Effect of summer green manuring crops and zinc fertilizer sources on productivity,Zn-uptake and economics of basmati rice

Field experiments were conducted for two consecutive years on basmati rice (Oryza sativa L.) during summer and rainy seasons (April–November) of 2009 and 2010 in a sandy clay-loam soil (typic Ustochrept) at the research farm of Indian Agricultural Research Institute, New Delhi. The aim of this study was to determine the influence of zinc fertilizer sources [ethylenediamenetetraacetic acid (EDTA)-chelated zinc (Zn; 12% Zn), zinc sulfate heptahydrate (ZnSO₄.7H₂O; 21% Zn), zinc sulfate monohydrate (ZnSO₄.H₂O; 33% Zn), zinc oxide (ZnO; 82% Zn), and ZnSO₄.7H₂O + ZnO (50% + 50%)] and summer green manuring crops [Sesbania aculeata, Crotalaria juncea and Vigna unguiculata] on productivity, Zn-uptake and economics of basmati rice. Among the summer green manuring crops, Sesbania aculeata accumulated highest amount of total dry matter, 5.46 and 5.77 t ha^?1 during 2009 and 2010, respectively. Incorporation of Sesbania aculeata also led to a significant increase in grain, straw and biological yields, Zn content and uptake and economics of succeeding basmati rice. With the incorporation of Sesbania aculeata, grain and straw yields of basmati rice was 4.89, 5.56 and 9.04, 10.21 t^?1 ha during 2009 and 2010, respectively. Among the Zn fertilizer sources, EDTA-chelated Zn (12% Zn) was found to be the best with respect to grain, straw, and biological yields, Zn content and uptake and economics. Application of EDTA-chelated Zn (12% Zn) recorded the highest basmati rice grain (5.15 and 5.76 t ha^?1) and straw yields (9.30 and 10.48 t ha^?1) compared to control (no Zn application), which produced 4.09 and 4.75 t ha^?1 of grain and 8.13 and 9.39 t ha^?1 of straw yields, respectively, during 2009 and 2010. Highest Zn concentration in grain and straw and its uptake was recorded with Sesbania aculeata incorporation compared with Crotalaria juncea, Vigna unguiculata and summer fallow. Highest total Zn uptake in basmati rice was recorded with EDTA-chelated Zn (12% Zn) application, followed by ZnSO₄.7H₂O (21% Zn), ZnSO₄.H₂O (33% Zn), ZnSO₄.7H₂O + ZnO (50% + 50%), ZnO (82% Zn), and control (no Zn application). Sesbania aculeata incorporation and EDTA-chelated Zn (12% Zn) treatments were found a better combination with respect to basmati rice productivity. The best economical returns were obtained with Sesbania aculeata incorporation and ZnSO₄.7H₂O (21% Zn) combination. Thus, adequate Zn fertilization along with green manure crop incorporation can lead to higher productivity of basmati rice.     

Increased yield of direct seeded rice (Oryza sativa L.) by foliar fertilization through multi-component fertilizers

Foliar application of fertilizers can guarantee the availability of nutrients to rice for obtaining higher yield. Rice responds favorably to macro- and micronutrients and the tolerance to salinity hazards improves by decreasing the N/S ratio. In this study, results showed that nutrient concentrations (g L^?1) for rice are: nitrogen (N) 108.0, phosphorous (P₂O₅) 6, potassium (K₂O) 81.0, calcium (CaO) 15.0, and magnesium (MgO) 6 g L^?1; and for iron (Fe), manganese (Mn), zinc (Zn), cupper (Cu), boron (B), molybdenum (Mo) and silicon (Si) the recommended concentrations are 0.6, 0.45, 0.21, 0.06, 0.09, 0.0002 and 0.004 g L^?1, respectively. A significant increase was recorded in number of panicles m^?2, 1000 grain weight, biological yield and grain yield with foliar application of nutrients. Five foliar applications of nutrients resulted in maximum number of panicles m^?2, grains panicle^?1, 1000 grain weight and biological yield. It is concluded that five foliar applications of balanced amounts of fertilizers at the seedling stage (two sprays), tillering (single spray) and at panicle initiation and panicle differentiation (two sprays) helped in enhancing yield and yield components of rice. In this research, five foliar applications produced the smallest damaging effects of blast (Pyricularia oryzae) in rice.     

