Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertil...Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertilizer on some soil properties;soil pH, soil phosphomonoesterases, inorganic nitrogen and extractable phosphorus. The study was conducted for two seasons (short and long rains) at two locations (Egerton University agricultural field and farmer’s field in Mau Narok) using a split-plot design in a randomized complete block (RCBD) arrangement with variety as the main plot and soil amendments as the subplot. Biochar and Diammonium Phosphate (DAP) at 0, 5, and 10 t⋅ha<sup>−1</sup> and 0, 250, and 500 kg⋅ha<sup>−1</sup> respectively, were applied, resulting in nine treatment combinations. Two potato varieties (Shangi and Destiny) were used in the study. A combination of 5 t⋅ha<sup>−1</sup> biochar and 500 kg⋅ha<sup>−1</sup> DAP and sole application of biochar at 5 t⋅ha<sup>−1</sup> resulted in an increase of 1.25, 2.54 units in soil pH in two seasons, respectively. Similarly, a combination of 5 t⋅ha<sup>−1</sup> biochar and 250 kg⋅ha<sup>−1</sup> DAP increased soil available phosphorus by 105 units from 30.7 mg⋅kg<sup>−1</sup> to 136 mg⋅kg<sup>−1</sup>. The application rate of 5 t⋅ha<sup>−1</sup> biochar with 250 or 500 kg⋅ha<sup>−1</sup> DAP significantly increased soil nitrate by 102.11 and 116.14 units, respectively. Soils amended with biochar at 5 t⋅ha<sup>−1</sup> combined with 500 kg⋅ha<sup>−1</sup> DAP, 10 t⋅ha<sup>−1</sup> of biochar combined with either 250 kg or 500 kg of DAP gave the highest alkaline enzymes (mM pNP × kg<sup>−1</sup> × h<sup>−1</sup>). However, the highest acid soil phosphomonoesterases were obtained under the sole application of DAP at 500 ha<sup>−1</sup>. Thus, using biochar with chemical fertilizer seems a plausible option to ameliorate the declining nutrient base of farmland in Kenya, which could sustainably support potato growth.展开更多
This study is aimed to investigate the activities of phosphomonoesterase (acid ,neutral ,and alkaline ),phosphodiesterase and phosphotriesterase in a rice planting meadow brown soil at the lower reach of Liao River,an...This study is aimed to investigate the activities of phosphomonoesterase (acid ,neutral ,and alkaline ),phosphodiesterase and phosphotriesterase in a rice planting meadow brown soil at the lower reach of Liao River,and their responses to different fertilization treatments.The results showed that there was no significant difference in soil total P and organic P contents among all treatments,but soil available P content was significantly higher in treatment OM than in other treatments.Soil acid and neutral phosphomonoesterase had a higher activity than alkaline phosphomonoesterase and phosphodiesterase,while phosphotriesterase had the lowest activity.No significant difference was found in phosphatase activities between different fertilization treatments.Soil acid phosphomonoesterase activity had a significant correlation with soil total P and available P contents,while soil phosphodiesterase activity significantly correlated with soil organic P content.展开更多
为研究氮添加影响森林土壤有机磷矿化的微生物调控机制,分析了10年的野外氮添加(100 kg N^(-2) ha^(-2)year^(-1))对沙地樟子松人工林土壤微生物中编码酸性磷酸单酯酶、碱性磷酸单酯酶和植酸酶的功能基因(phoC、phoD和appA)丰度及相关...为研究氮添加影响森林土壤有机磷矿化的微生物调控机制,分析了10年的野外氮添加(100 kg N^(-2) ha^(-2)year^(-1))对沙地樟子松人工林土壤微生物中编码酸性磷酸单酯酶、碱性磷酸单酯酶和植酸酶的功能基因(phoC、phoD和appA)丰度及相关酶活性和土壤理化性质的影响。结果表明,氮添加使樟子松人工林土壤中酸性和碱性磷酸单酯酶活性分别下降了18.09%和55.29%,植酸酶活性下降了41.88%。氮添加使土壤微生物中各基因拷贝数分别下降40.97%(16S-rRNA)、78.38%(phoD)、67.92%(phoC)、74.37%(appA)。各基因拷贝数占总细菌基因拷贝数的比例显著下降了61%(phoD)、44%(phoC)、55%(appA)。土壤微生物量碳、微生物量磷含量与酸性磷酸单脂酶、碱性磷酸单脂酶、植酸酶活性及16S rRNA、phoD、phoC、appA基因丰度显著正相关。土壤铵态氮含量与酸性磷酸单脂酶、碱性磷酸单脂酶活性及16S rRNA、phoC、appA基因丰度显著负相关。酸性磷酸单酯酶活性与其基因丰度显著正相关,其他两种酶活性与其基因丰度无显著相关性。以上结果表明,氮添加不仅降低了土壤解磷微生物丰度,还降低了解磷细菌在总细菌中的比例,从而大大降低了磷酸酶活性,抑制了有机磷的矿化。展开更多
