Water management options based on rainfall analysis for rainfed maize (Zea mays L.) production in Rushinga district, Zimbabwe

Maize (Zea mays L.), the dominant and staple food crop in Southern and Eastern Africa, is preferred to the drought-tolerant sorghum and pearl millet even in semi-arid areas. In semi-arid areas production of maize is constrained by droughts and poor rainfall distribution. The best way to grow crops in these areas is through irrigation, but limited areal extent, increasing water scarcity, and prohibitive development costs limit the feasibility of irrigation. Therefore, there is need for a policy shift towards other viable options. This paper presents daily rainfall analysis from Rushinga district, a semi-arid location in Northern Zimbabwe. The purpose of the rainfall analysis was to assess opportunities and limitations for rainfed maize production using 25 years of data. Data was analysed using a variety of statistical methods that include trend analysis, t-test for independent samples, rank-based frequency analysis, Spearman's correlation coefficient and Mann-Whitney's U test. The results showed no evidence of change in rainfall pattern. The mean seasonal rainfall was 631 mm with a standard deviation (SD) of 175 mm. December, January and February consistently remained the major rainfall months. The results depicted high inter-annual variability for both annual and seasonal rainfall totals, a high incidence of droughts ≥3 out of every 10 years and ≥1 wet year in 10 years. Using the planting criteria recommended in Zimbabwe, most of the plantings would occur from the third decade of November with the mode being the first decade of December. This predisposes the rainfall to high evaporation and runoff losses especially in December when the crop is still in its initial stage of growth. On average 5 to more than 20 days dry spells occupy 56% of the rainy season. Seasonal rainfall exhibited negative correlation (P < 0.001; R = −0.746) with cumulative dry spell length, and wet years were free from dry spells exceeding 20 days. The most common dry spells (6-10 days), are in the range in which irrigated crops survive on available soil water. Therefore, they can be mitigated by in situ rainwater harvesting (RWH) and water conservation. The potential evapotranspiration of a 140-day maize crop was estimated to be 540 mm. Consequently, short season maize cultivars that mature in less than 140 days could be grown successfully in this area in all but drought years. However, sustainable maize production can only be achieved with careful management of the soil as a medium for storing water, which is essential for buffering against dry spells. To this end soil restorative farming systems are recommended such as conservation farming, in situ RWH techniques for dry spell mitigation and a cropping system that includes drought-tolerant cereal crops as for example sorghum and pearl millet, and perennial carbohydrate sources as for example cassava to provide stable crop yields.     

甘蔗叶干法厌氧发酵工艺研究

为实现甘蔗叶的能源化利用,采用干法厌氧发酵方法研究发酵原料总固体含量为20%时,不同接种量、草粪比以及发酵温度对甘蔗叶产气量和产甲烷的影响。结果表明：接种量在30%和40%时发酵可以正常启动,接种量为40%时总产气量最高,但发酵后期甲烷含量下降很快;草粪比为1∶1和2∶1时总产气量高,甲烷含量均在60%以上,产气效果明显好于草粪比为1∶0的处理组;发酵温度为35℃时,总产气量和甲烷含量最高,发酵温度为30℃和40℃时总产气量相差不大。甘蔗叶干法厌氧发酵产沼气效果较好的工艺参数为：接种量30%、草粪比1∶1和发酵温度35℃。各处理组在甲烷含量达到最高值之前,甲烷含量与发酵时间之间呈现很强的线性相关性。产气高峰过后,虽然日产气量明显下降,但气体中甲烷含量下降幅度不大。     

内蒙古东部区主要作物降水利用率与生产潜力研究

2000～2002年在内蒙古东部区四盟市开展了主要作物降水利用率与生产潜力的研究。经过3年的调查研究,建立了大豆、玉米等六大主栽作物的降水生产潜力模型,分析讨论了各地区不同作物降水资源的利用现状。     

固沙植物甘草与土地荒漠化探析

阐述了我国甘草资源分布现状以及甘草在干旱荒漠区的生态作用 ,指出实行围栏护育和人工种植 ,是保护甘草资源 ,恢复干旱半干旱荒漠地区生态平衡 ,防止土壤荒漠化的有效途径     

