• Authors:
    • Wang, H. Z.
    • Chen, J. P.
    • Zhang, J. P.
    • Qiu, X. Q.
    • Duan, A. W.
    • Gao, Y.
  • Source: Chinese Journal of Eco-Agriculture
  • Volume: 18
  • Issue: 5
  • Year: 2010
  • Summary: In this study, a radiation interception and utilization model was developed through an experiment on maize/soybean intercropping systems with different intercropping proportions of maize and soybean to assess crop growth and yield. In the model, crop biomass and yield are calculated as functions of photosynthetic active radiation ( PAR), radiation interception fraction ( F) and radiation use efficiency ( RUE). PAR is estimated from ratios of PAR to solar radiation (). F is calculated by using the Keating and Carberry equation. Time for emergence, flowering and maturity are determined by growing degree days ( GDD) since planting. Results indicate that the model accurately simulates total biomass and yield of fully irrigated maize/soybean intercropping system.
  • Authors:
    • Song, W. X.
    • Zhao, W. Z.
    • Shi, S. L.
    • Zhang, E. H.
    • Zhao, L.
    • Li, F. R.
    • Wang, Q.
    • Vance, M. M.
  • Source: Plant and Soil
  • Volume: 337
  • Issue: 1/2
  • Year: 2010
  • Summary: Monitoring of drinking water has shown an increase in nitrate-nitrogen (NO 3--N) concentration in groundwater in some areas of the Heihe River Basin, Northwest China. A combination of careful irrigation and nitrogen (N) management is needed to improve N uptake efficiency and to minimize fertilizer N loss. A 2-year experiment investigated the effects of different irrigation and N application rates on soil NO 3--N distribution and fertilizer N loss, wheat grain yield and N uptake on recently reclaimed sandy farmland. The experiment followed a completely randomized split-plot design, taking flood irrigation (0.6, 0.8 and 1.0 of the estimated evapotranspiration) as main plot treatment and N-supply as split-plot treatment (with five levels of 0, 79, 140, 221, 300 kgN ha -1). Fertilizer N loss was calculated according to N balance equation. Our results showed that, under deficit irrigation conditions, N fertilizer application at a rate of 300 kgha -1 promoted NO 3--N concentration in 0-200 cm depth soil profiles, and treatments with 221 kgN ha -1 also increased soil NO 3--N concentrations only in the surface layers. Fertilizer N rates of 70 and 140 kgha -1 did not increase NO 3--N concentration in the 0-200 cm soil profile remaining after the spring wheat growing season. The amount of residual NO 3--N in soil profiles decreased with the amount of irrigation. Compared with N 0, the increases of fertilizer N loss, in N 79, N 140, N 221 and N 300 respectively, were 59.9, 104.6, 143.5 and 210.6 kgha -1 over 2 years. Under these experimental conditions, a N rate of 221 kgha -1 obtained the highest values of grain yield (2775 kgha -1), above-ground dry matter (5310 kgha -1) and plant N uptake (103.8 kgha -1) over 2 years. The results clearly showed that the relative high grain yield and irrigation water productivity, and relative low N loss were achieved with application of 221 kgN ha -1 and low irrigation, the recommendation should be for those farmers who use the upper range of the recommended 150-400 kgN ha -1, that they can save about 45% of their N and 40% of their irrigation water application.
  • Authors:
    • Xu, Y. L.
    • Jiang, J. H.
    • Conway, D.
    • Lin, E.
    • Holman, I.
    • Xiong, W.
    • Li, Y.
