Understanding crop water use in mixed crops over sole cropping is vital for developing optimum water management systems for crop production. In this study, a two-year field experiment with typical maize (Zea mays L.) and soybean [Glycine max (L.) Merr.] relay strip intercropping (2:2 maize-to-soybean rows; 200 cm bandwidth) was carried out in the 2013 and 2014 growing seasons. The quantitative effects of various planting patterns on the water-use efficiency (WUE) and water distribution were investigated. Our results indicated that soil volumetric water content and soil evaporation in the intercropping systems showed decreasing trends in the order: maize row (MM) < maize-to-soybean row (MS) < soybean row (SS). The highest leaf transpiration (1.91 and 2.07 mmol m−2 s−1) for the intercropped maize was measured in each of the two years in the 20 cm maize narrow-row planting pattern and decreased thereafter. Opposite trend was observed for the intercropped soybean; the highest soybean leaf transpiration (7.01 and 6.80 mmol m−2 s−1 for 2013 and 2014, respectively) was recorded in the 70 cm. The WUE of maize and soybean intercrops was lower than that of sole crop counterparts. However, the maximum group water use efficiency (GWUE) of 26.08 and 26.20 kg ha−1 mm−1 in the 40–50 cm maize narrow-row planting pattern was, respectively, 39.6% and 23% higher compared with that of sole crops. The water equivalent ratio (WER) values ranged from 1.60–1.79, suggesting better crop water use in the intercrops over sole cropping. Planting patterns provided by 40–50 cm maize narrow-row spacing were considered the most efficient in terms of maximum total yields, GWUE and WER. These results suggest that an appropriate reduction in the spacing of narrow maize row with wide soybean row could be an efficient crop management method to achieve optimal WUE and homogeneous water distribution in maize–soybean intercropping systems.

The resource conservation technologies (RCTs), being advocated for countering the threat to the sustainability of wheat–rice cropping system (RWCS) in the north–west (NW) Indo-Gangetic Plains (IGP) of India, have been evaluated mostly for the individual crops, without depicting the impact of these technologies on the succeeding or preceding crop. A study was thus conducted during 2012–2014 in NW India to assess the land and irrigation water productivity (WPI) of RWCS under different establishment and conservation tillage techniques in a sandy-loam soil (coarse loamy, calcareous, mixed, hyperthermic Typic Ustochrept). The treatments included zero (ZTW) and conventional (CTW) tillage in wheat as main plot, establishment methods (direct seeded (DSR) and mechanically transplanted rice (MTR)) as sub-plot and tillage in rice viz. puddle (PR), dry (CTR) and zero (ZTR) tillage as sub–sub plot treatments, replicated thrice in split–split plot design. The land productivity of RWCS was significantly lower in ZTW plots than in CTW plots. The residual effect of tillage in wheat on rice productivity was distinct during the second year of study, when the CTW plots recorded significantly higher (17.5%) rice yield than the ZTW plots. The productivity of the cropping system with DSR was statistically similar to that with MTR. The WPI of RWCS increased in the order ZTW–DSR–ZTR25 < CTW–DSR–ZTR < ZTW–MTR–CTR < ZTW–DSR–PR < CTW–DSR–PR < ZTW–MTR–PR26 < CTW–MTR–PR.

Seed cotton yield in Northern Cameroon has been declining since the 80s despite breeding efforts. In order to evaluate the impact of genetic improvement on this decline, we conducted field experiments in two locations with 10 widely grown cotton cultivars released in Cameroon between 1950 and 2009. The rate of genetic gain (GG) was estimated with a linear regression of the cultivar mean on its year of release (YR). Contrasts between rates of GG observed with different planting dates were estimated and tested. Our results revealed a rate of GG on fibre yield of 3.3 kg ha−1 year−1 due to increased ginning out-turn (3.9% and 6.2% in 60 years in Garoua and Maroua, respectively). There was no GG on leaf area index (LAI), radiation use efficiency (RUE), aerial biomass, harvest index and on seed cotton yield. We concluded that cotton breeding efforts in Cameroon have successfully improved cotton fibre yield but there is still some room for seed cotton yield improvement.

Seed-oriented planting provides a manner to influence canopy structure. The purpose of this research was to improve maize light interception using seed-oriented planting to manipulate leaf azimuth across the row thereby minimizing leaf overlap. To achieve leaf azimuths oriented preferentially across the row, seeds were planted: (i) upright with caryopsis pointed down, parallel to the row (upright); and (ii) laying flat, embryo up, perpendicular to the row (flat). These treatments were compared to conventionally planted seeds with resulting random leaf azimuth distribution. Seed orientation effects were contrasted with three levels of plant population and two levels of hybrid specific canopy structures. Increased plant population resulted in greater light interception but yield tended to decrease as plant population increased. The planophile hybrid produced consistently greater yields than the erectophile hybrid. The difference between planophile and erectophile hybrids ranged from 283 to 903 kg ha−1. Overall, mean grain yield for upright and flat seed placement increased by 351 and 463 kg ha−1 compared to random seed placement. Greater cumulative intercepted photosynthetically active radiation (CIPAR) was found for oriented seeds rather than random-oriented seeds. At physiological maturity upright, flat and random-oriented seeds intercepted 555, 525 and 521 MJ m−2 of PAR, respectively. Maize yield responded positively to improved light interception and better radiation use efficiency. Under irrigated conditions, precision planting of maize increased yield by 9 to 14% compared to random-oriented seeds.

