黑龙江西部旱作玉米水肥生产潜力试验研究

以氮肥、磷肥、补水量为试验因子,以玉米产量为指标,利用MINITAB15统计分析软件进行试验设计和数据分析,通过响应曲面法建立水肥相互作用对玉米产量影响的二次多项数学模型。利用模型的等值线图对影响玉米产量的关键因子及其相互作用进行了探讨,以玉米产量为响应值优化得出玉米生产潜力田间试验值的条件：氮肥为241.1 kg/hm2,磷肥为173.1 kg/hm2,补水量为108.3 m3/hm2,玉米田区生产潜力试验值为12 224 kg/hm2。

Sugarcane Requirement of Water and Effect of Fertigation on Sugarcane

The sugarcane is a main sugar crop in China. The seasonal drying is one of the problems that influence the improvement of output and quality of sugarcane in China. The experimental results for the water requirement and fertigation of the sugarcane showed, that the distribution of the rainfall in spring, autumn and winter, all could not suit the requirements for sugarcane growth. Detailedly, it can suit that sugarcane requirement of 74.4%, 68.6% and 35.7% respectively at seedling emerging stage, tillering stage and mature stage according to sugarcane growth. The drought has already limited the yield of sugarcane. Application of fertigation can enhance the fertilizer use efficiency, and it is also a water saving technique in sugarcane production.

Coupled Effects of Soil Water and Nutrients on Growth and Yields of Maize Plants in a Semi-Arid Region

Interaction between soil water and nutrients plays an important role in sustainable crop management in semi-arid environments.On the basis of a field experiment conducted from 2000 to 2003,this study examined the coupled effects of irrigation and fertilizers on maize growth and yield in a semi-arid region of northeastern China.In terms of plant productivity,nitrogen fertilizer had the most significant effect followed by irrigation and phosphate levels.The combined application of nutrients and irrigation exerted a synergistic effect on the grain yield of maize plants.Regression analysis indicated that optimal levels of nitrogen and phosphate,in addition to adequate irrigation,could greatly improve the efficiency of grain production.Similarly,optimization of soil nutrient availability substantially increased water use efficiency.These suggested that for the most efficient and sustainable crop production,irrigation and nutrient management should be based on a quantitative understanding of water/nutrients interaction,particularly in semi-arid and arid regions.

Evaluating Added Benefits from Combined Cattle Manure and Fertilizer Application in a Maize Cropping System

A field experiment was conducted at Kpongu in the Upper West region of Ghana to determine the added benefits in grain yield of maize derived from the concurrent use of manure and mineral fertilizer, and their cost effectiveness. Factorial combinations of cattle manure and mineral fertilizer each at 0, 50 and 100% of their recommended rates were evaluated in both the field and the laboratory studies. The treatments were applied in a randomized complete block design with three replications on the field. The same treatments were applied in the incubation study in a completely randomized design. The use of 100% NPK （Nitrogen, Phosphorus, Potassium） ＋ 5 t manure gave the highest grain yield of 4,678 kg·ha^-1. Synergistic interactions resulting in added benefits in grain yield were observed in all the combined nutrient inputs except 50% NPK ＋ 2.5 t manure which accrued an added disadvantage of 44 kg·ha^-1. Economic analysis proved that 100% NPK ＋ 2.5 t manure and 50% NPK ＋ 5 t manure were the most economically viable combined treatments in terms of grain yield. Based on the results from this study, resource poor farmers in the Upper West region of Ghana may reduce mineral fertilizer recommended rates by 50% and supplement it with 5 t quality （N 〉2.5%） cattle manure without compromising yield and profit.

Responses of Different Physiological Indices for Maize(Zea mays) to Soil Water Availability

Knowledge of plant responses to soil water availability is essential for the development of effcient irrigation strategies.However,notably different results have been obtained in the past on the responses of various physiological indices for different plants to soil water availability.In this study,the responses of various plant processes to soil water availability were compared with data from pot and field plot experiments conducted on maize(Zea mays L.).Consistent results were obtained between pot and field plot experiments for the responses of various relative plant indices to changes in the fraction of available soil water(FASW).A threshold value,where the relative plant indices began to decrease with soil drying,and a lower water limit,where the decline of relative plant indices changed to a very slow rate,were found.Evaporative demand not only influenced the transpiration rate over a daily scale but also determined the difference in transpirational response to soil water availability among the transient,daily and seasonal time scales.At the seasonal scale,cumulative transpiration decreased linearly with soil drying,but the decrease of transpiration from FASW = 1 in response to water deficits did not affect dry weight until FASW = 0.75.On the other hand,the decrease in dry weight was comparable with plant height and leaf area.Therefore,the plant responses to soil water availability were notably different among various plant indices of maize and were influenced by the weather conditions.

Aluminium Uptake and Accumulation in the Hyperaccumulator Camellia Oleifera Abel

Oiltea camellia （Camellia oleifera Abel.）, an aluminium （Al） hyperaccumulator, grows well on acid soils in tropical or subtropical areas. In this study, the growth of oiltea camellia in response to Al application and the characteristics of Al uptake and accumulation were investigated using laboratory and field experiments. The growth of oiltea camellia seedlings in the nutrient solution tended to be stimulated by addition of Al. Results of the field experiment showed that oiltea camellia accumulated 11 000 mg kg-1 Al in leaves within 10 months, and the average rate of Al accumulation in new leaves was about 1100 mg kg-1 month-1; however, the monthly rate varied and was highest in spring and autumn. The results of the laboratory experiment on Al uptake by oiltea camellia seedlings in CaC12 solutions with various forms of Al showed that large amounts of Al supplied as Al3＋ and Al complexes Al-malate （1：1） and Al-F （1：1） were infiuxed into oiltea camellia roots, whereas Al supplied as Al-citrate （1：1）, Al-F （1：6）, Al-oxalate （1：3）, and Al-oxalate （1：1） complexes exhibited low affinity to oiltea camellia roots. The kinetics of Al3＋ cumulative uptake in excised roots and intact plants showed a biphasic pattern, with an initial rapid phase followed by a slow phase. The Al cumulative uptake was unaffected by low temperature, which indicated that Al uptake in oiltea camellia was a passive process. The efficient influx of Al into the roots and the high transport rate in specific seasons were presumed to account for the plentiful Al accumulation in leaves of oiltea camellia.