  • Source: Agriculture, Ecosystems & Environment
  • Volume: 135
  • Issue: 1/2
  • Year: 2010
  • Summary: Climate scenarios from a regional climate model are used to drive crop and water simulation models underpinned by the IPCC A2 and B2 socio-economic development pathways to explore water availability for agriculture in China in the 2020s and 2040s. Various measures of water availability are examined at river basin and provincial scale in relation to agricultural and non-agricultural water demand and current and planned expansions to the area under irrigation. The objectives are to understand the influences of different drivers on future water availability to support China's food production. Hydrological simulations produce moderate to large increases in total water availability in response to increases in future precipitation. Total water demand increases nationally and in most basins, but with a decreasing share for agriculture due primarily to competition from industrial, domestic and municipal sectors. Crop simulations exhibit moderate to large increases in irrigation water demand which is found to be highly sensitive to the characteristics of daily precipitation in the climate scenarios. The impacts of climate change on water availability for agriculture are small compared to the role of socio-economic development. The study identifies significant spatial differences in impacts at the river basin and provincial level. In broad terms water availability for agriculture declines in southern China and remains stable in northern China. The combined impacts of climate change and socio-economic development produce decreases in future irrigation areas, especially the area of irrigated paddy rice. Overall, the results suggest that there will be insufficient water for agriculture in China in the coming decades, due primarily to increases in water demand for non-agricultural uses, which will have significant implications for adaptation strategies and policies for agricultural production and water management.
  • Authors:
    • Paltridge, N.
    • Tao, J.
    • Unkovich, M.
    • Gason, A.
    • Grover, S.
    • Wilkins, J.
    • Coventry, D.
    • Tashi, N.
    • Bonamano, A.
  • Source: Crop & Pasture Science
  • Volume: 60
  • Issue: 7
  • Year: 2009
  • Summary: In the south of the Tibet Autonomous Region of China there is a network of valleys where intensive agriculture is practiced. Although considered highly productive by Tibetans, farm incomes in the region are low, leading to a range of government initiatives to boost grain and fodder production. However, there is limited information available on current farming practices, yields, and likely yield constraints. The present paper uses available data and farmer interviews to describe the agro-climate and current systems of crop and livestock production, and considers possible strategies to boost production. Although winters in Tibet are cold and dry, summer and autumn provide ideal conditions for crop growth. Cropping systems are characterised by heavy tillage, frequent irrigation, high seeding rates and fertiliser applications, some use of herbicides, and little stubble retention or mechanisation. Spring barley and winter wheat are the predominant crops, followed by rapeseed, winter barley, and minor fodder and vegetable crops. Average yields for the main grain crops are around 4.0 t/ha for spring barley and 4.5 t/ha for winter wheat, significantly lower than should be possible in the environment. Farmers typically keep five or six cattle tethered near the household. Cattle are fed diets based on crop residues but are generally malnourished and rarely produce beyond the needs of the family. It is suggested that research and extension in the areas of crop nutrition, weed control, irrigation, seeding technology, and crop varieties should enable significant increases in grain yield. Increases in cattle production will require increases in the supply of good quality fodder. Cereal/fodder intercrops or double crops sown using no-till seed drills might enable the production of useful amounts of fodder in many areas without jeopardising food grain supply, and allow more crop residues to be retained in fields for improved soil health.
  • Authors:
    • Huang, W.
    • Xiao, L.
    • Wang, H.
    • Pan, G.
    • Zheng, Y.
  • Source: Guizhou Agricultural Sciences
  • Issue: 1
  • Year: 2009
  • Summary: The intercropping and interplanting between maize and potato were studied in Guizhou, China, to investigate the application rates and cultivation measures for balance high yield in the dry land with middle and lower yield. The maximum profit of the dry land with middle and lower yield in Nayong county with middle and high elevation was 1336.55 yuan/667 m 2 under the application ratio of 1:0.53:0.83 of N:P 2O:K 2O, and the comprehensive utilization rate of N, P 2O and K 2O was 33.52, 17.51 and 44.71%. The maximum profit of the dry land with middle and lower yield in Weining county with high elevation was 1349.09 yuan/667 m 2 under the application ratio of 1:0.69:1.10 of N:P 2O:K 2O, and the comprehensive utilization rate of N, P 2O and K 2O was 29.68, 10.58 and 26.80%, respectively.
  • Authors:
    • Li, S.
    • Chen, X.
    • Xu, H.
    • Liu, Y.
    • Zhu, L.
