凉山州水、旱作对陆稻产量的影响

通过水、旱作对陆稻产量影响的研究,结果表明:陆稻在水作条件下生育期缩短,但灌浆时间经旱作延长1～8天,株高、最高苗、有效穗、穗粒数和产量明显高于旱作;成穗率、结实率和千粒重因品种略有高或低的差异;陆稻旱作时应增加播种量和提高移栽密度才能取得较好的产量;旱稻502、旱稻297和旱稻277适应于无充分水源保障的地区种植。

Effects of Film-mulched and Dry-farming on Lodging Resistance of Medium Hybrid Rice

Effects of film-mulched and dry-farming on lodging resistance of medium hybrid rice 88S/1128 at late growth stage was studied in this study. The result suggested that the increasing of lodging resistance of rice showed a trend of no film-mulched and water-farmingfilm-mulched and water-farmingno film-mulched and dry-farmingfilm-mulched and dry-faming. The lodging index of water-farming treatment decreased by 9.47%-24.10% compared to that of dry-farming treatment,while the lodging index of no film-mulched decreased by 14.68%-17.09% compared to that of film-mulched treatment; lodging index was significant or extremely significant negative related to resistant press per plant,transpiration rate,intercellular CO2 concentration and photosynthetic rate but extremely significant positive related to biomass per plant; the largest contributed factor in lodging was the plant biomass,while the factors had greatest contribution to lodging resistance showed an order of resistant press per planttranspiration rateintercellular CO2 concentrationphotosynthetic ratestomatal conductance.

Genetic Analysis of Root Growth in Rice Seedlings Under Different Water Supply Conditions

To understand the genetic background of root growth of rice ( Oryza sativa L.) seedlings under different water supply conditions, quantitative trait loci (QTLs) and epistatic effect on seminal root length, maximum adventitious root length, adventitious root number, total root dry weight and ratio of root to shoot were detected using molecular map including 103 restriction fragment length polymorphism (RFLP) markers and 104 amplified fragment length polymorphism (AFLP) markers mapped on a recombinant inbred line (RIL) population with 150 lines derived from a cross between an lowland rice IR1552 and an upland rice Azucena in both solution culture (lowland condition) and paper culture (upland condition). Six QTLs and twenty-two pairs of epistatic loci for the four parameters were detected. Three QTLs detected for maximum adventitious root length in solution culture (MARLS), total root dry weight in both solution culture and paper culture (TRDWS and TRDWP) accounted for about 20%, 23% and 13% of the total variations, respectively. Only epistatic loci were found for maximum adventitious root length and adventitious root number in paper culture (MARLP and ARNP), and for ratio of root to shoot in both paper and solution culture (R/SP and R/SS), which accounted for about 12%-61% of the total variations in the parameters, respectively. No identical QTL or epistatic loci were found for the parameters in both solution and paper culture. The results indicate that there is a different genetic system responsible to root growth of rice seedlings under lowland and upland conditions and epistasis might be the major genetic basis for MARLP, ARNP, R/SP and R/SS.

Soil Conservation Measures in Rainfed Olive Orchards in South-Eastern Spain: Impacts of Plant Strips on Soil Water Dynamics

Sloping and mountainous olive production systems are widespread, occupying large parts of the Mediterranean landscape prone to water erosion. Soil erosion, runoff, and soil water content patterns over a three-year period were monitored in erosion plots on a mountainside with rainfed olive （Olea europaea cv. Picual） trees under： 1） non-tillage with barley strips of 4 m width （BS）; 2） non-tillage with native vegetation strips of 4 m width （NVS）; and 3） non-tillage without plant strips （NT）. The erosion plots, located in Lanjaron （Granada, south-eastern Spain）, on a 30% slope, were 192 m2 in area. For assessing soil water dynamics in real-time and near-continuous soil water content measurements, multisensor capacitance probes were installed in the middle of plant strips and beneath the olive tree at five soil depths （10, 20, 30, 50, and 100 cm）. The highest erosion and runoff rates were measured under NT, with a mean of 17.3 Mg ha-1 year-1 and 140.0 mm year-1, respectively, over the entire study period. The BS and NVS with respect to the NT reduced erosion by 71% and 59% and runoff by 95% and 94%, respectively. In general, greater available soil water content was found under BS than NVS and NT, especially beneath the olive tree canopies. These results supported the recommendation of non-tillage with barley strips in order to reduce erosion and to preserve soil water for trees in traditional mountainous olive-producing areas, where orchards cover vast tracts of land.

