Maize Monocrop Research Articles

An Assessment of Rain Water Supply for Kenaf- Maize Intercrop

Understanding the advantage of crop water use in mixed crops over sole cropping is vital in developing optimum water management crop production in the tropical wet-and-dry climate. This study investigated water supply potential for the cultivation of kenaf (Hibiscus cannabinus L.) – maize (Zea mays L.) intercrop in of South-western Nigeria. The phenological stages of each of the crops formed the basis for the investigation. The experiment comprises of two varieties of kenaf (Tainung 1 and Ifeken400), one variety of maize (DMR-LSR-Y) and two planting season (early and late). Selected moisture indices were measured daily and processed into ten-day (dekad) average for the 2007 and 2008 cropping seasons following FAO. Descriptive statistics was employed for the analysis. Relating the effective water availability to the indices of moisture adequacy for the growth of the crop in sole and intercrop, it was found that the agro-climatic moisture indices were optimum during the moisture sensitive stages particularly for early season planting irrespective of cropping pattern. A comparison of maize and kenaf production in sole or intercrop in the study area showed that early planting promotes the growth, development and yield irrespective of planting season. Mono-cropping maize and kenaf performed better than intercropping. However, water supply in rain-fed agriculture was confirmed to be efficient for maize/ kenaf intercrop in South-western Nigeria.

Soil Quality Assessment Strategies for Evaluating Soil Degradation in Northern Ethiopia

Soil quality (SQ) degradation continues to challenge sustainable development throughout the world. One reason is that degradation indicators such as soil quality index (SQI) are neither well documented nor used to evaluate current land use and soil management systems (LUSMS). The objective was to assess and identify an effective SQ indicator dataset from among 25 soil measurements, appropriate scoring functions for each indicator and an efficient SQ indexing method to evaluate soil degradation across the LUSMS in the Mai-Negus catchment of northern Ethiopia. Eight LUSMS selected for soil sampling and analysis included (i) natural forest (LS1), (ii) plantation of protected area, (iii) grazed land, (iv) teff (Eragrostis tef)-faba bean (Vicia faba) rotation, (v) teff-wheat (Triticum vulgare)/barley (Hordeum vulgare) rotation, (vi) teff monocropping, (vii) maize (Zea mays) monocropping, and (viii) uncultivated marginal land (LS8). Four principal components explained almost 88% of the variability among the LUSMS. LS1 had the highest mean SQI (0.931) using the scoring functions and principal component analysis (PCA) dataset selection, while the lowest SQI (0.458) was measured for LS8. Mean SQI values for LS1 and LS8 using expert opinion dataset selection method were 0.874 and 0.406, respectively. Finally, a sensitivity analysis (S) used to compare PCA and expert opinion dataset selection procedures for various scoring functions ranged from 1.70 for unscreened-SQI to 2.63 for PCA-SQI. Therefore, this study concludes that a PCA-based SQI would be the best way to distinguish among LUSMS since it appears more sensitive to disturbances and management practices and could thus help prevent further SQ degradation.

Mitigation potential of soil conservation in maize cropping on steep slopes

Maize (Zea mays) cropping has greatly increased in Southeast Asia since the mid-1990s, mainly by expanding its production into steep forested uplands. This led to severe erosion, soil degradation, and strong environmental impacts. This study aimed at assessing the magnitude of erosion in maize and the mitigation potentiality of soil conservation measures in such environments. Bounded experimental plots established in two catchments of the Son La province of Northwest Vietnam were monitored during 2009–2011. Three soil conservation measures represented by Guinea grass (Panicum maximum) barriers, minimum tillage with Pinto peanut (Arachis pintoi) as a cover crop, and minimum tillage with relay cropping of Adzuki beans (Phaseolus calcaratus) were compared against the current farmers’ maize cropping practice based on slashing, burning, and ploughing. Additional on-farm measurements of soil loss on maize fields were made using sediment fences on six convergent unbounded fields in 2010 and 2011. Under farmers’ practice, annual soil losses of experimental plots reached up to 174tha−1, being higher than those from sediment-fence plots (up to 111tha−1). The pattern of erosion events, however, was similar in both methods. Most of the soil loss occurred in the first weeks after sowing or under maize mono cropping when high rainfall intensities coincided with a low percent ground cover of fields. Under the prevailing conditions (1270mm rainfall, inclination 53–59%), a very high ground cover is required to keep erosion rates low, which is hardly achievable by maize mono-cropping. Conservation measures had no effect on soil loss in the year of trial establishment as rainfall was low and erosive rains fell only when ground cover by plants was already high. From the second year after establishment of soil conservation measures, erosion was reduced by 39–84% in grass barriers or by 93–100% in simultaneous cover crop treatments. Maize yields, however, decreased by 26% in grass barriers or up to 35% in cover crop plots if Pinto peanuts were not cut on time. Both of these options provided animal feed, up to 5.5tha−1yr−1 dry grass or 1.8tha−1yr−1 dry biomass of Pinto peanuts. Guinea grass even yielded higher in 2010, a dry year with erratic rainfall distribution. Minimum tillage with relay cropping reduced soil loss by 94%, while providing similar maize yields as the controls. This latter practice is a win-win situation and, hence, attractive to farmers fostering its acceptance.

