不同深松年限对半干旱区土壤物理性质和玉米籽粒产量的影响

为构建合理耕层,促进半干旱区农业节本增效,在半干旱区开展了隔年深松、隔两年深松、连年深松与不深松做大区对比研究。结果表明:播种前,土壤孔隙度在0～10cm土层,隔两年深松、连年深松可以增加土壤孔隙度。在10～40cm时,隔年深松、隔两年深松、连年深松处理的土壤孔隙度与不深松处理比增加9.35%～16.97%、13.54%～30.82%、6.46%～8.18%。收获后,在0～40cm土层,隔年深松、隔两年深松、连年深松处理土壤孔隙度与不深松处理相比增加9.01%～13.61%、5.29%～20.92%、6.15%～16.42%。播种前,隔年深松、隔两年深松、连年深松处理土壤容重平均比不深松处理低0.012、0.066、0.097g·cm^(-3)。收获后,隔年深松、隔两年深松、连年深松处理土壤容重平均比不深松处理低0.14、0.17、0.15g·cm^(-3)。气相率对比隔两年深松处理>隔年深松处理>连年深松处理的趋势,说明随着深松年限和频率的增加,深松处理对降低固相率、提高气相比效果明显。深松可以提高玉米产量。隔年深松处理、连年深松处理、隔两年深松处理分别比不深松处理提高12.08%、10.50%和6.34%,其中隔年深松增产幅度最大。说明不同年限的深松处理均有增产效果,以隔年深松处理增产效果最好。

生物可降解地膜覆盖对干旱灌区玉米产量和水分利用效率的影响

为探索生物可降解地膜在河西干旱灌区的增温保水和增产效应,于2014年3-10月在甘肃省黄羊镇甘肃农业大学试验站进行田间试验,研究不同覆盖材料(普通地膜、生物可降解地膜、秸秆和无覆盖)对玉米产量和水分利用效率(WUE)的影响。试验结果表明,普通地膜覆盖和生物可降解地膜覆盖表层土壤温度较无覆盖分别提高1.2℃和0.9℃,秸秆覆盖较无覆盖降低0.4℃;玉米生育期土壤贮水量由高到低依次为普通地膜覆盖、生物可降解地膜覆盖、秸秆覆盖和无覆盖;与无覆盖相比,普通地膜覆盖、生物可降解地膜覆盖和秸秆覆盖玉米净光合速率分别提高32.68%、28.04%和9.33%,玉米籽粒产量分别提高14.84%、13.70%和8.35%,WUE分别提高25.52%、22.26%和13.75%。综上所述,从增温保水、增产和环保方面长远考虑,生物可降解地膜环保无污染,有利于环境和农业生态系统可持续发展,适合在该地区推广应用。

Impact of Nitrogen Fertilization on the Oil, Protein, Starch, and Ethanol Yield of Corn （Zea mays L,） Grown for Biofuel Production

Nitrogen fertilization is one of the greatest challenges associated with the production of biofuel from corn grain. The objective of this research was to determine the effect of N fertilization on the content and yield of oil, protein, and starch in corn grain. The project was done in Southeast Missouri （USA）, from 2007 to 2009 in a silt loam soil. Corn grain contains 3.8-4.2% oil, 6.7%-8.9% protein, 68.0%-70.4% extractable starch, and 76.0%-77.7% total starch. The total starch yield ranged from 2.8 to 7.8 mg.ha1 whereas the extractable starch varied between 2.5 to 7.1 mg-ha1. As the N rate went up, the oil and starch content of the grain decreased, whereas the protein content and the protein, starch, and oil yields increased, reaching their maximum at the N rate corresponding to 179.0 kg N.ha~. The potential ethanol yield varied between 616.2 and 7,035.1 L-ha1 depending on the method of conversion of the starch into ethanol, the year and the N rate （P 〈 0.0001）. The negative correlation between N fertilization rate and starch content suggested that when farmers add too much N to their soil to increase grain yield, they reduce the starch content in those grains, and consequently the conversion into bioethanol. Therefore, for biofuel production to be beneficial for both farmers and the power plant owners, an agreement needs to be made with regard to the use of fertilizers.

Genetic Variations and Gene Effect Controlling Grain Yield and Some of Its Components in Maize

Diallel cross analysis among seven diverse pure lines of maize, （IK8, IK58, ZP-707, OH40, UN44052, DKI7 and HS） with their nonreciprocal 21 crosses, were carried out for estimating the nature and magnitude of gene effects through component and graphic analysis for characters： number of days to tasseling, number of days to silking, plant height, ear height, number of rows per ear, number of grains per row, 300 grain weight and grain yield per plant. The results showed highly significant mean square of genotypes for all studied characters. Additive and dominance variances were found to be significant from zero for all the eight characters except number of days to tasseling and silking for which additive genetic variance was no significant. Dominance variance estimation was relatively higher than the additive variance for all characters. The graphic analysis suggested the presence of epistatic gene effects （non-allelic interaction） for number of days to tasseling, number of days to silking, plant height, number of grains per row and grain yield per plant. The estimates of narrow sense heritability varied from 1.85% for 300 grain weight to 49.88% for ear height, it was moderate in case of ear height and low for the remainder characters.