Effects of Sowing Methods on Upland Rice in Lowland Rice-Vegetable Sequence in Inland Valley

Triple cropping in the inland valleys of southwestern Nigeria is technically possible but the third crop between the main crop and vegetables has poor establishment due to soil saturation. Identification of appropriate sowing methods is required in this niche. A field experiment was conducted at the University of Agriculture, Abeokuta, Nigeria in 2007/2008 and 2008/2009 cropping seasons to evaluate the effect of sowing methods on the performance of upland rice （Oryza spp.） in a lowland rice-vegetable sequence. The first, second, and third crops in the sequence were planted in May, September and December, respectively. Two upland rice varieties, namely New Rice for Africa 1 （NERICA 1） and ITA 150 constituted the main plot treatments while the subplot treatments were sowing methods. The mean grain yield of lowland rice for two years was 7.74 t ha^-1. The fluted pumpkin had a fresh leaf weight of 14.78 t ha^-1. The grain yields of the two upland rice varieties （1.81 and 1.85 t ha^-1） and sowing methods which ranged between 1.63 and 2.05 t ha^-1 were similar in both cropping seasons. However, the interaction of variety by sowing methods had a significant effect on grain yield. Transplanting and pre-germinated broadcast had the highest grain yield for NERICA 1 while dry broad cast and pre-germinated dibbled had the highest in ITA 150. Hence, the productivity of triple cropping in the inland valley was enhanced by sowing methods.

Chemical and Sensory Properties of Olive Oil as Influenced by Different Sources of Irrigation Water

This research was conducted throughout the years 2008-2010 to study the influence of irrigation water quality on oil quality of ＂Nabali Muhassan＂ olive trees. Reclaimed municipal wastewater and fresh water were used twice a week using drip irrigation system. Rainfed olive trees of the same farm were taken as control. No significant differences were observed between rainfed, fresh water and reclaimed wastewater treatments in terms of acidity, peroxide values and UV absorbance of the extracted olive oil. Heavy metals and microbiological pathogens were not detected in all tested olive oil samples. Oleic acid was significantly higher in olive oil obtained from rainfed trees than irrigated trees. Linoleic acid content was significantly higher in reclaimed wastewater irrigated trees than the rainfed trees. Total polyphenol contents were significantly higher in oil obtained from rainfed olive trees than oil obtained from the irrigated olive trees. Results of organoleptic analysis showed no significant differences in the fruity attribute within treatments, while the bitter and pungent attributes were higher in olive oil obtained from rainfed trees as compared to that obtained from irrigated trees. No negative attributes were observed in oil obtained from the irrigated or rainfed trees and they were all classified as extra virgin grade.

VARIATION OF PRECIPITATION DURING WINTER AS A CAUSE OF SUSTAINED DROUGHT IN GUANGDONG DURING THE PAST 50 YEARS

The variation characteristics of precipitation during the winter （between October and the following March, to be referred to as just ＂the winter＂ hereafter） in Guangdong province during the past 50 years （from 1957 to 2006） and the relationship with Pacific SST are studied using the methods of Empirical Orthogonal Function （EOF） analysis, wavelet analysis, and correlation analysis. The results show that The Guangdong precipitation during the winter exhibits quasi-periodic significant oscillations of 40 years and 2 years; rainfall is less from the end of the 1950s to the start of the 1970s and from the end of the 1990s to the present than from the mid 1970s to the mid 1990s. The frequency of sustained drought is more than sustained flooding during the winter. The Guangdong precipitation during this time period is in significantly positive correlation to the equatorial central and eastern Pacific SST, but in a significantly negative correlation with the western and northern Pacific SST east of the Philippine Sea. 61.5% of the sustained drought occurred in the phase of negative anomalies of the Nifio3.4 index and 38.5% in the phase of positive ones. A composite analysis of atmospheric circulation is performed for the positive and negative phases of the Nifio3.4 region associated with the sustained drought. The results showed that a weak polar vortex, a strong trough in Europe and a ridge near Balkhash Lake, active cold air and consistent northerly wind anomalies controlling Guangdong at low levels, an inactive westerly low disturbance in the low-mid latitude of the Asian continent, and a weak southern branch westerly trough, are all mutual causes for the sustained drought.

