In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to...In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to compare the grain qualities of rice under straw retained after single or double seasons per year. Four treatments were designed as: both wheat and rice straw retained(WR), only rice straw retained(R), only wheat straw retained(W), and no straw retained(CK). The varieties were Yangmai 16 wheat and Wuyunjing 23 japonica rice. The results showed contrasting effects of W and R on rice quality. Amylopectin content, peak viscosity, cool viscosity, and breakdown viscosity of rice grain were significantly increased in W compared to the CK, whereas gelatinization temperature,setback viscosity, and protein content significantly decreased. In addition, the effect of WR on rice grain quality was similar to that of W, although soil fertility was enhanced in WR due to straw being retained in two cycles. The differences in protein and starch contents among the treatments might result from soil nitrogen supply. These results indicate that wheat straw retained in the field is more important for high rice quality than rice straw return, and straw from both seasons is recommended for positive effects on soil fertility.展开更多
绰墩遗址第六次发掘的300m^2范围内出土22块古田块，通过对其田埂、灌排系统（水口、水沟、水井）等结构特征的观察研究，对古田块和水沟中出土的灌溉用具——陶罐和陶盆碎片的鉴定是属于马家滨文化时期的器物；从田块表土层中淘洗出大...绰墩遗址第六次发掘的300m^2范围内出土22块古田块，通过对其田埂、灌排系统（水口、水沟、水井）等结构特征的观察研究，对古田块和水沟中出土的灌溉用具——陶罐和陶盆碎片的鉴定是属于马家滨文化时期的器物；从田块表土层中淘洗出大量的炭化稻粒，每克土壤中检测到有上万至十余万颗水稻植硅体，这些结果证明所发现的田块是马家滨时期的灌溉稻田。对出土的炭化稻粒和土壤有机质的14^C定年结果表明其年龄分别为5907 a BP和6280 a BP，是新石器即晚马家滨文化时期的水稻文明。对在遗址挖掘的两个整段剖面（P-01和P．03）的研究发现，P-01剖面上42～103cm层位埋藏有马桥文化-商朝初期（3320aBP）和在103～200cm层位埋藏有马家滨时期（6280aRP）的两个古水稻土剖面，这一结果佐证了前人关于8000年来长江三角洲地区曾有过几次大的洪水泛滥而使人类耕作活动中断的气候变化事件的结论。然而距P-01仅15m的P-03整段剖面上仅出现了马桥-商朝初期的古水稻土剖面（40～100cm），未发现马家滨时期古水稻土剖面（100～200cm），说明当时的生产力非常低下，仅能利用低洼平坦的地方种稻，稍高一点的居住点附近的坡地就无法改成梯田种植水稻了。这两个埋藏的古水稻土剖面均已经发育了水稻土的明显特征。对出土炭化稻粒的形态学研究表明，外型多为椭圆形，长宽比的变异较大，稃面有方格凹陷结构、周边有稃毛，顶端残留有稻芒的基部，基部有护颖而没有小梗，“钝形”的双峰乳突、浅平的凹陷乳沟等均显示其为人工栽培的粳型水稻。结果与丁颖20世纪50年代在黄河流域发现的汉代的炭化稻粒的特征是吻合的，从而支持了关于“我国长江流域与黄河流域古代最早栽培的水稻都是粳稻品种”的论点。展开更多
基金financial supported by the National Key Technology R&D Program of China (2012BAD04B08, 2011BAD16B14)
文摘In rice–wheat rotation systems, crop straw is usually retained in the field at land preparation in every, or every other, season. We conducted a 3-year-6-season experiment in the middle–lower Yangtze River Valley to compare the grain qualities of rice under straw retained after single or double seasons per year. Four treatments were designed as: both wheat and rice straw retained(WR), only rice straw retained(R), only wheat straw retained(W), and no straw retained(CK). The varieties were Yangmai 16 wheat and Wuyunjing 23 japonica rice. The results showed contrasting effects of W and R on rice quality. Amylopectin content, peak viscosity, cool viscosity, and breakdown viscosity of rice grain were significantly increased in W compared to the CK, whereas gelatinization temperature,setback viscosity, and protein content significantly decreased. In addition, the effect of WR on rice grain quality was similar to that of W, although soil fertility was enhanced in WR due to straw being retained in two cycles. The differences in protein and starch contents among the treatments might result from soil nitrogen supply. These results indicate that wheat straw retained in the field is more important for high rice quality than rice straw return, and straw from both seasons is recommended for positive effects on soil fertility.
文摘绰墩遗址第六次发掘的300m^2范围内出土22块古田块，通过对其田埂、灌排系统（水口、水沟、水井）等结构特征的观察研究，对古田块和水沟中出土的灌溉用具——陶罐和陶盆碎片的鉴定是属于马家滨文化时期的器物；从田块表土层中淘洗出大量的炭化稻粒，每克土壤中检测到有上万至十余万颗水稻植硅体，这些结果证明所发现的田块是马家滨时期的灌溉稻田。对出土的炭化稻粒和土壤有机质的14^C定年结果表明其年龄分别为5907 a BP和6280 a BP，是新石器即晚马家滨文化时期的水稻文明。对在遗址挖掘的两个整段剖面（P-01和P．03）的研究发现，P-01剖面上42～103cm层位埋藏有马桥文化-商朝初期（3320aBP）和在103～200cm层位埋藏有马家滨时期（6280aRP）的两个古水稻土剖面，这一结果佐证了前人关于8000年来长江三角洲地区曾有过几次大的洪水泛滥而使人类耕作活动中断的气候变化事件的结论。然而距P-01仅15m的P-03整段剖面上仅出现了马桥-商朝初期的古水稻土剖面（40～100cm），未发现马家滨时期古水稻土剖面（100～200cm），说明当时的生产力非常低下，仅能利用低洼平坦的地方种稻，稍高一点的居住点附近的坡地就无法改成梯田种植水稻了。这两个埋藏的古水稻土剖面均已经发育了水稻土的明显特征。对出土炭化稻粒的形态学研究表明，外型多为椭圆形，长宽比的变异较大，稃面有方格凹陷结构、周边有稃毛，顶端残留有稻芒的基部，基部有护颖而没有小梗，“钝形”的双峰乳突、浅平的凹陷乳沟等均显示其为人工栽培的粳型水稻。结果与丁颖20世纪50年代在黄河流域发现的汉代的炭化稻粒的特征是吻合的，从而支持了关于“我国长江流域与黄河流域古代最早栽培的水稻都是粳稻品种”的论点。
