[Effects of stubble-standing mode on the grain yield and water use efficiency of wheat and maize in wheat/maize intercropping system].

Wheat/maize intercropping is the main intercropping pattern in the irrigation region of Hexi Oasis, Northwest China, but the traditional intercropping needs much water, making the regional water resource lacked increasingly. In 2010, a field experiment was conducted in the irrigation region of Shiyang River basin oasis, Gansu Province of Northwest China, aimed to study the effects of traditional stubble-burning, stubble-returning, and stubble-standing on the grain yield, water use efficiency (WUE), and economical benefits of wheat and maize in wheat/maize inter-cropping system. Compared with stubble-burning and stubble-returning, stubble-standing increased the grain yield of mono- and intercropped wheat by 7.2% and 5.1% , and 6.2%, 5.1%, and that of mono- and intercropped maize by 4.7% and 2.5%, and 7.2% and 3.3%, and increased the WUE of mono- and intercropped wheat by 20.4% and 16.2%, and 17.9% and 14.6%, and that of mono- and intercropping maize by 16.7% and 10.9%, and 11. 8% and 17.0%, respectively. As for the mono- and intercropped wheat and maize, their average net economical benefits under stubble-burning, stubble- returning, and stubble-standing were 10946, 11471, and 13454 RMB.hm-2, respectively. In considering the grain yield, WUE, and economic benefits, stubble- standing would be the optimal mode of wheat/maize intercropping in the oasis of Hexi irrigation region, Northwest China.

[Effects of different water harvesting modes on alfalfa planting in semi-arid areas of Northwest China].

A field experiment with complete random design was conducted to investigate the effects of different mulching materials [common plastic film (CMR), biodegradable mulch film (BMR), and soil crust (SR)] and different ratios of furrow to ridge (60 cm:30 cm, 60 cm:45 cm, and 60 cm:60 cm) on the runoff efficiency, soil water storage, soil water content, and hay yield and water use efficiency of alfalfa in semiarid areas of the Loess Plateau. The runoff efficiency in treatments SR, BMR, and CMR was 32.0%, 90.7%, and 96.4%, respectively. In the early growth period of alfalfa (from April to June) , the soil water storage between the treatments had no significant difference, but in the late growth period (from July to September), the soil water storage in CMR and BMR was significantly higher than that in SR. The soil water storage in SR was significantly higher than that in traditional planting (TP). At budding stage, the soil water storage in TP, SR, BMR, and CMR was 223.27, 248.56, and 277. 81, and 284.16 mm, respectively. In the whole growth period, the hay yield of alfalfa in TP, SR, BMR, and CMR was 4112.1, 3397.5, 4317.8, and 4523.8 kg x hm(-2), and the water use efficiency was 11.08, 10.48, 14.56, and 14.95 kg x mm(-1) x hm(-2), respectively. The ratio of furrow to ridge had no significant effects on the water use efficiency in the same treatments. When the ratio of furrow to ridge was 60 cm:44 cm, the hay yield in CMR and BMR reached the maximum.

[Effect of altitudes on the photosynthate accumulation and distribution pattern of Angelic sinensis].

OBJECTIVE: To study the effect of altitudes on the photosynthate accumulation and distribution pattern of Angelic sinensis in Gansu province and provide theontical for its expanding ecological planting region. METHODS: Used field test to study the photosynthate accumulation and distribution pattern of Angelic sinensis on three different altitudinal gradients from 2 300 m to 2 800 m. RESULTS: Before September 25, total photosynthate accumulation were decreased with the increasing of elevation, which amaunt was 176 g/plant, 166 g/plant and 128 g/plant, respectively. The total photosynthate of low-altitude and middle-altitude were significantly higher than that of high-altitude (P < 0.05). After September 25, middle-altitude was significantly higher than the other two altitudes (P < 0.05), respectively, by 13.9% and 11.1%. The photosynthate accumulation rate existed the altitude effects, there was no significant difference between high-altitude (46.7%) and middle-altitude (43.7%), but they were even significantly higher than that of low-altitude (33.1%). The root distribution proportion (> 30%) existed the difference, that of high-altitude was 10 days earlier than the other two altitudes, and later that of high-altitude (about 54%) was higher than the other two altitudes (49.8% - 50.9%), it laid the foundation for yield formation. Yield of Angelic sinensis was as follows: middle-altitude (28.4 g/ plant), high-altitude (26.6 g/plant) and low-altitude (21.8 g/plant). Yield of Angelic sinensis middle-altitude and high-altitude were higher than that of low-altitude, respectively, by 30.2% and 22.2%, and it had a significant difference (P < 0.05), this result was consistent with the photosynthate accumulation rate. CONCLUSION: Altitudinal gradients affect yield formation of Angelic sinensis by changing the photosynthate distribution pattern and dry matter accumulation rate. So by appropriately increasing altitude, the root distribution proportion and yield are improved, this provides theoretical reference for expanding Angelic sinensis planting ecological region.