摘要
土壤并非一个匀质体,而是一个时空连续的变异体,具有高度的空间异质性。管理好土壤养分,进而合理施肥,是关系到我国农业可持续发展的重大技术问题。然而,目前我国土壤养分管理研究工作尚不深入,应用有关信息技术(GPS和GIS)与更能反应田间实际状况的地统计学方法研究较大区域范围内土壤养分空间变异仍处于起步阶段,尤其是把土壤养分空间变异与作物品质、产量结合起来的研究罕见报道。本研究应用现代先进技术与方法,选择仁怀茅台酒原料基地为试区,研究土壤养分的空间变异特征,探讨土壤空间特性与高梁品质、产量的关系,为发展适合我国小规模分散经营体制下的作物高产优质分区平衡施肥技术提供理论基础。主要研究结果如下:
1.土壤养分状况初步评价
应用土壤养分综合系统评价法测定了取自仁怀茅台酒原料基地耕层土壤样品的速效养分,及部分全量养分含量,采用传统统计方法评价了仁怀茅台酒原料基地土壤养分状况。
结果表明:贵州省仁怀市19个乡镇的土壤有机质含量普遍偏高。对于土壤有机质含量偏低的土壤,如合马等地,在作物种植上应适量补施有机肥,加强有机物质在轮作周期中的使用,底肥中加大有机肥料比例,做到用地与养地相结合。
合马、二合、九仓地区土壤碱解氮含量的不适宜值相对较大,也仅为29%,适当提高氮肥的用量。仁怀其它各地区土壤碱解氮的含量均较高,对于土壤氮的供应较丰富的土壤,要适当控制氮肥的施用。
九仓、沙滩、合马三个地区处于低水平磷含量的土壤分别占57%、60%、65%,生产中应适当补充一些磷肥。各地区土壤有效磷含量变幅较大,在施磷运筹上要区别对待。
仁怀地区土壤中有效钾的含量总体偏高,施钾肥对作物的产量和质量影响不十分明显,生产上应控制钾肥的施入比例。
仁怀市土壤pH值总体水平较高,有70%属中性及碱性土壤,且变异系数不大,可能与研究区水热条件相似有关。
基地土壤有效态微量元素含量均较高,且变异系数较大,土壤有效锰的变异系数高达108%,属强变异性。只有个别地区,如:中枢有42%比例的土壤,其有效锰在缺乏范围内;龙井、合马、茅坝、沙滩、九仓地区比例依此分别为57%、50%、41%、40%、28%的土壤,其有效铁在缺乏和很缺乏范围内。所以对于施用微量元素肥料必须有的放矢,因土因作物合理施用。以确保土壤养分均衡
试区全氮含量丰富,全磷、全钾缺乏。变异系数均属于中等变异性水平。
2.土壤养分的空间变异性
应用地统计学的半方差分析方法对仁怀茅台酒原料基地土壤养分含量的空间变异结构进行了分析和探讨。
结果表明:研究区域的土壤主要养分含量的最大相关距离均较大,在8.7～61.9km之间,表明研究区域土壤主要养分含量均在较大范围内存在着空间相关性。研究区域中土壤的有机质的块金值与基台值之比较低,为14.7%,说明影响有机质含量分布的结构性因素作用很强(如土壤形成因子),它们的变化主要由结构性因素控制,导致样点之间的空间自相关作用强。速效磷、有效铜、全磷、全氮、有效铁的块金值与基台值之比比较高,分别为94.8%、84.4%、82.7%、78.4%、77.0%,说明系统空间相关性很弱,人为活动对速效磷、有效铜、全磷、全氮、有效铁的影响程度很大,削弱了结构性因素造成的强的空间自相关作用。其它的元素的块金值与基台值之比都在25%-75%之间,为中等强度的空间相关性,表明这些性质的空间变化是结构性因素(如土壤形成因子)和随机性因素(施肥、耕作措施、种植制度等)共同作用的结果。
3.土壤养分的空间格局
应用地统计学的Kriging差值法,对土壤养分含量的空间分布特征进行了研究。
结果表明:试区各种主要养分含量一般呈斑块状分布。土壤有机质含量的分布与土壤碱解氮、全氮、速效磷、全磷及微量元素有效态锌、铜、铁含量的分布均有极显著的正相关关系,表明有机质的积累和分解速率对土壤全氮、全磷的储积及碱解氮、速效磷、土壤微量元素的分布具有重要的影响。土壤中全氮和碱解氮、全磷和速效磷、全钾和速效钾的含量分布也均呈现极显著的正相关关系。全氮和碱解氮与速效钾、全磷、速效磷之间;速效钾与全磷、速效磷之间也存在着显著的正相关关系,说明土壤中的各种养分均存在着一定的空间相关性。pH值与全钾、速效钾存在着明显的正相关关系,相关系数分别为0.304~(**)和0.269~(**),可能是因为酸性土壤的淋溶作用强烈,钾容易流失;而pH值与有效锌、有效锰、有效铁呈极显著负相关,因为微量元素在酸性土壤中因可溶而有效性高。
试区土壤pH和全钾含量在不同土层深度上差别不大。而有机质、碱解氮、速效磷、速效钾、全氮、全磷的含量则呈现较明显的垂直分布规律,总的趋势是0～20cm土层养分含量明显高于20～40、40～60和60～80cm土层,其中0～20cm土层速效磷含量数倍高于20～40、40～60和60～80cm土层,显示磷肥应尽可能深施,以提高下部土层磷素肥力,改善土壤磷素空间分布严重不均的状况,促进作物根系的正常生长和对养分的吸收。
4.作物品质与产量状况评价
根据酒用高粱品质标准,对仁怀茅台酒原料基地高粱品质及产量状况作以评价。
结果表明:茅台原料基地高粱的总淀粉含量平均值在71.79%,支链淀粉占总淀粉含量的78.9%。酿酒高粱籽粒的蛋白质含量不宜过高,一般以8%～10%为宜,茅台原料基地酒用高粱蛋白质含量平均值在10.29%,在这个适宜值范围内的比例为39%。单宁一般以0.5%～2.0%较为适宜,基地酒用高粱单宁平均含量在2.05%,在这个适宜值范围内的比例为44%。
