水基废弃钻井泥浆对粗质地土壤物理性质和甜菜生长的影响

为探讨水基废弃钻井泥浆作为粗质地土壤改良剂的可能性,研究施加不同量水基废弃钻井泥浆对土壤基本物理性质和作物生长的影响,利用室内甜菜盆栽试验,分别在沙黄土和黄绵土中添加2%、4%、8%、12%(干基)含量的水基废弃钻井泥浆,为缓解添加水基废弃钻井泥浆可能引发的土壤pH值过高问题,补充添加石膏处理,试验分为对照组、泥浆组和泥浆+石膏组。结果表明,不添加石膏情况下,两种土壤施加不同含量的废弃泥浆均没有导致土壤盐碱化,且黏粒相对含量增加,蒸散量减少。添加石膏后pH降低,盐分含量显著升高,阻碍了作物生长。从作物生长来看,两种土壤施加8%含量废弃泥浆对甜菜生长促进效果最佳,种植40 d后,沙黄土甜菜株高比对应的对照处理增加了41.59%,叶面积增加了2.43倍,生物量增加了3.54倍,叶片SPAD值增加了58.18%;黄绵土甜菜株高比对应的对照处理增加了1.75%,叶面积增加了32.03%,生物量增加了14.59%,叶片SPAD值增加了27.65%。研究表明,一定含量的废弃泥浆对于粗质地土壤改良和作物生长有促进作用,研究结果对油气田水基钻井废弃物就地利用和开采区粗质地土壤改良具有一定的借鉴意义。

Wheat Grain Yield and Yield Stability in a Long-Term Fertilization Experiment on the Loess Plateau

To provide a scientific basis for sustainable land management, a 20-year fertility experiment was conducted in Changwu County, Shaanxi Province, China to investigate the effects of long-term application of chemical fertilizers on wheat grain yield and yield stability on the Loess Plateau using regression and stability analysis. The experiment consisted of 17 fertilizer treatments, containing the combinations of different N and P levels, with three replications arranged in a randomized complete block design. Nitrogen fertilizer was applied as urea, and P was applied as calcium superphosphate. Fertilizer rates had a large effect on the response of wheat yield to fertilization. Phosphorus, combined with N, increased yield significantly (P < 0.01). In the unfertilized control and the N or P sole application treatments, wheat yield had a declining trend although it was not statistically significant. Stability analysts combined with the trend analysis indicated that integrated use of fertilizer N and P was better than their sole application in increasing and sustaining the productivity of rainfed winter wheat.

Phosphorus Changes and Sorption Characteristics in a Calcareous Soil Under Long-Term Fertilization

Knowledge of phosphorus(P)behavior in long-term fertilized soils is essential for programming fertilization practices and for sustaining environmental quality.The long-term(1984-1997)effects of various fertilization treatments on P changes and sorption isotherms as well as the relationship of soil properties to P sorption and P forms were evaluated in an Ustic Isohumisol,a calcareous soil,on the Loess Plateau,China.Compared to 1984,after 13 years of crop production,total soil P in the no-P treatments(control and N treatment)decreased by 5%-7%,but in the phosphorus fertilizer alone(P), nitrogen and phosphorus fertilizers in combination(NP),manure alone(M),and nitrogen and phosphorus fertilizers and manure in combination(NPM)treatments,it increased by 22%,19%,28%,and 58%,respectively.Residual fertilizer P was found mainly in NH_4Ac-soluble P(Ca_8-P),followed by NaHCO_3-soluble P(NaHCO_3-P),and NH_4F-soluble P (A1-P).Phosphorus sorption in the soils with different fertilization practices fit the Langmuir equations.Phosphorus sorption capacity in the no-P treatments increased,whereas it decreased in the P-included treatments(P,NP,and NPM treatments).Phosphorus sorption maximum(Q_m)was significantly and negatively correlated to inorganic P including NaHCO_3-P,Ca_8-P,NaOH-Na_2CO_3-soluble P(Fe-P),and Al-P(P≤0.01).Moreover,long-term fertilization increased soil organic carbon in the NP,M,and NPM treatments and decreased pH in the NP and NPM treatments.Thus,the ability of the soil to release sorbed P to the environment increased under long-term P fertilization.

Effect of Nitrogen Management on Yield and Water Use Efficiency of Rainfed Wheat and Maize in Northwest China

A field experiment with four treatments and four replicates in a randomized complete block design was conducted at the Changwu Experimental Station in Changwu County, Shaanxi Province, of Northwest China from 1998 to 2002. The local cropping sequence of wheat, wheat-beans, maize, and wheat over the 4-year period was adopted. A micro-plot study using 15N-labelled fertilizer was carried out to determine the fate of applied N fertilizer in the first year. When N fertilizer was applied wheat (years 1, 2 and 4) and maize (year 3) grain yield increased significantly (P<0.05) (>30%), with no significant yield differences in normal rainfall years (Years 1, 2 and 3) for N application at the commonly application rate and at 2/3 of this rate. Grain yield of wheat varied greatly between years, mainly due to variation in annual rainfall. Results of 15N studies on wheat showed that plants recovered 36.6%-38.4% of the N applied, the N remained in soil (0-40 cm) ranged from 29.2% to 33.6%, and unaccounted-for N was 29.5%-34.2%. The following crop (wheat) recovered 2.1%-2.8% of the residual N from N applied to the previous wheat crop with recovery generally decreasing in the subsequent three crops (beans, maize and wheat).

不同降水年型下长期施肥的小麦产量效应

合理施用氮磷化肥是提高小麦产量的主要措施之一.用二元二次回归方程探讨不同降水年型下的氮磷优化用量,为黄土旱塬小麦施肥提供依据.结果表明:不同降水年型小麦最高产量所需要的氮磷肥用量不同,平水年小麦最高产量4229 kg·hm^(-2)时的氮用量为172kg·hm^(-2)、磷用量164 kg·hm^(-2);丰水年最高产量4896 kg·hm^(-2)时,施氮量较平水年多2%,为175 kg·hm^(-2),施磷量较平水年少约1%,为162 kg·hm^(-2);干旱年施氮磷量较平水年少约16%和5%,当施氮磷量超出这个用量时,小麦产量开始呈下降趋势.不同降水年型最佳经济施肥量不同,平水年最佳经济施氮量为161 kg·hm^(-2)、施磷量为151 kg·hm^(-2);而干旱年的最佳氮、磷量为135、143 kg·hm^(-2);丰水年最佳经济氮、磷量分别较平水年多约3%和1%,为167、153kg·hm^(-2).最佳经济氮磷施用量比最高产量氮磷施用量低6%~8%.实际生产中建议氮磷减少10%的用量,提高肥料利用率,获得最大经济效益.