This article was published with an incorrect Title. The correct title should read:

‘SEED-ORIENTED PLANTING IMPROVES LIGHT INTERCEPTION, RADIATION USE EFFICIENCY AND GRAIN YIELD OF MAIZE (Zea mays L.)’

The original article has been rectified with the correct title and a footnote detailing the error has been inserted in the online PDF and HTML copies.

Cotton–wheat is an important cropping system in South Asia. Introduction of BT cotton has caused the time conflict between sowing of BT cotton and wheat harvest in this cropping system. Wheat is harvested in late April but the best planting time of BT cotton is mid-March, which indicates a time conflict of 30–45 days between two crops in the region. However, this conflict can be managed by raising the cotton nursery and transplanting 30–45 days old seedlings in the field after wheat harvest. This two years field study was conducted to assess the economic feasibility of transplanting BT cotton in BT cotton–wheat cropping system at two locations (Multan, Vehari) in the cotton belt of Punjab, Pakistan. The BT cotton–wheat cropping systems included in the study were; flat sown wheat (FSW) – zero-tilled cotton (ZTC), FSW – conventional-tilled cotton (CTC), ridge sown wheat (RSW) – ridge-transplanted cotton (RTC) (30 days old seedlings), RSW – RTC (45 days old seedlings), bed sown wheat (BSW) – bed-transplanted cotton (BTC) (30 days old seedlings) and BSW – BTC (45 days old seedlings). BSW produced more grain yield than RSW and FSW during both years at both locations. Likewise, BTC (45 days old seedlings) had higher production at both sites during both years. The overall productivity of BT cotton–wheat, in terms of net income, benefit: cost ratio and marginal rate of returns, was the maximum from transplanting 45 days old cotton seedlings on beds after BSW during both years at both sites. Sowing cotton as ZTC following FSW was the least productive cropping system. In conclusion, transplanting 45 days seedlings of BT cotton on beds during late April after harvest of BSW wheat may be opted to manage the time conflict and improve the productivity of BT cotton–wheat cropping system in Punjab, Pakistan.

The crop rotation is a practice to protect and improve the soil properties and an alternative to improve the quality of crop residues is the application of fertilizers at the planting of cover crops. Thus, we evaluated the effect of fertilization with nitrogen, phosphorus and potassium (NPK) on organic matter production and chemical composition of cover crops succeeding the corn crop. The treatments consisted of the cultivation of Avena sativa L., Lupinus albus L., Pennisetum glaucum L., Raphanus sativus L. and Sorghum bicolor L. with (200 kg ha−1 of NPK [08-28-16] applied by broadcast seeding) and without fertilization at planting. Organic matter production by all cover crops, as well as concentrations of neutral detergent fibre (NDF) in shoots and roots of A. sativa L. and R. sativus L. were higher when they were fertilized. L. albus L. showed higher NDF and acid detergent fibre (ADF) contents than the other cover crops, with and without fertilization. Nitrogen concentration increased, but the carbon/nitrogen ratio (C/N) in the shoots of L. albus L., R. sativus L. and S. bicolor L. decreased when fertilization was applied. The use of N by the A. sativa L. and P. glaucum L. and of P and K by S. bicolor L. was 16, 54, 82 and 20% more efficient, respectively, when fertilization was applied. The A. sativa L., P. glaucum L. and R. sativus L. showed higher NDF/N, ADF/N and hemicellulose/N ratios in the fertilized treatment. Although the results obtained in this study are highly satisfactory, more research should be conducted to evaluate the decomposition of crop residues from cover crops fertilized with NPK, and the effects of this strategy on corn crops in succession.

In the oil palm plantations of Ecuador, two factorial trials (namely CP06 and CP08) were used to assess the effects of N, P and K fertilization on the soil chemical characteristics after 10 years of fertilizer application. The use of ammonia-based fertilizers has resulted in a drop in soil pH, which has reached 1.2 units in one of the two trials. A drop in cation exchange capacity (CEC) was also found, and a loss of exchangeable cations that probably reflected leaching of excess N as nitrates. The use of KCl enriched the soil in K, which contributed to impoverishment in Ca and Mg. In both trials, the highest N and K application rates had no significant effect on yield in comparison with an intermediate fertilization rate; however, their effects on the fertilized soil significantly increased the risk of N and cation leaching towards the deep soil layers. We also compared the effects of the N, P and K factors on soil properties outside the fertilizer application zone. In both trials, the mineral reserves played a major role in meeting the needs of the control palms, which had not been fertilized for 10 years, as no significant yield drop has been observed except in trial CP06 when no KCl was applied. However, uptake of nutrient in the control plots did not lead to significant impoverishment of the soil.