Comparative efficacy of ZnSO4 and Zn-EDTA application for fertilization of rice ( Oryza sativa L.)

Widespread Zn deficiency for rice crop has been reported from different parts of the world, including India. To correct such deficiency, Zn is often applied to the soil as fertilizer. Its concentration in soil solution and its availability to crops is controlled by sorption?–?desorption reactions at the surfaces of soil colloidal materials. The objective of this study was to compare the availability and relative effectiveness of Zn from Zn-EDTA and ZnSO₄ sources by applying different Zn levels to a calcareous soil in field experiments through soil application. The uses of Zn-EDTA also increase the yield of rice dry matter yield and grain yield. Regarding maintenance of Zn in soil, it has been observed that the amount of Zn content was recorded higher with the split application of Zn-EDTA as compared to ZnSO₄ with the simultaneous 26.1% increase in the yield of rice.     

Asymmetric warming effects on N dynamics and productivity in rice (Oryza sativa L.)

Climate warming exhibits strong diurnal variations, with higher warming rates being observed at nighttime, which significantly affects rice (Oryza sativa L.) growth and grain yield. The objective of this study was to determine the effects of asymmetric warming (all-day warming, AW; daytime warming from 07:00 to 19:00, DW; nighttime warming from 19:00 to 07:00, NW, and a control, CK) on rice nitrogen (N) dynamics and productivity. Two rice bucket warming experiments were performed in Nanjing in Jiangsu Province, China, using the free air temperature increase (FATI) technique. The daily mean temperatures in the rice canopy in the AW, DW and NW plots were 2.0, 1.1 and 1.3ºC higher than those in the rice canopy in the CK plots, respectively. The results indicated that the total N accumulation of rice was 8.27–40.53% higher in the warming treatment than in the control during the jointing, anthesis and maturity stages. However, there was no significant difference detected among the three warming treatments. The warming treatment substantially decreased N translocation efficiency, leading to the retention of more N in the plant stems during grain filling. The warming treatment also decreased the N harvest index, N utilization efficiency based on grain yield and N utilization efficiencies based on biomass in both growing seasons. The warming treatment significantly increased the aboveground biomass (9.26–16.18%) in the jointing stage but decreased it (2.75–9.63%) in the maturity stage. Although DW increased the carbon (C) gain by photosynthesis and NW increased the C loss by night respiration, the daytime higher-temperature treatment affected rice photosynthesis and reduced its photosynthetic rate and product. This effect may be one of the primary reasons for the insignificant difference in the aboveground biomass between the DW and NW treatments. In the AW, DW and NW plots, the grain yield was reduced by an average of 10.07, 5.05 and 7.89%, respectively, across both years. The effective panicles and grains per spike tended to decrease in the warmed plots, whereas irregular changes in the 1000-grain weight were observed. Our results suggest that under the anticipated climate warming, rice productivity would further decline in the Yangtze River Basin.     