The Effects of Cropping Methods on Growth, Crop Index and Yield Response to Water of Rice （Oryza sativa L.） in Rainfed Agriculture

In this study, four combinations of crops： rice （C）, rice-maize （MCSI）, rice-cassava （MCS2） and rice-maize-cassava （MCS3） with 3 m × 3 m each plots at two field areas--Saptosari and Tanjungsari were observed. Both field areas are located in Gunungkidul district, South-Central of Java Island, with that 93% at those areas are 185 m to 500 m above sea level and high proportion of multiple cropping systems （MCS）. The aim of this study was to investigate the effect of different cropping method on growth, crop index and yield response to water of rice in rainfed agriculture. Mathematical models were developed to describe rice growth. The rice height was followed monomolecular function and the number of tillers followed exponential polynomial function. Crop index was calculated from climate data during plant growth phase. And yield response to water was calculated from actual evapotranspiration （ETa） and the maximum evapotranspiration （ETm）. The results showed that the height of rice was not significantly different between each combination （P 〉 0.05）. Number of tillers was also not significant （P 〉 0.05）. However, monoculture treatment had more number of tillers than rice in MCS. Crop index of rice at Saptosari was higher than at Tanjungsari. Based on the calculation of evapotranspiration （ET）, water deficit at initial was less than at mid-season （ETa 〈 ETm） and affected water stress. Statistical analysis showed that cropping methods did not significantly affect rice growth and yield （P 〉 0.05）.

Physical Effectiveness of Soil and Water Conservation Technologies in Drought Prone Areas of Western and Central Uganda

The effect of soil and water conservation （SWC） practices on controlling surface runoff and soil loss was studied in drought prone banana growing areas of Uganda, during the two major rainy seasons of 2014. The study was conducted at two sites-- Ntungamo （Southwest） and Sembabule （Central）, with comparable slopes of about 13%-25%. The treatments included mulch, manure, manure ＋ mulch and a control with no conservation. Results indicated that conservation practices of mulch and manure ＋ mulch significantly reduced surface runoff and soil loss by about 72%-85%, when compared to farmers＇ up-and-down cultivation practice （control）. It was also observed that significantly greater amounts of soil loss occurred from manure and control plots than the ones with mulch. Thus, the combination of manure and mulch is recommended for uptake by crop farmers in the study areas, if they are to overcome drought stress and adapt to changes in climate. More research is needed to quantify nutrient losses resulting from runoff under the different SWC techniques. Modeling such effects is essential in assessing the impacts of SWC practices on soil and crop productivity.

Exploring Crop Yield Benefits of Integrated Water and Nutrient Management Technologies in the Desert Margins of Africa： Experiences from Semi-Arid Zimbabwe