Intensification of conservation agriculture systems for increased livestock feed and maize production in Zimbabwe

Livestock and crops are key components of mixed farming systems and are a source of household food and income. However, mixed farming systems face livestock feed shortages and low soil productivity challenges. Conservation agriculture (CA) systems based on minimum soil disturbance, crop residue retention and crop rotations offer an opportunity to grow both fodder and food crops on the available land to improve productivity and crop output per-unit area. A four-year experiment involving maize monocropping as control treatment and four relay or intercropping treatments with different legume and fodder crops was set up on contrasting soils in Zimbabwe. Lablab was superior in biomass production compared with radish on both soil types. On the clay soil, continuous maize, sole lablab, sole radish, maize/lablab relay and radish/common beans relay treatments produced similar biomass when soil moisture was adequate. When soil moisture was limiting, lablab produced more biomass than continuous maize, radish, maize/lablab relay and radish/beans relay treatments on clay soil. On sandy soils, lablab produced more biomass than continuous maize, radish, maize/lablab relay and radish/beans relay treatments. Leguminous and non-leguminous fodder crops can be grown successfully in CA systems that are being promoted in the mixed crop/livestock farming systems of southern Africa.

Cumulative effects and economic benefits of intercropping maize with food legumes on Striga hermonthica infestation

The parasitic weed Striga hermonthica, commonly known as striga, is a major biotic constraint to maize production in sub-Saharan Africa (SSA) where it causes serious food insecurity and poverty in smallholder farming communities. We previously discovered an effective control method for it involving intercropping cereals with fodder legumes in the genus Desmodium, commonly known as desmodium. The objectives of the current study were to evaluate cumulative effects of intercropping maize with the commonly grown food legumes on striga infestation, and to establish any economic benefits of the same. Treatments comprised maize plots planted in monocrop stands or intercropped with five different food legume species or desmodium. Intercropping maize with desmodium gave the most consistent and significant suppression of striga. Out of the food legume intercrops, only crotalaria, groundnut and greengram intercrops had significantly lower striga counts and only in some of the cropping seasons. Grain yields were consistently and significantly higher with desmodium intercrop, although they were also increased with food legume intercrops compared to maize monocrop, thus confirming superiority of intercropping with legumes over maize monocrop. Although production costs in terms of total labor and variable costs were significantly higher for the intercrops than for the maize monocrop, total revenue and net benefits were significantly higher in the former, especially for desmodium. The desmodium intercrop gave the highest economic benefits followed by crotalaria and greengram intercrops. These results confirmed the effectiveness of desmodium in suppressing striga and improving yields and economic returns to smallholder farmers. They also showed that it is profitable to invest in food legume intercrop systems, especially the crotalaria and greengram systems, and indicate that intensifying maize cropping systems through integration of these food legumes in combination with other approaches can contribute to an integrated management of striga and provide a more sustainable and profitable productive system to smallholder farmers.