黄土区荒草地土壤水平衡的数值模拟

林草植被深层土壤干燥化是黄土高原地区生态环境建设过程中面临的重大科学问题。采用人工降雨的试验方法,对黄土高原沟壑区荒草坡地不同水文年土壤水平衡进行了数值模拟,结果表明:当植被覆盖率较高时,WAVES模型可以应用于荒草坡地土壤水平衡的模拟;土壤储水量的模拟结果与实测值趋势很吻合,但有关参数的取值还有待于进一步研究;荒草地土壤水分收支基本平衡所需的雨季降雨量和年总降雨量分别为507.0mm和747.6mm,分别高于黄土高原地区多年平均的雨季降雨量和年总降雨量,预示黄土高原地区干旱年和平水年土壤水分易收支负平衡,从而形成土壤干层。     

Characterization of Promising Apricot (<Emphasis Type="Italic">Prunus armeniaca</Emphasis> L.) Genetic Resources in Malatya,Turkey

The study here was conducted on nearly 12,000 apricot seedlings in the Malatya Region in the Eastern part of Turkey. This region is famous for its horticulture based mainly on apricot production and the Country's highest apricot production originates from this region. The flower and fruit characteristics of all populations, which include apricot seedlings, in the region were evaluated. Based on their horticultural performances, 13 genotypes were selected, of which seven were considered as apricots served in dried form and six as in table consumption form. Among the selected genotypes, the fruit weight ranged between 28.5 and 71.19 g, soluble solids ranged between 12.7 and 26.5%, while the range in total acidity was between 0.35 and 1.80% and fruit development period was between 87 and 183 days. To determine the selected genotypes performance in a similar environment, they were grafted on to 4-year-old rootstocks. The results from these combinations showed that there was some decrease, especially in fruit size and soluble solids, in the genotypes performance when compared to the results of the initial observations. Some differences were also detected in taste, fruit shape, pit shape, fruit flesh firmness, skin and flesh colors. The dry fruit yield was determined as 22.50–28.36% for the selected dry apricot genotypes. The dry fruit yield of all seven genotypes considered for dry consumption were similar to ‘Hacıhaliloğlu’ and higher than ‘Canino’, which were evaluated as control cultivars.     

添加乳酸菌和葡萄糖对苜蓿青贮品质的影响

初花期收获的苜蓿经过0h、8h和32h的晾晒(干物质含量分别为27.15%、38.45%、50.87%),添加不同含量的乳酸菌 葡萄糖(0、105cfu/g 20g/kg、106cfu/g 15g/kg、107cfu/g 10g/kg)进行青贮,其品质测定结果表明:无添加剂直接青贮时,苜蓿低水分(干物质含量为50.87%)青贮的效果最好,其青贮综合评定为82分;添加乳酸菌 葡萄糖青贮时,3种不同干物质水平中以凋萎苜蓿(干物质含量为38.45%)青贮后青贮料的青贮品质和综合评定最好;苜蓿较低干物质含量(27.15%)条件下,适中的乳酸菌和葡萄糖添加量(106cfu/g 15g/kg)可以得到最好的青贮效果和最高的综合评分;而在干物质含量为38.45%和50.87%条件下,乳酸菌和葡萄糖添加量为107cfu/g 10g/kg时,可以得到较好的青贮效果和最高的综合评分。     

喀斯特地区典型峰丛洼地旱季表层土壤水分空间变异性初探

土壤水分空间变异性研究在喀斯特地区生态环境的恢复和重建过程中具有重要意义。通过网格(5 m×5 m)取样,用地统计学方法研究了喀斯特洼地典型区域(150 m×50 m)表层土壤水分(0~5 cm和5~10 cm)的空间变异特征。结果表明:土壤水分在采样区内呈比较简单的斑块状分布,相同性质斑块与土被连续分布区和石丛集中分布区范围相当;半变异函数在不同性质斑块内呈现出截然不同的变异特征,在整个采样区内表现出各向异性;旱季洼地表层土壤水分主要受石丛和地形两个不同尺度的环境因素影响;土壤水分具有一定的尺度效应,半变异函数的变程随着最小采样间隔增大而增大;当研究区域存在多重尺度的变异结构时,需要根据研究的目的和精度确定合理的采样尺度。     

论南方红黄壤地区饲草开发利用的几种途径

本文在论述我国南方红黄壤地区的自然特征、社会经济、资源与环境现状的基础上，对如何开发利用该区饲草进行了探讨，指出保护和改善生态环境，积极实行林草结合、种养结合、粮草轮作和发展种草配套养鱼以及调制人工干草制品，是该区丘陵山地发展饲草的有效途径。