Improving the productivity and sustainability of rainfed farming systems for the western Loess Plateau of Gansu Province
This project brings together the resources of two Chinese institutions, Gansu Agricultural University and Gansu Grasslands Ecological Research Institute, with three Australian institutions, New South Wales Agriculture, CSIRO Sustainable Ecosystems (Agricultural Production Systems Research Unit), and Adelaide University. The combined resources of these organisations conduct research, development and training activities aimed at improving the sustainability and productivity of rainfed faming systems for the western Loess Plateau of Gansu Province.

The project has four related themes:
Develop conservation tillage cropping systems.
Develop legume - cereal crop rotations.
Analysis of current and proposed new farming systems with the aid of system simulation models.
Building the capacity of Chinese staff in all research areas listed above.

The field research focusses on two contrasting locations, Dingxi and Xifeng. Dingxi County represents a drier climate (400 mm average annual rainfall) with spring wheat as the dominant crop. Xifeng County receives higher average annual rainfall (550 mm) and winter wheat accounts for 70% of the arable land area. In addition to average rainfall, the two locations differ in common crop rotations practised and general level of income. Results from these two locations will be representative for a large proportion of the 45 million hectares covered by the Loess Plateau.

The project commenced in April 2001 with the holding of a detailed planning workshop in Gansu. This meeting had been preceeded by an ACIAR planning workshop held in Lanzhou in May 2000 and by detailed correspondence between project collaborators.

Highlights for the period covered by this annual report include:
Preparation of detailed research preschedules for the initial experiments setting out objectives, experimental designs, research methods, and data collection.
Successful commencement of conservation tillage and lucerne-wheat rotation experiments at Xifeng.
Site selection and treatment preparation for experiments at Dingxi.
Characterisation of plant available water capacity for the soil at Xifeng and Dingxi.
Delivery of an APSIM training workshop for Chinese project members as part of a one month duration training visit to Australia held in November- December 2001.
Appointment of ACIAR funded research positions at NSW Agriculture (Dr. Gerard O'Connor) and Adelaide University (Dr. Wen Chen).

In 2002, research will focus on establishing and/or continuing the experiments commenced in 2001. This will be a particularly important year for research at Dingxi where spring wheat and field peas will be sown for the first time in spring (March/April) 2002. Further training in the use and application of APSIM to local Gansu conditions will continue with follow-up training and support planned to be held in Gansu and ongoing support via the internet.

China
1. Develop Conservation Tillage.
Two large field experiments were established in 2001/02 to compare different tillage and stubble management options. The experiments are located at Dingxi (annual average rainfall 390 mm) and Xifeng (aar 550mm). The experiments are planned to run over a medium- to long-term timeframe. Data are being collected on climate, soil, and plant variables. A large database has been established to facilitate statistical analysis and testing of the APSIM model against the observed data.

Although the experiments have been running for only one (Dingxi) or two (Xifeng) years, grain yields from the experimental no-till stubble retention (NTS) treatments have not suffered a yield penalty compared with the local conventional practice (T) of heavy cultivation and removal of all crop stubble. Grain yields of winter wheat, maize, and soybean were similar under the NTS and T treatments at Xifeng. At Dingxi, grain yields of spring wheat were higher under NTS compared to the control (T) treatment. There was no significant difference in yield of field pea between the two sowing treatments. Changes in soil water, soil nitrogen, and soil quality are being monitored.

2. Integrate legumes into cereal dominated cropping systems.
In addition to the experiments described above, experiments to investigate the impact of a phase of lucerne on following crops of spring wheat (Dingxi) or winter wheat (Xifeng) were established in 2001. Treatments include continuous lucerne, continuous fallow, and two lucerne removal times followed by consecutive wheat crops. These experiments were designed to generate a range of starting soil water and soil nitrogen conditions at the time of wheat sowing.

Data are being collected on soil water and soil nitrogen dynamics as well as growth and yield of lucerne and wheat. Lucerne is very productive in this environment. At Xifeng, total annual shoot dry matter production ranged from 11 to 13 t/ha from two or three harvests. At both Xifeng and Dingxi, lucerne roots extend beyond 3m and soil moisture is maintained close to the soil lower limit (LL15) over this depth. After two summer seasons, soil moisture under the fallow treatment is close to the Drained Upper Limit (DUL) down to a depth of 2m.