Dissolution of different zinc salts and Zn uptake by Sedum alfredii and maize in mono- and co-cropping under hydroponic culture

Previous soil pot and field experiments demonstrated that co-cropping the hyperaccumulator Sedum alfredii with maize increased Zn phytoextraction by S. alfredii and decreased Zn uptake by maize shoots. This hydroponic experiment was conducted to investigate whether the facilitation of Zn phytoextraction by S. alfredii resulted from improved dissolution in this co-cropping system and its relation to root exudates. S. alfredii and maize were mono- and co-cropped (without a root barrier) in nutrient solution spiked with four Zn compounds, ZnS, ZnO, Zn3(PO4)2 and 5Zn·O2CO3·4H2O (represented as ZnCO3) at 1000 mg/L Zn for 15 days without renewal of nutrient solution after pre-culture. The root exudates were collected under incomplete sterilization and analyzed. The results indicated that the difference in Zn salts had a greater influence on the Zn concentration in maize than for S. alfredii, varying from 210–2603 mg/kg for maize shoots and 6445–12476 mg/kg for S. alfredii in the same order: ZnCO3 > ZnO > Zn3(PO4)2 > ZnS. For the four kinds of Zn sources in this experiment, co-cropping with maize did not improve Zn phytoextraction by S. alfredii. In most cases, compared to co-cropped and mono-cropped maize, mono-cropped S. alfredii resulted in the highest Zn2+ concentration in the remaining nutrient solution, and also had a higher total concentration of low molecular weight organic acids (LMWOA) and lower pH of root exudation. Root exudates did partly influence Zn hyperaccumulation in S. alfredii.

Exploring Maize-Legume Intercropping Systems in Southwest Mexico

Maize yields in continuous maize production systems of smallholders in the Costa Chica, a region in Southwest Mexico, are low despite consistent inputs of fertilizers and herbicides. This study was aimed at investigating the prospects of intercropping maize (Zea mays L.) and maize-roselle (Hibiscus sabdariffa L.) mixtures with the legumes canavalia (Canavalia brasiliensis Mart. ex Benth) and mucuna (Mucuna pruriens var. utilis) for improving nutrient uptake and weed suppression. Farmer-managed experiments were established in two communities in the region during 2006 and 2007 using randomized split-plot designs. Maize monocrops and maize-roselle intercrops grown with different sources of nutrients were intercropped with both legume species, sown 4–6 weeks after maize. Neither the legumes decreased yields of maize nor roselle, whereas they caused a reduction of the weed biomass by 24–55%. Total aboveground biomass returned to the soil increased up to 36% and total N, P, and K uptake was increased on average by 52%, 24%, and 30%, respectively. Legumes acted not only as a N-fixing crop, but also as a “catch” crop, preventing N and K leaching. With its prostrate growth habit and adaptation to poor soil conditions, canavalia demonstrated agronomic advantages in comparison to mucuna.

Maize grain concentrations and above-ground shoot acquisition of micronutrients as affected by intercropping with turnip, faba bean, chickpea, and soybean

Most research on micronutrients in maize has focused on maize grown as a monocrop. The aim of this study was to determine the effects of intercropping on the concentrations of micronutrients in maize grain and their acquisition via the shoot. We conducted field experiments to investigate the effects of intercropping with turnip (Brassica campestris L.), faba bean (Vicia faba L.), chickpea (Cicer arietinum L.), and soybean (Glycine max L.) on the iron (Fe), manganese (Mn), copper (Cu) and zinc (Zn) concentrations in the grain and their acquisition via the above-ground shoots of maize (Zea mays L.). Compared with monocropped maize grain, the grain of maize intercropped with legumes showed lower concentrations of Fe, Mn, Cu, and Zn and lower values of their corresponding harvest indexes. The micronutrient concentrations and harvest indexes in grain of maize intercropped with turnip were the same as those in monocropped maize grain. Intercropping stimulated the above-ground maize shoot acquisition of Fe, Mn, Cu and Zn, when averaged over different phosphorus (P) application rates. To our knowledge, this is the first report on the effects of intercropping on micronutrient concentrations in maize grain and on micronutrients acquisition via maize shoots (straw+grain). The maize grain Fe and Cu concentrations, but not Mn and Zn concentrations, were negatively correlated with maize grain yields. The concentrations of Fe, Mn, Cu, and Zn in maize grain were positively correlated with their corresponding harvest indexes. The decreased Fe, Mn, Cu, and Zn concentrations in grain of maize intercropped with legumes were attributed to reduced translocation of Fe, Mn, Cu, and Zn from vegetative tissues to grains. This may also be related to the delayed senescence of maize plants intercropped with legumes. We conclude that turnip/maize intercropping is beneficial to obtain high maize grain yield without decreased concentrations of Fe, Mn, Cu, and Zn in the grain. Further research is required to clarify the mechanisms underlying the changes in micronutrient concentrations in grain of intercropped maize.