锌铬复合污染对水稻根系抗氧化酶活性的影响

为了研究水稻在金属复合污染条件下的适应过程,该文就成都平原两种常见的重金属污染元素(锌、铬)对土壤复合处理后,进行水稻盆栽试验.结果表明,锌铬复合污染条件下,在水稻不同生育期,水稻根系3种抗氧化酶(SOD,POD和CAT)活性随锌、铬浓度的增加而表现出不同的变化趋势.在水稻分蘖期,随铬浓度的增加,水稻根系SOD活性和POD活性呈先降后升的变化趋势;随锌浓度的增加,水稻根系SOD活性和POD活性呈升高的趋势;而水稻根系CAT活性则随锌、铬浓度的增加呈一定的降低趋势.在水稻孕穗期,随锌、铬浓度的增加,水稻根系SOD活性呈先降后升的变化趋势,POD活性及CAT活性则呈降低的趋势.在水稻灌浆结实期,水稻根系SOD、POD及CAT活性均呈一定的降低趋势.水稻籽粒产量随锌、铬浓度的增加呈降低的趋势.锌、铬浓度对水稻籽粒产量产生了复合效应,并与水稻籽粒产量有极显著的线性回归关系.这表明水稻通过调节自身的生理代谢能提高对锌铬复合污染的生态适应性,这能为培育适合重金属污染地区生长的水稻品种提供理论基础.     

Effect of green manuring,blue-green algae and neem-cake-coated urea on wetland rice (Oryza sativa L.)

Summary A field trial was set up to examine the effect of green manuring, blue-green algae, and neem-cake-coated urea on a rice crop. Summer green manuring using Sesbania aculeata increased the crop yield. Inoculation of blue-green algae increased the rice grain yield when 60 kg N ha^-1 was applied as prilled urea, but the increase in grain yield was greater when 60 kg N ha^-1 was applied as neem-cake-coated urea. The results of the present study show that applications of green manure, neem-cake-coated urea, and blue-green algae are complementary and that the three treatments can be used together in the rice ecosystem. The green manure and the fertilizer treatments had no effect on the algal flora of the soil.     

Increased zinc supply does not inhibit cadmium accumulation by rice (Oryza sativa L.)

Rice (Oryza sativa L.) grown on cadmium (Cd)-contaminated soils has caused health problems in Asian subsistence rice farmers. For other crops, normal co-contaminant zinc (Zn) inhibits the increased uptake of Cd. We used a multi-chelator-buffered nutrient solution to characterize the interaction of Zn and Cd in uptake-translocation of Cd in “Lemont” rice. The activity of free Zn²⁺ varied from 10^?7.6 to 10^?5.2 M, while free Cd²⁺ held constant at 10^?10.7 M. Zinc activity 10^?5.6 M and higher was phytotoxic to rice, resulting in severe chlorosis, reduced growth, and increased Cd transport to shoots. In contrast to previous studies with wheat, lettuce, and spinach, free Zn²⁺ maintained at adequate to sub-phytotoxic levels (10^?7.6 to 10^?6.1) did not inhibit Cd uptake by rice. The inability of Zn to inhibit Cd uptake by rice is a key factor in Cd risk from zinc-lead mine waste contaminated soil compared with other crops.     

Monitoring of meteorological drought and its impact on rice (Oryza sativa L.) productivity in Odisha using standardized precipitation index

The dynamics of meteorological drought and its relationship with block level rice productivity over the Eastern Indian state of Odisha was assessed during the wet season (June to November) using the standardized precipitation index (SPI). The time series of rainfall data (1983–2008) from 168 rain gauge stations was used to derive the 1- and 3-month SPI of different wet season months. The 1- and 3-month SPI data were interpolated to map spatial patterns of meteorological drought and its severity, and the maps of a drought (2008) and normal (2007) year were discussed in detail. Further, the time series of SPI was exploited to assess the drought risk in Odisha. Correlation analysis of 1- and 3-month SPI with rice productivity index (RPI) showed that the SPI of 1-month time scale particularly in July (r = 0.49) and October (r = 0.33) had significantly stronger relationship with RPI than any of the 3-month SPI individually during wet season. The cumulative degree of severity of drought could be better explained by 3-month SPI map when drought events are well spread in the preceding months. Regression models were developed using 1- and 3-month SPI for forecasting rice productivity of blocks with varying proportion of rainfed area in Odisha. Model developed based on 1-month SPI accounted for 27% yield variability in rice and could be used for forecasting rice productivity.     