3. Adapt existing simulation models to local current and new farming systems.
Good progress has been made towards developing a local capacity for simulating Gansu farming systems. Daily weather data from 1970 to the present has been collated for Dingxi and Xifeng. Plant available water capacity has been determined for winter wheat, maize, soybean and lucerne at Xifeng and for spring wheat, field peas and lucerne at Dingxi. Crop genetic coefficients that determine phenology, growth, and dry matter partitioning have been estimated for all of the above crops except for field pea where a new module is being developed.

Preliminary testing of model performance against observed data shows good agreement for lucerne production at Xifeng, spring wheat at Dingxi, and generally good agreement on soil water dynamics. It has not been possible to test model performance against the soil inorganic nitrogen data due to unresolved concerns over the observed data. Initial model performance is very encouraging but much work remains to be done.

4. Build research capacity.
This project places a high priority on building the capacity of our Chinese partner scientists to conduct agronomic research. A number of activities progressed in 2002:
Capacity to conduct agronomic research was strengthened in the areas of experimental design, data management, implementing treatments, maintaining site integrity, and integration of field experimentation with simulation modelling.
Simulation modelling skills were progressed through the provision of training workshops and follow up support. The initial focus has been on collecting the necessary soil, weather and crop data required as model inputs and/or for model parameterisation of soil and plant processes. Chinese scientists show good aptitude in testing and applying the APSIM model to their farming systems.
A workshop on 'Developing publishing skills in Agricultural and Environmental Sciences', was held in Lanzhou for ACIAR funded scientists from throughout north-west China. Ten Chinese scientists from this project attended the two-week workshop. (Note this activity funded externally to LWR2/1999/094)
Several Chinese scientists working on the project have enrolled as Masters (8 students) or PhD (5 students) candidates at Gansu Agricultural University or Lanzhou University.

Australia
1. Understanding poor seedling vigour of direct-drilled wheat.
This research, based at Wagga Wagga in New South Wales, aims to identify the compounds thought to be responsible for poor vigour in wheat seedlings following direct drilling. To date it has not been possible to identify the compounds involved. The research is continuing.

2. Integration of lucerne into cereal cropping systems.
This research is based at The University of Adelaide, South Australia. The research involves integration of on-farm monitoring with simulation modelling. Research sites have been established at Roseworthy and southern Yorke Peninsula with a further two sites to be established in 2003. The two existing sites are investigating companion cropping of wheat and lucerne. Companion cropping, sometimes called intercropping or over cropping, involves the sowing of wheat over a living stand of lucerne. Wheat grain yield under companion cropping is usually reduced compared to that under wheat monoculture and we are investigating lucerne winter dormancy level, lucerne suppression with herbicides and N fertilisation of wheat to minimise the potential grain yield reduction. This research is continuing with support from the CRC for Plant Based Management of Dryland Salinity.