Dynamics of root length and distribution and shoot biomass of maize as affected by intercropping with different companion crops and phosphorus application rates

Maize-based intercropping, especially with legumes, can result in overyielding of the whole cropping system and lead to efficient utilization of soil phosphorus (P). Field experiments were conducted in 2010 and 2011 to investigate the mechanisms behind overyielding of maize via root length and distribution in intercropping systems and how P application and companion crops may influence the process. The main plots received P applications of 0, 40, and 80kgha−1 and the sub-plots comprised maize (Zea mays L.) intercropped with turnip (Brassica campestris L.), faba bean (Vicia faba L.), chickpea (Cicer arietinum L.), or soybean (Glycine max L.), and monocropped maize. At turnip harvest and maize at stem elongation, total root length, growth space and corresponding shoot biomass (on a per plant basis) of maize intercropped with turnip, faba bean and chickpea were suppressed, especially in maize/turnip intercropping. Roots of maize and associated crops can intermingle with each other and the stronger the associated roots, the more depressed will be the corresponding maize root development and shoot biomass. At faba bean and chickpea harvest and maize at tasseling, total root length, growth space and corresponding shoot biomass of intercropped maize recovered to the same values as monocropped maize on a per plant basis. At soybean harvest and maize at grain-filling stage, total root length, growth space and shoot biomass of maize intercropped with turnip, faba bean, chickpea and soybean surpassed those of monocropped maize and showed overyielding and later maturity phenomena until harvest on a per plant basis. Total root length of maize on a per plant basis in the top 100cm of the soil profile at stem elongation and in the top 30cm at grain-filling stage and the shoot biomass of maize from stem elongation to grain-filling stage and at harvest were sensitive to P application. There were no interactions between P application rate and cropping system. A ‘competition–recovery–overyielding’ process was found in the dynamics of root length, distribution and corresponding shoot biomass of maize intercropped with turnip, faba bean and chickpea and the dynamics of root length and distribution correlated well with the corresponding shoot biomass of maize.

Maize Biomass Production, N-Use Efficiency and Potential Bioethanol Yield, Under Different Cover Cropping Managements, Nitrogen Influxes and Soil Types, in Mediterranean Climate

To evaluate the effect of cover cropping faba bean with maize, compared to maize monocrop cultivation, on yield (dry matter), nitrogen utilization efficiency (NUE) and N fertilizer recovery fraction of maize, field experiments were carried out over a period of three years. Experimental sites were located in central Greece, on a fertile, clayey soil and on a sandy soil of moderate fertility, A factorial combination of four nitrogen dressings (0, 80, 160, 240 kg ha-1) and three legume treatments (incorporated into the topsoil or harvested before the sowing of maize and mono-cropping) were tested in a split plot design in three blocks. Results showed a substantial importance of the legume cover crop for both soil types, for all studied factors. Maize total dry biomass yield fluctuated from 13.4 to 20.3 Mg ha-1 for the control plots, from 15.1 to 21.6 Mg ha-1 when faba bean was harvested and from 15.3 to 22.4 Mg ha-1 when incorporated, for clayey soil and from 12.4 to 16.9 Mg ha-1 for the control plots, from 14.9 to 19.4 Mg ha-1 when faba bean was harvested and from 14.5 to 19.6 Mg ha-1 when incorporated, for sandy soil. The NUE was estimated at 56 kg kg-1 and 55 kg kg-1 for clayey and sandy soil, respectively. The N recovery fraction was enhanced by 10-15% after faba bean cover cropping, for both soil types. Such systems should be seriously considered in future land use planning, with respect to the sustainable cultivation of maize.