  • Source: Scientia Agricultura Sinica
  • Volume: 42
  • Issue: 12
  • Year: 2009
  • Summary: Objective: According to the investigations on soil temperature dynamics in the spring maize growing season, a field experiment was conducted to examine the effects of different maize culturing practices on soil temperature dynamics and soil accumulated temperature (>10degreesC) in Loess Plateau. Hence it has a certain reference value for understanding the influence of different culturing practices on spring maize growth. Method: Shendan10 was used as the test crop. Three field water management practices, including supplementary irrigation (SI), rain-fed (RF) and plastic film mulching (FM), were adopted in spring maize fields in 2007. Maize straw mulching (SM) was added in 2008. The experiment was arranged in a randomized complete block design. Result: The results showed that the plastic film had a significant warming effect while the maize straw mulching had a cooling effect. During the course of crop growing season, soil accumulated temperature (>10degreesC) had the peak at vegetative growth stages (VE-R1), followed by growth stages (R1-R6), and reached the lowest value at seedling stage (PT-VE). Moreover, soil accumulated temperature was different in different culturing practices during the course of crop growing stages. Soil accumulated temperature was lower in the PT-VE period in plastic film mulching treatment, VE-R1 period in supplementary irrigation treatment and R1-R6 period in rain-fed treatment. The response of plastic film mulching soil temperature was most sensitive to air temperature, and the response of straw mulching soil temperature was most insensitive to the air temperature. The crop grain yield was significantly improved under both the supplementary irrigation and the film mulching treatments compared to the rain-fed treatment, with the increases of 30.0% and 18.1% in 2007, and 25.7% and 29.7% in 2008, respectively. Conclusion: It is concluded that different maize culturing practices in the Loess Plateau not only affect the soil temperature dynamic changes, but also affect the maize growth and the utilization of the soil heat resources.
  • Authors:
    • Zheng, M.
    • Wang, T.
    • Li, Z.
    • Cai, C.
    • Guo, Z.
  • Source: Agroforestry Systems
  • Volume: 76
  • Issue: 1
  • Year: 2009
  • Summary: Land management practices that simultaneously improve soil properties are crucial to high crop production and minimize detrimental impact on the environment. The effects of crop residues on crop performance, the fluxes of soil N 2O and CO 2 under wheat-maize (WM) and/or faba bean-maize (FM) rotations in Amorpha fruticosa (A) and Vetiveria zizanioides (V) intercropping systems on a loamy clay soil, in subtropical China, were examined. Crop performance, soil N 2O and CO 2 as well as some potential factors such as soil water content, soil carbon, soil nitrogen, microbial biomass and N mineralization were recorded during 2006 maize crop cultivation. Soil N 2O and CO 2 fluxes are determined using a closed-based chamber. Maize yield was greater after faba bean than after wheat may be due to differences in supply of N from residues. The presence of hedgerow significantly improved maize grain yields. N 2O emissions from soils with maize were considerably greater after faba bean (345 g N 2O-N ha -1) than after wheat (289 g N 2O-N ha -1). However, the cumulated N 2O emissions did not differ significantly between WM and FM. The difference in N 2O emissions between WM and FM was mostly due to the amounts of crop residues. Hedgerow alley cropping tended to emit more N 2O than WM and FM, in particular A. fruticosa intercropping systems. Over the entire 118 days of measurement, the N 2O fluxes represented 534 g N 2O-N ha -1 (AWM) and 512 g N 2O-N ha -1 (AFM) under A. fruticosa species, 403 g N 2O-N ha -1 (VWM) and 423 g N 2O-N ha -1 (VFM) under Vetiver grass. A significantly higher CO 2 emission was observed in AFM (5335 kg CO 2-C ha -1) from June to October, whereas no significant difference was observed among WM (3480 kg CO 2-C ha -1), FM (3302 kg CO 2-C ha -1), AWM (3877 kg CO 2-C ha -1), VWM (3124 kg CO 2-C ha -1) and VFM (3309 kg CO 2-C ha -1), indicating the importance of A. fruticosa along with faba bean residue on CO 2 fluxes. As a result, crop residues and land conversion from agricultural to agroforestry can, in turn, influence microbial biomass, N mineralization, soil C and N content, which can further alter the magnitude of crop growth, soil N 2O and CO 2 emissions in the present environmental conditions.
  • Authors:
    • Nagaki, M.
    • Ke, F.