The benefits of integrating locally adaptable water and nutrient management technologies were explored in semi-arid Zimbabwe. On-farm maize based experiments were set up on six farmers＇ fields in Ward 5, Shurugwi. Three tillage systems namely Post-Emergence Tied Ridging （PETR）, Rip ＆ Pot-Holing （RPH） and Conventional Mouldboard Ploughing （CMP） were integrated to three nutrient management regimes, i.e. a control with no fertility amelioration, pit-stored cattle manure band applied at 10 t/ha and the latter with an additional top dressing of ammonium nitrate （34.5% N） at 100 kg/ha. On each site the treatments were set up as a completely randomized split-plot block design replicated 3 times with tillage （water management） as the main treatment and fertility as the sub-treatment. CMP mimicked the farmers＇ common land preparation practice while PETR and RPH systems represented the improved water harvesting tillage techniques. Results revealed significant nutrient management effects right from the first season giving 3-year means of 1,298, 1,977 and 2,490 kg/ha for the control, manure and manure plus fertilizer treatments respectively. On the other hand, water harvesting tillage effects were insignificant initially （2003/4） but had beneficial effects in subsequent seasons （2004/5 and 2005/6） with 3-year grain yield means of 1,624, 2,032 and 2,108 kg/ha for CMP, PETR and RPH, respectively. Maximum yield benefits from integrating PETR and RPH with manure ＋ AN fertility ameliorants amounted to 218 and 261% respectively, compared to CMP with no fertility amendment. The results therefore showed increased benefits when in-situ water harvesting tillage techniques are integrated with appropriate nutrient ameliorants giving realizable food security benefits to the farmer.

Leaf and Ecosystem Gas Exchange Responses of Buffel Grass-Dominated Grassland to Summer Precipitation

Sporadic rain events that occur during summer play an important role in the initiation of biological activity of semi-arid grasslands.To understand how ecosystem processes of a buffel grass(Cenchrus ciliaris L.)-dominated grassland respond to summer rain events,an LI 6 400 gas exchange system was used to measure the leaf gas exchange and plant canopy chambers were used to measure net ecosystem CO2exchange(NEE) and ecosystem respiration(Reco), which were made sequentially during periods before rain(dry) and after rain(wet). Gross ecosystem photosynthesis(GEP) was estimated from NEE and Reco fluxes, and light use efficiency parameters were estimated using a rectangular hyperbola model. Prior to the monsoon rain, grassland biomass was non-green and dry exhibiting positive NEE(carbon source) and low GEP values during which the soil water became increasingly scarce. An initial rain pulse(60 mm) increased the NEE from pre-monsoon levels to negative NEE(carbon gain) with markedly higher GEP and increased green biomass. The leaf photosynthesis and leaf stomatal conductance were also improved substantially. The maximum net CO2uptake(i.e.,negative NEE) was sustained in the subsequent period due to multiple rain events. As a result, the grassland acted as a net carbon sink for 20 d after first rain. With cessation of rain(drying cycle), net CO2 uptake was reduced to lower values. High sensitivity of this grassland to rain suggests that any decrease in precipitation in summer may likely affect the carbon sequestration of the semiarid ecosystem.

Surface Soil Properties Influence Carbon Oxide Pulses After Precipitation Events in a Semiarid Vineyard Under Conventional Tillage and Cover Crops

In semiarid regions of the Mediterranean basin, a rainfall event can induce a respiratory pulse that releases a large amount of soil carbon dioxide （CO2） into the atmosphere; this pulse can significantly contribute to the annual ecosystem carbon （C） balance. The impacts of conventional tillage and two different cover crops, resident vegetation and Bromus catharticus L., on soil CO2 effiux were evaluated in a Vitis vinifera L. vineyard in La Rioja, Spain. Soil CO2 efflux, gravimetric water content, and temperature were monitored at a depth of 0-5 cm after rainfall precipitation events approximately every 10 d in the period from May 17 to July 27, 2012, during which the cover crops had withered. Additionally, on June 10, 2012, soil organic C, microbial biomass C, and I^-glucosidase activity were determined at soil depths of 0-2.5, 2.5-5, 5-15, and 15-25 cm. The results show that pulses of soil CO2 were related to the increase in soil water content following precipitation events. Compared to the conventional tillage treatment, both cover crop treatments had higher soil CO2 efflux after precipitation events. Both cover crop treatments had higher soil organic C, microbial biomass C, and β-glucosidase activity at the soil surface （0-2.5 cm） than the conventional tillage treatment. Each pulse of CO2 was related to the surface soil properties. Thus, this study suggests that the enhancement of soil organic C and microbiological properties at the soil surface under cover crops may increase soil CO2 efflux relative to conventional tillage immediately after precipitation events during the dry season.