Long-term fertilization effects on carbon pools and carbon management index of loamy soil under grass–forage legumes mixture in semi-arid environment     

A.K. Dixit  A.K. Rai  Mahendra Prasad  Sunil Kumar  M.K. Srivastava 《Archives of Agronomy and Soil Science》2020,66(10):1373-1383

ABSTRACT

Soil organic carbon (SOC) is a key component for sustaining crop production. A field experiment was conducted during 2004–2018 to assess the changes in soil carbon fractions under different fertilization practices in grass-legumes mixture. The result indicates that application of farmyard manure (FYM) at 80 Mg ha^–1 has increased SOC concentration leading to carbon sequestration rate of 4.2 Mg ha^–1 year^–1. Further, it has increased the proportion of labile carbon in the total SOC and have accumulated 126, 60, 83 and 95% higher very labile, labile, less labile and non-labile C stock than that of control plot, respectively, in top 30 cm soil layer. Inorganic fertilization and FYM 20 Mg ha^–1 influenced SOC concentration, SOC stock and C sequestration rate similarly. The highest carbon management index (264) was found in the treatment receiving FYM 80 Mg ha^–1 and it was positively correlated with SOC (r = 0.84**). The sensitivity index of the SOC varied from 26 to 152% and the differences were greatest in FYM treatments. The result indicates that grass-legumes mixture build-up the SOC in long term and the addition of FYM further increases it.  相似文献   

Carbohydrate metabolism during tuber initiation in potato: A transient surge in invertase activity marks the stolon to tuber transition     

J. S. Minhas  V. K. Rai  H. S. Saini 《Potato Research》2004,47(3-4):113-126

Summary The relationship between carbohydrate metabolism and tuber initiation in potato was determined by monitoring changes in the amount of starch and sugars along with the activities of sugar metabolizing enzymes upon transfer of plants to tuber-inducing conditions (TI; short days, cold nights) from non-inducing conditions (NTI: long days, warm nights). Switch to TI conditions caused an immediate slow-down in plant growth and triggered swelling of stolon tips, which went on to develop into tubers. Leaves of plants moved to TI conditions accumulated less starch and sugar while their stolon tips showed a sudden upsurge in starch content and a sharp decline in sugars even before any tip swelling was detectable. These changes were paralleled by a transient surge in the activity of cell wall invertase (74%) and soluble invertase (30%) in stolon tips of plants transferred to TI conditions in two unrelated cultivars under different experimental conditions. As the surge in invertase activity faded, it was replaced by a substantial increase in sucrose synthase activity as the tuber enlargement proceeded. The transient increase in invertase activity just prior to tuber initiation appears to mark a turning point in the transition of stolon tip to tuber.  相似文献   

Effect of selected amino acids and polyethylene glycol on maturation and germination of somatic embryos of guava (Psidium guajava L.)     

Manoj K. Rai  V.S. JaiswalU. Jaiswal 《Scientia Horticulturae》2009

Two selected amino acids (l-glutamine and l-proline) and polyethylene glycol (PEG) were evaluated for their effects on maturation and germination of somatic embryos in guava (Psidium guajava L.) cv. Banarasi local. Among the treatments of two amino acids (l-glutamine and l-proline) and PEG tested, 0.87 mM l-proline was most effective for maturation of somatic embryos. As compared to control, supplementation of PEG (1.0% or 2.0%) in maturation media showed significantly better maturation (increased maturation frequency). Lower stage somatic embryos showed prematuration germination with development of abnormal plantlets and only mature somatic embryos produced morphologically normal plantlets.  相似文献   

Effect of moisture content on ethylene glycol retention by clay minerals     

Dhanpat Rai  William T. Franklin 《Geoderma》1978,21(1):75-79

For the accurate determination of ethylene glycol retention by soil minerals, precision in moisture removal is extremely important. One percent decrease in moisture appears to increase the ethylene glycol retention by 10 to 12 mg/g of sample. Drying samples over P₂O₅ is tedious and requires considerable care. An alternate method that is precise and easy is presented. By this method, an air-dried Ca-saturated subsample suspected of containing irreversibly dehydrating clays is saturated and equilibrated with ethylene glycol. The retention values are determined on a moisture-free weight basis calculated from a duplicate subsample dried in an oven at 105°C. Ethylene glycol retention of samples that do not contain irreversibly dehydrating clays is determined directly by saturation and equilibration of 105°C oven-dried samples.  相似文献   

Smut reaction of pearl millet hybrids affected by fertility restoration and genetic resistance of parental lines     

K. N. Rai  R. P. Thakur 《Euphytica》1996,90(1):31-37

Summary Pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids based on the A₁ cytoplasmic-nuclear male-sterile (CMS) lines are more susceptible to smut (Tolyposporium penicillariae Bref.) than open-pollinated varieties. Seventy eight pairs of hybrids, made onto male-sterile (A) lines and their counterpart maintainer (B) lines, were evaluated to examine the effects of male sterility and genetic resistance of parental lines on the smut severity of hybrids. The A-line hybrids had higher smut severity and lower selfed seedset than the counterpart B-line hybrids, indicating that it is the CMS-mediated male sterility rather than the A₁ cytoplasm per se that caused greater smut severity of A-line hybrids. However, with the use of resistant parental lines even male-sterile hybrids of A-lines, in several cases, were as resistant as some of the highly resistant male-fertile hybrids of B-lines. It would be possible to produce smut resistant hybrids (< 10% severity) on A-lines, albeit in low frequency, even if only one parent of a hybrid were resistant. However, the probability of producing such hybrids would be higher when both parents were resistant to smut. Thus, improvement in smut resistance of parental lines and fertility restoration ability of pollinators would provide the most effective genetic approach to smut disease management in hybrids.Submitted as JA No 1737 by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT).  相似文献   