不同氮肥及施用方式对水稻养分吸收特征及产量形成的影响

通过田间试验研究了不同氮肥及其施用方式对水稻养分吸收及产量形成的影响。结果表明,一次性施用普通尿素、稳定尿素及缓释尿素的处理之间田面水中铵态氮浓度差别不大,施肥结束后田面水中铵态氮浓度均呈现出不断降低的趋势;分次施肥处理田面水中铵态氮浓度随追肥次数呈现出周期性的升高降低过程;一次性施用缓释尿素可以提高土壤中碱解氮及植株氮的含量,对光合速率、蒸腾速率、胞间二氧化碳浓度也均有提升作用,对水稻具有稳产作用。一次性施用缓释尿素可以促进整个生育期内水稻对养分的需求,可以促进灌浆期碳水化合物的累积,因此能达到与分次施肥相同的稳产效果。     

Energy efficiency,productivity and profitability of rice (Oryza sativa L.) based cropping systems for selected conservation practices

A field experiment was conducted in split plot design to examine the energy efficiency, productivity, and profitability of 6 rice based cropping systems for selected conservation agricultural (SCA) and the conventional (CNV) practices during the years 2010 to 2012. Results revealed that rice crop grown in wet season with SCA resulted in higher net energy, energy output: input ratio, energy productivity, and net returns as compared to CNV. Also, in the dry season, higher yield, net return, net energy and the net economic water productivity (NEWP) were noted for the SCA. Among the dry season crops, sunflower recorded highest net energy (57.2 GJ ha^?1) followed by horsegram and cabbage. The NEWP was highest for babycorn (US $ 0.198 m^?3), followed by cabbage and sweetcorn. However, the per cent increase in net return, net energy and the NEWP for SCA as compared to the CNV was highest for horsegram followed by sunflower. Despite having low system productivity, rice-sunflower and rice-horsegram cropping systems were more energy efficient with high net energy of 194.4 and 169.4 GJ ha^?1, respectively. These two systems were low water demanding and helped in buildup of soil organic carbon, nitrogen (N), phosphorus (P) and potassium (K).     

Characterisation of globally diverse blast-resistant upland rice (Oryza sativa L.) germplasms based on morpho-physiological and yield attributes

Upland rice is a valuable base population for protecting against genetic erosion and broadening the gene pool of rice germplasms, and rice is also the staple food of more than 100 million people across the world. Therefore, an experiment was conducted to elucidate the performances of 27 globally diverse blast-resistant upland rice genotypes in terms of morphological, physiological and yield trait characteristics and to determine the correlations between and assess the diversity among these characteristics. All of the genotypes were evaluated in a randomised complete block design with three replications. Analysis of variance revealed 18 traits with significant to highly significant variations among themselves. The BRRI dhan42, BRRI dhan43, Ja Loy, C, Choke Tang and Chirikata 2 genotypes matured early, and the Chirikata 2, C, Choke Tang, BRRI dhan43 and Padi Beleong genotypes were best in terms of yield. The greatest heritability was recorded for the numbers of filled grains/panicle and the yield/plant, which demonstrated that these traits can be successfully transferred to the offspring if selection for these characteristics is performed in a hybridisation programme. The 27 genotypes were grouped into six clusters based on the contributing morphological, physiological and yield characteristics. The first four principal components accounted for 40, 59, 70 and 79% of the total variation, respectively, which indicated abundant genetic differences between these genotypes. The Chirikata 2, C, Choke Tang and BRRI dhan43 were selected as the best genotypes and could be used as valuable resources for high-yielding, early maturing, blast-resistant cultivars and parental sources for hybridisation programmes for challenging environments in the future.     

