大田条件下,在早季和晚季以常耕抛栽为对照,对金优253免耕抛栽秧苗的根系生长与立苗特性进行了研究。结果表明,与常耕抛栽秧苗相比,免耕抛栽秧苗前期立苗速度较慢,后期立苗速度较快,总的立苗时间相同,但免耕抛栽秧苗的立苗更易受不良气候的影响。免耕抛栽秧苗立苗期发根较多,根系的总长度不及常耕抛栽秧苗。抛后7 d内,抛栽秧苗根系活力经历了由低到高再到低的变化过程,早、晚季免耕抛秧水稻在抛后7 d内的根系活力均高于常耕抛秧水稻,当根系活力上升时,免耕抛栽秧苗的根系活力上升速度慢,当根系活力下降时,免耕抛栽秧苗的根系活力下降也慢。

As one of the no-tillage cultivation,seedling-broadcast with no-tillage techniques has broken through the conception of conventional intensive cultivation.It combines the advantages of no-tillage and seedling-broadcast,reduces water loss and soil erosion,protects soil structure,and can save labour and reduce work load.In recent years,the study on seedling-broadcast with no-tillage techniques for rice showed that although it decreased the total of tillering,it could shorten the time of ineffective tillering with less waste of nutrition,rice individual growth was strong with corresponded colony growth,it was favourable for increasing the panicles formation rate and seed setting rate with large panicles and more grain,and increased the yield of rice.It also could improve soil physical and chemical characteristics and coordinate effectively water,heat,aeration and fertilizer to increase soil fertility.It could improve ecological environment,increase the enzymes activities of soil,strengthen the vigor of root system,and create a good conditions for rice growth and high-yield.For fertilizer management of seedling-broadcast with no-tillage in rice, heavy early-fertilization should be applied and fertilization in promoting flower and protecting panicles should be subsidiary;otherwise,increasing application rate of nitrogen is favor of high yield of rice.In the future,in order to solve the existing problems on seedling-broadcast with no-tillage in rice,researches on fertilizer management,tillering development and physiological characteristics of plant etc should be emphasized.

Nitrogen levels of 127.5,150.0,172.5 and 193.0 kg/hm~2 were designed in notillage(NT) cast transplanting rice and conventional tillage(CT) rice in this experiment to compare the population quality and yield.The results showed that as the nitrogen application increasing in both NT and CT,only seed set decreased,while the panicles,dry matter accumulation before and after heading,total dry mater accumulation,apparent transportation amounts and ratio of dry matter in stems and leaves,plant height,dry matter per stem,spike-leaf ratio,root activity and yield increased.The level of 193.0 kg/hm~2 nitrogen gained significant higher grain yield than that of 127.5 kg/hm~2 nitrogen.Comparing with NT,the CT obtained more panicles and greater spike-leaf ratios,but lower of total dry mater accumulation,apparent transportation amounts and ratios of dry matte in stems and leaves,plant height,dry matter per stem,root activity and bleeding potential in neck of panicle.Suggesting that population quality of cast transplanting rice under no-tillage is a little better than that under conventional tillage.Yield were not significant different between NT and CT.

早季在田间用管栽试验对免耕水稻和常耕水稻的若干生理特性进行了比较。证实了免耕水稻前期特别是抛栽后的禾苗生长慢的现象,免耕水稻在生育中后期表现出较强的生理优势。与常耕抛栽水稻相比,生育前期免耕抛栽水稻的游离氨基酸、酸性和中性转化酶活性及光合速率较小,生育中后期则提高了叶片游离氨基酸、光合速率和叶绿素含量及硝酸还原酶、酸性和中性转化酶及茎鞘可溶性糖、淀粉含量和籽粒可溶性糖和可溶性蛋白含量,而在成熟期的叶片叶绿素含量、光合速率、酸性和中性转化酶活性、硝酸还原酶和籽粒可溶性蛋白含量与常耕水稻的差异显著。

