[Effect of substrate of edible mushroom on continuously cropping obstacle of Rehmannia glutinosa].

The continuous cultivation of Rehmannia glutinosa causes the accumulation of phenolic acids in soil. It is supposed to be the reason of the so called "continuously cropping obstacle". In this study, phenolic acids (hydroxybenzoic acid, vanillic acid, eugenol, vanillin and ferulic acid) were degraded by the extracta of all the tested spent mushroom substrate (SMS) and the maximal degradation rate was 75.3%, contributed by extraction of SMS of Pleurotus eryngii. Pot experiment indicated that hydroxybenzoic acid and vanillin in soil were also degraded effectively by SMS of P. eryngii. The employment of SMS enhanced ecophysiology index to near the normal levels, such as crown width, leaves number, leaf length, leaf width and height. At the same time, the fresh and dry weight and total catalpol concentration of tuberous root weight of R. glutinosa was increased to 2.70, 3.66, 2.25 times by employment of SMS, respectively. The increase of bacteria, fungi and actinomycetes numbers in rhizosphere soil were observed after the employment of SMS by microbial counts. The employment of SMS also enhanced the enzyme activity in soils, such as sucrase, cellulase, phosphalase, urease and catelase. These results indicated that the employment of SMS alleviated the continuously cropping obstacle of R. glutinosa in some extent.

[Effects of Astragalus sinicus combined with chemical fertilizer on nitrogen absorption and utilization of rice and nitrogen distribution and residue of Astragalus sinicus in rice-soil system.] / ç´«äº‘è‹±é æ–½åŒ–è‚¥å¯¹æ°´ç¨»æ°®ç´ å¸æ”¶åˆ©ç”¨å’Œç´«äº‘è‹±æ°®åœ¨æ°´ç¨»-åœŸå£¤ä½“ç³»åˆ†é ã€æ®‹ç•™çš„å½±å“.

Clarifying the pattern of nitrogen absorption and utilization of rice under the treatments of Astragalus sinicus combined with chemical fertilizer application and the pattern of absorption, utilization, distribution and residue of A. sinicus nitrogen in rice-soil system could provide basis to rational fertilization for rice planting area in southern Henan. In this study, undisturbed soil column simulation and isotope tracer technology of 15N were used to examine the differences of nitrogen uptake and utilization of rice, nitrogen nutrient balance of rice-soil system and nitrogen uptake, utilization, distribution and residue of A. sinicus nitrogen after mineralization and decomposition among seven treatments. The treatments involved 1) no fertilization (CK); 2) chemical fertilizer+22500 kg·hm-2 A. sinicus (FM1); 3) chemical fertilizer+30000 kg·hm-2 A. sinicus (FM2); 4) chemical fertilizer+37500 kg·hm-2 A. sinicus (FM3); 5) chemical fertilizer+22500 kg·hm-2 A. sinicus +lime (FM1+CaO); 6) chemical fertilizer+30000 kg·hm-2 A. sinicus lime (FM2+CaO); 7) chemical fertilizer+37500 kg·hm-2 A. sinicus +lime (FM3+CaO). Results showed that compared with CK, fertilization significantly increased nitrogen uptake of grain and rice stalks, apparent nitrogen loss, and nitrogen surplus. The grain nitrogen uptake, rice straw nitrogen uptake and nitrogen use efficiency of rice increased firstly and then decreased with the increasing A. sinicus application rates, while the apparent nitrogen loss and nitrogen surplus showed the opposite trend. The best performance was presented under the treatment of chemical fertilizer combined with 30000 kg·hm-2 of A. sinicus. Lime addition could increase grain nitrogen uptake, rice straw nitrogen uptake, and nitrogen use efficiency of rice, while reducing apparent nitrogen loss and nitrogen surplus, with the best performance of FM2+CaO. For all the treatments, the proportion of nitrogen absorbed by rice from A. sinicus was 6.3%-13.2%, while that from soil and chemical fertilizer was 86.8%-93.7%. The utilization ratio of A. sinicus nitrogen by rice was 23.8%-33.6%. The utilization ratio of A. sinicus nitrogen in different parts of rice was grain > stem and leaf > root. The residue rate of A. sinicus nitrogen in soil was 37.6%-62.4%. The loss rate of A. sinicus nitrogen was 7.8%-38.6%. Comprehensively considering nitrogen absorption and utilization of rice, nitrogen nutrient balance of rice-soil system, and the distribution situation of nitrogen from A. sinicus in rice, FM2+CaO was the optimum fertilization pattern in the study area.

[The characteristics of decomposition and nutrient release of Vicia villosa under different fertilization treatments.] / ä¸åŒæ–½è‚¥æ¡ä»¶ä¸‹æ¯›å¶è‹•å­çš„è è§£åŠå »åˆ†é‡Šæ”¾ç‰¹å¾.

The effects of three fertilization treatments (no fertilizer, nitrogen fertilizer, and lime) on the characteristics of Vicia villosa decomposition and nutrient release were studied using the nylon bag method in the fields. The results showed that the cumulative decomposition rate of V. villosa was 65.3%-72.5% across the three fertilization treatments. V. villosa decomposed rapidly during 0-11 d, then slowed down and tended to be stable. The nutrient release rates across the three treatments were potassium > phosphorus > carbon > nitrogen. At the end of the experiment (148 d), the cumulative release rates of carbon, nitrogen, phosphorus and potassium were 83.6%-84.6%, 78.2%-81.2%, 89.8%-91.4% and 96.3%-97.0%, respectively. During the whole decomposition period, the characteristics of nitrogen release and decomposition of V. villosa were similar. Compared with no fertilizer treatment, lime application promoted decomposition and release of nitrogen, phosphorus and potassium. Nitrogen fertilizer application promoted phosphorus release but inhibited potassium release. Both nitrogen application and lime application had no significant effect on carbon release. The application of nitrogen fertilizer promoted the decomposition of V. villosa and nitrogen release in 0-11 d, but inhibited those processes in 11-148 d. The first-order kinetic reaction equation and logarithmic function equation well fitted the characteristics of V. villosa decomposition and the release of carbon, nitrogen, phosphorus and potassium in the rice fields of South Henan. The characteristic parameters of the equation were significantly correlated with the decomposition rate and nutrient release rate of V. villosa. In summary, lime application was better than nitrogen fertili-zer in promoting decomposition and nutrient release of V. villosa. Moreover, the parameters of the first-order kinetic equation and logarithmic function equation showed a good description of decomposition and nutrient release of V. villosa.