Agroforestry Impacts on Soil Fertility in the Rima'a Valley, Yemen

Yemen is one of the world's least developed countries and experiences problems of scarcity of natural agricultural resources as well as soil erosion and degradation. Agroforestry systems (AFS) are being promoted as a more appropriate land use system than monocropping systems (MCS) worldwide. Unfortunately, long-term studies on agroforestry and other land use systems (LUS) do not exist in Yemen. Agroforestry in the Rima'a region has started to deteriorate and many farmers turned to (MCS). This study was conducted in the Rima'a Valley, near Alsharq town, Dhamar, Yemen. The study evaluates the soil nutrients, organic matter (OM), and other soil properties such as pH, bulk density, and porosity under AFS and compares it with soil under MCS. Standard procedures for soil sampling and analyzing were used to collect and analyze 36 composite samples from Site 1 and 36 composite samples from Site 2 from six cropping systems (treatments). The results showed that there were significant variations in relation to LUS. Agroforestry practices—mixed trees with coffee (S1), and Cordia africana L. with coffee (S2) have higher nitrogen concentration (0.17–0.26%) as compared to the Ziziphus spina-christi L. with maize (S3) and the monocropping maize (S5), (<0.16% in both Sites 1 and 2). Similar results were seen on the effect of the different LUS on the soil P, K, and OM contents at the two sites (p < .01). While soil N, P, and soil K were higher under agroforestry systems S1, and S2 in both sites, it was the lowest in S5 in both sites. It can be concluded that agroforestry has more favorable effects on soil fertility and other soil properties. The government should establish programs and campaigns to disseminate AFS technology and promote the importance of agroforestry in soil conservation.

Microbial attributes and carbon and nitrogen stocks in Latosol under monocropping and intercropping irrigated

Monocropping and intercropping maize and pasture irrigated areas in Promoting changes in soil biological attributes , However , little is known about changes in these environments ecotone between Cerrado and Caatinga . The aim of the study was to the evaluate attributes and microbial carbon and nitrogen stocks in soil under distrophic yellow Latosol of maize monocropping and intercropping and brachiaria of these cultures under two irrigation blades . The study was Conducted in the Alvorada do Gurgeia city , Piaui State , Brazil , During the year of 2009 the treatments Consisting of three production systems ( monocropping of maize and intercropping between maize and brachiaria and brachiaria ) , under two irrigation blades ( L1 = L2 = 647.9 and 564.5 mm ) and two soil depths ( 0-0.10 m and 0:10 to 0:20 ) . The variables were Analyzed microbial biomass , basal respiration , microbial quotient , metabolic quotient , the contents of total organic carbon , nitrogen and the carbon and nitrogen stocks . Biological attributes of the soil are influenced by monocropping and intercropping of maize and brachiaria , irrigation blades and soil depth . The blades of irrigation , by Influencing the water content in the soil , have greater effect on the microbial attributes , may Occur individually , as in the case of microbial carbon , or associated production systems of maize and intercropping brachiaria or under monocropping , is the detected of total organic carbon , and microbial metabolic quotient , nitrogen content and carbon and nitrogen stocks .

Dependence of the productivity of maize and soybean intercropping systems on hybrid type and plant arrangement pattern

Intercropping systems could improve utilization of the most important resources (soil, water and nutrients), provide a better control of weeds, pests and diseases, and finally higher productivity, especially under rain-fed growing conditions. This study aimed to determine the effects of three maize (Zea mays L.) prolific hybrids (FAO 500, 600 and 700) and the spatial intercrop patterns on the above-ground biomass and grain yields of maize and soybean (Glycine max L. Merrill), on chernozem soil type at Zemun Polje, Belgrade, in 2003, 2004 and 2005. The experimental design was a complete randomized block with four replications and three treatments: 3 rows of maize and 3 rows of soybean in strips for each maize hybrid (three variants, 3 rows of maize and 3 rows of soybean in alternate rows for each hybrid (another three variants) and monocrops of both maize and soybeans. To optimize the ecological and economic benefits of maize/soybean intercrop in terms of yield, variety selection and compatibility of the component crops should be made using established agronomic management practices involving the two crops. Suitable maize varieties for maize/soybean intercrop systems are varieties that have less dense canopy. These varieties would therefore have lesser shading effect to the understory beans. However, establishment of an appropriate spatial arrangement of the component crops would be essential to alleviate negative effects especially on the less competitive crop. The intercropping system in alternate rows showed significantly higher above-ground biomass and grain yields in comparation with both the strip intercropping system and maize monocrops in 2004. Soybean gave significantly lower above-ground biomass and grain yield in intercrops than in monocrops. Maize prolific hybrid growing in intercropping with soybean as legume crop, increased productivity of cropping system, especially in favourable agroecological conditions. Maize and soybean yields reduction could have also been due to interspecific competition for resources such as nutrients and water. Moreover, performance of the currently grown varieties in the semi-arid regions depends on the amount of rainfall received during the growing season.