大田条件下,在晚季对免耕抛秧、常耕抛秧、稻草还田免耕抛秧和稻草还田常耕抛秧的立苗速度与立苗期的根系生长及其产量进行了比较。结果表明,免耕抛秧比常耕抛秧增产7.64%,稻草还田免耕抛秧与稻草还田常耕抛秧产量差异不大,但分别比常耕抛秧高10.72%和8.22%。免耕抛栽秧苗前期立苗速度较慢,后期立苗速度较快,总的立苗时间较常耕抛栽秧苗多1 d。免耕使立苗期根系及分枝数量、根系的总长度和根毛区长度及根系氧化能力下降。但是,稻草还田增加了立苗期根系及分枝数量和根系长度,提高了根系氧化能力,因而对抛栽水稻立苗有很好的促进作用,其促进作用在免耕条件下更明显。

对连续免耕2年的稻田,分层测定其土壤微生物数量、酶活性和理化性状。结果表明,免耕降低了土壤中细菌、好气性固氮菌的数量和土壤多酚氧化酶的活性,但增加了土壤中放线菌、真菌、嫌气性固氮菌、厌气性纤维分解菌的数量,并提高了土壤蔗糖转化酶、脲酶的活性;免耕2年后土壤容重和非毛管孔隙度下降,土壤总孔隙度略有增加,土壤中碱解N、有效P和速效K及土壤有机质含量上升。

After plastic tubes were buried in field,early rice under no-tillage(NT) and conventional tillage(CT) was planted in the tubes in 2004,and some physiological characteristics of rice were compared.The results showed that the amino acids content,acid and neutral invertase activities,and photosynthetic rate of no-tillage rice were lower as compared with the conventional tillage rice in early period.But the amino acids and chlorophyll contents,photosynthetic rate,and the NRA,acid invertase and neutral invertase activities in leaf of no-tillage rice were higher than that of conventional tillage rice in middle and late growth stages,as well as the contents of soluble sugar and starch in stems and sheaths,and the contents of soluble sugar and soluble protein in grain.At the maturing stage,the differences of the chlorophyll contents, photosynthetic rate,and the NRA,acid invertase and neutral invertase activities of leaf and the contents of soluble protein in grain were significant.

早季在田间用管栽试验对免耕水稻和常耕水稻的分蘖发生、成穗和结实特性进行了比较。结果表明,免耕水稻分蘖发生和成穗数分别比常耕水稻多8.12%和6.40%,分蘖优势明显。免耕水稻的分蘖优势主要表现在低位优势,其3~5节位分蘖发生数、分蘖成穗数及籽粒产量均比常耕水稻的高,其3~5节位单株一次分蘖发生数、成穗数及籽粒产量的增加量分别占全部节位单株一次分蘖数、成穗数及籽粒产量的增加量的75.00%,155.56%和146.91%。

以常耕抛栽水稻为对照,从叶面积大小、剑叶光合速率与衰老、库的大小及源库比率等方面研究了免耕抛栽水稻的源库特性。结果表明,与常耕抛栽水稻相比,免耕抛栽水稻各生育期的叶面积指数和叶片干物质分配比率较大,抽穗后叶片衰老较慢,光合能力强,有利于干物质生产与积累,免耕抛栽水稻的粒叶比较高。因此,免耕抛栽水稻的源库协调能力较强,有利于获得比常耕抛栽水稻更高的产量。

硅素和氮素是水稻正常生长必需的两大营养元素.水稻氮肥的施用技术及氮肥对水稻产量和品质的影响已有大量的研究[1-5].结果表明,适宜的氮素施用量和施肥时期,可以提高抽穗期群体源库质量和群体成穗率,形成高势粒比群体而高产;氮肥施用量对水稻的品质也会产生一定的影响,但不同品种对氮素施用量的反应不同.

2004年晚季在大田条件下,对免耕抛秧、常耕抛秧、稻草还田免耕抛秧和稻草还田常耕抛秧的立苗速度与立苗期的根系生长及其产量进行了比较.结果表明,免耕抛秧比常耕抛秧增产7.64%,稻草还田免耕抛秧与稻草还田常耕抛秧产量差异不大,但分别比常耕抛秧高10.72%和8.22%.免耕抛栽秧苗前期立苗速度较慢,后期立苗速度较快,总的立苗时间较常耕抛栽秧苗多1d.免耕使立苗期根系及分枝数量、根系的总长度和根毛区长度及根系氧化能力下降.但是,稻草还田增加了立苗期根系及分枝数量和根系长度,提高了根系氧化能力,因而对抛栽水稻立苗有很好的促进作用,其促进作用在免耕条件下更明显.

