[Effects of nitrogen reduction combined with organic materials on crop yield, photosynthetic characteristics, and product quality of corn-cabbage rotation system]. / å‡æ°®é æ–½æœ‰æœºç‰©æ–™å¯¹çŽ‰ç±³-ç™½èœè½®ä½œç³»ç»Ÿä½œç‰©äº§é‡ã€å ‰åˆç‰¹æ€§å’Œäº§å“å“è´¨çš„å½±å“.

Nitrogen reduction combined with organic materials is an important measure to achieve or even increase crop yield retention at the background of fertilizer reduction. We conducted a pot experiment to explore the effects of nitrogen reduction combined with organic materials on yield, photosynthetic characteristics, and product quality of agricultural products of maize-cabbage rotation system in yellow soil area of Guizhou. There were five treatments, including no fertilizer (CK), conventional fertilizer (CF), nitrogen reduction (20%, the same below) combined with biochar (RF+B), nitrogen reduction combined with rapeseed cake (RF+O), and nitrogen reduction combined with both biochar and rapeseed cake (RF+BO). Leaf photosynthetic characteristics were measured in maize (seedling stage, jointing stage, heading stage, and mature stage) and cabbage (seedling stage, growing stage and harvest stage). The biological characters, yield and quality indices were investigated in the harvest period. Compared with CF, RF+BO significantly enhanced the yield of corn and cabbage by 9.7% and 39.2%, respectively, while RF+O had no effect, and RF+B did not affet maize yield. RF+BO improved the biological properties of maize and cabbage, including the 100-kernel weight of maize, and plant height, maximum leaf length and total biomass of cabbage. Furthermore, the green holding period and high photosynthetic duration of maize and cabbage were prolonged, among which, maize leaf SPAD was increased respectively by 42.7%, 11.0%, 12.8%, and 30.3% at seedling, jointing, heading, and mature stages, the cabbage leaf SPAD was increased by 13.5%, 9.2%, and 30.3% in seedling, growing and harvest stages, respectively. The net photosynthetic rate (Pn) of maize was increased by 11.1%, 10.9%, and 119.8% in seedling, jointing, and mature stages, while that of cabbage was increased by 12.7% and 14.6% in growing and harvest stages, respectively. The stomatal conductance (gs) of maize was increased by 58.3% and 41.7% in jointing and harvest stages, while that of cabbage was increased by 10%, 64.7%, and 19.2% in seedling, growing, and harvest stages, respectively. The transpiration rate (Tr) of maize was increased by 55.0%, 10.6%, 14.0%, and 143.9% in seedling, jointing, heading, and mature stages, respectively, while that of cabbage was increased by 26.1% in growing stage. The nutritional quality of maize and cabbage was significantly improved. The contents of reducing sugar, starch, and crude protein in maize were increased by 16.2%, 3.5% and 20.3%. The contents of Vc, amino acid, and reducing sugar in cabbage were increased by 26.3%, 21.0% and 27.8%, separately. In conclusion, 20% nitrogen reduction combined with biochar and rapeseed cake had positive effects on crop growth, yield increase, green retention period, high photosynthetic duration, and agricultural product quality improvement in Guizhou yellow soil maize-cabbage rotation system, the overall effect of which was the best. Nitrogen reduction combined with single organic material overally did not affect crop yield, photosynthetic characteristics, and quality.

[Responses of dry matter, nitrogen accumulation and distribution and nitrogen utilization of pepper to new-type fertilizers in Guizhou yellow soil.] / è´µå·žé»„å£¤åŒºè¾£æ¤’å¹²ç‰©è´¨ã€æ°®ç´ ç§¯ç´¯ä¸Žåˆ†é åŠæ°®ç´ åˆ©ç”¨å¯¹æ–°åž‹è‚¥æ–™çš„å“åº”.

In order to explore the pepper yield responses to new-type fertilizers in yellow soil in Guizhou Province, a pot experiment, with the variety of "Bola 5", was conducted to estimate the effects of four new-type fertilizers, including water retaining fertilizer (BSX), stable slow release fertilizer (WDX), coated slow release fertilizer (BMX) and long-lasting nitrogen fertilizer (CXDF), on the accumulation and distribution of dry matter and nitrogen (N) uptake and N use efficiency. The results showed that the application of new-type fertilizers could significantly influence the accumulation and distribution of dry matter and shoot N uptake. Compared with dry matter accumulation, the start time and the end time of N accumulation during fast-growing period were advanced by 17-26 d and 28-45 d, respectively, and the duration of N accumulation in fast-growing period was shorter by 7-23 d, which indicated that the occurrence time of N accumulation was prior to the accumulation of dry matter. In contrast to the common compound fertilizer (FHF) treatment, the occurrence time of dry matter and nitrogen accumulation in the treatments with new-type fertili-zers (BSX, WDX, BMX and CXDF) were obviously lagged, and the lag time was longest in the BMX treatment. However, it had a shorter duration of fast-growing stage and a maximum accumulation rate for the WDX treatment, revealing that WDX could realize the high nutrient use efficiency in a short time. The post-anthesis dry matter and N accumulation accounted for 63.0%, 20.1% and 73.3%, 20.5% for the BSX and BMX treatments, respectively, while these proportions for the WDX were 59.3% and 11.6%, respectively. This indicated that BSX and BMX were beneficial to promote dry matter and N assimilation after flowering, while WDX was conducive to dry matter and nutrients accumulation before flowering. Compared with the FHF treatment, new-type fertilizers (BSX, WDX and BMX) application could significantly improve N use efficiency. Nitrogen partial productivity, nitrogen agronomic efficiency and nitrogen apparent utilization rate of the WDX treatment were the highest, with the average of 66.74 kg·kg-1, 44.28 kg·kg-1 and 54.7%, respectively. Consequently, these four new-type fertilizers were sui-table for pepper cultivation in Guizhou, in which the yield response to the WDX was the best.

[Variation characteristics of maize yield and fertilizer utilization rate on an upland yellow soil under long term fertilization].

An analysis was made on the 16-year experimental data from the long term fertilization, experiment of maize on a yellow soil in Guizhou of Southwest China. Four treatments, i. e. , no fertilization (CK), chemical fertilization (165 kg N x hm(-2), 82.5 kg P2O5 x hm(-2), and 82.5 kg K2O x hm(-2), NPK), organic manure (30555 kg x hm(-2), M), and combined applicatioin of chemical fertilizers and organic manure (NPKM), were selected to analyze the variation trends of maize yield and fertilizer use efficiency on yellow soil under effects of different long term fertilization modes, aimed to provide references for evaluating and establishing long term fertilization mode and promote the sustainable development of crop production. Overall, the maize yield under long term fertilization had an increasing trend, with a large annual variation. Treatment NPKM had the best yield-increasing effect, with the maize yield increased by 4075.71 kg x hm(-2) and the increment being up to 139.2%. Long term fertilization increased the fertilizer utilization efficiency of maize. In treatment M, the nitrogen and phosphorus utilization rates were increased significantly by 35.4% and 18.8%, respectively. Treatment NPK had obvious effect in improving potassium utilization rate, with an increment of 20% and being far higher than that in treatments M (8.7%) and NPKM (9.2%). The results showed that long term fertilization, especially the combined application of chemical fertilizers and organic manure, was of great importance in increasing crop yield and fertilizer use efficiency.