Rhizosphere properties in monocropping and intercropping systems between faba bean (Vicia faba L.) and maize (Zea mays L.) grown in a calcareous soil

The processes involving pH modification, carboxylate exudation and phosphorus (P) dynamics in the rhizosphere of crops grown in intercropping are poorly understood. Two groups of maize (Zea mays L.) or faba bean (Vicia faba L.) plants (monocropping) or one group of plant of each species (intercropping) were grown between three 1-mm-thick soil layers; the central soil layer is referred to as inter-rhizosphere, and the two outer soil layers are designated sole-rhizosphere. Faba bean intercropped with maize had an 11% increase in shoot biomass and a 15% increase in P uptake compared with monocropped faba bean. The cropping pattern did not significantly influence maize growth. After 4 weeks of growth, faba bean significantly decreased soil pH in both the sole- and inter-rhizosphere in monocropping, but no effects were apparent for the intercropping rhizosphere. The major carboxylates in the rhizosphere of faba bean were malate (18–45 nmol g–1 soil) and maleate (1.2–2.4 nmol g–1 soil). Only trace amounts of carboxylates were measured in the rhizosphere of monocropped maize. However, intercropped maize had a high concentration of malate (~11 nmol g–1 soil) in both sole- and inter-rhizosphere; the malate was likely exuded by faba bean and was then diffused to the sole-rhizosphere of intercropped maize. The amount of malate exuded by intercropped faba bean was 19% higher than with monocropped plants. The results indicate that diffusion of protons and carboxylates extended the interaction zone between maize and faba bean, and may have contributed to enhancements of P uptake in the intercropping system.

Policies and Socio-economics influencing on Agricultural Production: A Case Study on Maize Production in Bokeo Province, Laos.

&lt;p&gt;Since 2005s, agricultural land in northern Laos has become to be dominated by maize mono-cropping. The rapid expansion of this commercial crop has the resulted of policy implementations and demand of maize from the neighboring countries. The purpose of this study was aim to analyze the impact of commercial agricultural policy and socio-economic factors influencing on maize production in Houyxai Distirct, Bokeo Province of Laos. A survey of 98 maize farmers by face to face interviews was conducted in September 2010. Ordinary Least Square regression model was applied in order to explain how these policies and socio-economic factors effect to farmers and contribute to maize production. The results revealed that 94% of the variation in maize production (ton) is explained by the selected explanatory variables. Seven variables have a positive significant and one variable has a negative effect on maize production volume. The results also demonstrated that the most important effect to maize production is a “policy push” mainly variables of farmland, farmer organization, support market and credit access and a “market pull” by private sectors with providing input factors namely seeds, land preparation and techniques. Therefore, the government should look at the way of credit providing system that may effect in high production cost, at the same time the expansion of farm size is needed to take into account.&lt;/p&gt;

Land use practices and their implications on soil macro-fauna in Maasai Mara ecosystem

The composition, abundance, diversity and species richness of soil macro-fauna communities were assessed in four major land use types present within protected and agricultural landscapes in Maasai Mara savannah ecosystem (MME), Kenya. The four land uses were: natural grassland; woodland, inside and outside protected area; maize mono-cropping and maize-bean intercropping systems in adjacent agricultural farms. Sampling of soil macro-fauna was carried out in November, 2009 (short rain), April 2010 (wet rainy season) and September 2010 (dry season). Hand sorting of soil taken from 25 × 25 × 30 cm monoliths was used to extract all soil macro fauna greater than 2 mm body length. A total of 3,658 individuals comprising of 128 species mainly belonging to Phylum Arthropoda distributed across 3 classes and 13 orders, and Phylum Annelida with one order were collected across the four different land use systems. Termites and ants, and to a lesser extent coleopteran and earthworms were the most abundant groups. Significant effects of land use on macro-fauna abundance and species richness in all cases (p 50% and eliminating some Orders/Species. Human related disturbances outside protected area network declined macro-fauna density in grassland and woodland in dry region (65.07 vs. 39.74%) but increased the density by 107 vs. 340% in wet region. The study highlights the important effect of agriculture on macro-fauna communities and the need for conservation alternatives in unprotected areas. This study supports conservation of biodiversity beyond protected area network. Key words: Macro-fauna, grassland, woodland, agriculture, Maasai Mara, land use.

