A Knowledge Model-and Growth Model-Based Decision Support System for Wheat Management

By applying the system analysis principle and mathematical modeling technique to knowledge expression system for crop cultural management, the fundamental relationships and quantitative algorithms of wheat growth and management indices to variety types, ecological environments and production levels were analysed and extracted, and a dynamic knowledge model with temporal and spatial characters for wheat management(WheatKnow)was developed. By adopting the soft component characteristics as non language relevance , re-utilization and portable system maintenance. and by further integrating the wheat growth simulation model(WheatGrow)and intelligent system for wheat management, a comprehensive and digital knowledge model, growth model and component-based decision support system for wheat management(MBDSSWM)was established on the platforms of Visual C++ and Visual Basic. The MBDSSWM realized the effective integration and coupling of the prediction and decision-making functions for digital crop management.

Integrated management strategy for improving the grain yield and nitrogen-use efficiency of winter wheat

Understanding of how combinations of agronomic options can be used to improve the grain yield and nitrogen use efficiency（NUE） of winter wheat is limited. A three-year experiment involving four integrated management strategies was conducted from 2013 to 2015 in Tai＇an, Shandong Province, China, to evaluate changes in grain yield and NUE. The integrated management treatments were as follows： current practice（T1）; improvement of current practice（T2）; high-yield management（T3）, which aimed to maximize grain yield regardless of the cost of resource inputs; and integrated soil and crop system management（T4） with a higher seeding rate, delayed sowing date, and optimized nutrient management. Seeding rates increased by 75 seeds m^-2 with each treatment from T1（225 seeds m^-2） to T4（450 seeds m^-2）. The sowing dates were delayed from T1（5 th Oct.） to T2 and T3（8 th Oct.）, and to T4 treatment（12 th Oct.）. T1, T2, T3, and T4 received 315, 210, 315, and 240 kg N ha^-1, 120, 90, 210 and 120 kg P2O5 ha^-1, 30, 75, 90, and 45 kg K2O ha^-1, respectively. The ratio of basal application to topdressing for T1, T2, T3, and T4 was 6：4, 5：5, 4：6, and 4：6, respectively, with the N topdressing applied at regreening for T1 and at jointing stage for T2, T3, and T4. The P fertilizers in all treatments were applied as basal fertilizer. The K fertilizer for T1 and T2 was applied as basal fertilizer while the ratio of basal application to topdressing（at jointing stage） of K fertilizer for both T3 and T4 was 6：4. T1, T2, T3, and T4 were irrigated five, four, four and three times, respectively. Treatment T3 produced the highest grain yield among all treatments over three years and the average yield was 9 277.96 kg ha^-1. Grain yield averaged across three years with the T4 treatment（8 892.93 kg ha^-1） was 95.85% of that with T3 and was 21.72 and 6.10% higher than that with T1（7 305.95 kg ha^-1） and T2（8 381.41 kg ha^-1）, respectively. Treatment T2 produced the highest NUE of all the integrated treatments. The NUE with T4 was 95.36% of that with T2 and was 51.91 and 25.62% higher than that with T1 and T3, respectively. The N uptake efficiency（UPE） averaged across three years with T4 was 50.75 and 16.62% higher than that with T1and T3, respectively. The N utilization efficiency（UTE） averaged across three years with T4 was 7.74% higher than that with T3. The increased UPE with T4 compared with T3 could be attributed mostly to the lower available N in T4, while the increased UTE with T4 was mainly due to the highest N harvest index and low grain N concentration, which consequently led to improved NUE. The net profit for T4 was the highest among four treatments and was 174.94, 22.27, and 28.10% higher than that for T1, T2, and T3, respectively. Therefore, the T4 treatment should be a recommendable management strategy to obtain high grain yield, high NUE, and high economic benefits in the target region, although further improvements of NUE are required.

Performance of no-till corn precision planter equipped with row cleaners

In the continuous annual wheat-corn cropping area of North China Plain,no-till planting that promotes soil conservation and crop yield while reducing operation cost has been gradually accepted by local farmers.However,previous wheat residue is the main limiting factor affecting the performance of existing planters in placing seeds at uniform spacing and optimum depth in residue covered fields.In order to solve this problem,a kind of ground-wheel-driven row cleaner was designed,developed and mounted on row units of a four-row pneumatic precision planter.The planter has two adjacent row units equipped with the newly designed row cleaners and the other two adjacent row units equipped with the commonly used inactive row cleaners.This was used for planting at three forward speeds(4 km/h,6 km/h and 8 km/h)into half residue(HR)and whole residue(WR)plots.The amount of residue removal,seeding depth,emergence rate and indices of uniformity in seed spacing(missing-seeding index,quality of feeding index and precision index)were measured.The newly designed row cleaner performed better with regard to residue removal,with the average percentage of residue cleared as 63.0%compared to 40.3%for the inactive row cleaner.For the HR and WR plots,percentage of residue cleared of the newly designed row cleaner reached 57.1%and 68.9%respectively,suggesting that the newly designed row cleaner can work more effectively at high residue level.By contrast,with the percentage of residue cleared of the inactive row cleaner as 43.1%and 37.5%in HR and WR plots,suggesting that the inactive row cleaner just can work effectively under low residue condition.Values of missing-seeding index,QFI,precision index,coefficient of variation of depth and percent emergence for the newly designed row cleaner under whole residue level are comparable to those for the inactive row cleaner under half residue level.The result indicates that the effect of using the newly designed row cleaner is equal to that of reducing surface residue,and can help to maintain the uniformity of seed spacing and seeding depth.The newly designed row cleaner generally performed better at forward speed of 6 km/h,based on the distribution of seeds along rows and seeding depth uniformity.