间作作物及其还田时间对土壤碳素状况和相关酶活性的影响

Catch crops that are cultivated for green manure play an important role in improving soil properties. A 3-year field experiment was conducted to investigate the effect of catch crop(pea, Pisum sativum L.) management, i.e., incorporation of catch crop in October/November(autumn) and March(spring), and without catch crop(control), on soil organic carbon(SOC), microbial biomass carbon(MBC) and the activities of carbon(C)-cycle enzymes, including cellulase(Cel), β-glucosidase(Glu) and invertase(Inv). Additionally, soil total nitrogen(TN) and p HKClwere investigated. The catch crop was cultivated from August to October each year during 2008–2010. Soil samples were collected from the field of spring barley(Hordeum vulgare L.) that had been grown after the catch crop. Soil samples for microbial activity determination were taken in March, May, June and August in 2009, 2010 and2011, while SOC and TN contents as well as p HKClwere determined in March and August. The chemical properties studied did not show significant changes as influenced by the experimental factors. The use of catch crop significantly increased the MBC content and the activities of C-cycle enzymes compared to the control. When the catch crop was incorporated in spring, a significantly higher MBC content was noted in March and May compared to autumn incorporation. Moreover, the spring incorporation of the catch crop significantly increased the Glu activity(except March), while the activities of Cel and Inv as well as the rate of soil basal respiration were usually unaffected by the time of catch crop incorporation. Greater microbial biomass and higher enzyme activities in the catch crop-treated soil, compared to the control, indicated that the application of the catch crop as a green manure could be recommended as a promising technique to increase the biological activity of the soil. Since there was no significant effect or no consistent results were obtained related to the time of catch crop incorporation, both spring and autumn applications can be recommended as a management tool to improve the status of soil properties during the growth of a subsequent crop.     

论坡耕地不同治理措施的保土增产效益

本文通过试验实测结果, 论述了东北长白山区黑土地带的水土流失规律。同时对国家商品粮基地的低山丘陵区坡耕地, 在采取不同治理措施后, 保持水土的效果和增产效益进行了分析, 以及对如何改造中低产田, 增强山区农业发展后劲, 提出了有效的防治措施。此试验成果有普遍推广应用的价值, 并对实现农业发展新突破, 具有重要的战略意义。     

区域基尼系数及其在区域水土资源匹配分析中的应用

水土资源的匹配对于农业生产非常重要,因此如何定量测度区域水土资源的总体匹配 程度,对于合理开发利用水资源和耕地资源具有战略意义.通过区域基尼曲线及系数的构建 ,为区域水土资源的匹配研究提供了新的思路.研究结果表明,我国(省际间)的水土资源 匹配程度与世界(国际间)的水土资源匹配程度以及亚洲(国际间)的水土资源匹配程度相当.     

海南橡胶园土壤持续利用措施的研究

This research was designed to help solve existing sustainable use problems such as soil nutrient loss and soil fertility decline in natural rubber plantations located in the hilly land of the south central mountainous area of Hainan Island,China. Two different land management practices, sustainable and traditional, were adopted in a four-year experiment.Contour terraced fields and deep ditches for green manure were built in a sustainable way with a balanced, need-based application of complex fertilizer. Results of the four-year experiment showed that these sustainable measures compared to traditional measures improved available P and available K; had a 47.8% less soil erosion (an average of 3663 t km^-2 year^-1) and a 15.9% lower runoff coefficient of 0.53; increased the dry rubber yield by 42.4%; and improved the economic benefit by 2.4 times. The sustainable land management scheme not only improved land utilisation efficiency, hut also helped maintain soil fertility while increasing production in rubber plantations. It thereby offered a reasonable and sustainable use for land resources in the tropical mountainous areas.     

四川丘陵区农林系统和农草系统流域的径流和土壤水分特征

A study was conducted in a hilly area of Sichuan Province, Southwestern China, to compare the streamflow and soil moisture in two upland watersheds with different land use patterns. One was an agroforestry watershed, which consisted mainly of trees with alder (Alnus cremastogyne Burkill) and cypress (Cupressus funebris Endl.) planted in belts or strips with a coverage of about 46%, and the other was a grassland primarily composed of lalang grass (Imperata cylindrica var. major (Nees) C. E. Hubb.), filamentary clematis (Clematis filamentosa Dunn) and common eulaliopsis (Eulaliopsis binata (Retz.) C. E. Hubb) with a coverage of about 44%. Streamflow measurement with a hydrograph established at the watershed outlet showed that the average annual streamflow per 100 mm rainfall from 1983 to 1992 was 0.36 and 1.08 L s^-1 km^-2 for the agroforestry watershed and the grass watershed, respectively. This showed that the streamflow of the agroforestry watershed was reduced by 67% when compared to that of the grass watershed. The peak average monthly streamflow in the agroforestry watershed was over 5 times lower than that of the grass watershed and lagged by one month. In addition, the peak streamflow during a typical rainfall event of 38.3 mm in August 1986 was 37% lower in the agroforestry watershed than in the grass watershed. Results of the moisture contents of the soil samples from 3 slope locations (upper, middle and lower slopes) indicated that the agroforestry watershed maintained generally higher soil moisture contents than the grass watershed within 0-20 and 20-80 cm soil depths for the upper slope, especially for the period from May through July. For the other (middle and lower) slopes, soil moisture contents within 20-80 cm depth in the agroforestry watershed was generally lower than those in the grass watershed, particularly in September, revealing that water consumption by trees took place mainly below the plow layer. Therefore, agroforestry land use types might offer a complimentary model for tree-annual crop water utilization.     