Recent literature suggests that to make value chains in changing agrifood systems in sub-Saharan Africa more inclusive, intermediary institutions should foster coordination. The hub concept has been applied as such an intermediary institution that coordinates advisory services, input supply and smallholder access to markets. This study unravels hub coordination in smallholder dairy in Kenya, conceptualising the hub as a mix between a broker of relationships, a one-stop-shop for services and a cluster of producers and service providers, enabling horizontal coordination (between smallholders) and vertical coordination (between smallholders and value chain actors and service providers). Findings indicate that, in resolving challenges that limit smallholders’ integration in value chains, synergies emerged as the hub combined different types of horizontal and vertical coordination. This was done by simultaneously organising clusters of farmers and input and service providers (clustering role) and actively facilitating delivery (broker and one-stop-shop role), where the hub structure stimulated the matching of demand (better articulation) to supply (better organised access). However, tensions emerged in the combination of horizontal and vertical coordination as farmer organisations as hub operators had to balance a role as an honest broker between farmers with the intent of enhancing collective action and as a business-oriented entity which resulted in the exclusion of some farmers who cannot deliver the quantity and quality required to minimise coordination costs. Given these tensions and capacity problems of farmers’ organisations, complementary intermediary arrangements may be necessary to fulfil some coordination roles.

Multilocation experiments were established to determine the best strategy for using inorganic fertilizer in conservation agriculture (CA) systems that use green manure cover crops, namely sunhemp, velvet bean and cowpea grown in rotation with maize. The objectives of the study were to determine (i) the effect of half and full rates of basal fertilizer on maize and legume biomass yields, (ii) the residual effects of unfertilized, half and fully fertilized green manure legumes on maize grown after the legumes, and (iii) the residual effect of unfertilized, half and fully fertilized green manure legumes combined with basal and topdressing fertilizer on maize yields. Experimental design was a randomized complete block with basal fertilizer as a treatment in the green manure legumes phase. Previously, in the maize phase, green manure legume species were the main treatment with basal fertilizer as a subtreatment (sunhemp, velvet bean and cowpea: 0, 75, 150 kg ha−1 and 0, 50, 100 kg ha−1, respectively). Nitrogen was applied in the maize phase at 0, 23, 46, 69 kg N ha−1 as a sub-subtreatment in Malawi. Results showed that inorganic fertilizer is the most effective when applied to the maize, not green manure legumes. Biomass of green manure legumes, sunnhemp 8084 kg ha−1, velvet bean 7678 kg ha−1 and cowpea 4520 kg ha−1, was not significantly affected by application of basal fertilizer. Maize production increased after the application of green manure legumes with maize-after-maize, maize-after-velvet bean, maize-after-sunnhemp and maize-after-cowpea, yielding 3804, 5440, 5446 and 5339 kg ha−1, respectively. Nitrogen increased maize yield regardless of the previously used green manure legumes species. Our results suggest that farmers should apply fertilizer to maize and grow green manure legumes on residual soil in CA systems. Despite growing green manure legumes, smallholders should apply nitrogen topdressing to maize grown using the green manure legumes in some agro-ecologies.

The capability of some plant species to mobilize phosphorus (P) from poorly available soil P fractions can improve P availability for P-inefficient plant species in intercropping. White lupin (Lupinus albus) has been investigated as a model P-mobilizing plant for its capability of enhancing the P acquisition of neighbouring species under P-limited conditions. To date, investigations have led to contrasting findings, where some reports have described a positive effect of intercropped lupins on companion plants, whereas others have revealed no effects. This review summarizes the literature related to lupin–cereal intercropping. It explores the underpinning mechanisms that influence interspecific facilitation of P acquisition. The P-mobilization-based facilitation by lupins to enhance P-acquisition of co-occurring plant species is determined by both available P concentration and P-sorption capacity of soil, and the root intermingling capacity among two plant partners enabling rhizosphere overlapping. In lupin–cereal intercropping, lupin enhances the below-ground concentration of labile P pools through mobilization of P from sparingly available P pools, which is accomplished through carboxylate exudation, where neighbouring species acquire part of the mobilized P. The non-P-mobilizing species benefit only under P-limited conditions when they immediately occupy the maximum soil volume influenced by P-mobilizing lupin. Positive effects of mixed cropping are apparent in alkaline, neutral and acidic soils. However, the facilitation of P acquisition by lupins to companion species is eliminated when soil becomes strongly P-sorbing. In such soils, the limitation of root growth can result in poorer root intermingling between two species. The P mobilized by lupins might not be acquired by neighbouring species because it is bound to P-sorbing compounds. We suggest that the lupins can be best used as P-mobilizing plant species to enhance P acquisition of P-inefficient species under P-limited conditions when plant species are grown with compatible crops and soil types that facilitate sharing of rhizosphere functions among intercropped partners.