Nitrogen acquisition and its relation to growth and yield in recent high-yielding cultivars of rice (Oryza sativa L.) in Japan

During the last two decades, high-yielding cultivars for multipurpose use of rice have been bred and released in Japan. Some of them have repeatedly recorded high yields of over 9?t?ha^?1 of brown rice (about 11.25?t?ha^?1 of rough rice). Here, characteristic features of nitrogen (N) acquisition and its relation to formation of yield components, dry matter production and grain yield at yield levels over 9?t?ha^?1 of brown rice in recent high-yielding cultivars, a large grain type of japonica variety, “Akita 63,” extra-panicle weight types of indica variety, “Takanari” and “Saikai 198,” and a panicle weight type of japonica variety, “Fukuhibiki,” are described as compared with those in the standard japonica cultivars, “Toyonishiki” and “Nipponbare.” The grain yield of the recent high-yielding cultivars was 9.4 to 11.6?t?ha^?1 of brown rice; that is 1.2?1.7 times greater than those of the standard cultivars. Sink capacity (1000-grain weight?×?spikelet number per unit land area) was 47?62% greater in the recent high-yielding cultivars, largely due to their 1.3?1.5 times greater N-use efficiency for sink formation (sink capacity per unit amount of total plant N in the aboveground part at maturity), although major component(s) responsible for their greater sink capacity differ among the cultivars. The ratio of grain yield to total dry matter was 1.1?1.4 times greater in the recent high-yielding cultivars than in the standard cultivars, indicating that the former efficiently translocate dry matter into spikelets during the grain-filling period. N-use efficiency for dry matter production (total dry matter per unit amount of total plant N) was comparable between “Akita 63,” “Fukuhibiki” and “Toyonishiki,” and slightly greater in “Takanari” and “Saikai 198” than in “Nipponbare.”

These results indicate that greater N-use efficiency for sink formation and efficient translocation of dry matter into spikelets contribute greatly to the high-yielding potential of the recent high-yielding cultivars.     

Effects of inorganic fertilizers and micronutrients on methane production from wetland rice (Oryza sativa L.)

We compared the effects of adding different forms of nitrogenous fertilizers on the production of CH₄ in soil and on CH₄ emission from rice plants, Urea and diammonium phosphate gave the highest rates of CH₄ production from the soil and emission through rice plants, followed by (NH₄)₂SO₄. NaNO₃ was the least effective. The effects of micronutrients like Mo, Ni, or B were more prominent than those of Fe, Mn, Zn, V, or Co. It is concluded that CH₄ emission from rice paddies is influenced by both macro- and micronutrients, through effects on both microbial methanogenesis in soil and elimination through rice plants as a consequence of the effects on plant growth.     

施钾对有些茄科作物产量和品质的影响

Over a period of two years,field experiments were conducted on wto silty loam soils grown with four solanaceous vegetable crops of geggplant(var.serpentinum Bailey),tomato(var.commune Bailey),sweet pepper(var.grossum Bailey) and chilli (var.lengum Bailey),respectively,Each experiment included four treatments with from low to high doses,0-450 kg ha^-1 for eggplant ,tomato and sweet pepper,and 0-270 kg ha^-1 for chilli,of K fertilizers in the from of sulfate of potash(SOP) applied together with N and P fertilizers. One CK treatment without K,N and P fertilzers applied and one treatment of K fertilizer in the form of muriate of potash(MOP) applied at the high level(450kg ha^-1) together with N and P fertilizers were included in the experiments of eggplant,in order to compare the effects of SOP and MOP,The fruit yields of the tested crops increased significantly with the increasing rate of K application.The crops supplied with K fertilizers yielded more stably as the CV% of their yields decreased with the rate of K application,The K fertilizers yielded more stably as the CV% of their yields decreased with the rate of K application,The dry matter and vitamin C contents in fruits of tomato,sweet pepper and chilli,and the sugar content and the titratable acidity level of tomato fruits were increased,and the S/A ratio( ratio of sugar content to titratable acidity) of tomato fruits were decreased by K fertilization,indicating that K fertilization could improve the fruit quality of the solanaceous vegetable crops.However,the high rate of Kfertilizer might lower the dry matter and vitamin C contents of tomato fruits and sewwt pepper fruits.SOP was more effective than MOP in increasing the yield and quality of eggplant fruits at the high fertilization rate;therefore,the choice of applying SOP may be better for high levels of K fertilization.     