Year 3 (01/01/2003-31/12/2003)
China: Develop Conservation Tillage.
The conservation tillage experiments at Dingxi and Xifeng were well managed and continued to produce very valuable results in 2003. At Dingxi the first cycle of the two-course rotation (field pea - spring wheat, one crop per year) was completed in 2003. At Xifeng the experiment was in the second cycle of the three-course rotation (soybean - maize - winter wheat, three crops grown in two years) in 2003. Phase 1 at Xifeng was sown to maize in spring 2003, and immediately following the maize harvest in September, was sown to winter wheat. Phase 2 saw winter wheat harvested in June (from a September 2002 sowing date), immediately followed by soybean.
Rainfall at Dingxi was below average, with a dry spell around the time of anthesis resulting in lower than average crop yields in all treatments. Under these dry conditions, wheat and field pea grain yield was higher in the no till plus straw (NTS) treatment compared to the tillage (T) treatment (traditional tillage and all crop residues removed). At Xifeng rainfall was lower than average during spring but much higher than average from July - September. Winter wheat grain yield was higher under traditional tillage (T) than the NTS treatment. Maize grain yield was highest in the tillage plus straw (TS) treatment followed by the NTS treatment with the traditional tillage treatment (T) recording the lowest yield. Soybean grain yield was highest in the NTS treatment. Overall, the NTS treatment has compared favourably with the T treatment in 2002 and 2003 although there are seasonal interactions influencing the ranking of treatments.
In 2003 two farmers at Dingxi and two at Xifeng began on-farm research to compare the experimental NTS treatment with their traditional practice. The farmers are managing side-by-side comparisons of the two systems beginning with the crop harvest in 2003.
Integrate legumes into cereal dominated cropping systems
In addition to the conservation tillage experiments described above that include soybean (Xifeng) and field pea (Dingxi) in the rotation, the effect of a lucerne phase on subsequent growth and yield of wheat has been studied at Xifeng and Dingxi. Soil water under lucerne has been maintained close to the soil lower limit (LL15) to the depth of monitoring (3m). After two years of continuous fallow, soil water is approaching the drained upper limit (DUL). At Dingxi, spring wheat yields were very low in all treatments, partly attributed to a very low harvest index. At Xifeng, winter wheat yields were close to average, with no difference in grain yield between lucerne removal times but with a response to additional N fertiliser. Wheat will be sown across all treatments in 2003-04, including the extended fallow treatment to measure the potential yield of wheat when sown onto a full profile of water. These experiments have generated a wide range of starting soil water and soil nitrogen conditions that have been very useful in testing the performance of APSIM.
Adapt existing simulation models to local current and new farming systems
The development and testing of APSIM in the Gansu environment has progressed throughout 2003. Daily climate data files have been maintained and description of plant available water capacity has been refined for all crop and pasture species involved in the research. Existing APSIM modules have been adapted for winter wheat, spring wheat, maize, soybean and lucerne. A new module is under development for field pea.
Performance of APSIM in Gansu has been very encouraging with soil water dynamics simulated. However, simulation of the effect of stubble management and tillage on runoff and infiltration requires further experimentation and model development. Simulation of crop growth and yield is close to the observed data in most cases. Given the good performance of APSIM in Gansu, the focus of future APSIM research will gradually shift from model testing to model applications.
Build research capacity
This project places a high priority on building the capacity of our Chinese partner scientists to conduct agronomic research. Six Chinese scientists from Gansu Agricultural University and Gansu Grasslands Ecological Research Institute) attended a training workshop at the University of Adelaide and the Australian Agronomy Conference in Geelong in January - February 2003.
Dr Zhang Guosheng (Gansu Agricultural University) received a Crawford Fund Fellowship to undertake a three-month program in soil physical measurements and operation of rainfall simulators provided by NSW Agriculture. Several Australian project scientists were awarded Honorary Professorships at Gansu Agricultural University and Lanzhou University in recognition of their role in supporting staff and supervising postgraduate students.
Australia: Understanding poor seedling vigour of direct-drilled wheat
In 2003, an experiment was conducted to better understand the factors contributing to reduced early growth of wheat using undisturbed soil cores from a site near Cowra where reduced growth has been regularly observed. Treatments included four sowing dates, wet or dry soil conditions, and addition of a large population of known inhibitory pseudomonads to half of the pots. Unfortunately, addition of pseudomonads did not result in reduced early growth. There was no significant effect of sowing time on reduced growth. Further statistical analysis is needed before final conclusions can be made.
Integration of lucerne into cereal cropping systems
Experiments have been established to investigate lucerne - wheat cropping systems at two sites. At Roseworthy, growth and yield of wheat after a phase of lucerne or as a companion crop will be compared for the first time in 2004. At Stansbury, triticale was grown as a companion crop with lucerne in 2003. Research to define plant available water capacity (PAWC) for lucerne and wheat continues at both sites. APSIM is being used to simulate the experimental treatments and extrapolate beyond the seasons, soils, and treatments experienced in the research. This research is being conducted in collaboration with local farmers and with support from the CRC for Plant Based Management of Dryland Salinity.

China
1. Evaluate conservation tillage
Conservation tillage experiments continued to provide encouraging results in 2004 at both Dingxi and Xifeng. At the drier Dingxi site, grain yields of wheat and field pea were surprisingly high given the very dry spring conditions. Grain yields from the no till stubble retained treatment (NTS) continue to be equal or greater than those from the conventional tillage and stubble removed treatment (T). At Xifeng, grain yield of maize and soybean was slightly higher under NTS compared to T, but grain yield of winter wheat was slightly lower under NTS compared to T.

Overall, NTS has performed well across locations, phases (seasons), and crops. It is clear that crops can be successfully grown without tillage and with stubble retained on these Loess soils and in these climate conditions. Another encouraging result is that the benefits of retaining stubble and no tillage occur quickly. Improvements in surface soil water and reduced crust formation are evident in just one season of treatment. Research effort in 2005 and 2006 will shift to on farm research to evaluate how farmers adapt the principles of conservation tillage to local conditions.

2. Integrate legumes into cereal based cropping systems
The lucerne - wheat experiments were completed in 2004 with the harvest of the third consecutive wheat crop. Grain yields of 3.7-4.2 t/ha in the absence of N fertiliser and after three consecutive wheat crops indicate the potential for these soils to mineralise N after a lucerne phase. The response to fertiliser N in these same rotations (5.6-5.9 t/ha) reveals that mineralised N supply alone is inadequate to meet wheat N demand in these systems. After two years and four months of fallow, and a near full soil water profile, grain yield without fertiliser was 5.1 t/ha, and increased to 6.3 t/ha with addition of fertiliser N. The interactions between climate, soil water, soil nitrogen and wheat yield will be analysed with APSIM and long term rotation and N fertiliser strategies identified.

