It is of practical significance for the decision-making on country food security and farmland protection to analyze the conversion margins for the major uses of agricultural land and their variations. Based on the pan...It is of practical significance for the decision-making on country food security and farmland protection to analyze the conversion margins for the major uses of agricultural land and their variations. Based on the panel data of wheat, corn, vegetable, fruit, and forests productions from 520 investigated farmer households of 13 investigated villages in Shandong Province from 2003 to 2009, and using Cobb-Douglas production function, the revenue conversion margins can be obtained separately, between different grain-crops （wheat, corn） and different non-grain crops （vegetable, fruit, forests）, and the conversion relationship between growing grain（ wheat, corn） and going out for non-farm work. The results show that from 2003 to 2009, growing wheat and corn are more economically and reasonably for farmers, compared with growing vegetable, but growing wheat and corn are becoming less economically and less reasonably day by day, compared with planting forests. Moreover, the conversion margin between wheat and fruit shows obvious scissors difference. Just from 2007, farm- ers＇ growing fruit became economically and reasonably, but until 2009, compared with going out to work after abandoning farm- land, growing wheat had no economic rationality. From 2003 to 2009, farmers＇ growing corn is more profitable than growing fruit and going out for non-farm work after abandoning farmland. The subsidies for wheat and corn have increased farmers＇ comparative income from food production remarkably, but the subsidies cannot change the general tendency that farmers transform food （wheat, corn） production into non-food （especially forests） production. The revenue difference between growing wheat, corn and vegetable and growing fruit and forests is being pulled ceaselessly bigger, and the tendency that farmers transform wheat, corn and vegetable growing lands into fruit and forests growing lands has become increasingly apparent.展开更多
The knowledge and understanding of African leafy vegetables has diminished over time, but in the recent past year there is more interest in their research for their nutritive and medicinal values. Of value are those t...The knowledge and understanding of African leafy vegetables has diminished over time, but in the recent past year there is more interest in their research for their nutritive and medicinal values. Of value are those that have the potential to ameliorate soil nutrient levels. This is with the background that despite inorganic fertilizers （IF） have a dramatic impact on agriculture in the world, the economic situation in Sub-Saharan African calls for alternative methods to reduce soil fertility degradation. The use of leguminous vegetables may be a solution. The study looks at the potential contribution of a leguminous traditional vegetable-- Crotalaria brevidens to soil nitrogen under various treatments. During the study which was conducted over two seasons, C. brevidens was grown under two treatments of IF and organic fertilizer （OF） with a control in which there was no fertilizer （NF） applied. A non-leguminous vegetable--Amaranthus dubious （Amaranth） was grown under the same treatments for comparison purposes. Soil analysis was done before and after planting in the treatment subplots. Growth parameters were measured every fortnight and these included leaf number, shoot length, dry weight and nodule number for Crotalaria. Results indicated that the leguminous vegetable was not affected by external inputs and there were no significant differences between treatments and control. The non-leguminous vegetables responded well to both IF and OF treatments in all the measured parameters. This underlines the potential for improving soil nitrogen levels using leguminous vegetables, especially as intercrops with the non-leguminous types.展开更多
Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic...Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic carbon （SOC） accumulation in a Mediterranean vegetable cropping system. The study involved four treatments： biowaste compost （COM）, mineral NPK fertilizers （MIN）, biowaste compost with half-dose N fertilizer （COMN）, and unfertilized control （CK）. The SOC stocks were increased in COM, COMN, and MIN by 20.2, 14.9, and 2.4 Mg ha-1 over CK, respectively. The SOC concentration was significantly related to mean weight diameter of aggregates （MWD） （P 〈 0.05, R^2 = 0.798 4） when CK was excluded from regression analysis. Compared to CK, COM and COMN increased the SOC amount in macroaggregates （〉 250 μm） by 2.7 and 0.6 g kg-1 soil, respectively, while MIN showed a loss of 0.4 g kg-1 soil. The SOC amount in free microaggregates （53-250 ttm） increased by 0.9, 1.6, and 1.0 g kg-1 soil for COM, COMN, and MIN, respectively, while those in the free silt plus clay aggregates （~ 53 ~m） did not vary significantly. However, when separating SOC in particle-size fractions, we found that more stable organic carbon associated with mineral fraction 〈 53 μm （MOM-C） increased significantly by 3.4, 2.2, and 0.7 g kg-1 soil for COM, COMN, and MIN, respectively, over CK, while SOC amount in fine particulate organic matter （POM） fraction （53-250 μm） increased only by 0.3 g kg-1 soil for both COM and COMN, with no difference in coarse POM 〉 250 μm. Therefore, we consider that biowaste compost could be effective in improving soil structure and long-term C sequestration as more stable MOM-C.展开更多