The impact of Desmodium spp. and cutting regimes on the agronomic and economic performance of Desmodium–maize intercropping system in western Kenya

Low soil fertility, stemborers (particularly, Chilo partellus) and Striga weeds (Striga hermonthica and Striga asiatica) are major limitations to production of maize in western Kenya. The “Push–Pull” technology (“PPT”) has been described as an appropriate innovative technology capable of addressing these constraints. The technology involves intercropping maize with Desmodium and planting Napier grass (Pennisetum purpureum) around the intercrop, but in the current study a modified PPT was used and Napier grass was not included. Field trials were conducted in two locations in western Kenya during 4 subsequent seasons to test the hypothesis that maize yield, the degree of Striga suppression and economic benefits of intercropping maize with Desmodium are affected by: (i) the related biomass production by different Desmodium species and (ii) the cutting regime of the Desmodium. Maize was intercropped with Desmodium uncinatum (Jacq.) DC, cv Silverleaf or Desmodium intortum (Mill.) Urb. cv Greenleaf, and treatments with sole maize (with and without urea) were included for comparison. To eliminate phosphorus (P) deficiency, all treatments received basal P. The first two Desmodium cutting events were fixed at land preparation i.e. at the start of every season, and 4 weeks later, following the recommended practice, while the third cutting was varied and conducted at 9, 12 or 18 weeks after planting maize. Maize yield in the Desmodium–maize intercropping system was only higher than sole maize without urea from the third season. This implies that when P is not limiting inclusion of Desmodium spp. into the maize cropping system would provide a substitute for inorganic N fertilizers to enhance crop growth and yield after Desmodium becomes well established. Cumulative maize grain yield over the four seasons with the D. intortum and D. uncinatum intercrops were 6.3 and 7.0, and 10.9 and 11.6tha−1 in Busia and Siaya, respectively, and significantly higher than or comparable to a maize monocrop (5.8 and 11.8tha−1). Average net benefits from Desmodium intercropping over the four seasons were increased by 1290 and 918$ha−1 relative to the maize monocrop in Busia and Siaya, respectively. Biomass yields were significantly higher for D. intortum than for D. uncinatum. Varying the time of the third Desmodium cutting had little effect on Desmodium biomass yields or maize grain yields in Busia, while in Siaya, D. intortum biomass yields were highest when cut at 12 weeks after planting. In the Desmodium intercropping systems, Striga counts were reduced by 95% in Busia and by 65–90% in Siaya with higher reductions when Desmodium was cut at 18 weeks after planting. In summary, the use of PPT provides robust and high economic benefits to smallholder farmers in western Kenya. The use of D. uncinatum with the third cutting at 18 weeks after planting is recommended, but can be modified according to the need for fodder without much effect on maize yield or revenue.

Conservation agriculture systems for Malawian smallholder farmers: long-term effects on crop productivity, profitability and soil quality