包膜复合肥对水稻生长及营养特性的影响

试验以早稻品种早凡5号和晚稻品种新香优80为材料,利用自行研制的低成本包膜复合肥(N:P2O5:K2O=17％:7％:12％)设置不同用量处理,以相同养分含量的未包膜复合肥为对照,在大田条件下采用随机区组小区试验,比较研究了供试水稻品种的生长生理和营养生理特性。结果表明包膜肥各处理分蘖增长平缓,成穗率高,而对照前期分蘗发生快,无效分蘗增多。包膜肥各处理剑叶叶绿素含量和SPAD测定值在后期显著高于对照。与等量或减量20％-25％的未包膜复合肥处理比较,早稻产量增加5.0％-12.8％,晚稻实际产量提高7.5％-13.6％,均达5％显著水平。因此,施用包膜复合肥前期养分释放平稳,水稻生长健壮;中后期可提供较多的养分,延长水稻叶片的光合功能期,促进光合产物向籽粒中转运,增加干物质产量和稻谷产量。     

Crop growth and nitrogen transformations in wheat (Triticum aestivum L.) planted after wetland rice (Oryza sativa L.)

Summary A field study was undertaken to examine the effects of various management strategies on wheat (Triticum aestivum L.) performance and N cycling in an intensively cropped soil. Microplots receiving 100 kg N ha^–1 as¹⁵NH₄ ^{+ 15}NO₃ ^– at sowing, tillering or stem elongation were compared with unfertilized microplots. Stubble from the previous rice crop was either incorporated, burnt without tillage, burnt then tilled or retained on the surface of untilled soil. Wheat grain yield ranged from 1.5 to 5.1 t ha^– and was closely related to N uptake. Plant accumulation of soil N averaged 36 kg N ha^–1 (LSD 5% = 10) on stubble-incorporation plots and 54 kg N ha^–1 on stubble-retention plots. Fertilizer N accumulation averaged 18 kg N ha^–1 (LSD 51% = 6) on stubble-incorporation plots and 50 kg N ha^–1 on stubble-retention plots. Tillage had little effect on burnt plots. Delaying N application from sowing until stem elongation increased average fertilizer N uptake from 26 to 39 kg N ha^–1 (LSD 5% = 6), but reduced soil N uptake from 50 to 37 kg N ha^– (LSD 5% = 10).Immobilization and leaching did not vary greatly between treatments and approximately one-third of the fertilizer was immobilized. Less than 1% of the fertilizer was found below a depth of 300 mm. Incorporating 9 t ha^–1 of rice stubble 13 days before wheat sowing reduced net apparent mineralization of native soil N from 37 to 3 kg ha^–1 between tillering and maturity. It also increased apparent denitrification of fertilizer N from an average 34 to 53 kg N ha^–1 (LSD 5% = 6). N loss occurred over several months, suggesting that denitrification was maintained by continued release of metabolizable carbohydrate from the decaying rice stubble. The results demonstrate that no-till systems increase crop yield and use of both fertilizer and soil N in intensive rice-based rotations.     

施用钾肥对叶菜产量和品质的影响

Over a period of two years, field experiments were conducted on four silty loam soils grown with foliar vegetable crops including Chinese cabbage (Brassica pekinensis Rupr., cv.Lu-Bai 3), autumn greens (B. chinensis L., cv.Piao-Geng-Bai), winter greens (B. var.rosularis Tsen et Lee, cv.You-Dong-Er), and summer greens (B. chinensis L., cv.Zao-Shu 5), respectively. Each experiment included one CK treatment without K, N and P fertilizers applied, and four treatments with from low to high doses, 0~300 kg hm^-2 for Chinese cabbage, 0~150 kg hm^-2 for autumn and winter greens and 0~180 kg hm^-2 for summer greens, of K fertilizers in the form of sulfate of potash (SOP) applied together with N and P fertilizers. One treatment of K fertilizer in the form of muriate of potash (MOP) applied at high levels (150 or 180 kg hm^-2) together with N and P fertilizers was included in the experiments of autumn, winter and summer greens, respectively, in order to compare the effects of SOP and MOP. The market yields of the tested crops increased significantly with the increasing rate of K application. The crops supplied with K fertilizers yielded more stably as the CV% of their yields decreased with the rate of K application. K fertilization increased not only K contents but also the amounts of N, P and K absorbed in shoots of autumn, winter and summer greens, which were statistically significantly correlated to their yields. It can also be found that potassium improved the quality of the foliar vegetable crops as their dry mater contents were generally increased and Vc contents obviously increased and nitrate contents markedly decreased. As compared to MOP, SOP was more effective on the yields and quality of autumn, winter and summer greens at the high levels of fertilization.     