仁怀茅台酒用高粱亩产平均值为314.58公斤,变幅为198～406公斤,变异系数为14.51%。其中,坛厂地区的高粱平均亩产量最高,为363.54公斤,而且变异系数也相对偏小,为5.17%,产量相对比较稳定;三合地区的高粱平均亩产量最低,为263.25公斤,且变异系数相对较大,为13.7%。产量高的地区其稳定程度也相对偏高;产量低的地区其稳定程度也相对交差,可能与各个地区的土壤类型与养分状况有关。
5.土壤空间特性与作物品质、产量的关系
通过对土壤空间特性因子与作物品质、产量进行相关分析而得到的结果表明:代表酒用高粱整体品质的一些指标在较大程度上受着土壤自然养分状况的影响。土壤pH值与高梁支链淀粉比重呈显著的负相关,偏相关系数为-0.186~*,说明酸性土壤有利于高梁支链淀粉含量的蓄积。土壤速效磷与高粱支链淀粉比重的偏相关系数分别为:-0.156~*;土壤碱解氮与淀粉呈极显著负相关,偏相关系数为-0.259~(**)。本研究通过高粱品质、产量指标与土壤空间特性因子的两种相关性分析可以看出,高粱产量及各品质指标大小分别受土壤空间特性因子的共同影响,而非单一作用,只是作用大小与方向不同。
海拔高度与高粱中单宁、淀粉均呈正相关;海拔高度与支链淀粉比重呈负相关,但相关性不是很明显,相关系数分别为:0.066、0.072和-0.093。
海拔高度与高粱中蛋白质含量、产量的相关性相对比较复杂,高粱蛋白质含量和产量均随着海拔的升高有先增多后降低的趋势。
海拔高度低于870m样地的高粱,其蛋白质含量和海拔高度呈显著正相关,相关系数为0.263~*;海拔高度大于870m样地的高粱,其蛋白质含量与海拔高度呈负相关,相关系数为-0.111。海拔高度低于960m样地的高粱,其产量和海拔高度呈极显著正相关,相关系数为0.262~(**);海拔高度在960m到1250m之间样地的高粱,其产量和海拔高度呈正相关,相关性不是很明显,相关系数为0.027;海拔高度大于1250m样地的高粱,其产量和海拔高度呈显著负相关,相关系数为-0.811~*。这与太阳辐射量、有效积温、昼夜温差、空气湿度以及土壤类型、养分有效性等常随海拔高度的变化而发生显著变化有关,海拔高度正是集成了多种生态因子而影响作物的品质和产量。
Soil is not a homogeneous body, but a continuous space-time variant, with a high degree of spatial heterogeneity. To manage soil nutrients well and reasonable fertilization is major technical which is related to the sustainable development of agriculture. However, soil nutrient management is not yet in depth research in China, study the scope of a larger regional spatial variability of soil nutrients that application of the information technology (GPS and GIS) and statistical methods which is better response to the actual situation of the field is still in its infancy. Researches that combined spatial variability of soil nutrients to crop quality and yield was rarely reported. In this study, modern advanced technology and methods were applied, characteristics of spatial variability of soil nutrient and the relationship between spatial variability of soil nutrient and quality and yield of broomcorn were studied in the Maotai Renhuai raw materials base, in order to provide theoretical basis for the balance fertilization technology of high yield and quality of crop under China's small-scale decentralized management system. The main results were as follows:
1. A preliminary assessment of soil nutrient
The available nutrient and some total nutrient content from tilth soil samples of raw materials base were determined. Soil nutrient status of raw materials base was evaluated by the traditional statistical methods.