Ergot reaction of pearl millet hybrids affected by fertility restoration and genetic resistance of parental lines     

K. N. Rai  R. P. Thakur 《Euphytica》1995,83(3):225-231

Summary High ergot (Claviceps fusiformis Loveless) susceptibility of pearl millet (Pennisetum glaucum (L.) R. Br.) hybrids has often been associated with the A₁ cytoplasm of male-sterile lines (A-lines). To understand the underlying basis of this association and to examine the prospects of breeding ergot-resistant hybrids, we evaluated 56 hybrids and their 15 parental lines for ergot reaction and selfed seedset for 2 years in disease nurseries at ICRISAT Asia Center. Hybrids were made by crossing seven pollen parents (2 susceptible and 5 resistant) onto two resistant and two susceptible A-lines, and their four corresponding maintainer lines (B-lines). A-lines had no selfed seedset while B-lines had 32–75% selfed seedset. Hybrids of A-lines had significantly less selfed seedset than the hybrids of the corresponding B-lines. The reduced seedset of A-lines and their hybrids, however, was not always accompanied by significantly higher ergot susceptibility. Highly resistant hybrids were obtained where both A-lines and pollen parents were highly resistant, regardless of male fertility levels of the hybrids. Thus, although the A₁ cytoplasm, by its reduction of male fertility, had a large and significant effect in increasing ergot severity of hybrids, the contribution of nuclear genetic factors of female parents was about 1.8 times larger than that of the cytoplasm.Submitted as JA No. 1776 by the International Crops Research Institute for the Semi Arid Tropies.  相似文献   

Effect of d2 dwarfing gene on grain yield and yield components in pearl millet near-isogenic lines     

K. N. Rai  A. S. Rao 《Euphytica》1991,52(1):25-31

Summary A d₂ dwarfing gene in pearl millet [Pennisetum glaucum (L.) R. Br.] is currently being extensively used for the development of hybrid parents. Its effect on grain yield and yield components is poorly understood. Twelve pairs of tall and dwarf near-isogenic lines developed in the diverse genetic background of three composites were evaluated for grain yield and yield components for 2 years at two locations in southern India. The d₂ gene or the genes linked to it, on an average, reduced plant height by 42%, grain yield by 14%, and head girth by 8% but increased head length and number of tillers per plant by about 5–6%. Large variations were observed among pairs (genetic background) for the difference between tall and dwarf near-isogenic lines for all of the above yield components resulting in no significant difference in five pairs and 17–35% less yield in dwarfs as compared to their tall counterparts in six pairs. Days to 50% flowering and seed weight were least affected by the d₂ gene with the average difference between tall and dwarf groups of near-isogenic lines being of the order of 1–2%. These results indicate that the advantageous effects of d₂ dwarfing gene can be effectively exploited by manipulating the genetic background. The difference between the average grain yields of tall and dwarf groups of near-isogenic lines showed considerable variation across environments with the dwarfs yielding as much as tall group in one environment and up to 30% less than the tall group in the other, thus, indicating that the d₂ gene effect may be substantially modified by the environments.Submitted as JA No. 979 by the International Crop Research Institute for the Semi-Arid Tropics (ICRISAT).  相似文献   

Competitive saprophytic colonization of pigeon-pea substrate by Fusarium udum in relation to environmental factors,chemical treatments and microbial antagonism     

Bharat Rai  R.S. Upadhyay 《Soil biology & biochemistry》1983,15(2):187-191

The competitive saprophytic colonization (CSC) of pigeon-pea substrates by Fusarium udum was studied in relation to environmental factors, chemical treatments and microbial antagonism. CSC was best at 22°C, good at 30°C, but at 40°C the substrate was vigorously colonized by Coprinus lagopus and Aspergillus nidulans which suppressed colonization by F. udum. High competitive saprophytic ability of F. udum was noted at pH 7 and 9 at soil moisture contents between 5 and 30%. At pH 4 and 5 F. udum was replaced by A. flavus and A. nidulans. The CSC of F. udum decreased in the soil-sand inoculum mixture amended with the fungicides bavistin, dithane Z-78 and difolatan. The herbicides 2,4-D and machete also reduced CSC by F. udum whereas urea promoted it. Colonization of pigeon-pea substrate by F. udum was highly suppressed by antagonism from Pénicillium citrinum, A. niger, Micromonospora gtobosa, A.flavus, A. terreus and Trichoderma viride when these were used in inoculum mixtures with F. udum or when substrates had already been colonized by them. Otherwise F. udum was shown to have a high competitive saprophytic ability.  相似文献   

Decomposition and competitive colonization of leaf litter by fungi     

Bharat Rai  Atul K. Srivastava 《Soil biology & biochemistry》1983,15(1):115-117

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Current-controlled magnetic domain-wall nanowire shift register   总被引：1，自引：0，他引：1  

Hayashi M  Thomas L  Moriya R  Rettner C  Parkin SS 《Science (New York, N.Y.)》2008,320(5873):209-211

The controlled motion of a series of domain walls along magnetic nanowires using spin-polarized current pulses is the essential ingredient of the proposed magnetic racetrack memory, a new class of potential non-volatile storage-class memories. Using permalloy nanowires, we achieved the successive creation, motion, and detection of domain walls by using sequences of properly timed, nanosecond-long, spin-polarized current pulses. The cycle time for the writing and shifting of the domain walls was a few tens of nanoseconds. Our results illustrate the basic concept of a magnetic shift register that relies on the phenomenon of spin-momentum transfer to move series of closely spaced domain walls.  相似文献