roy Arpita Sharma Neelam Bharadvaja Navneeta 《Genetic Resources and Crop Evolution》2022,69(1):209-219
Genetic Resources and Crop Evolution - Selection of elite accessions is important to get the maximum quantity of bioactive compounds in medicinal plants. In this study, thirteen accessions... 相似文献
97.
Thakur Manisha Luharch Rakshandha Sharma Vishal Sharma Dharam Paul 《Genetic Resources and Crop Evolution》2022,69(2):567-575
Genetic Resources and Crop Evolution - Santa Rosa and Frontier are the major Japanese plum (Prunus salicina Lindl.) cultivars grown throughout the world. The present investigation was performed to... 相似文献
98.
Kumari Madhu Kumar Vikas Kaur Ramandeep Kumar Satish Sharma Rakesh 《Plant foods for human nutrition (Dordrecht, Netherlands)》2022,77(2):241-249
Plant Foods for Human Nutrition - Ficus geniculata (FG) is one of the underutilized fig species in India and throughout the world. However, the different parts of the plant have numerous... 相似文献
99.
Early in-season loss of N continues to be a problem in corn (Zea mays L.). One method to improve N use efficiency is fertilizing based on in-season crop foliage sensors. The objective of this study was to evaluate two ground-based, active-optical (GBAO) sensors and explore the use of corn height with sensor readings for improving relationships with corn yield. Two GBAO sensors (GreenSeeker® (GS), Trimble, Sunnydale, CA, USA; and Holland Crop Circle (CC) ACS 470 Sensor®, Holland Scientific, Lincoln, NE, USA) were used within 30 established corn N-rate trials in North Dakota at the V6 and V12 growth stages in 2011 and 2012. Corn height was recorded manually at the date of sensor data collection. At the V6 growth stage, the GS relationship to yield and the INSEY (in-season estimate of yield) value was improved when the sensor reading was multiplied times corn height. At the V12 stage, using the GS, the INSEY relationship with yield was also generally increased when height was considered. The CC-based red/near-infrared INSEY relationship with yield was similar to the GS INSEY. The CC-based red edge/near infrared INSEY relationship was increased with height only at the first sensor date, but not with the second. The second CC-based sensor–INSEY relationship with yield was maximized using sensor reading only. Segregating the 30 site data set into sites with high clay surface textures and sites with medium texture improved all INSEY relationships compared to pooling all sites. Relationships between INSEY and corn yield at no-till sites were significant at the V12 stage in the wetter 2011 growing season, but not at the V6 stage either year, nor at the V12 stage in the very dry 2012 season. In the high clay and medium textured soils at the V6 stage, corn height improved the relationship between INSEY and yield often enough to suggest that incorporating corn height into an algorithm for yield prediction would strengthen yield prediction, and thus improve N rate decisions. 相似文献
100.
Tree plantation is a proven strategy to improve the salt‐affected soils. However, the efficiency of trees to reclaim the soil varies from species to species. This study was therefore, carried out with the objective of assessing the efficiency of 3‐yr old plantations of Prosopis juliflora (Swartz) D.C. (Mesquite), Eucalyptus tereticornis Sm. (Forest Red Gum) and Dalbergia sissoo Roxb. Ex. D.C. (Indian Rosewood) to improve the sodic soil characteristics in Sultanpur districts of Uttar Pradesh, India (26°10′–26°23′N, 81°50′–82°5′E). Soil samples collected from six depths; 0.0–0.1, 0.1–0.3, 0.3–0.6, 0.6–0.9, 0.9–1.2 and 1.2–1.5 m below the surface, were analysed for chemical and physical properties by following standard methods. The infiltration rate (IR) was determined by double concentric infiltrometer and the permeability by constant head permeameter. The trees were measured for their girth at breast height (at 1.33 m from ground) and crown area within a 100 × 100 m sector at each of the sites selected. There were decreases in soil pH (from 10.06 to 9.64) and exchangeable sodium percentage (from 70.6 to 26.9) at the P. juliflora plantation relative to the E. tereticornis and D. sissoo plantations. The organic carbon and nitrogen content increased from 2.0 and 0.18 g/kg to 3.9 and 0.45 g/kg under P. juliflora at the surface (0.0–0.1 m) layer. There was also more exchangeable Ca2+, Mg2+and K+ at exchange sites and a reduction in exchangeable Na+ 3 yr after establishing the plantations. There was a significant decrease in surface soil (0.1 m) bulk density from 1.66 to 1.37 (t/m3) but an increase in porosity from 41.2 to 46.3% and water holding capacity from 4.3 to 4.8 g/kg. The IR and soil permeability also increased after 3 yr of tree growth. Prosopis juliflora proved more effective than E. tereticornis and D. sissoo in its ability to enrich a sodic soil with organic matter and establishing better soil–water characteristics. 相似文献