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1.
Changes in soil properties and yield response in relation to tillage and residue management treatments in an irrigated groundnut (Arachis hypogea L.)—wheat (Triticum aestivum, L.) rotation on a sandy soil (1972–1974) and on a sandy loam soil (1974–1976) were evaluated. Tillage treatments (T1 and T2) did not cause significant changes in soil properties. Incorporation of crop residues (5 t residue per ha per crop, T3) caused a substantial increase in organic C, available N, and NaHCO3 -extractable P contents in the top 15 cm of both soils. Residue management treatments (T3, T4 and T5) showed no significant effect on soil bulk density and exchangeable K. Crop yields under no-tillage (T1) and conventional tillage (control, T2) were comparable on sandy soil but on the sandy loam soil, no-tillage yielded significantly lower than conventional tillage. Compared with the control, incorporation of crop residues (T3) caused higher yields on sandy soil for groundnut and wheat by 34.1 and 47.4%, respectively, and on sandy loam by 17.1 and 7.2%, respectively. Mulching with crop residues conserved soil moisture and reduced maximum soil temperature (1.5–5.3°C in groundnut and 1.5–2.9°C in wheat) but other measured soil properties were not significantly affected. Significant yield increase due to residue mulching (T4) was observed in sandy soil but it was significantly less than when total crop residue was incorporated (T3). Increased wheat root-weight density in the top 15 cm soil with residue mulching was not reflected in grain yield. Compared with the incorporation of the total amount of crop residue (T3), incorporation of half the amount and application of the other half as mulch (T5) caused lower yields — on sandy soil for groundnut and wheat by 31.5 and 15.7%, respectively, and on sandy loam by 4.8 and 3.6%, respectively. 相似文献
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Two strains (derepressed-nitrogen fixing, Mac-27 and phosphate solubilizing, PS-21) of Azotobacter chroococcum were inoculated in fish culture ponds, singly and in combination with inorganic fertilizers (urea, single superphosphate–SSP). Physico-chemical parameters of pond waters, plankton production and fish biomass were studied. Inoculation of A. chroococcum (Mac-27) enhanced nitrogenase activity and rate of nitrogen fixation. A slight reduction in nitrogen fixation and nitrogenase activity was noticed when urea at 96 kg ha–1 y–1 was mixed with the biofertilizer (Mac-27). Inoculation of PS-21 enhanced phosphate solubilization, but Kjeldahl-nitrogen concentration values remained low in comparison with controls. On the other hand, inoculation of Azotobacter (either strain) enhanced the accumulation of ammonium-N, nitrite-N and nitrate-N. A significant (p < 0.05) reduction in dissolved oxygen (DO) concentration also took place when Azotobacter (both Mac-27 and PS-21) was inoculated in fish ponds. However, when used along with inorganic fertilizers, the reduction was not significant. The pH values were only slightly lowered when the phosphate-solubilizing strain (PS-21) of Azotobacter was inoculated. Inoculation of biofertilizer enhanced plankton production, net primary productivity and fish biomass. However, highest values in most of these parameters were noticed only in ponds that were treated with the higher doses of inorganic fertilizers (urea 192 kg and SSP 1500 kg ha–1 y–1). © Rapid Science Ltd. 1998 相似文献
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The objective was to test the hypothesis that dopamine regulates prolactin (PRL) secretion by determining acute changes in catecholamine concentrations in hypophyseal portal blood of cattle, and their relation to peripheral blood concentration of PRL in hypophyseal stalk-transected (HST) and sham-operated controls (SOC). Holstein heifers (606 +/- 21 kg BW; mean +/- SE) were subjected to neurosurgery for 8 h to collect hypophyseal portal blood with a stainless steel cannula designed with a cuff placed under the pituitary stalk and peripheral blood via a jugular vein catheter. PRL plasma concentration was measured by radioimmunoassay, and dopamine and norepinephrine in portal plasma by radioenzymatic assay. During anesthesia before HST or SOC, PRL plasma concentration ranged from 20-40 ng/ml throughout 255 min. PRL abruptly increased and remained above 90 ng/ml after HST compared with a steady decrease to <20 ng/ml in SOC heifers throughout 440 min. Within 5 min after severing the hypophyseal stalk, dopamine in portal blood (>8 ng/ml) was significantly increased (P < 0.05) compared with peripheral blood (<2 ng/ml). Norepinephrine concentration in portal blood was significantly greater (P < 0.05) than in peripheral blood during the first 60 min. The sustained high PRL level in peripheral plasma after severing the hypophyseal stalk stimulated hypothalamic dopamine secretion from hypophyseal portal vessels during the prolonged period of blood collection. Norepinephrine concentration in these cattle was greater in hypophyseal portal than in peripheral blood, implicating both an important hypothalamic source of the catecholamine as well as an adrenal gland contribution during anesthesia. 相似文献