2003年早季和晚季在大田条件下,以常耕抛栽为对照,对金优253免耕抛栽秧苗的根系生长与立苗特性进行了研究.结果表明,与常耕抛栽秧苗相比,免耕抛栽秧苗前期立苗速度较慢,后期立苗速度较快,总的立苗时间相同,但免耕抛栽秧苗的立苗更易受不良气候的影响;免耕抛栽秧苗立苗期发根较多,但根系生长受阻,根系的总长度不及常耕抛栽秧苗;抛后1周内,抛栽秧苗根系活力经历了由低到高再到低的变化过程.当根系活性上升时,免耕抛栽秧苗上升速度慢;当根系活力下降时,免耕抛栽秧苗下降也慢.

In early and late seasons of 2001, 30 varieties were planted in the field experiments for determination ofnitrogen and silicon accumulation in plants. Results showed that there were highly significant correlation between nitrogenaccumulation and silicon accumulation with r of 0.7496**, 0.6046**, 0.7546** at tilling, heading and ripening stage at earlyseason respectively, and 0.7446**, 0.7758**, 0.8026** at tilling, heading and ripening stage at late season, respectively. Yetplant nitrogen content was not significantly related to silicon content. Plant nitrogen utilization was associated with thebalance of nitrogen, phosphorus, potassium and silicon accumulation, which were expressed by nutrient balance index(NBI) and nutrient deviation index (NDI). Nitrogen dry matter production efficiencies in rice varieties were positivelycorrelated with NBI and negatively correlated with NDI, but nitrogen accumulation in varieties was not related to NBI andNDI. In early season of 2002, a field experiment was carried out to study the influence of efficient silicon fertilizer on nitrogenuptake and utilization in two varieties selected from previous experiments in 2001. Results showed that efficient siliconfertilizer increased activities of GPT enzyme in leaves and Q enzyme in grains with enhanced nitrogen uptake, but decreasednitrogen dry matter production efficiency. Silicon rate had an obvious impact on decrease of Q enzyme activity during grainfilling, high silicon rate resulted in rapid decrease of Q enzyme activity.

Field experiments were conducted to study N uptake and utilization under different N rates and panicle fertilizerdistribution ratios (PFDR) and influence on grain yield and quality in three rice varieties. Results showed that high N rate increasedtotal N accumulation and reduced N production efficiency and N harvest index. Under the same N rate, greater PFDR increasedtotal N accumulation, N recovery efficiency, N transportation efficiency and decreased N production efficiency. Changes of Nuptake and utilization under different N management have an important influence on grain yield and quality. Increase of Naccumulation increased protein content in grains and effective panicles, but reduced seed setting rate. N dry matter productionefficiency increased with increase of seed setting rate, protein contents in grains and effective panicles reduced. N harvest indexincreased and chalky rice ratio and area enhanced, and effective panicles reduced.

研究了30个水稻品种氮素吸收、利用与硅素积累的关系及高效硅肥对2个水稻品种氮素吸收与利用的影响.结果表明,水稻品种氮素积累量与硅素积累量呈极显著正相关,但氮素含量与硅素含量的相关性不显著.水稻品种的氮素干物质生产效率(NDMPE)与其体内N、P、K、Si积累的平衡有关,NDMPE与养分平衡指数呈显著正相关,与养分偏离系数呈显著负相关,但氮素吸收量与养分平衡指数和养分偏离系数的相关不显著.硅肥提高了叶片GPT转氨酶和籽粒淀粉分支酶(Q酶)活性,从而促进了水稻对氮素的吸收,但其NDMPE却随氮素积累量的增加而降低.施硅水平对灌浆期籽粒Q酶活性的下降速度产生重要影响,施硅水平愈高,Q酶活性下降愈快.