查看更多>>摘要：Soils of the Regional Station Gurdaspur of Punjab Agricultural Universityhave been surveyed, characterized, classified as per Soil Taxonomy and mapped. All the soils have ochric epipedon and argillic sub surface horizon. Soil pH is neutral to alkalinewith surface texture varying from sandy loam to silty clay loam. However, the subsurface texture varies from loam to silty clay loam. Soils have 10YR hue with value 5 and chroma varying from 3 to 5. The soils are well developed as indicated by the presence of textural B horizon in all the soils. Most soils have CaCO_3 in the surface only. CEC of these soils vary from 5.80 to 18.10 c mol kg~(-1). These soils have been classified as fine loamy mixed hyperthermic family of Typic Haplustalf. Four soil-mapping units were identified based on surface texture and pH differentia and soil map of Regional Station was prepared. Mineral assemblage of coarse and fine fractions of these soils has been investigated using X-ray diffraction. Soils have mixed mineralogywith illite as a dominant mineral in clay fraction. Coarse fraction mineralogy is dominated by quartz, feldspar, mica and chlorite. Soils are mostly medium in OC, high in available P and medium in available K. Only 5 per cent samples of these soils aredeficient in DTPA-extractable Zn. DTPA-extractable Cu, Mn and Fe are sufficient.
查看更多>>摘要：For studying the benefits of inoculation of N_2 fixing diazotrophs in the root zone of sorghum crop, a pot culture was conducted on neutral red sandy loam soil with sorghum cv. CO26, using ~(15)N tracer. At the end of 45 days duration after sowing, Beijerinckia indica inoculation contributed 56.9 per cent N derived from N_2 fixation, out of total N concentration in whole drymatter of sorghum plant. It proved to be the efficient N_2 fixer by contributing N from N_2 fixation to the tune of 17.6 Kg N ha~(-1). Accumulation of N derived from N_2 fixation from B. indica was primarily in leaf blade (50.0%) followed by stem (31.8%), leaf sheath (14.0%) and root (4.2%). Inoculation of Azospirillum brasilense accelerated uptake of N from soil and fertilizerN sources compared to B. indica and hence registered low N fixation.
查看更多>>摘要：A pot experiment was conducted in 2009-2010 to study the effect of root extracts of Brachiaria humidicola on fertilizer nitrogen use efficiency in rice and wheat crops. The experiment was conducted with rice (var.Pusa Sugandh-5) as the test crop in kharif season and in rabi season wheat (var. HD-2894) was grown as the test crop with seven treatments. Three level of nitrogen were applied as 30, 60 and 90 mg N kg~(-1) soil through ~(15)N labelled (NH_4)_2SO_4 as source of N. Recommended dose of P (30 mg P_2O_5 kg~(-1) soil) and K (30 mg K_2O kg~(-1) soil) through KH_2PO_4 and KC1 were applied. Nitrogen levels and inhibitors had significant effect on rice grain yield. It was maximum 20.37 g pot~(-1) in case of T_4 (buffer solution extract) and low 13.10 g pot~(-1) in T_7 (control). Nitrogen uptake in rice straw was found more in BNI treatments as compared to plant based (neem oil coating) and standard nitrification inhibitors. Nitrogen use efficiency in rice plant was highest in case of T_1 (70 % alcohol extract) 41.90 followed by T_4 (buffer solution extract) 41.30. Among the treatments T_5 (neem oil coating) performed better in wheat yield as compared to other treatments. Nitrogen uptake and NUE were maximum in T_3 (salt solution extract) followedby T_5 (neem oil coating) in wheat crop. The maximum nitrogen use efficiency was observed at 60 mg N kg~(-1) soil as compared to other levels.
查看更多>>摘要：A phytotron experiment was undertaken in which wheat was grown as a test crop under two levels of atmospheric CO_2: ambient (385 mu mol mol~(-1)) and elevated (650 umol mol~(-1)); two levels of temperature: ambient (ambient air temperature of rabi season in Subtropical India) and elevated (ambient+3 deg C); and three levels of P: zero (control), 100% and 200% of recommended P dose to wheat. There were significant increases in total P and fertilizer P uptake by plant under singly elevated CO_2 as wellas concurrently elevated CO_2 and temperature, with no significant change in %Pdff. As a consequence, fertilizer P use efficiency (PUE) also showed significant improvements both under the elevated CO_2 alone as well as under combined elevation of CO_2 and temperature. While this increase in fertilizer PUE was a welcome change under the projected levels of CO_2 and temperature, low efficiency at higher doses of P application still remained a matter of concern.
查看更多>>摘要：Tomato dry seeds of the hybrid "Gladiador" Fl were exposed to low doses of gamma radiation from Co-60 source at 0.509 kGy tax rate in order to study stimulation effects of radiation on germination and plant growth. Eight treatments of different radiation doses were applied as follows: 0 (control); 2.5, 5.0, 7.5, 10.0, 12.5, 15.0, 20.0 Gy. Seed germination as well as green fruits number, harvested fruit number, fruit weight and total production were assessed to identify occurrence of stimulation. Tomato seeds and plants were handled as for usual tomato production in Brazil. Low doses of gamma radiation treatment in the seeds stimulate germination and substantially increase fruit number and total production up to 86% at 10 Gy dose. There are evidencesthat the use of low doses of gamma radiation can stimulate germination and plant production thus, showing hermetic effects.
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