大气CO2浓度的升高、施氮及土壤水分对春小麦干物质积累和氮吸收的影响

Spring wheat (Thiticum aestivum L.cv.Dingxi No.8654) was treated with two concentrations of atmospheric CO2 (350 and 700 μmol mol^-1),two levels of soil moisture (well-watered and drought) and five rates of nitrogen fertilizer(0,50,100,150,and 200 mg kg^-1 soil) to study the atmospheric CO2 concentration effect on dry matter accumulation and N uptake of spring wheat.The effects of CO2 enrichment of the shoot and total mass depended largely on soil nitrogen level,and the shoot and total mass increased significantly in the moderate to high N treatments but did not increase significantly in the low N treatment.Enriched CO2 concentration did not increase more shoot and total mass in the drought treatment than in the well-watered treatment.Thus,elevated CO2 did not ameliorate the depressive effects of drought and nitrogen stress.In addition,root mass decreased slightly and root/shoot ratio decreased significantly due to CO2 enrichment in no N treatment under well-watered condition.Enriched CO2 decreased shoot N content and shoot and total N uptake;but it reduced root N content and uptake slightly.Shoot critical N concentration was lower for spring wheat grown at 700 μmol mol^-1 CO2 than at 350μmol mol^-1 CO2 in both well-watered and drought treatments. The critical N concentrations were 16 and 19 g kg^-1 for the well-watered treatment and drought treatment at elevated CO2 and 21 and 26 g kg^-1 at ambient CO2,respectively. The reductions in the movement of nutrients to the plant roots through mass flow due to the enhancement in WUE (water use efficiency) and the increase in N use efficiency at elevated CO2 could elucidate the reduction of shoot and root N concentrations.     

红壤地油菜上施用的尿素态氮的去向及尿素在提高油菜产量中的效率

Fate of urea nitrogen(N) applied to rape grown on a red soil was investigated by the 15N mass balance technique.and efficiency of urea and effect of nutrients balance in raising rape yield were investigated in a field plot experiment.One hundred and thirty -eight kg N/ha,86kg N/ha as basal dressing and 52 kg N/ha as top dressing,was applied with band application technique.The experiment was conducted in the southeast of china ,near Yingtan City,Jianxi Province.Results from 15N mass balance study showed that when urea urea was applied as basal dressing the plant recovery was 44.0% of the applied N for Treatment T (with application of N,P,K,B and lime),Plant recoveries were 38.0%-40.5% for Treatments-K,-B-lime and RS(without application of K,B or lime as well as with additional rice straw compared with Teatment T),which were not significantly different from Treatment T.In contrast ,plant recovery was only 5.1% for Treatment-P(without application of P), indicating that P was the factor limiting N uptake by rape.However,N remaining in 0-0.30 m soil was high up to 71.6% for Treatment-P,while the corresponding data were 33.0%-42.6% for the other treatments.The total recovery of applied N(including plant recovery and N remaining in 0-0.60 m soil) was 91.5% for Treatment T when urea was applied as basal dressing,while almost all the applied N was recovered when ureawas applied as top drssing,It was suggested that N loss was greatly controlled by using band application method in this experiment.Results from the field plot experiment field plot experiment showed that N supply capacity of this red soil was very low,and the efficiency of the applied N was quite high,7.1kg rape seed was increased by application of one kg N for Treatment T.Nitrogen and phosphorus were the key factors limiting rape yield,and the yield was very low when neither of them was applied.The yield in Treatment-K was significantly lower than that in Treatment T,With the former accounting for 77% of the later.     

中国东南部红壤地区不同植被对土壤侵蚀和土壤养分的影响

The effect of different vegetation systems including bamboo plantation (BP), forest ecosystem (CF), citrus orchard (Ctr) and farmland (FL) on erosion and nutrients of red soil were investigated in hilly region of southeastern China to find effective control measures for soil erosion. The results showed that all the vegetation systems could significantly reduce soil erosion and nutrient losses compared to bare land (Br). The ability of different vegetation systems to conserve soil and water was in the order of Ctr > BP > CF > FL > Br. Vegetation could also improve soil fertility. The soil organic matter, total N and total P contents were much higher in all the vegetation systems than in bare land, especially for the top soils. Vegetation systems improved soil physical properties remarkably. Compared to the bare land, soil organic matter, TP, TK and available K, especially soil microbial biomass C, N and P, increased under all the vegetation covers. However, they were still much lower than expected, thus these biological measurements are still needed to be carried out continuously.     

不同种类中国杉对土壤养分状况的影响

The effects of different types of Chinese fir stand,including those with varous composition (pure and mixed),in various cropping systems (first and continuous cropping system)and at different ages,on the nutrient status of soils the hilly regions of southern Anhui Province were studied by means of ecological sequential comparison on the basis of similar climate and soil type.The work was carried out in the Xiaoxi Forest Farm of Jingxian County and the Caijiaqiao Forest Farm of Jingde Coundy,where the soil is parayellow soil derived from phyllite and sandstone,The results revealed that with the increase of age,Chinese fir pure stand could accumulate organic matter and nitrogen in the soil but it resulted in decreasing of soil pH and base ions(especially Ca^2 ) compared to its mixed stand with broad-leaf trees such as Chinese sassafras,In order to improve the soil fertility,It would be better to mix Chinese fir with broad-leaf trees when afforestation In the management of Chinese fir pure stand,base compounds and phosphates should be added to the soil for mintaining soil fertility and raising and raising forest productivity.