文摘Declining soil fertility is a major constraint to potato farming, the second most important food crop in Kenya. The objective of the study was to determine the effect of different rates of biochar and inorganic fertilizer on some soil properties;soil pH, soil phosphomonoesterases, inorganic nitrogen and extractable phosphorus. The study was conducted for two seasons (short and long rains) at two locations (Egerton University agricultural field and farmer’s field in Mau Narok) using a split-plot design in a randomized complete block (RCBD) arrangement with variety as the main plot and soil amendments as the subplot. Biochar and Diammonium Phosphate (DAP) at 0, 5, and 10 t⋅ha<sup>−1</sup> and 0, 250, and 500 kg⋅ha<sup>−1</sup> respectively, were applied, resulting in nine treatment combinations. Two potato varieties (Shangi and Destiny) were used in the study. A combination of 5 t⋅ha<sup>−1</sup> biochar and 500 kg⋅ha<sup>−1</sup> DAP and sole application of biochar at 5 t⋅ha<sup>−1</sup> resulted in an increase of 1.25, 2.54 units in soil pH in two seasons, respectively. Similarly, a combination of 5 t⋅ha<sup>−1</sup> biochar and 250 kg⋅ha<sup>−1</sup> DAP increased soil available phosphorus by 105 units from 30.7 mg⋅kg<sup>−1</sup> to 136 mg⋅kg<sup>−1</sup>. The application rate of 5 t⋅ha<sup>−1</sup> biochar with 250 or 500 kg⋅ha<sup>−1</sup> DAP significantly increased soil nitrate by 102.11 and 116.14 units, respectively. Soils amended with biochar at 5 t⋅ha<sup>−1</sup> combined with 500 kg⋅ha<sup>−1</sup> DAP, 10 t⋅ha<sup>−1</sup> of biochar combined with either 250 kg or 500 kg of DAP gave the highest alkaline enzymes (mM pNP × kg<sup>−1</sup> × h<sup>−1</sup>). However, the highest acid soil phosphomonoesterases were obtained under the sole application of DAP at 500 ha<sup>−1</sup>. Thus, using biochar with chemical fertilizer seems a plausible option to ameliorate the declining nutrient base of farmland in Kenya, which could sustainably support potato growth.
文摘This study is aimed to investigate the activities of phosphomonoesterase (acid ,neutral ,and alkaline ),phosphodiesterase and phosphotriesterase in a rice planting meadow brown soil at the lower reach of Liao River,and their responses to different fertilization treatments.The results showed that there was no significant difference in soil total P and organic P contents among all treatments,but soil available P content was significantly higher in treatment OM than in other treatments.Soil acid and neutral phosphomonoesterase had a higher activity than alkaline phosphomonoesterase and phosphodiesterase,while phosphotriesterase had the lowest activity.No significant difference was found in phosphatase activities between different fertilization treatments.Soil acid phosphomonoesterase activity had a significant correlation with soil total P and available P contents,while soil phosphodiesterase activity significantly correlated with soil organic P content.
基金the National Natural Science Foundation of China(41171241)National Key Basic Research Development Program of China(973 Program)(2011CB100506)National Twelfth Five-Year Science and Technology Support Plan(2012BAD14B04)