  • Source: Agricultural Information Research
  • Volume: 18
  • Issue: 2
  • Year: 2009
  • Summary: In the arid areas of Northwest China, agriculture especially crop farming consumes most of water resource. Water-intensive and low value-added wheat is cultivated as a staple food of the local people in large scale. Because of the surface water scarcity, irrigation mainly depends on pumping the groundwater in these areas. Based on field surveys conducted in 2005 and 2006 both in the south and the north of Minqin County, Gansu province, this study is designed to study the role of groundwater irrigation on wheat production and how to improve the technical efficiencies (TEs) of wheat farmers by estimating a Stochastic Frontier Production Function (SFPF). The above information is valuable for how to save wheat water consumption and improving the food safety in the arid areas. The empirical results showed that expenditure on pumping groundwater played important role in wheat production. Meanwhile, the same expenditure played more effectively on wheat intercropping with maize in the south than that in the north. As a result, the farmers in the south are more likely to increase expenditures on pumping water than the farmers in the north. Therefore, the government should make new program to restrict wheat water consumption and to secure the farmers in both areas to use the groundwater fairly. Meanwhile, it is suggested that younger farmers can achieve a higher TE both in the south and the north. For the input-intensive intercropping in the south, a larger family, higher education of the farm managers, and coordination of their part-time jobs with agricultural production activities can also help to get higher TEs.
  • Authors:
    • Wang, X.
    • Yang, Y.
    • Wu, F.
    • Li, Q.
  • Source: Acta Agriculturae Scandinavica Section B-Soil and Plant Science
  • Volume: 59
  • Issue: 5
  • Year: 2009
  • Summary: We studied the effects of rotation and interplanting on soil bacterial communities and crop yields using cucumber as the main vegetable. Onion and garlic were used as interplanting species, and wheat, soybean, villose (more commonly, villous) vetch, clover, and alfalfa were used as rotation plants. T-RFLP techniques were used to show the effects of rotation and interplanting systems on diversity index and richness index of cucumber rhizosphere soil bacterial communities. The results showed that both rotation and interplanting systems increased the richness index and diversity index of soil bacterial community structures, except where alfalfa was used as the rotation plant. The diversity index of the cucumber rhizosphere bacterial community structure was highest in the wheat rotation cropping system, and the richness index of soil bacteria was highest in wheat and clover rotations and in the onion interplanting system. Our results show that rotation and interplanting systems beneficially altered community structures of dominant soil bacteria, and increased cucumber yield and soil bacterial diversity. The best cultivation system to increase cucumber yield utilized onion as an interplanting species and wheat as a rotation plant.
  • Authors:
    • Cui, L.
    • Wu, B.
    • Zhang, Z.
    • Xu, W.
  • Source: Acta Agronomica Sinica
  • Volume: 35
  • Issue: 12
  • Year: 2009
  • Summary: Oat ( Avena L.) is one of the most important cereal crops in the world, ranked at the sixth top place in planting area and yield among all cereal crops, and possesses high values in food and nutrition, health protection and feeding livestock. Naked oat ( A. nuda) is an endemic type in China. However, a few studies on naked oat germplasm at molecular level have been reported. The aim of this study was to evaluate the genetic diversity of core collection of naked oat using AFLP markers. A total of 281 accessions of naked oat were analyzed using 20 AFLP primer combinations. Selective amplification created 1 137 bands, of which 260 were polymorphic, accounting for 22.96% of the total bands. The mean polymorphism information content (PIC) was 0.0326. For different geographic groups, Simpson's index ranged from 1.235 to 1.495, and Shannon's index varied from 0.1558 to 0.4437. The majority (83.45%) of the AFLP variation resided within accessions of each group, and the rest (16.55%) existed among accessions between groups. The sample size of geographic groups was significantly associated with the number of polymorphic loci, proportion of within-group variation, Simpson's index and Shannon's index. Accessions from Inner Mongolia and Shanxi were most diverse, and those from northeastern China were most distinct. Genetic resemblance was found within accessions from western China. Germplasm from East Europe was genetically close to that from Inner Mongolia, China. The genetic diversity of Chinese accessions was significantly higher than that of exotic accessions. Compared with breeding cultivars, landraces presented a higher proportion of within-group variation. Naked oat landraces were suggested to be collected in the regions where are not well represented by the current collections, and collecting activities should be continuous in the diversity-rich areas such as northwestern and southwestern China in order to enrich naked oat gene pool in China.