基金The Important Project of Knowledge Innovation Engineering of Chinese Academy of Sciences:the Pilot Project of Farmland-conservation and Modern Sustainable High Efficiency Agriculturethe Second Subject:the Regulation Mechanism for Requisition-compensation Balance of Cultivated Land and the Pilot Study on Productive Farmland Conservation in Yucheng,Shandong Provincethe Seventh Special Topic:the Strategic Research on Farmland-conservation and Agriculture Sustainable Development in Shandong Province
文摘It is of practical significance for the decision-making on country food security and farmland protection to analyze the conversion margins for the major uses of agricultural land and their variations. Based on the panel data of wheat, corn, vegetable, fruit, and forests productions from 520 investigated farmer households of 13 investigated villages in Shandong Province from 2003 to 2009, and using Cobb-Douglas production function, the revenue conversion margins can be obtained separately, between different grain-crops （wheat, corn） and different non-grain crops （vegetable, fruit, forests）, and the conversion relationship between growing grain（ wheat, corn） and going out for non-farm work. The results show that from 2003 to 2009, growing wheat and corn are more economically and reasonably for farmers, compared with growing vegetable, but growing wheat and corn are becoming less economically and less reasonably day by day, compared with planting forests. Moreover, the conversion margin between wheat and fruit shows obvious scissors difference. Just from 2007, farm- ers＇ growing fruit became economically and reasonably, but until 2009, compared with going out to work after abandoning farm- land, growing wheat had no economic rationality. From 2003 to 2009, farmers＇ growing corn is more profitable than growing fruit and going out for non-farm work after abandoning farmland. The subsidies for wheat and corn have increased farmers＇ comparative income from food production remarkably, but the subsidies cannot change the general tendency that farmers transform food （wheat, corn） production into non-food （especially forests） production. The revenue difference between growing wheat, corn and vegetable and growing fruit and forests is being pulled ceaselessly bigger, and the tendency that farmers transform wheat, corn and vegetable growing lands into fruit and forests growing lands has become increasingly apparent.
文摘The knowledge and understanding of African leafy vegetables has diminished over time, but in the recent past year there is more interest in their research for their nutritive and medicinal values. Of value are those that have the potential to ameliorate soil nutrient levels. This is with the background that despite inorganic fertilizers （IF） have a dramatic impact on agriculture in the world, the economic situation in Sub-Saharan African calls for alternative methods to reduce soil fertility degradation. The use of leguminous vegetables may be a solution. The study looks at the potential contribution of a leguminous traditional vegetable-- Crotalaria brevidens to soil nitrogen under various treatments. During the study which was conducted over two seasons, C. brevidens was grown under two treatments of IF and organic fertilizer （OF） with a control in which there was no fertilizer （NF） applied. A non-leguminous vegetable--Amaranthus dubious （Amaranth） was grown under the same treatments for comparison purposes. Soil analysis was done before and after planting in the treatment subplots. Growth parameters were measured every fortnight and these included leaf number, shoot length, dry weight and nodule number for Crotalaria. Results indicated that the leguminous vegetable was not affected by external inputs and there were no significant differences between treatments and control. The non-leguminous vegetables responded well to both IF and OF treatments in all the measured parameters. This underlines the potential for improving soil nitrogen levels using leguminous vegetables, especially as intercrops with the non-leguminous types.
文摘Biowaste compost can influence soil organic matter accumulation directly or indirectly. A 5-year experiment was conducted to assess the influence of biowaste compost on the process of soil aggregation and soil organic carbon （SOC） accumulation in a Mediterranean vegetable cropping system. The study involved four treatments： biowaste compost （COM）, mineral NPK fertilizers （MIN）, biowaste compost with half-dose N fertilizer （COMN）, and unfertilized control （CK）. The SOC stocks were increased in COM, COMN, and MIN by 20.2, 14.9, and 2.4 Mg ha-1 over CK, respectively. The SOC concentration was significantly related to mean weight diameter of aggregates （MWD） （P 〈 0.05, R^2 = 0.798 4） when CK was excluded from regression analysis. Compared to CK, COM and COMN increased the SOC amount in macroaggregates （〉 250 μm） by 2.7 and 0.6 g kg-1 soil, respectively, while MIN showed a loss of 0.4 g kg-1 soil. The SOC amount in free microaggregates （53-250 ttm） increased by 0.9, 1.6, and 1.0 g kg-1 soil for COM, COMN, and MIN, respectively, while those in the free silt plus clay aggregates （~ 53 ~m） did not vary significantly. However, when separating SOC in particle-size fractions, we found that more stable organic carbon associated with mineral fraction 〈 53 μm （MOM-C） increased significantly by 3.4, 2.2, and 0.7 g kg-1 soil for COM, COMN, and MIN, respectively, over CK, while SOC amount in fine particulate organic matter （POM） fraction （53-250 μm） increased only by 0.3 g kg-1 soil for both COM and COMN, with no difference in coarse POM 〉 250 μm. Therefore, we consider that biowaste compost could be effective in improving soil structure and long-term C sequestration as more stable MOM-C.