AbstractConservation agriculture (CA) systems are based upon minimal soil disturbance; crop residue retention and crop rotation and/or intercrop association are increasingly seen to recycle nutrients, increase yield and reduce production costs. This study examines the effects of CA practices on crop productivity, profitability and soil quality under the conditions encountered by smallholder farmers in two farming communities from 2005 to 2011 in Malawi, as part of the contribution to remedy a lack of supporting agronomic research for these relatively new systems. The drier agroenvironment of Lemu of Bazale Extension Planning Area (EPA) is characterized by sandy clay loam soils and lower rainfall. Here, CA showed positive benefits on maize yield after the first season of experimentation, with highest increases of 2.7 Mg ha−1and 2.3 Mg ha−1more yield in CA monocrop maize and CA maize–legume intercrop, respectively, than the conventional tillage in the driest season of 2009/10. In the high rainfall environment of Zidyana EPA (characterized by sandy loam soils), substantial maize yield benefits resulted in the fifth season of experimentation. Farmers spent at most 50 days ha−1(US$140) producing maize under CA systems compared with 62 days ha−1(US$176) spent under conventional tillage practices. In Lemu, both CA systems resulted in gross margins three times higher than that of the conventional control plot, while in Zidyana, CA monocrop maize and CA maize–legume intercrop resulted in 33 and 23% higher gross margins, respectively, than conventional tillage. In Zidyana, the earthworm population was highest (48 earthworms m−2in the first 30 cm) in CA monocrop maize, followed by a CA maize–legume intercropping (40 earthworms) and lowest (nine earthworms) in conventionally tilled treatment. In both study locations CA monocrop maize and CA maize–legume intercrop gave higher water infiltration than the conventional treatment. Improvements in crop productivity, overall economic gain and soil quality have made CA an attractive system for farmers in Malawi and other areas with similar conditions. However, for extensive adoption of CA by smallholder farmers, cultural beliefs that crop production is possible without the ubiquitous ridge and furrow system and residue burning for mice hunting have to be overcome.

Xanthium Suppression Under Maize||Sunflower Intercropping System

Weed control is one of the major constraint factors in crop production around the world. Field experiments were conducted during 2008-2009 under intercropping systems involving alfalfa (Medicago sativa L.), sweet potato (Ipomoea batatas [L.] Lam.), peanut (Arachis hypogaea L.), and sunflower (Helianthus annuus L.) in maize (Zea mays L.) without any weeds control methods taken. The results demonstrate that maize||sunflower is most effective on weed suppression and that it also has a more competitively inhibitory effect on Xanthium compared with the other patterns by evaluating the Xanthium density and dry weight under different intercropping systems with maize. Maize||peanut, maize||alfalfa and maize||sweet potato intercrops have no apparent inhibitory effect on weeds. To further investigate the effect of maize||sunflower on weed control, indoor pot experiments were conducted by determining the effect of extractions on germination rate (GR), root vigor, MDA (malondialdehyde), SOD (superoxide dismutase) and POD (peroxidase) content of Xanthium. The results better prove that maize||sunflower extractions have more significant inhibitory effect on GR and young root vigor of Xanthium than maize monocrop extractions.

Reduced tillage, mulching and rotational effects on maize (Zea mays L.), cowpea (Vigna unguiculata (Walp) L.) and sorghum (Sorghum bicolor L. (Moench)) yields under semi-arid conditions

Proponents of conservation agriculture (CA) argue that the CA approach offers the greatest opportunity to increase the productivity in smallholder agro-ecosystems. This study was designed to assess (1) first year maize, cowpea and sorghum yield responses to a combination of reduced tillage and mulching and (2) maize yield responses to rotation with cowpea and sorghum in reduced tillage systems. Two conservation tillage methods (ripping and planting basins) combined factorially with seven mulch levels (0, 0.5, 1, 2, 4, 8 and 10tha−1) were compared with conventional mouldboard ploughing. The experiment was run for four consecutive growing seasons allowing for a rotation of maize, cowpea, sorghum and maize in some fields used in the study. Crop yields were determined across all tillage and mulch combinations in each year.Tillage system had no significant effect on maize yield while maize grain yield increased with increase in mulch cover in seasons that had below average rainfall. Mulching at 2–4tha−1 gave optimum yields in seasons with below average rainfall. Tillage system and mulching had no significant effect on cowpea yield when soil moisture was not limiting. However, the ripper and basin systems had 142 and 102% more cowpea grain than the conventional system in 2006/2007 because of differences in planting dates used in three systems and poor rainfall distribution. The conventional and ripper systems gave 26 and 38% more sorghum grain than the basin system. Rotating maize with cowpea and sorghum resulted in 114, 123 and 9% more grain than first year maize, maize–maize monocrop and maize–cowpea–maize in the conventional system. In the ripper system, maize–cowpea–sorghum–maize rotation gave 98, 153 and 39% more grain than first year maize, maize–maize monocrop and maize–cowpea–maize rotation. In the basin system, maize–cowpea–sorghum–maize rotation gave 274, 240 and 43% more grain than first year maize, maize–maize monocrop and maize–cowpea–maize rotation. However, long term studies under different soil, climatic and socio-economic conditions still need to be conducted to substantiate the observations made in the reported study.