Effects of water-fertilizer coupling on root distribution and yield of Chinese Jujube trees in Xinjiang

Water and fertilizer are the two main factors which promote the rapid growth of Jujube(Ziziphus jujuba)trees.Studies of root systems and the nutrition-use efficiency of dense,dwarfed fruit trees are limited,especially in an extremely arid region with drip irrigation.The experiment was conducted in a 12-year-old dwarf jujube planting basement in Hami from 2013 to 2015.In this experiment,root length density and root weight density were calculated and found to range from 75 cm to 275 cm in horizontal distance,and from 0 to 90 cm in vertical depth,treated with three drip irrigation quota gradients and three fertilizer rates with each treatment replicated three times.The results showed that,as the amount of nitrogen applied increased gradually,the jujubes’growth amount increased,reaching a maximum when an optimal concentration was applied.However,the jujubes’growth was inhibited,and the growth declined when the amount of nitrogen applied was more than the optimal concentration.At an appropriate level of nitrogen,the growth,yield and quality of jujube trees could be guaranteed.If the rate of nitrogen application was lowered,the jujubes’growth would inhibit,and hence the yield wound be seriously impacted.The optimal irrigation quota and fertilization amount were found to be 900 mm and 1500-1800 kg/hm^(2),respectively.The research findings were of significance and hold great promise for the development of the forestry and fruit industries in the arid region of Xinjiang.At the same time,there was a further study on irrigation technique,focusing on the combined effect of the dwarfed-planting technique and drip irrigation on jujube trees;with this information,the application efficiency of water and fertilizer can be optimized,leading to higher profits and economic efficiency.

Optimizing water and nitrogen inputs for winter wheat cropping system on the Loess Plateau,China

Optimal use of water and fertilizers can enhance winter wheat yield and increase the efficiencies of water and fertilizer usage in dryland agricultural systems. In order to optimize water and nitrogen （N） management for winter wheat, we conducted field experiments from 2006 to 2008 at the Changwu Agro-ecological Experimental Station of the Chinese Academy of Sciences on the Loess Plateau, China. Regression models of wheat yield and evapotranspiration （ET） were established in this study to evaluate the water and fertilizer coupling effects and to determine the optimal coupling domain. The results showed that there was a positive effect of water and N fertilizer on crop yield, and optimal irrigation and N inputs can significantly increase the yield of winter wheat. In the drought year （2006-2007）, the maximum yield （Yma~） of winter wheat was 9.211 t/hm2 for the treatment with 324 mm irriga- tion and 310 kg/hm2 N input, and the highest water use efficiency （WUE） of 16.335 kg/（hm2.mm） was achieved with 198 mm irrigation and 274 kg/hm2 N input. While in the normal year （2007-2008）, the maximum winter wheat yield of 10.715 t/hm2 was achieved by applying 318 mm irrigation and 291 kg/hm2 N, and the highest WUE was 18.69 kg/（hm2.mm） with 107 mm irrigation and 256 kg/hm2 N input. Crop yield and ET response to irrigation and N inputs followed a quadratic and a line function, respectively. The optimal coupling domain was determined using the elas- ticity index （El） and its expression in the water-N dimensions, and was represented by an ellipse, such that the global maximum WUE （WUErnax） and Ymax values corresponded to the left and right end points of the long axis, respectively. Considering the aim to get the greatest profit in practice, the optimal coupling domain was represented by the lower half of the ellipse, with the Yma~ and WUE^ax on the two end points of the long axis. Overall, we found that the total amount of irrigation for winter wheat should not exceed 324 ram. In addition, our optimal coupling domain visually reflects the optimal range of water and N inputs for the maximum winter wheat yield on the Loess Plateau, and it may also provide a useful reference for identifying appropriate water and N inputs in agricultural applications.

Different Fertilization Modes of Sugarcane in Latosolic Red Soil of Guangxi

[Objectives] This study aimed to compare the effects of water-fertilizer integrated drip irrigation modes and traditional fertilization mode on growth,yield,production costs and economic benefit of sugarcane in latosolic red soil of Guangxi. [Methods]A field test was conducted. [Results] The agronomic traits and comprehensive economic benefit of sugarcane under the water-fertilizer integrated drip irrigation modes were superior to those under the traditional fertilization mode. Among them,the comprehensive economic benefit of sugarcane with special granular fertilizer as the base fertilizer and water-fertilizer integrated drip irrigation as topdressing were the highest,increased by 15 813 kg/ha,an increase of 15. 8%. Considering the cost input,the comprehensive economic benefit increased by 5 676 yuan/ha. [Conclusions]Taking the production cost,economic benefit and input-output ratio into account,it is recommended to promote the application of water-fertilizer integrated drip irrigation mode in bases with water and fertilizer equipment conditions.