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Michihiko?SaitoEmail author Deepak Raj?Rai Ryoichi?Masuda 《Journal of General Plant Pathology》2003,69(5):304-306
During storage studies on asparagus spears packed in plastic film and held at 15°C, a Penicillium fungus was associated with subsequent spoilage. On the basis of colony characteristics, the isolate was identified as Penicillium hirsutum Diercks. This report is the first of Penicillium hirsutum causing spoilage of asparagus spears in Japan. Inoculation tests showed that among all the Penicillium species tested in this study only the identified fungus was able to infect asparagus spears. 相似文献
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The physical properties of fruit are important in designing and fabricating equipment and structures for handling, transporting, processing and storage, and also for assessing quality. The study was conducted to investigate some physical properties of jatropha fruit at various moisture levels. The average length, width, thickness and 1000 mass were 29.31 mm, 22.18 mm, 21.36 mm and 1522.10 g, respectively, at moisture content of 7.97% d.b. The geometric mean diameter increased from 24.03 to 24.70 mm and the sphericity varied between 0.82 and 0.83 as moisture content increased from 7.97% to 23.33% d.b., respectively. In the same moisture range, the bulk and true densities decreased from 278 to 253 and 546 to 435 kg m?3, respectively, whereas the corresponding porosity also decreased from 49.08% to 41.84%. As the moisture content increased from 7.97% to 23.33% d.b., crushing strength was decreased from 275 to 79 N, whereas the angle of repose and surface areas were found to increase from 36.41° to 41.72° and 1815.73 to 1917.59 mm2, respectively. The static coefficient of friction of jatropha fruit increased linearly against the surfaces of three structural materials, namely plywood (47.81%), mild steel (62.88%) and aluminium (34.82%) as the moisture content increased from 7.97% to 23.33% d.b. 相似文献
8.
Shaky-leg lameness is a poorly defined, mild to very severe, painful lameness occurring mainly in 10-to-18-week-old fast-growing male turkeys. Since there are no significant gross or microscopic lesions in early or uncomplicated cases, the cause of the lameness is likely soft-tissue (muscle or tendon) pain. A case history of a flock problem of shaky-leg lameness is described, and it is suggested that stiffness and inactivity secondary to footpad dermatitis in these turkeys was responsible for the severe shaky-leg lameness in the flock. The cartilage lesion described is an avascular lesion and appeared to be the result of inactivity rather than the cause of lameness in these turkeys. 相似文献
9.
The study was conducted to investigate some moisture-dependent physical properties of jatropha seed namely, seed dimension, 1000 seed mass, surface area, sphericity, bulk density, true density, angle of repose and static coefficient of friction against different materials. The physical properties of jatropha seed were evaluated as a function of moisture content in the range of 4.75–19.57% d.w. The average length, width, thickness and 1000 seed mass were 18.65 mm, 11.34 mm, 8.91 mm and 741.1 g, respectively at moisture content of 4.75% d.w. The geometric mean diameter and sphericity increased from 12.32 to 12.89 mm and 0.66 to 0.67 as moisture content increased from 4.75 to 19.57% d.w., respectively. In the same moisture range, densities of the rewetted jatropha seed decreased from 492 to 419 kg m−3, true density increased from 679 to 767 kg m−3, and the corresponding porosity increased from 27.54 to 45.37%. As the moisture content increased from 4.75 to 19.57% d.w., the angle of repose and surface area were found to increase from 28.15° to 39.95° and 476.78 to 521.99 mm2, respectively. The static coefficient of friction of jatropha seed increased linearly against the surfaces of three structural materials, namely plywood (44.12%), mild steel sheet (64.15%) and aluminum (68.63%) as the moisture content increased from 4.75 to 19.57% d.w. 相似文献
10.
Shantharaj Deepak Sathyanarayana Niranjan-Raj Shekar Shailasree Ramachandra K. Kini Wilhelm Boland Hunthrike S. Shetty Axel Mithfer 《Physiological and Molecular Plant Pathology》2007,71(1-3):96-105
The synthetic 1-oxo-indanoyl-l-isoleucine methyl ester (Ind-Ile-Me) represents a highly active mimic of octadecanoic phytohormones, which are involved in plant defenses against pathogens and pests. Seed treatments and foliar spray with Ind-Ile-Me were tested for induced resistance against downy mildew disease caused by the phytopathogenic oomycete Sclerospora graminicola in pearl millet (Pennisetum glaucum) under greenhouse and field conditions. Under greenhouse conditions, a 50% protection level was achieved after seed treatment. Seed treatment in combination with foliar spray resulted in 60% protection. The induction of resistance was correlated with the enhanced activities of defense-related proteins such as phenylalanine-ammonia-lyase, peroxidase, and enhanced level of hydroxyproline-rich glycoproteins. Under field conditions, a maximum protection of 62% was recorded upon seed treatment along with foliar spray. Hence, it infers that Ind-Ile-Me can be used as a valuable protection compound at least in downy mildew disease management. 相似文献