The results showed that: 19 towns with high soil organic matter content of Renhuai City, Guizhou Province. Some towns with low soil organic matter content like Hema. Organic fertilizer should be adequate up in those soils to strengthen the organic material in the rotation cycle, the use of fertilizer in increasing the proportion of organic fertilizers, so the land and raise land combination.
The unsuitable value of soil nitrogen content in Hema Erhe and Jiuchang is relative high; it is 29%, an appropriate increase in the amount of nitrogen fertilizer. Total nitrogen level is high in the rest areas of Renhuai, it is necessary to properly control the application of nitrogen fertilizer in those areas which have high nitrogen.
The amount of low level in phosphorus, respectively, 57%, 60%, 65%, in Jiuchang, Shatan, Hema. More phosphorus is needed in those areas in yielding. Soil available phosphorus content of the large variation, operations should be treated differently.
Content of effective potassium is overall high. Add potassium has no obvious effect on crop yield and quality .potash fertilizer should be control in yielding. pH of soil is higher, 70% are neutral or alkaline soil, and coefficient of variation is small, may be related to of the similar hydro-thermal conditions in study area.
Effective trace elements in soil are higher, with a high coefficient of variation, soil effective coefficient of variation of manganese up to 108%, which is strong variability. There were a few isolated areas, such as: the ratio of the Zhongshu 42% of the soil, in the absence of an effective framework of manganese; Longjing, a horse, Mau dam, Shatan, Jiuchang area and so the proportion of 57%, 50%, 41%, 40 %, 28% of the soil, its iron in the absence of an effective and very lack of range. So for the trace element fertilizer application must be targeted, because of soil due to application of a reasonable crop, to ensure soil nutrient balance.
Test area rich in total nitrogen, total phosphorus, but total potassium is lack. Coefficients of variation are the middle level of variability.
2. The spatial variability of soil nutrients
Spatial variability of soil nutrient content in raw materials base was analyzed by the semi-variance of statistical methods, the results showed that:
The most relevant content of main nutrients in the soil of in study area is large, between 8.7 km and 61.9km, showed that spatial correlation of soil nutrient content were mainly in the larger scope. the ratio of the block of soil organic matter and the base gold value is relatively low, 14.7 percent for a description of factors influencing the distribution of organic matter content of the strong role of structural factors (such as soil formation factor), changes in their control by structural factors , resulting in samples between the role of strong spatial autocorrelation. The ratio of Available P and effective copper, total phosphorus, total nitrogen, iron nugget effective the block of soil organic matter and the base gold value is higher, respectively, 94.8%, 84.4%, 82.7%, 78.4%, 77.0%, that of space-related is Weak, impact of man activities on the available P and effective copper, total phosphorus, total nitrogen, the effective iron is large, it weaken the structural factors of the strong role of spatial autocorrelation. the ratio of Other elements of the block of soil organic matter and the base gold value is between 25% -75%,its moderate intensity of space-related, and that these changes result from the nature of the space is a structural factors (such as soil formation factor) and the stochastic factors (fertilization, cultivation measures, cropping systems, etc.).