3. Develop capacity for simulating agricultural production systems
Progress in simulating Gansu production systems has been very good in 2004. Progress has been made possible through excellent field experimentation and data management. The stage of deriving soil and crop parameters has been largely completed. Performance of the model against observed data has been very good for soil water and plant growth, but several areas require ongoing improvement, including surface soil conditions and runoff and evaporation; winter dormancy physiology in winter wheat and lucerne; and simulation of inorganic nitrogen dynamics.

Given the promising performance of the model some preliminary long-term simulations (Xifeng 1961-2003, Dingxi 1970-2003) were undertaken. A study of long-term average water balances under a range of crop rotations and lucerne has provided new insights and reinforced findings based on experimental results. For example, the water balance is dominated by soil evaporation at Dingxi, runoff and drainage are very small components at this dry site. At the wetter Xifeng site, lucerne can reduce runoff and drainage compared to annual cropping, with implications not only for the local farmer, but also for the wider context surface and groundwater flow systems.

Australia
1. Integration of lucerne into cereal cropping systems (University of Adelaide)
In 2004 wheat was sown in an experiment comparing phase (after lucerne terminated) or companion (into living lucerne) cropping systems at Roseworthy. A late start to the season and a very dry spring meant that the growing season rainfall was well below average and there were no significant differences in grain yield between treatments. Under dry conditions and in the presence of lucerne, wheat experienced very severe water stress. The treatments will be repeated in 2005 under hopefully wetter conditions. Long-term simulation indicates that wheat yields under phase and companion cropping can be acceptable in average to above-average rainfall years.

2. APSIM field pea module development (University of Adelaide)
A combination of field research and literature search has resulted in the development of a field pea module that will find application in southern Australia and Gansu. The new field pea module has been included in APSIM releases from version 3.6 and beyond. The model was developed following the standard crop template approach, and has been tested against data from Roseworthy and Dingxi. Current research includes collating existing data sets to improve crop phenology routines and collaboration with SARDI pathologists to evaluate foliar disease management options.

3. Investigating the role of Pseudomonads in reduced early growth of wheat (NSW DPI)
Despite intense investigation, it has not been possible to reproduce the inhibitory effects of Pseudomonads on early wheat growth under laboratory or glasshouse conditions. The exact causes of the possible inhibitory effects of Pseudomonads on wheat remain unresolved. An interesting finding was a possible role of plant nutrition in modifying plant response to the Pseudomonads. The research will be synthesised and a publication describing the research submitted.

Project activity centred around two areas in 2005. These were the conduct of On Farm Research and publication of research results from the previous four years. Good progress was made on both fronts. In addition, the conservation tillage experiments established earlier in the project were maintained using non-project resources.

1. On Farm Research
Following training workshops in December 2004 and March 2005, a program of On Farm Research (OFR) was begun in 2005 at Dingxi and Xifeng. At both locations the aim of the OFR was to compare a system of conservation tillage (stubble retention and no-tillage) with conventional farmer practice. In 2005 the main objectives were to evaluate the implementation of OFR under Chinese conditions and to set up soil and stubble conditions in farmers' fields for the 2006 growing season. Two Australian Youth Ambassador positions were assigned to the OFR component of the project in 2005.

2. Publication of project research results
A publication plan outlining 8 scientific journal papers was accepted by project staff in 2005. This plan outlines how the key papers arising from the research will be published. While it is possible that additional papers may be published, it is important that the key papers in the plan are not compromised by ad hoc publications. The first paper in the plan, "Lucerne-wheat rotations on the Loess plateau", was due to be submitted in February 2006 but will be actually submitted in April 2006. The next two papers in the plan will present the main results from the conservation tillage experiments at Dingxi and Xifeng. These papers are planned to be submitted in August 2006 and good progress is being made.

3. Continuation of long-term conservation tillage experiments
The two long-term CT experiments at Dingxi and Xifeng will be maintained with non-project resources from 2005 onwards. The transition from ACIAR to non-ACIAR funds appears to have gone smoothly. The experiments continued to be well maintained during 2005. At Dingxi, the NTS (no-tillage, stubble retained) treatment continues to yield higher than the conventional tillage (T) treatment. At Xifeng, there were no significant differences between treatments, confirming earlier trends.