Zinc Concentration in Rice (Oryza sativa L.) Grains and Allocation in Plants as Affected by Different Zinc Fertilization Strategies

Concern over the food chain transfer of zinc (Zn) is increasing because of its importance in human health. A field experiment was conducted on a low Zn soil to determine the effect of different Zn fertilization strategies on grain Zn concentration and Zn allocation in different plant tissues of rice. Six treatments were used: (1) no Zn fertilization; (2) soil fertilization at transplanting; (3) Zn soil fertilization at transplanting and flowering; (4) foliar application during grain filling; (5) foliar applications during tillering, flowering, and grain filling; and (6) combination of treatments 3 and 5. Zn fertilization significantly increased Zn concentration in brown rice. The largest effect on grain Zn was observed by combination of soil and foliar applications. The increase in brown rice was much smaller (20%) than the increase in the vegetative parts (100%), indicating that grain Zn concentration of rice is not strongly increased by Zn fertilization. More increased Zn by Zn fertilization was allocated into straw not into grain. From the perspective of human nutrition, it seems that there is too little scope to enhance Zn concentration in rice by fertilization alone. the major bottleneck to increase Zn concentration in rice grain seems to be internal translocation/retranslocation of Zn from shoot to panicle or from rachis to grain, rather than root uptake of Zn from the soil.     

Influence of vesicular-arbuscular mycorrhizal fungi (Glomus etunicatum L.) on mobilization of zinc in wetland rice (Oryza sativa L.)

In a greenhouse trial, rice (Oryza sativa L.) cultivar Pusa Basmati-1 was grown in a Zn-deficient Typic Ustochrept soil from IARI farm, New Delhi, India. The experimental design included two rates of inoculation with vesicular-arbuscular mycorrhizal fungi (VAMF), Glomus etunicatum (nil and inoculated) and different combinations of organic (farmyard manure, FYM) and inorganic (NPK, ZnSO₄) fertilizers. The results revealed that a high intensity of root colonization in rice inoculated with G. etunicatum could be achieved by raising seedlings in P- and Zn-deficient soil in the nursery under aerobic conditions. Moreover, the VAMF that infected rice seedlings in the nursery also survived when the same seedlings were transplanted into pots under waterlogged conditions. The application of ZnSO₄ significantly increased the inflow of Zn to rice roots at the panicle-initiation stage (40 days after transplanting) relative to NPK. The former treatment also increased root length, root weight, root volume and total uptake of Zn and thereby increased the grain and dry matter yields. Alternatively, these variables were substantially enhanced by inoculating rice with the VAMF, G. etunicatum. The VAMF-colonized rice plants were more active in acquiring Zn from either added or native sources than non-colonized plants, and consequently the available-Zn content in soil was lower after the harvest of rice.     

氮肥运筹对晚稻产量和氮素利用率的影响

用杂交水稻中优679为试验材料,研究氮肥运筹对晚稻产量和氮素利用率的影响。结果表明,在目标产量7 500 kg/hm2,总施氮量150 kg/hm2条件下氮肥运筹不同处理中,以基蘖肥∶穗肥=6∶4且基肥采用碳铵深施方式,其实际产量、齐穗后干物质生产量、成熟期干物质积累量、氮素利用率等均为最高。