3. The spatial pattern of soil nutrients
characteristics of the spatial distribution of the nutrient content of soil were studied by Kriging Geostatistics difference method, the results showed that: the nutrient content distribution in test area was dollop shape. The distribution of soil organic matter content and the distribution of soil nitrogen, total nitrogen, available phosphorus, total phosphorus and trace elements in effective state of zinc, copper, iron content are significant positive correlation, it is showed that the accumulation of organic matter decomposition rate has an important role on the distribution of soil total nitrogen, total phosphorus and storage of nitrogen, available phosphorus, trace elements in soils. The total and available contents on nitrogen phosphorus potassium in soil Showed significant positive correlation, the description of the various nutrients in the soil there are a certain amount of space related to each other. pH and total K, available K there is a clear positive correlation , the correlation coefficients were 0.304** and 0.269**, indicate that more acid enhanced inhibition activity of potassium and total potassium in soil; pH have negative correlations with effective zinc, manganese effective, efficient iron, it showed that the effectiveness of trace elements in alkaline soils is poor.
Test soil pH and total potassium content in different soil depth is not very different. but organic matter, nitrogen, available phosphorus, potassium, total nitrogen, total phosphorus content with a pronounced vertical distribution, the general trend is soil nutrient content was significantly decrease while the depth increase, in which 0 - 20cm of soil available phosphorus content is several times higher than the 20 - 40, 40 - 60 and 60 - 80cm soil layer, indicating deep fertilizer should be incentives to upgrade the lower part of soil phosphorus fertility to improve the spatial distribution of soil phosphorus status of severe inequality, and promote the normal crop root growth and absorption of nutrients.
4. Evaluation of Crop's quality and yield
Evaluation was made in the Crop's quality and yield of Maotai Renhuai raw materials base in the terms of quality standards of broomcorn.
The results showed that the total starch content of 71.79% in average in sorghum, the total amylopectin starch content of 78.9%. Wine protein content of grain sorghum should not be too high, generally 8% - 10% is better, and the average protein content of sorghum is 10.29% in Maotai base materials, in the appropriate value's ratio is 39%. Tannins content appropriate value generally 0.5% - 2.0%. Tannins content of sorghum with an average of 2.05 percent, and in the appropriate value's ratio is 44% in Maotai base materials. Maotai Renhuai with average yield of sorghum 314.58 kilograms, varying from 198 - 406 kilograms, the coefficient of variation was 14.51%. Among them, the Tanchang area of the sorghum plant yield is the highest ,average for the 363.54 kilograms, and with relatively small coefficient of variation for 5.17%, the output is relatively stable; Sanhe region of sorghum yield is the lowest, average for the 263.25 kilograms, and the coefficient of variation relatively large, 13.7%, Also with High output level and its relatively high stability; those areas with low production that its stability is low too, may be resulted from the various regions of the soil type and nutrient status.
5. relationship between Spatial characteristics of soil and crop's quality and yield
correlation analysis between factors of Spatial characteristics of soil and crop quality, yield showed that the representative indexes of quality of sorghum liquor have been impacted by natural soil nutrient status. Soil pH and the proportion of sorghum amylopectin showed significant negative correlation, partial correlation coefficient was -0.186*, it showed that acid soil is conducive to sorghum amylopectin content of the accumulation. available P and the proportion of sorghum amylopectin, soil nitrogen and starch all showed a significant negative correlation, partial correlation coefficient are as follows: -0.156* and -0.259**; In this study, correlation among the indexes of sorghum's quality yield spatial characteristics was analyzed, sorghum and quality indicators of the size of the space by the soil characteristics were the common factor, rather than a single role, but the role of the size and direction of different.
Altitude and sorghum tannins or starch were positively correlated; Altitude and the proportion of amylopectin was a negative correlation, but correlation is not very obvious, the correlation coefficients are: 0.066,0.072 and -0.093.
The relevance of elevation and protein content with sorghum or its production is relatively complex, sorghum, protein content and yield were increased then decreased with the elevation has increased. In detail ,Less than 870m above sea level, the sorghum's protein content and the altitude was a significant positive correlation, a correlation coefficient is 0.263*; 870m above sea level, the sorghum's protein content and the altitude was a negative correlation, correlation coefficient is -0.111. Less than 960m above sea level, the sorghum's yield and elevation was highly significant positive correlation, a correlation coefficient of 0.262**; altitude of 960m to 1250m, the correlation between Sorghum's output and altitude is not obviously, the correlation coefficient is 0.027; 1250m above sea level, sorghum's yield and elevation was negatively correlated, correlation coefficient -0.811*. May be because of solar radiation, effective temperature, day and night temperature, air humidity and soil type, nutrient availability, such as regular changes with altitude and a significant change, and the altitude is the integration of a variety of ecological factors affecting the quality of crops and production.
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